sydneyACE

Hey everyone!
I've been reading lots of threads here on the NASA TT and PT classes, but haven't found anything for a C5 (non Z06).

I have a 2001 C5, DAILY DRIVEN, street car.
I have been doing HPDE events locally with the PCA in my area for a few years now. (Somewhere around 7 events or so.)
Unfortunately here in Montana, there isn't anything in the way of roadracing... at all...

I was thinking if I didn't have to travel too far, NASA TT would work pretty well for me. I've been looking-at the Utah and Rocky Mountain regions. Rocky Mountain seems to do all there events in Southern Colorado and New Mexico. I really don't want to travel that far for now, so I think it will be Utah. It looks like the Utah region only runs at Miller which is only about 6 hours from me. (Would be sweet if they started running in Spokane too as that is only 3.5 hours from me.)

Anyway, on to the questions.
This is what I've figured-out so far:
My car is a TTB +7, so by my calculations, if I want to get it to the limit of TTA, I have 32 points left to work with right?

39
-7 Base penalty for C5s in TTB

32
-13 For A6s. Based on my reading A6s are pretty much the only way to be competetive.
19

So basically here I am with 19 points left right? Now it seems everybody who wants to do it "right" will keep the class tire-size (or even drop sizes) and spend the rest of thier points on weight-reduction right?

That makes a lot of sence to me as dropping weight is pretty-much the #1 thing you can do to decrease lap-times. (Besides seat-time of course.)
Problem is, as I said, This is my daily-driver, and stipping/gutting it just isn't an option. I think I will have a VERY hard time even getting to the minimum.

Since pads, ducts, rotors, etc. are free, I think I'm good in the brakes department with Carbotechs and SS lines (which I already have).

I was thinking the best thing I could do is spend the rest of my points on tire-width and power. Maybe if I'm lucky I will have a chance of getting to the min wt/pwr ratio.

I have a Cat-back and no cats so there's 3 points right there.
Down to 16.

The best way I can think-of to get close to the wt/pwr ratio is with a cam for 6 points. Now I'm down to 10.

In my mind the best thing to do with the last 10 points is tire-width to help my heavy car.

Anyway, this is becoming a long post. (I always seem to do that.)
What are you guys' thoughts?

Am I basically "Wasting" my time AND $$$ because I'm gonna get my a$$ handed to me unless I gut my car?
Obviously it will be fun regardless, and more experience never hurts, BUT I would really like to be competetive too.

sperkins

Correct.

Kinda sorta. The problem is 13pts is the hit you take for your base class tire size with the A6. TTB base tire is 265mm. You can't get an A6 in a 265. So you have 2 choices if you want to run A6's and still have points left to play with. Go smaller or go wider. There's a new rule this year that states the 255 Hoosier will be treated the same as a 275 due to it's actual width. So you can't go one size smaller to get any benefit. That leaves you with either running a 245 (or smaller if you're really brave) or running the 275. That being said, a 245 will cost you 9 points and the 275 will cost you 14 points.


Not necessarily. You have to have some idea of your competition weight before you begin. In TTA (In most regions), you'll get murdered with stock suspension and a light car. You have to remember that the ZO6 base weight is 3118. You'll gobble up a lot of points getting that light (which it sounds like you can't anyway).


Probably not a bad idea if you can't afford to shed weight.

It depends on the region, but in most cases - probably.

That's what it's all about right?



For what it's worth, I have the only non-ZO6 C5 in TTA that I know of (I'm sure there are others). I've built my car to be competitive so it can be done. It takes a lot of time, energy and money to build a front running car these days. Long gone are the days of being able to win consistently with a basically stock car.
Good luck!

Z06Tracker

Scott is being modest. He has more than a competitive car. take his advice.

AU N EGL

DAMN some one "actually measured" the Hoosiers

sydneyACE

Thanks for all the advice Scott!

The idea on the tires was to take the initial 13 point hit for running the A6s. Then use 7pts to run a 295. Which should leave me 3 points.

Maybe use 2 points on headers or a sway-bar? I dunno.
I see lots of builds have used aftermarket sway bars. Do they really make a big difference? If so, it would make more sense to use 2 points on that rather than headers because I think I can make enough power without headers to get to the minimum wt/pwr ratio.

I replaced my factory crank-pulley with a one-piece too because the stock one seperated on me. It's factory diameter, will they hit me with a point for that?

Help me with the wt/pwr ratio if you would please.

If my car's curb-weight is 3250 and I weight 150, my weight would be 3400 with a full tank. Obviously I wont have a full-tank after a session.
My car should weigh about 3125 with no fuel plus 150 for me = 3275 + 25 pounds of gas (around 3-4 gallons left after a session) = 3300.

Not bad! That's only 50 lbs over my min. IF my competition weight ends-up being over 3300lbs I get an extra .05 on the wt/pwr ratio right?

So the base-limit is 8.7:1 and if I'm weighing-in between 3300-3350 with 295 tires I will have an adjusted limit of 8.65:1. Which means I should be able to run up-to 381hp right? The .05 adjustment is only good for a whoping 2hp lol! To be safe I would want to be-sure I was at less than 375hp.

Anyway, my post is gettin rediculously long AGAIN... Sorry...

BTW I'm looking to run-in the Utah region which is brand-new this year. I probably wont do any TTs this season, more-likely next season. Do you guys think the competition will be very stiff in the Utah region?

drivinhard

I wouldn't use 6 pts for a cam, that's a lot of pts

you can get rid of a lot of weight pretty easy/quick (small battery, fan swap, passenger seat, headlight delete). All can be put back to stock in a matter of minutes. 100 lbs is not hard to knock off pretty easy/cheap

sydneyACE

Thanks for the advice. Look at my calculations in the post above yours.
If I did everything right, I should be at around 3300lbs. If I can loose 100 as you say that would put me at 3200. That's 50 lbs under the limit, so that's 4 points. You think it's better to use 4 points and be 100lbs lighter? Or were you recomending I get to minimum then use the 6 points saved from not using the cam for something else?

I'm just speculating here so don't think I'm trying to argue with you because you have way more experience than I do. I just ask questions to learn.

If I was 3200lbs and say I'm at 310rwhp with my exhaust (and if I added a CAI), my wt/pwr ratio would be 10.32:1.

If I could make 375rwhp with a cam and the car still weighed 3300 (I think I can get it down to 3250 easily enough after your examples), wt/pwr would be around 8.8:1-8.67:1.

I think the cam sounds really appealing, but I don't know a lot about it. Do you think it's possible to get to 370-375rwhp without a cam?

What would you use the 6 points-on that would really help?

Thanks for all the advice guys!

sperkins

20pts for 295's just isn't worth it - been there - done that. The 275 is a better tire in my opinion. It just feels better and it's only 14pts.

I use 8 points (125lbs) to get my min comp weight to 3121. It's worth it.

You can't do headers for 2 points because no header will connect to the factory mid pipe. That being said, any header will be a 5 point mod. Don't bother with shorty headers.

Stock LS1's can make decent power with long tube headers. My tired old LS1 makes 350hp/350tq. Those aren't great numbers, but they're not horrible.

Use 2 points for sway bars. Yes they are worth it. Especially since you have puny stock bars.

Get some '04Z shocks and any year ZO6 or Z51 springs.


If I were you and I didn't want to gut the car, here's what I would do:

TTB* = 7
275 A6 = 14
T1 or Pfadt bars = 2
Springs = 2
Shocks = 3
Headers/Exhaust = 5
Weight = 6pts for comp weight of 3,151

Free mods:
Pfadt poly control arm bushings
Shock bushings
Track alignment
High flow stock style air filter
2pc rotors front and rear
Tune
etc...

redtopz

Sounds like a winning setup!

Jason

For a street car you probably wouldn't want a 5" clutch some guys are running, but you can most likely live with something like a Spec w/aluminum flywheel. No point mod and well worth it.

brkntrxn

Sway bars are worth it at some tracks. However, the National Champion TTB car was a C5 on stock sways. So it depends on your driving style and what your competition has.

Here is my Z06 car on stock and Pfadt bars. I have better pictures that show the difference more dramatically, but these are hosted and easy to get to.


Stock sways -- Oak Tree at VIR on A6s, hard right hand turn:







Pfadt -- T14 at CMP on A6s, hard right hand turn.

z06801

If your coming to Miller they have a series there that is called Lap battle
and its more of a "run what you brung" it is as simple as AWD, RWD, and FWD and street or race classes in each based on tire selection 140 and up is street, below is race and its cheap 225.00 for the day and they have a test and tune on sunday the day after for 150.00. It is a great way to get on the track and learn it. I hope they don't change when NASA takes over the MPRA this year.

sydneyACE

Thanks for the pics! Very pretty. The difference is dramatic to say the least. The stickiest tire I've ever run is a Potenza RE760S 265 up-front and 295 out-back. I know everything is going to go out the window once I put A6s on-it. You said it depends on your driving style. Can you elaborate on that some? Which driving styles favor which set-up?

I probably wont have the $ to run at Miller this year. Our track-day here in MT is $90 for the whole weekend. It's no MMP but the track is very nice (new pavement) and the PCA puts it on, so it's very well organized.


I'm not sure what NASA plans on doing this season, but based on their schedule:
http://nasautah.com/?page_id=10
It looks like they have "Time Attack" listed.
I don't know if they will be instigating any TT/PT stuff or not.
Maybe you could give me some more info about "Time Attack" or is there a site where I could see the rules?

Thanks Guys!

brkntrxn

In my opinion, a smoother driving style can get away with having softer sway bars. If you are jerky with the inputs on the steering wheel, soft sway bars will have the car rocking from side to side. Same thing goes for the track layout. If the track has all sweeping turns, then the softer bars will be ok because you are not making quick left-right or right-left transistions. Which is where a stiffer bar will help control the weight transfer from side to side.

sydneyACE

I'm told I have a smooth driving-style. If I assume I'm running at Miller all the time, there are very few quick transitions, and lots of sweepers. I'm gonna do some more math/figuring and see where I'm at. If there are two points left-over, then bars are a no-brainer. Thanks for the advice.

z06801

I probably wont have the $ to run at Miller this year. Our track
It looks like they have "Time Attack" listed.
I don't know if they will be instigating any TT/PT stuff or not.
Maybe you could give me some more info about "Time Attack" or is there a site where I could see the rules?

Thanks Guys![/QUOTE]

this is Lapbattles web site
http://lapbattle.com/

sydneyACE

So much good info! Thanks!

That looks like a good combo for sure.
I don't know if I will get weight that low though. (What did you have to do to get there?)
If we assume I can get 100lbs out by running a light-weight battery, removing the pass seat, and maybe taking-out the headlights then...

3250 (curb weight)
-125 (no gas, I figured 18 gal x 7lbs)
3125
-100 (batttery, seat, etc.)
3025
+025 (3-4 gal of gas left after session)
3050
+150 (with me, I guess being "skinny" all these years might actually pay-off)
3200 = 4 points

39
-7 TTB +7
32
-2 Cat-back (on my car when I bought it)
30
-1 No Cats (stock ones fell-apart so I gutted them)
29

This is currently how my car sits as far as I can tell. This is assuming I wont get docked any points for having an aftermarket crank-pulley. (It's factory diameter not under-drive or anything. The factory one seperated though.)

Variables I can work-with:
-4 3200 lbs
25
-13 for A6s (do you think I can get-away with anything else?)
12

Let's say I have 12 points to play-with right?
If I can get to 3200lbs that means I will need at least 360hp to get to 8.7:1. I'm really concerned I can't get that much HP out of my tired old LS1 with just cat-back and cat-delete. Headers MIGHT do-it for 2 points, but we're talking $1000 there (obviously less if I can get them used). Right now I'm pretty convinced a cam is the only thing that will get me to 365RWHP. I dunno, I could be wrong, please let me know if you think so. You said you got 350 out-of yours, was that with headers?
For now, I'm kinda hung-up on the cam thing, plus I wouldn't mind having one for the street.

12
-6 Cam (The other cool thing about a cam is, you can upgrade the rest of the valvetrain without more points. Upgraded trunions on the rockers, "CTSV" lifters, pushrods, beehive springs, titanium retainers, all sound very apealing. With a valvetrain like-that I could maybe get-away with 7000rpm too which would prob help a lot with gearing.)
6
-2 Sway bars OR springs. (Which do you think would be better?)
4 Left
I could run 285s (Very appealing cause 3200 is kinda heavy, and I would like them to last. BUT would 285s fit on the front??)
or I could use the last 4 points for shocks and 275s as you recomended. (Shocks are more $ but then again, so Is a cam.)

Jason

I think swaybars are worth the 2pts.

PushinTheLimit

I just don't think getting a cam to run TTA is really going to get you where you need to be in TTA. Its alot of points that could be better spent elsewhere. Shocks, springs and swaybars will be much more beneficial than a cam package. The 275 Hoosier A6 just works so well and the C5 Mafia have proven this many times. Its better to lose more weight off the car to get to 8.7 than it is to add power with a heavier car. But afterall, that is the beauty of Nasa TT... it welcomes different ideas and platforms if you chose not to take the well-beaten path.

To be nationally competitive in TTA... the bar has been raised to where it would be difficult to podium with a daily driver/street/track C5 without alot of the creature comforts gone. Regionally could be a different story where you're at.

Also, a C5 can run a 315 wide tire in the front just fine so anything less than that works as well.

SteveDoten

Stock sways -- Oak Tree at VIR on A6s, hard right hand turn:




tire looks like it's peeling off the rim, great pic