SRT Chat Sessions

Here are the responses of the Oct. 5, 2009 SRT Engineers Chat Session (1 of 2):

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:1. (toofart) I have a catch can/oil separator, and at every oil change I empty an ounce or two of black oil. If I did not have this device, do you agree this oil would coat my intake manifold, valves, and enter the combustion chamber thus effectively lowering my fuel octane?
We have run full validation across all the different vehicle lines with the 6.1L engine and not see any issues. That being the case, we don't feel they are necessary.

We do not see it as a issue. But if you wish to use one make sure it is of quality.

Quote:
Originally Posted by toofart Posting on behalf of Challenger lovers at CT:4. (rodderrick) Why do the brakes dust up so bad with stock pads, and what is the best substitute without losing braking capability?
One of the 5-pillars of an SRT is outstanding brake performance. With all high performance brake systems, one trade off is a bit more brake dust. In order to maintain the same braking performance we develop these cars to, we recommend using OEM parts only. If you use other brake pads , you may get less brake dust, but you will give up performance.



Originally Posted by toofart Posting on behalf of Challenger lovers at CT:2. (toofart) For 6-speed cars, is the differential able to support hard launches and shifts at the drag strip using slicks, or very high traction radials?
We did some testing on Nitto and BFG Drag radials, although we did not run them to failure. You will significantly reduce the life of the differential and other driveline components with stickier than stock F1s, but it won't break the first time you do.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:7. (spencer60) You mentioned previously the cats are major exhaust restrictions. Whats' the airflow rating (cfm) for the RT and SRT factory parts?
Production cats are not rated in this way. We measure it in inches of backpressure. The cats are not a major restriction at all. They are just more than the cat back exhaust which is very little. You may get about 15 hp out of ditching the cats.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT (we did our homework, guys!)13. (rumpass) If I plan on buying a used SRT8, can a Chrysler dealership tell me if the computer (tune) has been altered at some point in time?
Yes.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:8. (randycat) Can the ecm provide any other engine/transmission operation parameters through the obd-II port other than the industry standard mode 1's? Are there any Dodge/Chrysler specific mode-22's pid's that can be monitored? Are these pid codes documented anywhere?
It does, but they are propriatary to Chrysler. The Diablo has some cracked capabilities...

Originally Posted by toofart Posting on behalf of Challenger lovers at CT (we appreciate your time investment in coming here and answering what you can!!)10. (rodderrick) I've heard of many people mention throttle hesitation / lag under varying conditions. What could be the cause? Is there any drivetrain preservation program in the ECM?

Electronic throttles unfortunately have some delay compared to cable throttles that everyone is used to. The engine is also cammy with a torque hole in the 3000 rpm range which gives the impression of a bog.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:14. (Speedy!) When designing an engine, where do you set the bar in terms of longevity? 100,000 miles? 150,000 miles, etc?
150000+ for the 6.1.

riginally Posted by toofart Posting on behalf of Challenger lovers at CT:12. (randycat) While it is well accepted that using higher-than-recommended octane gasoline should yield no benefits on the hemi 5.7 under normal operation, is it possible that such octane could mitigate performance losses when the engine gets into one of its "heat-soak fits" during operation in hot weather?
Not neccessarily. The engine will derate due to high coolant temp, or air charge temp. The derate due to high coolant/air charge temp won't be affected by a higher octane. But, if the engine senses knock, and reduces spark, high octane fuel would reduce the spark retard.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:16. (13 sec fix) If you owned a Challenger and it exhibited wheelhop under hard acceleration, which components what would you do?
The most effective means of mitigating wheel hop on the Challenger is to change the motor mounts. SRT uses stiffer ones than than the R/T manual. Going stiffer than stock will significantly degrade NVH but will help.

If you launch it properly for the best times, it hops very little. If you dump the clutch at high rpm they spin clean. If you get it just a little too aggressive, you will get into a hop.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:17. (mokeman3) I've had the Getrag 226 differential replaced in my SRT auto at 5K miles because of a "whine" at 46 Mph when floating between power and coast. The new differential also does this, but now this new differential also has a very distinct whine under power between 59 and 60 Mph (and goes away at 58 Mph or 61 Mph). What can engineering tell us about this insofar as what is causing this with the Getrag 226, what can be done to eliminate/reduce this whine, and is it normal, or detrimental to continue to drive the car like this ?
Normal. The 226 will not be completely silent. The noise will not decrease the life of the diff.

Originally Posted by toofart Posting on behalf of Challenger lovers at CT:18. (randycat99) Is there a distinct and intentionally-designed difference in the responsiveness of the electronic throttle in the automatic between when you are in regular automatic mode and when you are in autostick mode? This is not so much when you hit the pedal from a standstill, but rather, if you are already moving along with your foot making small/med, but distinct, motions on the pedal. If you are bound from answering candidly, use the code, "You are better off not knowing".
No, there is no difference in the ETC calibration between the automatic or autostick mode.


riginally Posted by toofart Posting on behalf of Challenger lovers at CT:19. (can't remember who) Will running a lower temp than stock thermostat on a stock engine setup cause any sort of residue buildup or premature wear?
Sorry, that's something we've never tested and so we can't give you any feedback on this.

 

(2 of 2)- Oct. 5, 2009

Originally Posted by toofart 3. (toofart) If your task was to shed 300 lbs of weight from a Challenger SRT8 to make the car more, uh, competitive, while retaining all the security features, what would you do?

The easiest way to drop weight is for the driver to go on a diet. The AL hood isn't too heavy, but the trunk weighs 40 lbs. Are you willing to give up Nav, Sunroof, power seats, etc...? Unfortunately, she comes from a hefty bloodline.

riginally Posted by toofart Posting on behalf of Challenger lovers at CT:20. (alpine zang) What EXACTLY does it do when you do the "key trick" (ie., key to START position while driving >10mph) and the ESP/BAS light and ESP light come on? I know it disables the ESP, but the car drove completely differently. The throttle was much snappier and I had to be careful not to jerk when barely changing throttle positions
The "key trick" actually sets a fault in and shuts down the ABS, traction control and ESC system. That is why the lights come on. The only change in throttle would be because the traction control is gone.
Originally Posted by toofart Posting on behalf of Challenger lovers at CT:21. (alpine zang) Is the EVIC actually different in the SRT-8 or is it just a different firmware? Can an R/T get the 1/8 & 1/4 mile as well as the Gs info with a change in firmware?That's it for the CT questions. Thanks guys!
Sorry, the performance pages are configured to only operate on the SRTs.

Originally Posted by SRT8Andre Question regarding breakin procedure for the 6.1... I have read on various forums that the SRT engines already have breakin miles on them prior to be delivered to the customer... is this true?
Not true. The emissions test rolls in the plant and some random quality checks can put on a minor amount of miles on the car. Other than that, there should be no miles on a new SRT.

Originally Posted by ricksinva Hello,09 Challenger SRT8.1. My car came with the Performance, staggered tire option. If I change to 245's all around, will that affect anything such as the traction control system or the speedometer? If so, can the dealer reprogram the car for that?2. The Service Manual (CD) for this car has not been available from Tech Authority for at least 2 months. It must be either a legal issue, or maybe some paperwork is simply sitting in someone's end basket, because it surely doesn't take this long to copy a CD. Can you look into this and maybe help push them along?3. I have a spare set of OEM, SRT wheels. Can I store them (real long term) in a hot attic (in Virginia)?Thanks for a great car!!!Rick

1) The cals are the same. Feel free to put the same size front and rear.
2) A number of things were held up during bankruptcy. We'll see if that is what is going on.
3) The wheels will be fine. Tires will not like the heat and age. It is a good idea to get new tires every 5-6 years regardless of tread depth. Brand new unscuffed tires may go 10 years if hermetically (sp?) sealed...

Originally Posted by Stylz One other question for us 5.7L owners. With the aftermarket so full of engine performance products (with many of them not, or even negatively affecting performance), do you guys know of any mods which could be made to a 5.7 motor to increase the horsepower without adversely affecting the reliability/drivability?

We do have a kit out here for your car but it's "off road use only". However, we cried when the test car left us with ~50 k. miles......

Originally Posted by charger08srt what is the best 0-60 and 1/4 times you guys achieved on a stock SRT charger?
1.52 for 0-60! See proof below. Won't tell you how I did it.

We run 12.90's in good air
Originally Posted by toofart From this question: 2. (toofart) For 6-speed cars, is the differential able to support hard launches and shifts at the drag strip using slicks, or very high traction radials?If you did run them to failure, which component(s) do you think would fail first?

Probably the diff or halfshafts. with stock cars just like you guys.

Originally Posted by 2nd SRT-4 Hello Engineers! 1. My C-SRT4 is consuming about 1 qt of oil per 3k mile with Mobil 1 0-40. Is this normal? I do drive hard, but mostly, city stop and go type traffic.2. Any numbers on the final production of the Caliber SRT-4?

1. What you are experiencing is normal.

2. Cannot respond to your question at this time.

Originally Posted by kevbo10 For your consideration:SRT8 Challenger:I have installed a Kenne Bell Super Charger on a stone cold stock 6.1L Challenger with a six speed. I’m running ten pounds of intercooled boost and using unleaded 108 octane racing fuel, putting out 600+ rwhp. The car is used for mild club racing; 50 – 170 mph (I don’t drag race). What are the chances of the motor living a nice life and retiring to Arizona? Seems to just fly now, w/o any problems.Thank you,Kevin

Your pistons are not happy.

Originally Posted by charger08srt is the 6.1 underrated hp wise... is it possible it's really making 440-450 hp stock at the crank... could this be the reason the engine hasn't had a power increase like the 5.7 thank you for your time
The 5.7L power upgrades are from the new version of the motor with variable cam timing.

Originally Posted by Viperam2 Question for the SRT10forumCan additives such as Lucasoil or Zmax be used with the Viper motor?
Additives are NOT recommended please reference your owners manual. (Full synthetic only)

Quote:
Originally Posted by charger08srt if I put high-flow cats on my srt wouldn't that throw an engine code
Yep. "off road use only"

 

Here are some of the engineers’ responses to the Aug. 6, 2009 SRT Engineers’ Chat Session on caliberforms. As you can see, the session was dominated with Challenger-related questions (1 of 2):

Originally Posted by Rob440Magnum
What’s the best way to launch an automatic SRT8 Challenger for best 0 – 60 times? Should I leave in drive or shift with the autostick for the fastest time?

Put it in Drive and foot to the floor (stay in the grooves). That will get you the best times.

Originally Posted by 08ChallengerDad
I have a 2009 6 speed SRT8 Challenger. The car suffers from the "Key Fob Not Detected", "Damaged Key" syndrome in hot weather. When the car sits for a time in the sun, removing the Keyless Go button and manually inserting the fob into the socket becomes necessary to start the car. I live in upstate New York. If the problem is an annoyance for me, I can only imagine what it's like for folks in the SouthWest. Has a fix/TSB been issued/initiated for this problem?


I would recommend taking the vehicle to the dealership for diagnosis and repair.

Originally Posted by 08ChallengerDad
I have a 2009 6 speed SRT8 Challenger. The car has the factory option GoodYear F1 Supercar tires. It's an outstanding car in virtually every aspect. However, I am having a problem with severe wheelhop under hard acceleration, particularly from a standing start. I assume this condition can't be good for the suspension or driveline.
It doesn't matter what the ambient temperature is, or whether I have ESP on, partially off, or completely off - the wheelhop is still severe. I have not made any modifications to the suspension of the car, and run the F1's at the recommended pressures.
I know this is a common complaint from MANY of the 6 speed owners. Are you folks aware of this, working on a resolution, or have a cure already?

Power hop exists, to some extent, on all performance vehicles. Minimizing the amount of hop will maximize the vehicle's performance. This is usually accomplished by developing a vehicle specific launch/driving style.

Originally Posted by Rob440Magnum
If I install the Mopar CAI and the Mopar aftermarket exhaust on the Challenger SRT8, because the motor will breathe better do you think the stock 80mm throttle body is now the weak link and that the motor would benefit from a larger TB? If so what size would you recommend for peak performance?

Save your cash. In our experience, the throttle body is not the weak link at this level.

Originally Posted by Miamimike
SRT Team - I recently installed a Corsa "Cat Back" Exhaust on my 2008 Dodge Challenger SRT8 along with a cold air in-take. In order to get the full benefit of these upgrades, should I reflash the chip? If so, is there a system you would recommend? If I re-program the chip myself, is there any danger of hurting the engine?

Nope. There's no need to recalibrate for these upgrades.

Originally Posted by Rob440Magnum
What is a bone stock SRT8 Challenger six speed and automatic supposed to dyno at the rear wheels?

Because of the new and improved rear-end for the 2009 Challenger does that have higher hp & torque numbers at the rear wheels versus and 08 Challenger?
We don't usually dyno at the rear wheel, but I would expect to see about 5 or 6% drop through the driveline. Technically the 08 axle will be more efficient due to its smaller size, but the difference will not be measurable on the chassis dyno.

Originally Posted by Rob440Magnum
Any reason why my brakes would be squeaking on light braking on my 2008 SRT8 Challenger with the stock Brembo brakes? I have to say the brake dust generated from the Brembro brakes is very annoying and time consuming to keep clean. Why did you choose not to install ceramic pads as standard equipment to eliminate brake dust? Secondly, any reason why I should not install Hawk Ceramic Brake Pads, to nearly eliminate all that annoying brake dust on my 08 Challenger SRT8?

All performance brake systems will have certain conditions which will generate brake noise (temp, humidity, brake pressure). The hotter the brake pad the more resistant the system is to brake noise.... We can not recommend using ceramic pads, due to the reduction in overall preformance. We designed the system to meet our performance and minimize brake noise and dust.

Originally Posted by charger08srt
Why do the SRT 6.1 Stock Intake Air Boxes have a hole cut out in the bottom? Is it for performance reasons or just extra sound? Pic below for reference. I also noticed the Road and Track 5.7 Chargers have the same type of bottom air box but no hole is cut out of those.

The cut out was to help to provide a sound for the vehicle but it also helped reduce air restriction.

 

(2 of 2)- Aug. 6, 2009

Originally Posted by MoparX
I own a 2009 Challenger SRT8, 6 speed. It is the best car I have ever owned in every way. And I've had quite a few. My question regards to the use of catch cans. Are they really worth it, for keeping the intake/engine clean. Its been suggested that the 6.1's get a little "more" oil into the intake past the PCV valve than really wanted and therefore possibly causing some detonation & causing the computer to retard the timming, therefore stealing some HP's. Is this BS, or is it worth the addition of a catch can?


The 6.1L engine can be expected to collect some oil residue in the intake manifold over time and this is heavily influenced by how hard the engine is used. The fact is that oil residue in the manifold is extremely hard to get "aerosol" such that it can be burned as part of the combustion process given the intake runners pull from the roof of the intake plenum and the residue is typically at the very bottom. Generally speaking, catch cans are more of a mental pacifier than anything and any positive performance impact is virtually impossible to quantify. In such a case, you really need to go with your gut, but we can find no overwhelming reason to recommend this modification.

Originally Posted by Rob440Magnum
I have 08 Challenger SRT8 with the 20" Eagle F1 tires. I was always told because of the extra weight in the front of the car versus the rear that you want 2-3 more pounds of tire pressure in the front tires. What front and rear tire pressure cold do you recommend for the best wear, comfort, and performance for everyday driving with the 20" tires?

32psi cold, all the way around.


Originally Posted by MrMischief
Another question came to me last night, hope it's ok that I'm asking two questions.
My 2007 Charger SRT8 with about 15,000 miles consumes about 1 quart of Mobil1 0W-40 every 3,000 miles. My 5 Star Dodge dealer continues to recommend putting in 8 quarts of Mobil1 0W-40 at oil change intervals rather then the owner manual's called for 7 quarts. The mechanics at the dealer have said there are a number of good reasons to do this and no reason not to. One of the reasons was to ensure that the oil level never drops below safe if the vehicle goes a bit over 3,000 miles before the change. So is this oil consumption normal, and is there any reason I would want to take the dealer's advice and use 8 quarts of oil rather then 7?

Wow. Hard to know where to start here. First and foremost, absolutely DO NOT overfill the engine with oil under any circumstances. The list of negatives are many, but the most concerning are as follows:

Oil Aeration: Our testing has shown that just one extra quart drastically increases the oil aeration level to the point of significantly reducing oiling efficiency, increasing oil temperature and increasing oil consumption. It will also ruin the oils shear stability in the process.

Fuel Economy: Fuel economy suffers considerably with extra oil volume due to internal windage (e.g. drag)

Contrary to your dealer's advice, there is absolutely NO good reason to run extra oil whatsoever.

Originally Posted by Dartman69
My question pertains to a problem I'm having with my '09 Challenger SRT8 6-speed. I am encountering a nasty grind/clashing when shifting from 4th to 5th gear above 4000 rpm. The closer to redline I get, the harsher the sensation. It does not matter how casually or aggressively I shift, the grind always occurs. Just today I took it to a local dealership to have the problem checked out. Oddly, I wasn't permitted to go on the test drive. However, after racking up 41 kilometers on my odometer and burning a 1/4 tank of gas, the mechanic/technician determined that the transmission shifts just fine and that I must be rushing my shifts and banging off the shift gate. When I asked where he test drove it, I was told that he "drove it all over town and didn't notice anything". ('cuz I'm sure he shifted from 4th to 5th above 4000 rpm in congested city traffic!). Anyhow, I've had 3 different friends of mine drive the car (all of which have been driving stick for about 10 years or so just like me) and they all encountered the same grind. I therefore conclude that I am not crazy nor an inept driver.

A 4-5 shift a 4 grand puts you at about 90mph. I agree that seem a bit fast for city traffic. My thoughts are you are shifting too early. The gage goes to 6200 for a reason. the 4th gear synchro sounds like it's hurt.

Originally Posted by Deuuuce
Has rev matching been considered on the automatic SRT-8s when downshifting? I thought that would be a cool little feature and eliminate the lurch that occurs otherwise. Could it be flashed into the trans?

Rev Matching has been considered, but we are unable to comment on future product.
The current SRT w/ A/T cannot be flashed to accomplish same.

 

I extracted the SRT engineers’ comments from the May 13, 2009 Challenger Chat Session. Here they are (1 of 2):


I've asked this question before about a "nanny program" that restrains the performance during the first few thousand miles and was told no it does not exist by your team. However many members of this forum consider it gospel that the car achieves a better level of performance after a few thousand miles, care to speculate?
I don't know, I'm still at 2000 kilometers!

That's true, no "nanny program" in any of our SRT products. However, it is normal to feel your car's performance improve (sometimes significantly) with a proper break-in. It will also get slightly better fuel economy after a proper break-in.

I read the Visor warning label about no full throttle for the first 500 miles. My question is how much damage do think could be done if that is not adhered to? I know my car had been driven alot before I got it with 327 miles on the clock. I suspect it was not grannied either, can you enlighten us on how critical the break in is? I also want to comment on the "Nanny", my car ran 17.6 mpg for the first tank, we refilled at 519 miles and upon returning to the freeway my mpg went up to 22.8 with cruse on set at 80(in Texas on I10) driving was the same only difference was over 500 miles on the clock. It changed again at 1500 miles, care to comment on the break in program, no nanny just break in specs?
Trust me again, no Nanny. The 6.1L is built "tight" and take some level of miles (~500) to properly seal the rings and reduce the friction in the rotating components. MPG will go up...5mpg seems a bit high, but not totally out of the norm...especially when you consider the differences in wind during your trip.


Question 1: Is there a throttle response and/or transmission up shift update in the works to help eliminate the time lag of throttle transitions that lead to a more linear and consistent driving experience throughout the RPM range? In typical light to medium city driving, my car (and some of the other posters here) experience a lackadaisical throttle response which leads to flat spots (in addition to a delay in downshifts) that make the car feel like a lumbering giant slowly awaking from a nap...unless you mash the throttle and/or use the autostick.

I'd keep mashing the throttle But to be honest, the 6.1L is cammed to make the big power it makes up to and therefore yes, the torque is a bit low light city driving. The throttle cal would feel worse if it was changed (trust me)....we felt this was the best balance for city driving at part throttle and track driving at WOT.

Question 2: I believe the car up shifts too quickly in light to medium driving. Any possible programming changes for this?

The transmission in your car is adaptive and will adjust to the way your driving each time you drive your car (it resets each time you start your car). So, if you drive more aggressive, the car will shift the way you like it. Try it out and get back to us next time.

What is the deal with the 180 deg tstat that everybody talks about. They guys at the SRT track experience were saying that it was nothing but snake oil. Is there anything to by gained with the lower tstat. It regularly gets over 100 deg in my town during the summer.

A 180 degree thermostat is nothing but a waste of money. Your car will run at ~212F and run very good at that temp. There is also part of the calibration that accommodates the engines warm-up and running <200F....there is less spark advance in those areas, which equals less performance.

Wish I could mash the throttle all the time, but then everyone would have to get out of my way! Would changing the rear end gears help or would that contribute to the problem?

It could help, but that's quite a tear-up...does it really bother you that much.

Will do regarding the tranny shifts. Aggressive driving good - passive driving bad.
Any other tips to keep the car tuned for the optimum everyday driving experience? Thanks for being here and answer our questions - cool deal.

Make sure your car is breathing cool air. These cars are prone to sucking some warmer air expecially in city traffic. There is a nice big hole at the bottom of the airbox, make sure that is lined up with the hole in the sheet metal below that.

Read your reply about 180 t-stats. Wondering if I should take both off and go back to stock. I was not expecting to gain much, but I certainly don't won't to lose power!
Is there any condition that this would be beneficial?
What about the Mopar CAI?

I don't think you'll lose power from the testing and development I've done, but your welcome to prove me wrong. Try both combinations out at the track next time you go. The best way to go is a warm engine and cold air. So, my suggestion would be stock t-stat and CAI.

I am sure you guys play with these engines.
How much power is the 6.1 good for without bolting on a supercharger?
What are some of the biggest bang for you buck bolt-ons for the 6.1?

See you've got a CAI, that's the easiest. Catback would be next. Beyond that you have to be extremely careful not to impact calibration.

If the new reorganized company said you could raid the parts bin and create a “Super Challenger” what would your dream Challenger have?

We already did it when we stuffed the Viper V10 motor in the SEMA Challenger. Those Italian motors make power, but not much torque until you twist them hard. We'll see what they let us play with. If times were different, we're sure we would have that V10 Challenger in production for you.

What are your thoughts on a larger (85mm) Throttle Body?

My guess....potentially 1-2hp. Let me re-answer your question...I've tested an 84mm throttle on the 6.1L and it was 1-2hp. The cork is on the exhaust side...specifically in the cats.


In a previous Chat Session, you stated that the biggest tire for the front of a Challenger is a P245/35/20. What is the biggest tire that will fit on the rear with the stock 9" wheels? A 275/40/20?

245/45/20 front
255/45/20 rear

Lots of people put 255/45 on front and 275/40 rear and get away with it but under extreme suspension compression and steer angle conditions they will rub.

 

(2 of 2)- May 13, 2009

1. Several forum members are reporting problems with cracked rocker panels (in front of rear wheel opening) and leaking rear differentials on their Challengers. Are you aware of these problems and any corrective measures?


2. How accurate are the tire sensors? I compared my tire pressure on the EVIC with my digital tire pressure guage and the EVIC registered 2 psi more.
1) The only time we experienced cracked rocker panels was when we misplaced the car on the hoist or improperly placed the floor jack. We have "zero" warranty for differential leaks. We need more info on this one... where are the leaks coming from? Are these all SRT's? All we can recommend right now without more details is to take your car to an authorized dealer and have it checked.

2) TPM's are accurate to +/- 1.5 psi and about as accurate as most tire pressure gauges.


So I would need free(er) flowing cats and possibly larger diameter exhaust to get maximum output from a larger TB. How do the cats or total exhaust system factor in when adding a supercharger, and you start pushing more air through the engine?

Your on the right track HotRod....take the systematic approach to this. Just remember: Air In = Air Out. Uncork the exhaust with some Mopar Headers (which will eliminate the cats) and you should be open to a fair amount of mods. Just don't blow it up with a ton of boost...Or if you do, build it bigger!

The EPA approved headers and Cat's are what came on your car stock. Any Off-Road part offered by Mopar, or the Aftermarket is not approved by the EPA (hence the "Off-Road designation).



Was a true high performance CAI shot down as a stock item for this car? It's certainly a consideration to replace the stock air box.

A CAI open element intake won't happen on the Challenger due to water ingestion and pass by noise requirements. We'd love to if we could.

I didn't buy my Challenger SRT8 because it was easy on gas, but I can't help but wonder why don't get better fuel economy out of the SRT8? Highway should be mid to upper 20's running at 75mph. GM is doing it with the Corvette without compromising performance. I know some of this is due to drag, but GM is claiming the Camaro can do the same.

We are constantly improving our vehicles, check the fuel economy numbers between the 08 and 09 Challenger SRT8.

I would like to know why the Drivers seat does not have a quick release for entry to back seat? Is Mopar working on EPA approved Headers/ Cats?

Blame the beancounters for the seat situation. We win a lot, but not all the time...

Are the ALCOA wheels supposed to have more than one set of weights on them? My experience tells me with stick on weights there should only be one set. My car has two sets of weights on one of the wheels, some vibration is present, can you verify the correct balancing of the wheels?

There should only be two groups of stick on weights. One for the inboard side of the rim, and one for the outboard side of the rim.

I don’t have my Challenger SRT8 yet, but it’s being delivered next week. However, I would like to ask a question concerning the clutch. Is there an easy way to verify the throw-out bearing is not putting un-due pressure on the release fingers when the pedal is in its full-up position? There seems to be quite a few members in this forum that have had to replace their clutch already, and perhaps one of the symptoms is that the pressure plate is being pulled away from the clutch disc or they are not fully releasing the pedal.

The hydraulic clutch release system is self adjusting. We have seen a few clutches come back and the vast majority have been burst due to a missed shift.

I have read about the "Bump Steer" on the Challenger, did you guys do anything to address it on the SRT cars? I am also concerned about the alignment being "AT" specs with no room to adjust, was this addressed on the SRT line of Challenger?

For 2009 the base Challenger has roll understeer in the front suspension (toe- out in jounce). The 2009 SRTs maintained roll oversteer in the front suspension (toe-in in jounce) that SRTs have had since 2005. Roll oversteer really helps the responsiveness. Neither is enough to qualify as high amounts of bump steer.

Now that you have the opportunity to try both the LSD and BLD on the SRT8, which do any of you all prefer and why?

The mechanical diff offers big advantages in traction by hooking up faster, before slip occurs, and being able to transfer more torque to the higher traction wheel. The trade off is a slight reduction in initial turn-in response.

 

Here are some of the responses to questions appropriate to the Challenger, from the April 15, 2009 300C SRT Engineers' Chat Session (1 of 2):

I was wondering what you guys thought about a hard break in with these srt engines? There have been articles going around lately saying that a few hard runs on the first uses of the engine will help the rings seat better and will keep it running great and low on oil usage throughout the life of the motor and I was wondering what you guys thought about that.

A- SRT recommends that you follow the run-in procedure recommended in the owner's manual. That works better for seating rings.

Also, when should the order banks open for detonator yellow challenger srt8 spring specials?

A- Ordering should open towards the end of May.

Which models will be available at the SRT Track Experience at Thunder Hill when I attend on November 18?

A- All SRT products will be represented at this event...Enjoy!


1) Are these engines run on a dyno using conventional oil to seat the rings at the factory in Mexico before getting shipped to the assembly plant? I know that it is recommended by all motor builders I know of, that a new engine should never be broken in on synthetic oil and since these come from the factory with synthetic oil in them I want to make sure the rings will seat properly.

2) When should I first change the oil? I've heard everything from 60 miles up to 6000 miles.

3) What is the proper procedure for bedding in the Brembo's. There is nothing in the owners manual on this subject. Once they are bedded in do I have to do anything else with the breaks? Will they need to be bedded in again?

4) During the break in period should I keep it under 55 MPH? Or is there a certain RPM that I should try to stay under?

5) Is there any other break in advice that you can give me?

6) When can I drive this beast like it was meant to be driven?

I've done alot of research and I'm getting conflicting information so I hope you guys can help me with this. Thanks.

A- SRT recommends that you follow the run-in procedure in the owners manual which is ok with synthetic oil. The engine plant does not run-in the engines. We always run-in our dyno engines with synthetic oil.
The brake guys recommend 1000 miles of "normal" driving before you hammer on them.

A supporting vendor posted on another forum that the 5.7 engine is more advanced than the 6.1. He stated that the 5.7 has a better cam, similar intake, similar heads, and is 'king" until 5,200 rpm. What is your response to this?

A- No question the upgrades to the 5.7L that went into production in last year are impressive, but... the fact that you had to include the "until" qualifier makes it pretty clear who the real winner is.

What is your advice regarding Superchargers? The market has a big offer (Techo, Whipple, STS, Vortech, ATI Procharger, ...) with different concepts (Roots Blower/ TwinScrew or Centrifugal).

My understanding is as long as you do not try to get the last HP out of the
setup with the 6.1 and a blower, keep the boost as low as possible (max of 4-5psi ~520HP)
and don't race your car every weekend it should be a durable setup.

What do you think? Is it a no go in a long term view because the engines will not survive the extra load or is it as long as you keep the boost low more or less save?

Big TwinScrew's do >7PSI but I suppose that's definitely too much if you want to drive your engine 100.000miles+

Do you recommend bedding of the SRT breaks when squealing
is somewhat frequent?

A- If your brakes have gotten more noisy and you are driving around like a granny, do 3 or 4 hard but non-ABS stops from 60-20 mph (the performance pages are nice for this, do 0.5-0.6g stops on the longitudinal meter). That should clean excessive brake pad material off the rotors. You also may notice the brakes are more noisy on humid days. You should realize that these are performance brakes, so they will make noise.

 

(2 of 2)- April 15, 2009

This is a hypothetical question and not about a future product.
If a 6.4L Hemi were to exist about how much horsepower would it produce?

A- A 6.4L Hemi does exist, check the 392 crate out at mopar.com
EFI: 525 hp, Carb: 540 hp

About the half shafts that are breaking and you beefing them up in 2009 is there a specific problem that you found in the heat treating of them ? what was the reason for the change?

A- The only concerns we had with the halfshafts was when big power adders were installed (ie, Nitrous, superchargers, etc). In 2009 the halfshafts were upgraded to live behind a manual trans.

Did you guys design the mopar cold air intake for the 6.1 ? I notice on my stock air box there is a baffle going off to te left on my 2006 300cSRT8 I notice there is not one on the challenger or the charger or the newer 300srt8's what is the reason for this and what does it do? and what are your thoughts on the aftermarket cold air intakes fo the 6.1 ?

A- The change was to improve the induction sound so it sounds more like an SRT should. As for the cold air, mopar has one for you.

Also, the dyno has consistently shown the 6.1 to be underrated. Why isn't it rated for the actual power that its making? I've never seen one make less then 450 (though several higher), so why not rate it at 450 instead of 420-425?

A- SRT does not allow "Marketing" to influence our horsepower ratings. You'd be surprised how common of a practice that is at other car companies, hence the tightening up of SAE horsepower rating procedures a couple of years ago. Notice how we did not loose power, but many other manufacturers did? Also, haven't Mopar horses always been bigger than the other ones?

My 09 SRT 300 shifts significantly better than my 06 SRT Charger did. Was there any additional tweaking to the tranny set up in the last few years to achieve this, outside of the shift hesitation TSB that was available?

A- Glad you like it! There has not been any more major changes, but we continue to fine tune the system with every model year.

Will the SRT program continue on in 2010 and beyond? I would hate to see a good thing disappear because of CAFE or fed guidelines that may squelch it due to the SRT being a niche market for hotrod, motorheads and pure Amercan muscle horsepower aficondos, like me, err, rather us!!

A- As long as people keep buying our cars, we'll be around!

Is the air box on the 6.1 different then the one on the 5.7?

A- Yes, they are different. SRT designed the 6.1L box for less airflow restriction and a better "performance" sound.

Would you guys like to see the 'Cuda back in Chrysler's line up??

A- We'd love to see one.

Please provide ballpark (average) suspension spring stats for both the R/T and SRT versions of the Magnum, Charger, and 300?

A- The R/T Charger uses 204 lb/in front and and 514 lb/in rear with Nivomat rear shock.
The R/T Challenger uses 224 front 514 rear with Nivomat rear shock, 547 rear without nivomat.
The 300C SRT8 uses 227f, 622r.
The Charger and Magnum SRT8 use 284f, 778r.
The Challenger SRT8 uses 261f, 669r.

SRT8s sit 1/2" lower than the 5.7L and 3.5L rwd cars.

The cop car springs are 250f, 652 rear (with Nivomat), but sit even taller than base car due to how they are typically loaded down.

 

Here are the comments made by the SRT Engineering Team, during the Feb. 18, 2009l SRT Caliber Chat Sesion, in response to some Challenger questions (1 of 2):

Are rotors directional on the Challenger SRT?

1)Rotors are not directional....

Are the 20” wheels on the Challenger SRT clear-coated?

2) The wheels are machined, polished, and clear-coated

When should plugs be changed on the 6.1?

3) Should be 75,000 severe miles and 100,000 normal miles ... replace them with NGK's PLZTR5A-13.

What would cause a drop in engine idle?

Loads on the engine at idle, such as A/C compressor, alternator load, P/S, cooling fan speed will cause the idle to vary.

Why do many automotive magazines get slower drag and track times?

Indeed an alarming number are hacks, but a few are decent. They probably represent a good cross section of the general population. We have Championship winning racers from autocross, road course, circle track, and drag racing tuning the stock SRTs. NO compromises are made without a solid reason. We build the cars for you, not magazine editors, yet it is impossible to make everyone 100% happy, which is why we also offer Mopar Perf parts to tune the cars for your needs if you choose.

When is this year’s SRT Experience?

We are working out the schedule details. Looking to start it in April. More to come very soon.

How much high RPM testing did you do on the 6.1, and what made you choose 6100 as the redline?

How dangerous is it to operate the 6.1 above 6100 rpms?

What parts of the motor/drivetrain are most likely to fail from RPMS occasionally jumping in the 6500 range...or 7000 RPMS?

What is a "for sure going to fail" PRM for this motor?


1. The automatic transmission 6.1L vehicles redline is dictated by the transmission. The automatic needs a little buffer room to complete wot shifts with a safety factor.

2. Without some valvetrain upgrades, you shouldn't go too much above 6200rpm.

3. Valvetrain parts - rocker shafts and valve springs

4. &gt;6400rpm


How do I reset the pcm / ecu to the original factory setting when delivered? How do i backup the ECU 1 step at a time? Chrysler SRT8. poor performance

You can't really backup the ECU 1 step at a time. However, you can clear the adaptives by pulling the battery positive connector for a few minutes. This will take your module back to the way it was even before you took delivery on your car - since I'm assuming your car had at least a few miles on it when you bought it. What is the poor performance issue your having?


My brake rotors on my 08 CSRT were pitting and rusting started to pulsate when hot I had them replaced just before 15,000 after just a few thousand miles I have 18,000 now they are the same way again dealer won't replace again what should I do... Other people do not seem to have the same problem any ideas.... I am not hard on brakes if anything very easy on them could that be the problem...?

Not too sure about the pitting, do you get the car wet (wash it) and let it sit? The pulsating could definitely be from being too easy on the brakes. Trying doing a couple hard stops, sub ABS, (approx .5 g's) and see if that cleans it up.


First off, thanks for the new 5.7L mods, they are GREAT, Hope you have something for the 6.1L in the near future!!
1.I have had problems with oil pooling in the throttle body, near #7&8 runners, it's causing smoking and misfire codes, I have only 8K on the clock, and don't track it. Do you have a suggestion on what to do, the Dealer is mistified!
It's an 06 SRT Charger
2.What changes were done to the Diff. in the 09 Challenger as compared to the 08 and prior Diff's, are the halfshafts better(hope) and if so, by how much.

The 2009 rear axle goes to a larger ring gear (226mm vs 215mm) and gives you a real limited slip in addition to the brake based stuff. The halfshafts get bigger too.

As for the oil in the intake... It's hard to diagnos from here, but you could try putting a catch bottle on the PCV tube to see if its coming from there.


Will a CAI give any improved performance over the stock system?

Depends. Under most conditions we can show you get a bump from CAI. However, if you're sitting in city traffic and everything under the hood is good and hot the answer would be a resounding no.

Is there any truth to the rumor that Chrysler had to dumb down the SRT8 performance level due emissions controls?

Absolutely not.

 

(2 of 2)- Feb. 18, 2009

1. What is the behavior of the PCM / TCM if the dynamics sensor is hypothetically disconnected? How does this compare to when the ABS fuse is hypothetically removed?

2. How far inboard could I hypothetically relocate the UCA pivot in the front suspension without causing the driveshaft to bind in suspension travel?

BTW, hope you guys are fairing okay... you've done a great job for us, and made it worthwhile to buy american cars again. Some of us are looking forward eagerly to the SRT version of the upcoming "WL" : )

1)The PCM/TCM uses information from the wheel speed sensors, but the ESP would send out a fault that both modules would see..... the ABS fuse should not be pulled.

2) Propably about about 1/4 inch.... the halfshaft should never have an issue with binding...

Will Dodge ever provide a way for us to order a "spare" tire/mini jack for the CSRT? If I have a blow out I am kind of dead in the water with a little "air pump". The R/T has a full spare... I think a spare should of been included, or at least a premium AAA membership!

The air pump is good for up to 7mm holes in the tread of the tire. For extra protection you can carry the mini-spare from the base Caliber. This will clear the rear brake package and a rear tire can always be moved to the front to clear the SRT brake package.

With the way economy is going. GM has already disbanded the high performance team. Any chance this will happen to SRT?

We sure hope not!!! Funny, we get that a lot from the base platform guys here at work. We are here because OUR CUSTOMERS are still buying SRTs! Thank you so much for keeping us employed!! Please keep it up if you can.


1. What changes were made on the challengerR/T and SRT8 to the Diff's and halfshafts and if so, what was it...And the most important, are the specs. better than previous years??

We've posted a pretty complete list of specs and but basically the ring gear is 10mm bigger, it has a real limited slip, it as an extra set of diff gears. The halfshafts go from 28 spline to 32 spline.


What oil is recommended?

Mobil-1 products are hard to beat. There's a reason it's spec'd for SRT's and other high perf cars. We know the 0W40 Mobil-1 works. Best bet is stick with the Mobil-1 brand. If you can't find 0W40, try 5W40. If you're lucky enough to live where it never gets cold, you could try 15W50 (but you may notice worse fuel economy). We're told (but haven't confirmed) that Shell Pennzoil Platinum 5W40 is good stuff, too.

Per the WK SRT8 - I just changed my T-case oil for the first time. Trying to get the oil to the right level seemed to be somewhat of a pain, having to add a little, check level, add more, etc. The suggested "bent rod" dipstick method didn't seem to work too well, I was not comfortable with trusting the reading.

1. My question is this - it seems like it would be a lot easier to fill the t-case until it flows out the fill hole, and then just drain out "x" ounces to bring it down the spec'd level of ~1" below the fill hole. Can you tell me how many ounces from "full" to drain out to bring to spec?

2. The NV146 fill spec calls for "3.8 pts. (60.8 oz.)". For my own t-case, and that of many others, the amount used ended up being far less than the spec. For example, after a thorough drain mine took only around 50 oz. Some owners have reported only using ~40 oz. Any concerns here, or why such a discrepency?

We can't give you an exact number how much to drain since we've always used the service manual procedure for our durability vehicles.

More than likely the variation is due to the amount of fluid still in the clutch pack and the angle of the vehicle......


A few sessions ago you opened the door to discussions about the SRT10 Challenger, asking what we'd be willing to pay for one. Are you willing to entertain more questions on this???

Why, has the price you are willing to pay gone up?

While that’s good practice...please remember there are speed limits. So next time I get nabbed for speeding, I'll claim it’s not my fault and send you my ticket.

What, you let the cops catch you?!