14.10 ENGINE AND DRIVETRAIN
A. Oil pans and pickups may be modified or substituted. Addition or modification
of windage trays or crankshaft scrapers is not allowed. Engine oil,
transmission fluid, and power steering fluid coolers may be added or substituted
(including oil to coolant heat exchangers) but may not serve any
additional purpose.

 

The OS Giken prepared Corvette that Lugod drove last year just landed in my region:



The owner is still figuring the car out, but he's crazy fast already. He just ordered the 285/30R18 RE-71Rs for it, so it's only going to get faster from here. I'll just hope for rain at every local event going forward.


I'm enjoying the 265s so far, although I was surprised at how much the taller tires negatively impacted acceleration. Quantitatively it's not a huge difference, but I was slightly disappointed when I first went WOT in 2nd gear on the new tires.

 

What size were you running before? The 265's are OEM height...

 

most of us ran the 245/40/17, which is 0.6" shorter.

 

I drove a BS corvette with 150k+ miles that had a front swaybar and near end of life RE-71s at Crows Pro when I broke my car. That 150k means that many miles on shocks, bushings, engine... everything. While it was pretty dang soft, it was dang good. I was just learning the car cause I've never driven RWD more than an occasional car swap but I think that car would be a beast at Tours over the Evo.


At this point I don't know if a top evo would really stand up to a top C5 without a pro launch (basically a .6-1sec handicap). Maybe the Focus will come with a bit more something and get an AWD in the game but thinking the evo may always be fast and collect pro trophies but wont be the car to have for a jacket.

 

You are talking about C5 in STU, not BS. Right? Or you were thinking about both?

 

here's that thrust graph I put together last winter, it shows the impact of tire sizes on acceleration (Gs) for the different cars.

 

Well to be honest, I think both. S2000 will always beat the C5 in BS when power doesn't matter but when the C5 can stretch its legs that is a tough car to beat. I'm not sure AWD guys are gonna do it in BS at the top level.


Doug, wanna add an SM car to that for Sh*ts and Gr*ns?

 

Doug is right, the Evo acceleration response was good with the 245/40-17s. 255/40-17s are sluggish, and 265/35-18 are worse out of slow corners from falling off boost. As mentioned in 2014, the STU Evos really need 285/30-18s. When the Evo's were is ESP, the 285/30-18s were much better than the 275/40-17s.

Now with the higher grip tires that came out in 3/15, 2wd gained even more advantage than AWD, so this should've been taken into account with the tire proposal. It was not.

Construct, I feel your pain. The OSG C5 and STU champion 350Z are from my region, and I see how big the gap is to AWD with comparable drivers.

Conversely the STi seems to have picked up a lot of time with the 265's, due to lower gearing, more low end torque and less turbo lag. So this puts the Evo as the 4th slowest car in STU.

Now that more Evo owners are aware of the results, we need to ask for 285s for 2017, to even out the field.

 

here's another little chart I put together recently...

<link>

 

Another interesting thought on that, if we were allowed 285s the STI would likely be better\faster on 275s, better gearing, even more so than now. Taller would help them, wider would help us... then maybe we'd have parity with the sports cars (although, I'd still doubt it).

 

I still think 285s and one diff is the key

 

Dough, where would EVO X be on that chart of yours from above?

 

That is quite accurate! BS cars fit right in between S2ks and C5s. Perhaps, middle setting on two day event when each day favors one of those might bring things closer. Than it could rain too!

 

Is it legal in stu to wrap the charge pipe with heat resistant wrap?