J-Rho autocrosses an SRT-10 in SCCA SS class

[j-rho]

Hi All,
Using this thread as a placeholder for the 2008 season, campaigning my 2004 SRT in the SCCA's "Super Stock" autocross class.

Most people don't think of the the Viper as a good autocross car because of its size and power, but I think there's some things about it that make it a good choice. Its main competitors are the Porsche GT3 (2007 winning car), Lotus Elise (2006 winning car), and C5 Corvette Z06 (2005 winning car). Viper Pros/Cons,
Vs. the GT3-
Pros:
Has more power/accelerates better, esp. when GT3 is "off the cam"
Is ~250lb. heavier but has much better tire/weight
Is better balanced overall
Cons:
It's much much wider
It doesn't put power down as well

Vs. the Elise-
Pros:
Accelerates better, esp. when Elise is "off the cam"
Probably better in sweepers
Cons:
MUCH heavier
MUCH longer

Vs. the Z06-
Pros:
Puts power down better
Shorter wheelbase = more maneuverable
Better wheel and tire per weight
Cons:
A bit wider
Not as good 2nd gear acceleration when under 55mph

Also, I tend to focus on the "ProSolo" series within the SCCA a bit more than others. These events feature a drag-race start, where I believe the Viper's great traction and 1st gear acceleration will be of large benefit.

As a bit of background on myself, I started autocrossing in 2002 with my Honda S2000 in the "A Stock" class. I did pretty poorly that year at the National Championship, finishing near the back of the pack. The following year I did a lot of driving at autocross and track days, including the Open Track Challenge, where I got to hang out with some cool people like John Dearing, Ron Wasserman, Paul Mumford, and Brian Provost. Doug Hayashi, Erik Messley, and myself won Touring 3 in Doug's Honda S2000 sporting a moving wing I built:

I also finished a close second in Dave Kennedy's Unlimited 2 class Honda S2000, which we'd swap the wing on to between sessions:


That year I also built-up a friend's Honda Civic for the "STS", in which he won his first National Championship, and I finished a much better fourth.


2005 was pretty interesting, I co-drive with multi-time National Champion Gary Thomason in his 600hp Corvette (with stock Z06 gearing!). That was my first time in a properly powerful car a real eye-opening experience. Gary won nationals that year and I placed a decent third, ahead of some guys I thought pretty highly of, including Viper racer Scotty White.


Having done pretty well I decided I needed to race my own car again to get "first priority" for winning. So I bought a Nissan 240sx, built it up for the STS class I'd built the Honda Civic for, and managed to win the 2006 National Championship in that class.


Having been bitten by G-Tho's powerful Corvette in 2005, I wanted to get back into something with some balls. In a bout of bizarre logic, I thought the easiest way might be to make the 240sx faster, after all, all the drifter guys were doing it. So I slapped on a big turbo, a stout clutch, killer diff, and some monster wheels and tires. The result:

and a quick autocross lap:

That car was a blast but with a diet of race gas and life as a trailer queen, it was also a bit high-maintenance. With some life changes going on I sought something just as fun but a bit lower maintenance. It just so happened that the aforementioned Viper racer Scotty White had his mamba for sale, so we made a deal, and I went and picked it up from him in Washington.

It took me a while to get it ready and back into a healthy "Stock-class" trim. We are only allowed to change the fron swaybar, cat-back exhaust, tires (must be DOT approved) and wheels (must be stock width and diameter with offset within 1/4" of stock). So I built my own beefy front swaybar, ordered some CCWs, and kept the completely mufflerless exhaust it had from Scotty.

At the first event with the car put together, on my second run, I was within a couple tenths of a second of what will be my toughest competition. Needless to say, there is bound to be some "time" I've yet to find in setup and learning to drive the car better (as the video below clearly shows). This looks to be a very promising year for the Viper in SS...

Thanks for reading everyone, wish me luck!

[rcl4668]

Jason --

Thanks for posting the awesome pics and video. I will be very interested in seeing your results as I hope to partcipate in some novice SCCA Oregon autocross events this summer.

Good luck!

/Rich

[Alan Patterson]

Since you now own Scotty's old Viper, you own parts of my VOI-9 coupe! Scotty and I traded his delrin bushed control arms for my stock ones which are now on your viper. FYI, I am a pretty serious autocrosser running in ASP. I have done nearly all that can be done to the car in the street prepared class: quaife diff, light weight flywheel, Corsas, Hi-flow cats, Extreme alignment (very low with 3 deg front/2 deg rear camber for A6 Hoosiers) Moton shocks, etc.
I have found that the stock swaybar works pretty well as long as there is enough stagger in front/rear tire pressures. Only thing left is headers which may or not be needed...

Prior to going to the ASP setup, I tried my car in SS class for a few events and found that the shocks/springs just didn't work well enough and the rules say you can only use "stock length" springs which means custom built shocks to mate with the "tall" springs. Also, I found that the stock positraction just did not work well. You will find it locking up suddenly when trying to put power down coming out of corners. (Oddly enough my old gen2 viper did not have this problem) the quaife diff solves this problem.

Anyway I hope you are successful in your endeavors and perhaps we can meet one of these days. I plan to run the Calif tour events and pro solos plus the Nationals this year.
Good news is I have a co-driver who is a previous BSP national champion to help me along. He will probably beat me most of the time, but it will be a good to learn from him!
Send me an email if you want to chat about autocrossing our vipers...
Al Patterson

[Alan Patterson]

I just noticed you live in the San Diego area... I will see you there at the tour event in 2 weeks! Last time I was there (2006 Tour event) Scotty took first place in ASP in your car! I came in "mid pack" in my old '98 GTSR...
Al

[j-rho]

Hi Alan,
I see you've got Harold Olsen co-driving with you. Harold is a great guy and a fantastic driver, it'll be very interesting to see how he does in your car.

Unfortunately (or fortunately, depending on the point of view) Scotty swapped out those nice delrin-bushed arms for some stock arms before I took delivery of the car. Those bushings wouldn't be legal in Stock class.

I have found the car works quite well with the big front swaybar I put together. Remember, with the stock springs, shocks, and diff, (Stock class rules) we only have a couple things to work with.

I'll be interested to see how your car works in ASP trim, and how close you guys can get to SS times...

[SnakeInTheGulf]

Jason
Great post! I'm really rooting for ya! As a true novice that I am 4 events to date, and I don't like losing at anything, especially in a Viper, I'll be following your progress! Good Luck!!!
By the way what tires do you use?
Thks Larry

[j-rho]

I use the only competitive R-compound tire out right now that fits stock-sized Viper wheels, the Hoosier A6.

[j-rho]

So we finished the first big event of the year, the San Diego National Tour.

Life's been busy so I thrashed to get the stock diff in the car on Thursday night. That was a bit trickier without a proper ball joint separator, but I got it done eventually. The car had performed brilliantly with the racing diff in it, and I was hoping that because of the rest of the setup, that the car would be similar with the stock diff.

Boy was I wrong!

Saturday was a real mess. I had to stand on my first run, leaving me in fourth. A couple course workers said I was leaving the longest black streaks they'd ever seen at an autocross, on the track's two big (by autocross standards) straightaways. Where the car would squat and accelerate before, it was zinging the inside tire, and the off-camber sections made it tough to get the rear tires evenly loaded.

I started to get the hang of it on Sunday, and got a better feel for how to get the car to work. I went for a hail mary on my last run, and might have actually pulled it off but for a single (big) mistake. The class was slow overall, but overall I was pleased with the showing.

I'll be playing around with the diff fluid before the ProSolo in 2 weeks. Better lockup will make this car a TON faster. My first experimental brew definitely wasn't getting it done - the diff never locked up.

Results:
SCCA - Results

Couple pics, please no 4x4 jokes... :




Will report back in two weeks after the Pro!

[j-rho]

The ProSolo this past weekend went...okay. Still getting used to the car. The new diff fluid worked fine - it's still not nearly as good as it was before with the race diff, but the different fluid definitely worked better, and overall the diff felt like a regular viscous.

Biggest problem was I drove pretty poorly. In particular, I had no "clean" runs on the right course, and it's hard to do well when that's the case. Results:
SCCA - Results

I collected a lot of data with my DL1 data acquisition system that I can review and lament how much time I left out there. I also rigged up a very un-Viper-esque camera mount at the last minute that also served as a mounting plane for the GPS antenna.

Here is a "blooper" run, from Saturday morning. My front tires still had some crap on them from the previous event - plus I was still getting used to the course, which felt about 25% smaller than how it walked. I ended up overshooting a lot of things...

This video is from Sunday morning, similar temps but the course and tires were both much cleaner, and I was a bit more comfortable. This was a super conservative run, though in that conservation I managed to hit the first right-side apex cone after the start straight. Oh well...

I'll try to follow up with pics as they become available...

Oh, another blooper - this was my very first run on totally cold and dirty tires, a total mess. Look at how badly the GT3 kills me at the launch:

[SnakeInTheGulf]

hey Jason
A 4th and a 3rd is pretty good in a new car!!! Love the updates. How about picking off that Lotus Elise next event! You'll get that Porsche GT3 soon!
At least you have the Vettes down, I still can't catch the ones here in my local event
Larry

[SnakeInTheGulf]

Jason
Another question what wheel alignment do you use?
Thanks larry

[j-rho]

Front
Camber: -2.5
Caster: 6 degrees
Toe: 0

Rear
Camber: -1.25
Toe: 1/8" in

[rcl4668]

Jason -- congrats on your results thus far. Just a quick question: what would you recommend running as cold tire temps for a novice autocross? What hot temps should one be shooting for? The Viper in question has the Michelin Pilot Sport PS2 tires on stock size rims and no suspension modifications. The literature from the SCCA novice school recommends filling up all tires at home to the maximum sidewall pressure (which is 51 psi -- yoiks!--for the PS2s). I would rather not do this for safety reasons. Is this really nececessary as I will be bringing a compressed air tank to the event? Thanks for your help!

/Rich

[j-rho]

Hi Rich,
I don't know much about the PS2s, I've only ever had the old-school runflats or Hoosiers on my car. In any case, I don't recommend running those tires that highly inflated on your car, especially in the rear. I'd try something like 32 rear, 37 front. They'll go up a few pounds as you're running, but you aren't likely to notice the difference.

The SCCA recommendations were written with an "average" car in mind, the sort with really awful suspension geometry that gets around with skinny, high-profile tires.

[rcl4668]

Thanks for the recommendation Jason. I'll start with 36 cold front and 32 rear and see how it goes. I don't have a tire pyrometer yet so does the low tech approach of using a dot of white shoe polish at the sidewall/tread edge still work?

/Rich