Z06 Fever

Some of you guys may think this is a stupid question, but I'm going to ask it anyway. I am currently in the market for a C4 (85-90) that I can make a dedicated autocross and HPDE car. I have autocrossed a 96 auto coupe and an 02 Z06, hence the desire for a manual car.

I'm wondering if there are any of you C4 guys out there running 4 speed cars. My problem is basically budget driven. I don't think I can find an 89 or 90 6 speed car within my budget. I can probably find a 4 speed car though. TIA for your input.

rasrboy

What is your budget? You may just find a good C4 car already done for HPDE or autocross. Stay with the 6 speed though, cause the 4+3 is weak for racing. Here is a link from this forum on one for sale at a very fair price.

RED 1990 6-SPEED AND TRAILER 4-SALE. FOR DETAILS LOOK IN http://s125.photobucket.com/albums/p79/red90l98group2e/

Race Prepared

4+3 is not suited for racing - not to mention the shifter. I would look at the 89 - 91 6 speed L98. The L98 makes alot of torque and those year models are less expensive. I currently race an 89 and with the suspension setup have defeated "faster" cars on many a Saturday afternoon. There are several race ready cars for sale in the forum - but you can always look in the local auto trader or ebay and find something. Just take your time...

Barbara_S

I have been autoXing an 88 (4+3) with a z51 suspension and the car is really well balanced and nimble. The 4 speed is fine, you shift to second pretty early autocrossing and then just go . Everyone loves the 6 speeds (and I have one of those now too) but I don't think I ever lost time from the 4+3 so I would not hesitate to consider it if the car you find is the right price. I bought a ZR1 for faster stuff, I just re read your post - I have no comment on the 4+3 in HPDE events, just autocrossing.

Bill Dearborn

I agree on the autocrossing that a 4+3 is not a problem. However, at an HPDE you run of gear quickly. A 4+3 car has a 3:07 rear and with the power curve of the engine dropping off so quickly beyond 4300 rpm you will see about 125 max in 4th gear. I used to run an 86 4+3 at various HPDEs at Pocono and Watkins Glen. The North course at Pocono was no problem but anything longer and the car just sat at 125 and that was it. This was with a 5600 rpm rev limiter. At Watkins Glen I used to run with a guy who had a 90 6 speed and I could follow him from Turn 1 (the 90) through the Esses (Turns 2, 3, 4) but he would leave me going up the back straight. When I asked him how he was pulling away from me he just said 5th gear.

To get the next higher gear over 4th you would have to downshift to 3rd while hitting the overdrive button to get 3rd overdrive. That gets a little tricky since if you don't do it right you are going into third and will have an exciting event to talk about.

Go for the 6 speed if you are going to do HPDEs at high speed tracks otherwise you will run out of gears.

Bill

rudyarias

mrc24x

I think Bill summed it up nicely. I was in your shoes about 18 months ago and I could only afford the '88 w/ 4+3. It was fine on the track but I had to spend a lot of time adjusting the shift linkage to make it tolerable. The 125mph wall happens pretty early down the backstretch at Mid Ohio so needless to say I am swapping in the ZF6 as we speak.(type?) If you find a 4+3 car for the right price don't be affraid of it but just know that you may be shelling out 2-3 grand for a 6 spd later if needed.

** yes, the link that Racerboy provided looks like a great deal. Aaron, is that your new car in your avatar??

rasrboy

Hey Matt,
Yep, thats the new (To Me) 2003 T1 car I bought from Jeff Robbins out of Detroit. I am going to try my hand at some regional and national events this year and get my butt handed to me.

Hope all is well with you and the vette. I am in the middle of swapping the tranny in the red vette aswell to a ZF. I pulled the Richmond 6 speed roadrace tranny out that has a bad syncro in 2nd.

Aaron Quine
2003 Z06 T1 Corvette
#21 Kumho Tire,RSIG
rasrboy@hotmail.com

96LT1

The $3 grand is closer to the real number. Flywheel, clutch, pressure plate, drive shaft yoke, clutch slave and line all have to be replaced. I did the 4+3 in my '86 for 3 years at BeaveRun, VIR Full and North, Summit Point and Mid-Ohio. The 125mph wall with 3.07s is a fact that you will face at each one of those tracks.

You do need to be aware that the ZF6s do have problems with synchros as they get miles of hard use on them. ...and the cost to get them rebuilt is prohibative.

Red5

And don't even think about buying a 4+3 and switching out to a 6 speed. Been there.. What a PITA with little return.

Z06 Fever

Thanks for all your input. Y'all covered pretty much every one of my concerns / questions....right down to switching out a 4+3 for a 6 speed later.

It sounds like my problem is my budget. I saw the thread for the prepared car for sale and if I had that kind of money I'd be all over that deal. I'm looking spend about $4K. I have a feeling that it's going to be really hard to find a 6 speed car for that kind of money, right? I understand that I'll end up with a car that might need a little work before I take it to the track, but that's okay. I'm willing to do that. It's a little weird to go from looking for a near perfect car to looking for one that has bad carpet and stuff like that.

So if I understand correctly, I shouldn't get a 4+3 car and swap out the tranny later? Too much work? Are there any other suggestions that you guys might have?

stairman

If you can afford a 4+3 car for now then get it. No it is not to much work to convert over to the 6 speed later, if you have some good wrenching skills it is pretty easy. Heck switch over an auto to a 6 speed aint that hard either, just a weekend project. I would not recomend the auto for track use though. Get what you can and work on it later, going to the six speed just takes some bucks.

RAFTRACER

4+3 to 6-spd conversion will also require some fiberglass work....

96LT1

Two things...

1. How much experience do you have doing HPDEs? If you are just starting out HPDE Novice then a 4+3 can get you through the first year and maybe the 2nd depending on how many events you attend.

2. If you spend $4K on a 4+3 car then do the swap yourself later you are probably talking about $7K plus what ever you put into the car to get it ready for HPDEs and track expenses. Hotels, entry fees, tires, pads and rotors can get a little expensive.

You can probably pick up a 6spd car for ~$6K now. So the questions are; when do you want to spend the money, how handy are you working on cars and what are your expectations / skill level in being able to push the car to the max?

Kanmer

I had an 86 with the 4+3. went to one HPDE at CMP and went out and bought a C5 MN6 Z51. Thats just me. I wuld try to stay way from the 4+3. THe 4 speed side is bullet proof but the overdrive side is made of tissue paper I think. Just my .02

Bob

Z06 Fever

I've done one HPDE so far, but I did it in my former car (02 Z06) that I also autocrossed for 2 years. I plan on attending several track events per year...schedule and funds permitting.

You bring up a good point. The $4K number came from the fact that I can spend that without having to try for some sort of financing. A feat that would be nearly impossible for a car of that age I'm sure. But I also understand that the only things the $6K car (barring any major issues) would need is the items to get it track ready. Total investment may be the same in the end, just take longer and be more work with the cheaper car.

I'm pretty handy with the wrench and am willing to learn a lot more. As far as driving skills...I always think there is room for improvement and I want to build a car that will allow me to push it to the limit.

BrianCunningham

1st, I've got the ZF 6sp and I love it.


Could you but a solid shaft into the OD case? Then run a taller gear in the rear to take car of the 125 barrier. Of course, if you change intakes ( miniram, superram or modded LT1 ) the engine will rev past 4200 quit easily.

c4cruiser

From some previous posts I have read, the OD portion of the 4+3 does like being used at high speeds especially when it's used for downshifting. As long as you don't upshift/downshift the OD, it should live for a long time assuming you follow a good maintenance schedule of flushing the fluid every 12K or so and installing a new filter. Use Dexron II/III and it should be fine.

The shifter is not great but if you're careful and don't shift like you're on a drag strip, the shifts can be fairly quick and positive. The short shfit arms will help some but the key is proper adjustment of the linkage and no slop.

The 125-128 MPH limit can be an issue depending on the track and length of straights. When I do track days at Portland and Seattle, the straights aren't really long enough to see much more that 125 in my 87. Even with a mild cam and some internal mods I have, the 3.07 rear is the limiting factor.

I can hit 5600RPM in 4th (128MPH) on the long straight at Portland but that's the upper limit. The other limiting factor for me is the stock-size 87 brakes. The stock rotors are only 11.5" and I really have to depend on the right pads to help with braking. Until I spring for some sort of big-brake kit, I'm going to have to be satisfied with the way the car is set up now.

Kielser make a T56 5-speed version that's a bolt-in as well as the Richmond Gear 6-speed that will bolt in. The Richmond comes with a shifter but some cutting of the tunnel is necessary. Figure on $3500 for a tranny and a new clutch would certainly be advisable at the time the tranny is out. But a rebuilt OD unit can run to $1200 and if the 4-speed portion needs work, figure another $700-900 for parts.

Z06 Fever

After reading all the replies it makes me wonder how the guys who raced the Challenge cars in '87-88 did it with the 4+3! That must have been interesting.

I'll just have to keep looking and hope that a car comes along with the right price and the right stuff. Even if it means I have to get a salvage title car. I mean it is going to be a dedicated track / autocross car so it doesn't really matter. Decisions, decisions...

sothpaw2

I loved my ZF 6spd too, much better than the T56 in the Z06. I probably should have kept my cash and just got another 1993-96 with ZF.