I ran a local STU Prepped 350z this weekend at Mineral Wells. It was a mirror cross. So quasi-pro solo type event. Sadly, there were no other nationally prepared or nationally driven STU boost buggies to compare to. Scott's car is probably 90-95% prepped. His rates are a bit softer than BP's 350z car. And he's on 275 w/10.5's.

But holy crap was I impressed. Mineral Wells is known for it's gravely, abrasive and generally slick surface. Even running 1st heat, I was blown away not only by the grip. But the overall balance. This is easily the most well balanced autocross car I have driven in 10 years. Data shows consistent 1.15-1.3g in steady state corning. I was a little aggressive on the throttle exiting some corners. But wheel spin was manageable.

To be fair, I have never driven an STU evo. I drove my ASP car on 265/35/18 hankooks. And it never was happy. And I drove an STU STi back in 06 when I was still learning. Still, these are very impressive cars.

Jesus man! That looks like quite the ride LOL

 

Although, you could have too much spring for sure, most of that roughness usually comes from the dumpers. Once I switched to the top of the line setup, even increased spring rates all around made bumpy surface (like damaged concrete on North course at Forbes Field back than) feel like smooth asphalt!

Basically, if your shocks have too much low speed compression and not adequate high speed compression settings, any bump will affect your chassis tremendously.

Fedja

 

I know, there are a lot of factors that come into play and significant differences between the Evo and 350Z. My point was, until seeing Dallas J's very recent FS thread which mentioned trying 900/900, I couldn't recall anyone trying such high spring rates and challenging the thought that those rates would overwhelm street tires. Maybe others have tried it and I just haven't seen it or heard about it.

There are conversations which wax on about the huge grip of the latest crop of street tires and that they're getting closer and closer to R-Comps, but it doesn't seem like conversations on spring rate have changed.

I'm aware of and have huge respect for all the equations for car setup, but putting them into practice is well beyond my Liberal Arts Major. I take the approach of learning what to change and why, then testing and tuning to see how it works and how I like it. So it seems like if the tires are increasing in grip, increasing spring rate could be something worth testing. I'd try it myself and may eventually end up doing so, but I'm not at that point right now.

 

I also was very surprised how stable the 350Z was off throttle. If you watch the El Toro Pro sweeper finish. All 3 of the top Evos (Geoff, Me and Sean) were sideways after the lights at one time, then had to go WOT in the marbles. The Evos would have been dead on that course, if there were any slaloms to upset the car.

Interesting to see the 350Z in action vs the 2-3? time STU ProSolo champion.
While it's still up on Ustream, happens in the first few minutes:
http://www.ustream.tv/recorded/46122680
I like Kevin Dietz nickname for the 350Z on 285s - "BigFoot"! Also see the 7 time Japanese Gymkhana champ that Cusco flew in to drive their STi, nice guys.

 

Toledo registration is open. Better hurry

 

See you there Butt.

Wish you and your brake lines luck this year!

 

I was thinking about the tire width issue for STU AWD cars and one think popped up that could make things a bit better for all - allowed tire widths related to the weights of the car.

I am sure they would penalize AWD cars a bit more for unfair advantage, but as long as that increase is not insane (perhaps 10% or 10 mm or anything else that makes more sense compared to the RWD guys). That would make it more even between the different cars and it would allow some heavier cars to get into the game as well.

Fedja

 

Anything weight-based becomes messy very quickly. You'd have to either trust everyone's self-reported vehicle weights or be prepared to weigh vehicles on site in the case of protests.

Plus you'd require competitors to either guess at their weight or find accurate scales to use before they can figure out what tires they can run. That's a bit excessive for a street class.

 

I could not agree with this statement. On any National type event scales are always there. There are other classes that already have similar weight requirements and all of the cars that are in trophies (plus some more on the first day) have to be weighted.

The fact that STU (or any other ST class for this matter) are on street tires does not make them any less worth compare to others on race tires instead.

As of guessing, there is no need for that. We pretty much know what people run with for our own classes. Google is there to give us pretty close info for most of the cars, so I don't think that would be an issue.

Fedja

 

If an already limited prep ST class had weigh in to determine tire size, I'd be gone from the class in a heart beat... and I'm no light guy....

good luck to the nj and mineral wells folks running this weekend.

 

That failure in 2012 was kind of a blessing I guess... I had spares with me at the ProFinale when it happened. It did screw Corey out of getting all his runs, though I guess if I get to Toledo fast enough I can stop by Toledo Hoses Direct and thank them for staying open at 4:30 on a Friday and making a brake line, when a lot of businesses would probably have called it a day.

 

STU friends, we're selling a few go-fast things, including our spare set of CIRO camber/caster plates, spare hub assemblies, spacers and a few other things... if you're interested, here:
https://www.evolutionm.net/forums/no...l#post11210818

 

FWIW, Buttdyno's car easily out powers my BSP car in a straight line, and my car makes considerable more power than BP's car (and is probably 100+lbs lighter). 350 is well suited to STU, you can fit 18x11's and 285's without any drama on all 4. E46 and C5 should run well in STU trim as well. Also, BP runs a lot of spring, in fact it is about the same as I run on the BSP car. I don't think that set-up would work all that well for the right coasters, sans Toledo and Wilmington.

 

Hmmm, ok. Given this logic it would then seem reasonable that the sti/evo would be a better fit in STX.

 

It wasn't until I got aggressive with ride height that I had to start cutting things on the BSP car. Hell, the rear has just a hard roll and a light flare (pushed the lips up/out a bit) to make room for an 18x12 with 315.