Bought race prepared C4, build advice for project
 

I just bought a used race prepared C4. Not considering engine, just the race prep, I felt it money well spent. The purpose was to start with a solid platform, that would be worth building on to, as a project road race car. The workmanship was extremely nice. Has stuff like, Full role cage (to certified specs), Fuel cell, toe hooks, fire extinguisher, fully gutted interior/dash, with custom made sheet metal dash for basic gauges, Metal box coolant tank, AC/Heat parts removed I think, ext oil pump/filter, catch can and breathers for crankcase ventilation, ext fuel regulator, ext high flow fuel pumps, battery relocated, custom hood (Pin locks, center 2-4" rise, Headlights removed/filled, repainted ), coil overs in the front, MSD ignition (6AL), dewitts radiator w/ dual SPAL fans, chevy performance aluminum heads, Headers, freeflow exhaust, real ZR1 5 spoke rims, good race tires with tread, 6 speed trans. No oil leaks. engine runs. But there is likely some minor engine work needed. Not sure what motor type yet. Its appears to be a 350 block, but not a stock block. But based on the quality work everywhere else, its likely that engine has been hardened and improved. When I get the paperwork, I'll know, If engine is good and meets my liking, its a bonus, if not, I had planned on building one anyway. The car has a carb, and carb intake. The ECU/Harness and Fuel Inj had been removed.

So my questions are....

1. Im considering putting Fuel Injection back.in. .Which means I'd need new intake, rails, MAF, injectors, ecu, and harness. Which type I use would depend on whether I keep the 350 or do a LSx build. But Im likely gonna stay with 350 block and heads. I'd probably do a ProXT or Strealth intake w/ matching rails. But that's not the issue.

Q1. Whats the best low cost option for ECU or fuel management? Pull a newer used Corvette ECU and wire harness? or should I go with something like the Fast system? Is there any fuel management computers that would work with both 350 and LSx, (support coil packs) so I could use the same system, if I upgraded engine later? .

2. It has one light weight hard plastic racing seat,.thats not so comfortable. I'd like to put in two seat. Any recommendation on racing seats, that are comfortable and adjustable enough?

3. It needs harnesses. Any recommendations on comfortable harnesses, that aren't to expensive, and meet rules.?

So far, I've only had a few HPDEs with SCCA and EMRA last season, so I still got some driving learning to do, and I'll still be driving my stock 85 for a bit, until I find a good deal on a trailer.. But looking to obtain my racing license sometime this upcoming season, and maybe do some Time trials.





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The engine has a carb
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what carb is on it ?

if you want to convert it back to efi it will be a long and costly exercise, considering that it has no efi stuff left, including a harness and ecm.
if you want to race an efi setup you will need a tunable ecm, so apart from the money you will need to learn efi tuning or pay someone else to do it.

I have been watching Engine Masters this week with the wife out of town. They did a test of EFI vs Carb, and the carb made the same HP/torque as the EFI. Now thats on a dyno at WOT, but power isn't the reason to go EFI. Daily driving, automatic adjustment to temperature and elevation, etc, all good efi things. But for a race only car, a well setup carb can be just as good.
https://www.dailymotion.com/video/x3moa13

Helpful video, thanks..
Like the part when they were making up the point system, and for one category gave the carb only 5 out of 10, because chicks don't like to be left stranded in the car, lol.

True, a Carb can deliver just about as much power as EFI, possibly less restrictive intake as well.
There is a reason more of the pro racers use carbs. Right now, Im gonna just keep the carb setup and see how it works out for me.
But, which is easier depends on experience of the mechanic. Many people think Carb is easier, because don't have to do ECU programing.
But, for me, it seems easier to be able to quickly reprogram tables, a simple matter of math, compared to reorder, swap out, and adjusting jets, without a DYNO to evaluate the results. And I just have a hard time with the concept that dribbles of gas will mix as well as sprayed injection.

So I picked up the car this past weekend, and started to look it over. It has a 383 Stroker in it with flat top pistons, with supposedly 12:1 compression, even a dyno sheet. I put race gas in because the high 12:1 compr. Seems to have a real nice Carb in it, at appropriate size. A Holley 4barrel, 4150 Listing 80511-2, casting 6R 7880 B, which I believe is about 830 cfm. Its difficult to get started, (easy to flood and drain battery), but once started and warmed it starts pretty quick, and sounds strong. But it doesn't run long before it randomly instantly shuts off. That's not unexpected though, considering the car has been sitting for about 3 years. Not sure if its ignition electrical or fuel delivery yet. But Im gonna start working on it tommorrow, and checking all the typical basic things (compression, fuel pressure, plugs, distributor, etc).

What car did you buy? Is it red? I'm curious if its the car I'm thinking of.

1. You could also go with a carb style fuel injection. A "cheap version" would be a Sniper EFI setup. Or you could look at a Holley HP and have the option of carb style intake or Stealth Ram , since you have a hiugh rise cowl, no fitment issues. Holley can work with SBC and LS, you just need to swap wiring harness, but if you are planning an LS swap, you may want to consider the Dominator, more expensive for sure, but it's the only Holley able to control DBW. Personally I'd go HP.
note: you said high flow fuel pump, but it may not be high pressure, carb fuel pumps can cap out at half what a fuel injected engine would need, something to check before the swap.

2. Adjustable is not often used in racing seats, and may or may not be permitted depending on your club rules. I would recommend a containment seat, and then it's just finding what is comfortable, Momo, Sparco, Recaro, etc. Then it's finding the right place to mount it for you and get the bracket setup. You can always swap your current seat to the passenger side for instructor or passenger use.

3. W2W you need an up to date certified belt. I have used G-Force and Schroth, Schrothe is more comfortable and with the 2" upper part fit the neck restraint easier than cramming in a full 3" belt.

I'm a sucker for a C4 race car, reach out to me with any questions.

Tom,

I have a ’90 Corvette race car and have remounted the racing seat that came in it on an adjustable track. Normally I would not have an adjustable racing seat, but my reason for doing this was to allow my son, who is taller than I am, to drive the car also.

When I did this a couple of years ago, there was only one acceptable slider for track use that fit my car. My car is raced in NASA and I have had no tech issues. The adjustable seat mount was Sparco 00493. Here are my seat specifics:
Sparco EVO, FIA 8855-1999, CS91898 June 2001
Seat width at rear: 15 5/16"
Seat width at front: 16 1/8"

In Feb ‘17 I replaced the seat mounting with Sparco 00493 adjustable sliders mounted on 1/4" aluminum plate bolted thru the floor at the factory reinforcement area with additional !/4" aluminum plate pieces reinforcing under the car.

The tracks did not fit the factory seat mounting bolts. To make things fit, I cut them off and made a ¼” thick aluminum base to mount the seat tracks on. The base covers the entire seat mounting area and was bolted to the bottom of the car using bolts mounted in the same track as the factory bolts, but in holes drilled next to where the factory bolts were installed.

The aluminum plate is designed so it can be mounted in either of two positions, one more forward than the other. This was done to increase the range of travel for the seat.

This was a project and not an easy task, so removing the seat to take pictures is not an option. I checked and do not have any pictures.

I think I have the template of the aluminum plate the sliders are mounted on and I can make a copy from cardboard if you want it. Due to current commitments it will be a few days before I can get to it.

Just for your information, here are the specs for my stock seat mounting in the car:
13 7/8" between front bolts
14" between rear bolts
16 1/4" between both sides running front to back
front bolts are 3/4" high x 5/16" dia, holding base and seat bracket
rear bolts are 1 1/8" high x 5/16" dia,holding just the base

As an FYI, in my ’86 race car I used the stock electric seat with harnesses. It was a great way to tighten the seat belts…..back the seat up, tighten the harnesses and move the seat forward until it was as tight as you could tolerate.

Hope this helps.

Ed

PS to Bad Karma….He did not buy my red car, if that is what you were thinking.

https://cimg0.ibsrv.net/gimg/www.cor...9b09e5024f.jpg
tom's new race car

Thank you, bad carma and oegel.

My purchase was one of convenience. While I had one of my car at the shop, I told my mechanic I was planning on race prepping one of my cars, And he just happened to have an extra race car sitting around that he offered to let me buy instead :-)

Oegel, That would be awesome, if you could make me a copy of your template, when you have time.

https://cimg0.ibsrv.net/gimg/www.cor...871be56218.jpg
Kinda Similar project. We picked up this SCCA Improved Touring R, 1984 last year. We are just getting around to getting her ready after spending this past year finishing our 1968 Corvette HSR car. This one has to run the L83 cross fire motor. We just had Byron Koury Racing engines freshen it. It doesn't make a lot of HP but the torque is pretty impressive. We hope to have it out in a few months at Sebring and Daytona.

Sweet. Yours just reversed the colors of mine :-)

"This one has to run the L83 cross fire motor. "

Are you running a class that requires stock engine?

In my case, I figured I'd start out with the L98 383stoked engine in it. The Dyno that came with it, showed RearWheel numbers about what Flywheel numbers typically are for stock. Not that big a jump, and less than expected. But to me the important thing was to start with a solid base prepped car.
I can always easily put in a new faster engine anytime, when Im ready for that level.

I had this issue a couple of years ago. Replaced the Coil - dies, replace the ICM - dies, replace the OPTI (LT1) STILL DIES!!!! SO i started over, ordered another coil. ran just fine.... Turned out he first coil i got was the wrong one!!!

We have to run the crossfire motor if we want to stay in the ITR class. There are other regional class options.

Tom, you have an email
Ed

tom@rapiddsl.net

thanks

Congrats on your new race car!

I mostly do track days with a C5Z, but I also run a C4 in vintage racing. There are usually two or three other C4s in my group whenever I do an event. Have you considered vintage racing? It's not difficult to get a license through a vintage racing organization, and they usually provide you with an inexpensive racing school conducted by their own instructors.

kdm123,

Im not certain which type class racing I'll do yet. Depends which my car will meet the classification rules for. Im definitely open to detailed suggestions.
Im in the MD area. I did some track days last season with SCCA and EMRA at Summit, which were super fun, and some autocrosses with National Corvette club. All of them, great people.. I figure I have some time to get a few more track days under my belt before I have to decide which class to race. SCCA is doing their annual Licensing event in a couple weeks at Summit, and I was planning on participating, provided I can finish getting my car ready in time. I still plan to run my red 85 vette some, just because its streetable to drive the track, to save on truck/trailer rentals. But for the SCCA school, I need the race prepared car.

I've had a little time to look over the car, this past week. Engine is Solid. Clean. No leaks. Compression tests good. Promptly within 180-210psi..
Went over ignition. put in new plugs and distributor components. Just bought Vizard's book on Holley Carbs, to learn more about them. I think the jets might be sized too large. Just bought Vizard's book on Holley Carbs, to learn more about them Im gonna go through the brakes tomorrow. I still got to buy my harness, and install a passenger seat.