2020 Scat Pack

Hello and thank you for reading this. I dont know if i am in the right place but here we go!


I have had my car tuned and i cant seam to stop spinning.
I have nitto NT555RII 305/45/17

Below is a list of what was done to the car:

1. JBA 6965 s Headers
2. high flow ceramic Cats
3. BOR-140640 Exhaust System, S-Type, Cat-Back, Dual, Stainless Steel, Natural, Split Rear Exit, Dodge, 6.4L, Kit (Mfr. #: 140640) from summit racing It has the TURBO style Muffler
4. K&N Air filter
5. JLT oil Catch Can
6. Hell Cat Lower Air box with the Air Scoop that connects to the light
   
7. SRT CNC Ported Throttle Body 85mm (SKU: MMP-1AAMM-85CAR-13 from summit)
   
8. MOPAR Dodge Hellcat 600cc OEM Fuel Injector - 68170238AB (ordered from High Horse Proformance)
9. I think that everything besides the Hp Pro tuner and PLX Wideband.
10. Tuned

I Know my car feels faster with the stock 20's because now when I am on the freeway and lets say I punch it from 65 or 70 it will feel like the back end is on ice skates like i am about to loose it.

my in-dash drag time is the same (befor and after 11.7) but my mile per hour is higher (115 befor and 119 after)

i feel like i am spinning for at least 60 feet with the simi-used drag tires ( i did them new)

if you can help me with some ideas to help me stop spinning that would be great ( waiting on tuner to get back to me)

What i was thinking of going with :


Mickey Thompsons P315/50/15 ET Street R

 

What about trying to upgrade the rear upper and lower control arms or shocks/springs or go to coil overs to help plant the tires better?


Sent from my iPhone using Tapatalk

 

I will defiantly look into that. I am so lost.

 

If you can't put the power to the ground, it doesn't matter how much power you have! You'll never go anywhere if you can't get traction. I know that I had wheel hop issues on my 2013 Ram and changing the rear control arms fixed it.

 

You said that you're using 17" tire. Can I assume that it's a significantly smaller outer diameter than your factory tires? If so, even though the tire is a drag radial, it being a smaller diameter gives your drivetrain more mechanical advantage to overcome the contact patch (which is also smaller). The difference in tire diameter would also explain the 4mph increase in terminal mph while not seeing a change in 1/4 mile time.

 

Katshot brings up a good point regarding tire diameters. Going with a smaller diameter tire is like going to a steeper differential gear. That would contribute to tire spin. I looked up each tire size assuming the stock ones are 245/45R20.

245/45R20 tires have a diameter of 28.7", a section width of 9.6", and a wheel diameter of 20". The circumference is 90.1" and they have 704 revolutions per mile. Generally they are approved to be mounted on 7.5-9" wide wheels.
305/45R17 tires have a diameter of 27.8", a section width of 12.0", and a wheel diameter of 17". The circumference is 87.3" and they have 726 revolutions per mile. Generally they are approved to be mounted on 9.5-11.5" wide wheels.

 

As others have said .... work on the suspension.


I'd think about adding a differential brace and sub-frame connectors in addition to working with different springs. Have you dropped the pressure in your tires to help them get some bite?

And it doesn't help that the weight bias on your 2020 is 55/45 (front/back.). Back in the day when I had my '68 Charger R/T, I used to throw a couple of bags of fertilizer in the trunk before I headed out to "Mexico."

BTW ... Your speedometer is going to be off when you change the tire diameter.

 

Cool thing about now adays,

"There's an App for that" (Actual Speed)

I was wondering how he was going to get
Mickey Thompsons P315/50/15
over the Brakes Calipers

 

As I recall, one of Don Garlits' final comments about the Demon was that Mopar should consider larger diameter rear wheels/tires to combat wheel spin.

 

I have the stock Perrelli all season tires on mine. I tried launch control last week and found out pretty quick that different tires are needed. Launch control aborted seconds after I released the brake. She started spinning and pulling off to the side. Definitely need something to optimize traction to get it to grab the road. Doubt I’ll do any mods that way as I don’t plan to race it.