Race season is fast approaching and I'm going to make some drive train changes in my 92. My first trips to the race track last year were both encouraging and disappointing at times. I really want to do away with the disappointing.

For those that don't know my combination. Engine mods are in my sig. The rest of the drivetrain/suspension of the car is pretty much stock. Blacktag ZF6S, Stock case/posi D44, suspension is dead stock FX3 with 70K hard miles. The car does have a 4pt roll bar, Fidanza Alum FW, Spec Stage 3 clutch, and currently a small pinion 3.91 rear gear.

So far it's run a best of 7.28@97mph in the 1/8th mile. My best 60ft on 315/35/17 MT Radials has been 1.80 with a lot of bog on a 3500-4500RPM launch. Times have varied a bunch with weather and traction.

There are 1/4 mile tracks in my "area" but they are a 60-100 mile drive. I've had some broken rear end problems this year already and with no way to get the car home other than drive it, I've stayed close to home at Old Dominion Dragway which is 1/8th mile and a short 10 mile drive for me.

I'm going against everything I know about racing, but I'm making a few changes at once.

The first thing I'm changing is the rear gear. I have a 4.11 pumpkin ready to go. I actually had this rear in the car 2yrs ago but broke it playing around on the street.... The 3.91 was always a stop gap to put miles on the new engine and one day I just figured I might as well see what it was going to do....

Second thing I'm changing out is the FW. I have a Steel single mass SPEC FW on order. It's like 24lbs. My Fidanza Alum FW is only 12lbs, so twice the rotating mass should help me with the bog problem on launch.

Third thing I'm changing is the front wheels and tires. Currently 17X9.5" A molds with 275/40/17 Summi HRTZ's. I'm looking at Race Star (old Greg Weld Company) or Centerline for some 17X4" and the M&H 6" wide radial drag tire. It's all down to what I think looks better. Weight is about the same and either way the wheels are $500 and the tires $300.

If this don't get me a 6.99 in the 1/8th, depending on where I'm getting hurt, I may look at changing the clutch to something that don't lock up as hard (launch) and/or changing my headers and going to a shorty 3" exhaust system (more top end pull).

The weather is getting better here so I'll be able to get in the garage and get started next week.
Will

The wheels and tires will be a significant weight loss. I also have a molds with dr's each front tire/wheel weighs 56lbs ea.(approx.), and the rears are more. The new rims fronts weigh 9lbs ea. and tire weighs 20lbs. Rears are 35ea. tire and rims are 16lbs ea.

rotating mass is a killer.

If you don't intend on streeting it much, then consider going from the 13" rotor down to a 12" rotor. Lighter! This assumes you have 13" rotors, but I thought they were part of the FX3 package.

Does your vette have the clear or painted top? The clear top is lighter.

If you want fast in a straight line, nothing says fast better than a 4 link live axle!

couldn't you have added some timing to help prevent some bogging? when my car was a 355 it would bog out of the hole with the 12lb flywheel. i never did any tuning to it aside from its mail order.

Andy
My car orginally had 12" rotors (I think) but I converted it to C5 Z06 brakes back in 2005.

I don't want to revert back to the small brakes. My vision for the 92 has always been a REALLY FAST street car. I don't want to make it into a drag car that I CAN drive on the street. The new 17X4" front wheels will be for racing at the drag strip only.

Same deal with the rear suspension. I know I could knock half a second off my car instantly ditching the IRS - but to me, it wouldn't really be a 92 Corvette anymore. When I go that route I might as well toss the 6spd and put a glide in it and go bracket racing.... Which would bring up the problems of why I've wasting my time and $$$$ to go bracket racing with a EFI, GEN II pump gas motor.

I want to be able to get this car into the 10's (on motor) with some expectation that it won't break..... I want to be able to switch out the wheels and tires, hook the sway bars back up and have some expectation that it will turn a corner and stop like a Corvette should. All while looking fairly stock.

Maybe what I'm wanting is too far out of reality but I don't think so.
Will

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Honestly I have no idea.

I paid someone to tune the car orginally. Since then I've made some pretty signifigant changes to the engine combination but never had it re-tuned (hell it's never even been back on a dyno)....

The fellow that tuned the car orginally is out of business and working for someone else now. It's a 3-4hr drive to go there.

I don't have the equipment to do any tuning/data logging ect myself. I have contemplated buying a portable wide band O2 just to see what's going on, but honestly.... Ignorance is bliss. Someday I'll look into getting the tune cleaned up.

Will

Will,

Ah, ok. The full vision reveals itself. I can dig that!

So, yes, backing down the brakes is counter productive.

I don't think what you are after is that impossible. Your ideas sound doable.

If you need thoughts on weight loss let me know. Mine currently weights around 2950 lbs wet, including about 150 lbs of steel in the cage...

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Sounds like it's time for a tune - I bet that would cut those times, too!

you could get an lc1 for about $200. if a tune is already in order that is where i would start. i will not drive mine without it being better tuned. i got way too much into it. machine work isn't as big of a deal for you but i couldn't even think about affording to start over.