RX-Ben

Trying to figure out where to start for TTA-

- 255 A6s allow 9 points for suspension mods (= could run single adjust coil-overs and sways or single adjust shocks, leafs, sways and have 2 pts leftover)

- 285 A6s would mean stock C5Z suspension

The 285s look to be about ~.3" wider per corner than the 255s when mounted on 18" C5z wheels. Doesn't seem like much wider, but all the adjustability that I gain with 255s is worrisome.

I was hoping to do aero, but the aero mods eat up most of the available points and don't leave anything to adjust the suspension accordingly. Unless '04Z shocks can accommodate a bit higher spring rates.

Anyone have a guess at how much a gain of 60hp and reduction of 130lbs will affect lap times?

ukrbmw

It seems everybody in SE is running 255s and enhanced suspension. Suspension setups vary pretty seriously.

Jason

In racing and the law, the answer is always the same:

It depends.

RX-Ben

That is really lame. After how many years and they still haven't they figured the best setup that we can all copy??

drivinhard

We are to the point where there is no do it all set up. Every track likes something different.

If you are going to a really short tire regardless, like the 285 or 255, I'd do the 255. The marginal difference in width is just lost in the sauce at the end of the day. You'll never notice it and you're getting way more back.

I liked the 255 at Road Atlanta in June/Aug, didn't like it at MO, scott didn't like it at CMP (but did well with it at Road Atlanta as well.) I didn't try it at VIR but Brian has run very well with it there (2:04.xx on scrubs).

sperkins

You won't know where you're at until you get your re-class from Greg. You probably won't be playing by the same rules as the rest of us.

travisnd

Car feels more neutral on 275s, pushes a little on 255s, but was overall faster running 255s and a 5" Blainfab spoiler. Car is much more stable under braking with the spoiler. Effective gearing with the 255s is great... noticeable difference from 275s.

That said mark set the new TTA record at VIR with 275s and no aero of any kind... like he said... it depends. I'm locked in to 255s for PTA/TTA now since I put Wilwoods up front for race duty.

RX-Ben

That rear wing is a points hog and seems tough to balance the front using 0pts.
I have noticed lately that stability under braking is wanting.

You guys are making my head hurt. At least true double and triple adjustables are out of reach points-wise.

JohnAlley

If you are running a Z06 you start with 7 pts, A6's add 13 pts go with 255 you get 4pts back, sway bar adds 2 pt that puts you with only 1 pt to play with. Not a lot you can do with 1 pt.

drivinhard

yeah scott got hammered on his reclass prop and the only difference in his car from a Z06 was gonna be an M6 and smaller injectors He had to run the car heavier I think and like 10:1 ratio. It will probably be an uphill battle with greg on that (and scott even had the correct Z06/FRC body, you don't - coupe has better drag cf).

drivinhard

A double adjustable is 3 pts as long as you don't have a remote canister.

Penske can build you a dual bleed shaft in their 7500 body

brkntrxn

He is running a base C5, so he has a ton of points to play with unless he gets a base reclass. This is the TTB C5 that won Nationals.

brkntrxn

Did you ever try the 255s without the ducktail spoiler? I still say your push is because you have some rear aero and zero front aero.



-Kevin

travisnd

255s actually get you 10 points back... 6 more than 275s.

Haven't done that yet... The push is only really evident at low speed where the spoile isn't doing anything. I think it's the low profile of the 255s making the front swaybar act like it's stiffer.

Should take the spoiler off to test one of these days.

drivinhard

we seriously need to send an email to hoosier about making some of the sizes that are avail now in R6, in the A6. if the molds exist, I can't imagine changing the compound in production would be that big a deal. The 255/40/18 looks interesting (a little skinnier than the 255/35 but proper height, might work well)

drivinhard

275s/T1 bars and 04 shocks is a good all around set-up, it's fast and proven and well balanced.

RX-Ben

Dyno reclass. Final #s pending but looks to be fair (i.e. ~z06).
I don't see a viable route from TTB* to a good TTA setup. When doing the math, I am at TTA+9pts after weight adj and tires. Still with base model suspension and power.

I found the Penske 7500s. Looks like a great way to empty my bank account and lead to frustrating weekends at the track. Sign me up. Anyone use these? A lot of the shocks I am seeing are inverted...1pt for that doesn't seem worth it.

yakisoba

I think the best one point you can spend is on an intake mod. IMO, of course.

I have a set of wheels for 275 R6 and a set for 255 A6. I'm liking the A6 so far, and have set a couple of track records in Texas with them. I run T1 bars and stock shocks. I've added a lot of lightness to the car too. Heh.

drivinhard

Scott has done it for years.

drivinhard

I run a SA 7500 with the 255's. I'm having a harder time getting a hold of the tire than the shock. The shocks were faster with the same tire (255) at Road Atlanta. I haven't tried them with the 275's yet. I ran them with some old junk 285 R2's during a thunder race in Aug, what blew me away was how consistent the car stayed (even on junk tires) and how little wear the tires got during 2 races. They probably have more advantage as a racing shock vs a TT shock.