JerryTX

I race a narrow body C6 in NASA Texas ST1 class. IF I had money to burn, which mod do you think would be the best one to spend on, and what kind of lap time improvement do you suspect I would see?

1: Trans/Diff: Today, I run stock 06' C6Z06 T56 trans and diff with the stock gearing in the T56 and the stock 3.42 ring gear in the diff. Upgrading to a ZR1 spec close ratio T6060 and a 3.73 rear diff: COST ~ $8K for parts.

2: Widebody: Today I run 305mm square slicks and there is NO more to stuff any wider a tire under there. If I add a Z06 widebody fenders and quarters, I expect I can almost do 335mm square! Parts, 3 sets of wheels, install and paint... COST: ~ $8K

3. Aero: Today I have a Z06 nose, ZR1 splitter and spoiler, homemade fender vents, belly pan (to front axle), and a vented hood. The hood/belly pan did help with front end grip, but a true 4-5" plywood splitter (under the ZR1 splitter) plus a good wing mounted to the frame (likely LG's) for the rear. Home install: COST: ~$5K

So vote for which one, and how much laptime improvement you think I would see, and then add any other random food for thought I should put in my noggin. I will add that today the car is pretty maxed out, at the previous 455rwhp (50 under the ST1 max) I was driving it at the limit and sliding everywhere, always waiting to apply throttle and dancing with all the controls. I'm sure a pro would get another second out of my car, but there is not much to be gained. I have since had to rebuild the LS3 and I am now of course AT the ST1 max of 505rwhp and about to test it for the first time this weekend, I'm guessing I'll be wishing for all 3 options by lunch time Saturday. Thx!!

Jerry

Supercharged111

I'll venture an uneducated guess that aero would have the largest impact followed by widebody then trans/diff.

redtopz

I would start from the ground up and go with bigger wheels and tires first. You have enough power that gearing is less important to lap times. So aero would be my 2nd step. Then I would do race clutch, tranny, and diff. However, if your clutch and diff are not up to the task right now I would upgrade them before aero.

96CollectorSport

Widebody hands down would make the most improvement right now, if the car is dancing all over the place and you have to wait to apply the throttle at 455 rwhp what do you think is going to happen when you add more hp?

Aero only will help you on faster turns, more grip will help you on every turn.

ratt_finkel

Aero.

Also, no reason to keep the tires under the fenders. Although aerodynamically inefficient. The tires can stick out beyond the fenders.

PS. I think you can do aero for much cheaper than 5k. A sheet of alumalite is under $200.

zigspeed10

What shocks springs and sway bars are you running? Saying that you are dancing with the controls and sliding all over the place sounds like you might have a problem with your setup that could be fixed with some tuning. What are your camber and toe settings?

Is this on fresh rubber?

21STCENTURYMUSCLECAR

1) Fresh/top quality slicks will make more difference than the width of the tire and the more frequent you can change them the better but $$$

2) Aero

3) I put a 6060 and changed my gear and on some tracks it made more difference than others but its nice to have taller low gears and shorter upper gears, especially at a track like TWS or COTA

John B

Bigger tires

JerryTX

Camber is -2.5 front, -1.5 rear 0 toe front -1/4 toe rear, always scrub slicks. T1 bars and LG G2 coil overs. The handling is actually really good, it is just at the limit I can induce understeer or oversteer at will, both ends are out of grip.

Clutch btw is a Quartermaster 7.25" triple with pressure plate so the whole thing weighs 16lbs. The trans and diff are stock minus the clutch.

I know fresh tires would probably net me 1.7 - 2.5 seconds which is huge. But at $1400-$2200 per weekend (R6 or Pirelli)... I'm racing for plastic trophies. A season of scrub slicks SAVES me $8000 year (8 events/year). I could run fresh slicks all year, do great, but the car would only be faster on fresh tires. I would rather take that $8000 saved and put it into something that provides a solid improvement (over the current config) that stays with the car. I'm CHEAP, I know... !

With the car as low as it is, having the tires stick out of the fenders is not an option, they would get cut down

zigspeed10

Sounds like you are at least in the ballpark on setup. Something to consider on the G2's is if they are the short bodies you will need to use spacers to get the ride height up high enough. Also the bump travel on them is limited so you could be bottoming out the shocks and not even know it. Great shocks by the way, that's what I'm running now.

If you are racing for trophies how about race for free tires with the Hoosier and BFG contingency. Sticker tires will probably be worth more time than any option you listed.

If you have to choose one of your options, I would go with aero. I know some others have said bigger tires but I come from the crowd that runs on little 275's and make them work. So a 305 is not a small tire, it may not be optimal but it's enough tire.

Another thing is that real aero will transform the car. You will really notice the car is different where bigger tires won't change the car much. What you will notice the most with bigger tires is that it's easier to put power down out of slow corners.

JerryTX

Great points:

- Yup, already added spacers in the rear to regain bump travel, it was bottoming out. The shocks are really really good!
- Contingency would likely save me $250-350/weekend
- Good to hear your feedback on the difference in wider tires, thank you!