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Converting a Z28 to track car - future race car?


ffspecracer

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I have an old Z28 sitting and rusting. With the new Bluegrass track so close to me, I'm considering making it a track car and not dragging the race car down every time I go.

 

It is an automatic Gen3 '87 5.0TPI. Engine has been modified slightly. So I need to switch it over to manual. A couple questions.

 

1. What tranny is recommended, fits and would be legal if the car ends up in CMC or AI?

2. Can a clutch pedal be addted to the stock footbox or do I need to look for a complete manual footbox?

 

I know there are other parts needed but this is just to get me thinking.

 

TIA

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What year Z28 is it? My guess is a simple T5 swap would work fine. The Auto and Manual Footboxes would be identical, as I am sure GM wouldn't make two different chassis for the two different tranny choices. All you need is a manual pedal (brake and clutch) setup and you are good to go.

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If it's a 3rd gen (82-92) then you need the T5. If it's a 4th gen (93-2002) you'll need a T56 with different hyrdaulics depending on whether it's a LT1 or LS1 engine.

 

The T5 will be weaker than the T56's.

 

Knowing the generation and current modifications would be helpful.

 

CMC is the best starting point if it is relatively stock.

 

AI is the next step if it already a bunch of mods.

 

PT is the catchall.

 

I have run all three classes in an f-body.

 

I have owned one or two f-bodies continuously since 1983. I started autocrossing in 2000, tracking in/around 2002 and road racing in 2004. Tell me what you have and I think I might be able to assist.

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Thanks Keith and Mike,

 

It is a Gen3 '87 5.0TPI. Engine has been modified slightly. Don't know the exact HP numbers but should be approaching 300HP.

 

Like I said, it is going to be a track car at first. Hard to run 2 race cars when both classes are on the track at the same time.

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The mods might be a problem for CMC so let's assume AI.

 

The car as it sits needs a T5 (you knew this, I'm sure). I would recommend an aftermarket T5 within the AI ruleset. You may find that this will be cost-prohibative. In this instance, you might want to sell the car and get a similar car for the $$$ with the T-5 already in it.

 

Otherwise, you could figure out where all that power is coming from and return the car to CMC (stock-ish) trim and continue with the auto-to-manual conversion. I am unaware of anything 3rd gen motors making that kind of power, including the L98 motor (huge torque, low hp - I had one of these). Lord knows that the 3rd gens can be exceedingly competitive in CMC.

 

Just one man's opinion, I suppose.

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If it's only going to be a track car and the motor is fairly stock, I think you'll be fine with a T5 in the car. CMC cars seem to do pretty well with T5s, but AI cars like to kill them. You'll have to find pedals from a 5spd car to get the setup to work. I've heard that 4th gen pedals work also, but never tried it myself.

 

Unless the car has huge mods, like cutting out the radiator support or the roof, it'll be easier to de-mod to CMC specs then to move up into AI unless you want to spend more money and do more work. T5s and 10-bolts don't like to hold up at AI power levels and you can probably sell the 350 and pick up a 305 for free to build a CMC motor.

 

As far as 3rd gens go, there isn't much difference chassis wise unless you build closer to the limits of the rules (gutting, tying the cage into the body, etc.) We still run stock A-arms and stock style springs up front in AI, and the rear is pretty simple and works for AI or CMC.

 

Don't get me wrong, I like running in AI, but to run AI in an F-body you have to not mind making your own parts or doing fab work yourself. There isn't anywhere near the aftermarket that there is for Mustangs.

 

I'm sure my fellow Midwest region Firebird brethren will be in here soon enough to add in anything I miss.

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He should probably keep the motor and just do a T5 swap. Put it on a chassis dyno and find out what it's really making, because I highly doubt it's anywhere close to 300RWHP, but depending on the mods, it might fit into CMC-2 also. I have a mechanical linkage 3rd Gen T5 bellhousing (1 year only I think) if you decide to go that route. Otherwise I think the later hydraulic clutch parts are more common.

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My humble opinion. Sell the automatic car and buy an existing car already set up for the track. The time and money spend doing the swap won't be worth the effert. Take that time and money and put it toward an existing track car. There are many race and/or HPDE cars available at this time. Check NASA forums, racingjunck.com, ebay, frrax.com, and many other race car and/or Fbody sites.

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Having been involved with Team 309 and many F-body racecar builds...GM made the auto/manual cars very interchangable. T/M crossmembers, pedals, boosters,...etc all bolt right up. The hardest part of this swap is finding the pedals out of a donor car.

 

http://www.team309cmc.blogspot.com/

 

Sidney

CMC #64

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Just for the sake of arguement, here's my guess on the cost to swap to a manual, assuming some new and some good used parts

 

pedal assembly $ 100 used

computer and wiring $200 used

crossmember $75 used

clutch assembly $ 400 - $600 new

Flywheel $300-$400 new

throw out & acc $150 new

manual trans $ 500 - $1000 (not including a fifth gear swap, no gaurantee on condition) used

 

So, for around $1700 to $2500, depending on condition of parts.

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Dave,

 

You're off on prices for 3rd gens somewhat. I'm sure the master of used 3rd gen prices will post here soon...TJ...but I've personally bought most of this for much, much less.

 

WC T-5 is $500. A cheaper, poor shifting one can be freshed for $200.

Stock flywheel $50-$100 depending on how hungry the seller is.

Stock bellhousings are $25

Slave cylinder probably $40

Crossmembers are basically free. We've got plenty.

Clutch. I run an Autozone clutch that has been in (3) different 3rd gens since 2004.

Pedals - quick search of ebay finds a set for $75

I don't think a computer swap is necessary but then I run a carb so I really have no idea!

 

These parts are used with the assumption that this will be a CMC build...not AI. Kind of the point I'm trying to make is this swap may be cheaper than finding a solid, nonT-Top manual car as they are just not that common. Your point of buying a running racecar is always valid and should be the first consideration. There have been a handful of former AS rollers for less than $1,500 that make great starting points for a CMC racer.

 

Sidney

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So to clarify, Sidney is taking a much more thriffty approach and could get it done for around $1000. On the higher end with some new parts, expect $1,500 to $2,000.

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I've bought 2-3 T5 swap setups for $500 give or take $100. Pedals, hydraulics, trans, shifter, flywheel, clutch, etc.

 

I hate leaky hydraulics, so I usually throw the 3rd gen stuff on the shelf and buy a brand new, pre-bleed hydraulic setup for a LT1 car for ~$100 from GM Parts Direct. It even has a braided line.

 

The stock 305 TPI flywheel is the best unless you want an SFI flywheel (30lbs?, Bob?). It's 18lbs and usually has enough left to machine when you pick them up unless they were in a 300k mile car or one that was drag raced hard.

 

Stock bellhousings are $50-75 on ebay. Sometimes you get lucky though.

 

I, too, use a Vatozone clutch. My clutch has 3 years on it and it's still almost like new.

 

Cross members are the same 84-92 for manual and auto cars. Someone even told me that the crossmembers are the same all the way through, but that the TH350/T10 use different bolt holes. Never seen a 82-83 crossmember, so I can't tell ya.

 

As far as a computer swap, it's not necessary, but you can do it if you like. The biggest difference in the code is in the IAC stuff (anti-stall, etc). Stock computers are great. I haven't ever had luck tuning them to a modified motor and no shops tune them. Run the stock EFI on a stock motor, or get rid of it completely and put a carb on it. When I started out in HPDE, I ran a 350 TPI converted from auto to manual and never touched a thing in the computer. My 305 TPI AI motor was a fiasco. Good riddance. I'm a carb convert.

 

Other then T5s themselves, the rest of the parts last a long time. I had 4 T5 transmissions in my car last year in 10 races. Granted, only one was fresh, the rest were junkyard/100,000+ street car crap. I took 4rd gear out of one at Grattan on an upshift, 3rd gear on another at Putnam on a downshift, and the other two were synchro/blocker rings/stupid stamped keys. I firmly believe that a T5 will live a long and prosperous career behind a CMC 305 shifting at <5500RPM. However, my 300+ HP AI motor that I shift at 6500-7000RPM kills them quick (as does my ham-fisted driving). I think heat has a lot to do with the failures after looking at the fluid coming out last year. It always came out black, even though it was M1 synthetic ATF with 2-4 races on it. Heat is due to too much RPM and too much 3rd gear use. My $.02.

 

Brian, if you're not in a hurry, I'll have some T5 stuff for sale later this year when I put a T10 in the car.

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To everyone, thanks for the info.

 

I'm in no hurry to do this and just got to thinking about one day. I've done no research for the parts but wanted to get a general list needed to make the conversion. I've tried selling the car several times in the last few years but it never happened.

 

TJ, Sydney and Bob - I had already planned on looking you guys up at RA to discuss this. See ya there.

 

BTW, this car will not be a race car anytime soon. I'm just looking to have a car that I can drive to Bluegrass and run. I'm still loyal to the FFR Series. But why do something to the car that would make it harder to convert to an AI or CMC someday if the need arises.

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