Tips or Hints for new to SRT-4

[jnathan68]

Looking for any tips or hints for running the track in an SRT-4.

My experience includes about 6 years of auto-x, 2 years of SCCA regional road racing and about 15 open track days in mostly front wheel drive cars. However, the SRT-4 is the most powerful FWD car I have driven on the track.

Already done 3 open track days (issues on 2 of them that kept me from running full day) in the car and preparing for Redline Time Attack.

Mods include:

• Stage 2 with toys
• Bigger throttle body
• Cold Air Intake
• Exhaust
• BC Inverted Coilovers with 8k/6k (stock rates)
• Camber Plates up front
• Front and Rear upper strut bar
• Bolt in Roll Bar
• Mopar Sway Bars
• Poly bushings all the way around
• Lightweight wheels (17x7.5) with Federal 595RS tires (street class=street tires)
• Wilwood Brakes up front with upgraded pads
• Hawk HP+ pads in the rear
  • Somewhat stripped interior

Car corner balanced at 2720lbs (w/o me in it) and seems to handle pretty well for a front driver. Car is also street driven.

Questions:
I have a bigger rear sway (Perrin 22mm) for the back...will it make much of a difference?

Or, better to go with stiffer rear springs? Or both?

Are traction bars, adjustable rear control arms or rear tension strut kit worth it?

What toe settings should I run?

Any other tricks to the car's handling?

Sorry, somewhat random and long but any help would be greatly appreciated.

Thanks.

[DrmCtchr]

You didn't tell us what year your car was. This is relevant as far as the rear tension struts. If you have a 05 then they are not needed. However, I replaced them in both my ACRs and re-torquing them, at minimum, helps a great deal with threshold braking stability in the rear end.

As for the rear swaybar: ask someone to follow you on the course (if they can) and have thier passenger watch your inside rear tires for lift at weight transfer. If you have lift now, increase spring to flatten the car and not bar. if you dont have any lift ( we are targeting about < 0.5 inches here ) then you are safe to add bar. There is no point whatsoever in huge amounts of inside rear tire lift. Once the tires load goes to zero there is nothing to be gained by lifting further and infact hampers things more as settling the car becomes work and not a natural 'smooth' progression.

Adjustable control arms (rear) are ok if you are a suspension engineer and have a alignment rack in your garage. most alignment guys have no idea what to even do with them. They do offer you a degree of adjustability not available to you normally and are good to burn $$'s on if you have removed all the extra compliance from the rest of the suspension. Front adjustable control arms GREAT to have. You can adjust so much with them. GLH is tooling up to produce a set that should be very nice indeed. See the other thread in this section.

Traction bars are not recomended on the road course due to clearance at the rad support. I HIGHLY recomend Rage-Tek solid LCA's instead. They do pretty much the same thing (properly), but do increase the transfer of surface noise to the chassis a bit more. ( ie. gf will notice it .. you should be noticing the crisp turn in and lack of wheel hop and wont even think about the wee bit of extra noise/vibration )

Toe setting: this is a subjective question... I recommend you set the car to stock ride height then set the suspension to stock ACR settings. Then go from there. you will find a billion threads on what people 'like best' and they range all over the place. Start at stock and then play depending on how you like the car to handle. Besides that is a good safe starting point ( yes even the stock front camber setting: have the shop set stock at the crash bolts with the plates set at full positive then you can add more negative at the track if needed then its easy to set it back when you go back to the street )

Tires: get a set of decent DOT competition tires: Hoosier R6, toyo r888, Hankook Ventus, Kumho Ecsta, michelin pilot sport cup, BFG R1, Yokohama Advan, Nitto Nt01, among others are all good DOT rated radial competition tires. Tires are by far the best thing you can do to the handling of your car for the money.

Good luck.
David Jackson

[jnathan68]

Quote: Originally Posted by DrmCtchr

You didn't tell us what year your car was. This is relevant as far as the rear tension struts. If you have a 05 then they are not needed. However, I replaced them in both my ACRs and re-torquing them, at minimum, helps a great deal with threshold braking stability in the rear end.

As for the rear swaybar: ask someone to follow you on the course (if they can) and have thier passenger watch your inside rear tires for lift at weight transfer. If you have lift now, increase spring to flatten the car and not bar. if you dont have any lift ( we are targeting about < 0.5 inches here ) then you are safe to add bar. There is no point whatsoever in huge amounts of inside rear tire lift. Once the tires load goes to zero there is nothing to be gained by lifting further and infact hampers things more as settling the car becomes work and not a natural 'smooth' progression.

Adjustable control arms (rear) are ok if you are a suspension engineer and have a alignment rack in your garage. most alignment guys have no idea what to even do with them. They do offer you a degree of adjustability not available to you normally and are good to burn $$'s on if you have removed all the extra compliance from the rest of the suspension. Front adjustable control arms GREAT to have. You can adjust so much with them. GLH is tooling up to produce a set that should be very nice indeed. See the other thread in this section.

Traction bars are not recomended on the road course due to clearance at the rad support. I HIGHLY recomend Rage-Tek solid LCA's instead. They do pretty much the same thing (properly), but do increase the transfer of surface noise to the chassis a bit more. ( ie. gf will notice it .. you should be noticing the crisp turn in and lack of wheel hop and wont even think about the wee bit of extra noise/vibration )

Toe setting: this is a subjective question... I recommend you set the car to stock ride height then set the suspension to stock ACR settings. Then go from there. you will find a billion threads on what people 'like best' and they range all over the place. Start at stock and then play depending on how you like the car to handle. Besides that is a good safe starting point ( yes even the stock front camber setting: have the shop set stock at the crash bolts with the plates set at full positive then you can add more negative at the track if needed then its easy to set it back when you go back to the street )

Tires: get a set of decent DOT competition tires: Hoosier R6, toyo r888, Hankook Ventus, Kumho Ecsta, michelin pilot sport cup, BFG R1, Yokohama Advan, Nitto Nt01, among others are all good DOT rated radial competition tires. Tires are by far the best thing you can do to the handling of your car for the money.

Good luck.
David Jackson

Car is a 2004 so I will look into the rear tension struts and in regards to rear wheel lift I will see if I can get someone to follow me at the track although pics from the last event I ran don't show any lift.

You said, "recommend you set the car to stock ride height then set the suspension...." Are you saying that the ride height should be close to stock or are you saying start there but ride height can be lower if it works.

On tires, I have to stay with a street tire because I am running in street classes that require it but know the benefits of DOT approved race tires

Thanks for the great information!

[DrmCtchr]

right. stock height seems to provide a bit more forgiveness if you over do it. the car has a bit less of a tendancy to bite you and is easier to catch if it does nibble. great place to start.