advice pls...

Discussion in 'Dodge Challenger General Discussions' started by LEGENDARY70, Aug 3, 2022.

  1. LEGENDARY70

    LEGENDARY70 Active Member

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    Hello all.


    Was curious if I wanted to put more horse power into my 2010 srt8 what would yall recommend that would not break the bank that bad? Any ideas and advice would be great. thx
     
  2. 70-426_10-SRT

    70-426_10-SRT B&E body lover

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  3. LEGENDARY70

    LEGENDARY70 Active Member

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    Looking for a little street fun, no track. maybe an increase of 50-125 hp.
     
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  4. 70-426_10-SRT

    70-426_10-SRT B&E body lover

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  5. Moparisto

    Moparisto Full Access Member

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    If you want super-cheap and easy, I think a junkyard turbocharger, (or two of them)a tune, and an aftercooler, will amplify your current car's capabilities. Look at Richard Holdener on Youtube. The Hemi THRIVES on boost, and the stock bottom end also thrives on boost. You don't need a forged unobtanium crank, but in my own opinion, some higher-quality valve springs would be recommended, and easy to install.

    Heck if you aren't too greedy for power, you can use big, loafing turbos that will be more efficient and an electronic, adjustable wastegate to just dial whatever boost you are in the mood for on that day.

    As he says, "All cams are turbo cams." Take whatever your car does as far as power and torque curves, and just move mostly the right 80 percent of the curve up by a similar amount on turbos, no other modifications. If you get cute little turbos, they will be aggressive down low, spool up quickly, amplify your peak torque number, and need the wastegate(s) to keep them from overrevving.

    At the power level you are looking at, I don't even think you'd need to put a bit more gap in the rings, but it would not hurt if you plan on doing some high-power and high-ambient-temperature fun. Gapping the rings is one of the most forgotten points of boost for the average guy.

    If you wanted better mileage, you can lean really hard on the boost AND put in a rear end ratio that turns your engine more slowly at a given speed, and just loaf down the highway like a diesel truck at low, low RPM. Parasitic loss from turning the engine and all that is a big downer on fuel mileage.

    According to the big diesel truck industry, every drop in 100 RPM is a one percent increase in efficiency. (keep in mind that is for big rigs, not sure how it relates to cars.) If you could go down the highway at 700 RPM, you could by that theory, get 13 percent better fuel mileage than at 2000 or so for the same speed.

    IN FACT, if you want a nice, relaxed pace for your project, just drop by the junkyard, pick up a truck Hemi 5.7L for a few hundred bux and boost THAT. The 5.7 ABSOLUTELY ADORES BOOST, so much so that Mopar used it as the basis for the 1600hp Drag Pak with the Whipple on it. Gap the rings, stiffer valve springs, cheap turbo(s?) and aftercooler, and you're good with a tune for that car's usual gasoline. You can have the turbos only really wake up above 4000 RPM to save torque stress on your driveline, if you wish.

    It ain't expensive or exotic.

    https://www.youtube.com/channel/UC8uf_zVTV63l1-uRSx6XbnQ/search?query=5.7 hemi

    You could plop some aftermarket (read: Edelbrock) heads on it and a cam, and voila! You're done, with no boost required, especially if you go for some long-tube headers to aid consistency.

    The turbo gives better fuel mileage at the same power level wanted, but the cam gives a sexier idle if you like that sort of thing, like other RBAM's.
     
    Last edited: Aug 3, 2022
  6. Moparisto

    Moparisto Full Access Member

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    This video is a direct comparison of stock with the Edelbrock heads.



    It ran into valve float at around 6500 RPM, or its peak would have been even higher.
    60 more hp than stock.
     
  7. Moparisto

    Moparisto Full Access Member

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    And the Eagle heads, which flow a relatively large 330 cfm, which is good for 2X330=660 hp (that's a rule of thumb for a naturally-aspirated American V8.)
    This is at only 0.65" of lift, too.
     
    Last edited: Aug 7, 2022
  8. Cloverdale

    Cloverdale Full Access Member

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    My sense from your post(s) is that you're not planning to do the work personally. Suggest you discuss your options (goal and budget) with those who will be doing the work (local shop).
     
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  9. BunnyMom

    BunnyMom Full Access Member

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    Are you on the in with the local PO's? Ha kidding, have fun!
     
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  10. Moparisto

    Moparisto Full Access Member

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    BTW, I did the math on this to do a small and mathematically obvious demonstration of the physics behind "Why would anyone ever go with a shorter deck/shorter rod?"

    This is FAR more critical in a diesel engine, where the cylinder pressure spike in the first 45 degrees is the highest in any engine of any type, anywhere, riding almost vertically upon injection.

    I exaggerated the rod/stroke ratio differences to show the physics of why a shorter rod actually results in more power, all other things being equal

    At 45 degrees of crank rotation from TDC to 45°ATDC:

    Infinite rod length: piston travel is 0.87867965644035742679746691368545”

    2.4:1 rod: stroke ratio, piston travel with 45 degrees of crank rotation: 0.15710703543693690796443171408546"

    1.2:1 rod: stroke ratio piston travel with 45 degrees of crank rotation: 0.31959303529217103330786509026681”

    Difference in force times distance for the 1.2:1 rod:stroke ratio versus the humongous 2.4:1 rod: stroke ratio rod, for the purpose of demonstration: an almost identical force multiplied by distance that is larger by a factor of: 2.0342375782429956481918002137172

    This results in over double the actual work being done on the piston during the same time period, due to a shorter connecting rod increasing the acceleration of the piston away from TDC.

    I understand side loading and piston slap. What side loading and piston slap does not do, however, is erase the facts surrounding the physics of the combustion process time compared to the piston travel with the longer and shorter rods.

    As I have learned, shorter-deck B Chryslers of the same displacement produce more power, largely due to the shorter rods, than the same displacement in an RB (raised block, as in, the 440 block) Chrysler.

    If super-long rod: stroke angle was the cat's meow, unlimited-budget racing teams would be using motors with much taller decks, to more closely approach it.

    As it is, they use as much deck height as is needed to allow the crank to not hit the pistons as it swings around, evidently, and no more.

    But, yes, historically, the low-deck B engine produces more power for a given displacement than a tall-deck RB engine. Racers choose the low deck when they have both available.

    Shorter rod-to-stroke ratios take better advantage of the available combustion pressure in the first portion of the combustion stroke.

    The most critical power-extracting part of the power stroke, most especially in diesels, is the first 45 degrees.

    In nitromethane cars, especially, the combustion pressure extends all the way down the stroke and afterwards, continuing to burn right out the tips of the zoomies, so it is not as much of a point of benefit, but with normal gasoline combustion, the combustion pressure is very much biased towards the first few degrees of crank rotation near TDC.

    So, in short, don't be afraid to increase the stroke of your Gen III Hemi. You aren't going to punch the pistons through the cylinder walls with the shorter rods and longer stroke. I wonder just how big we can make a Gen III Hemi stock-block motor!
     
    Last edited: Aug 9, 2022 at 3:33 AM