PhysicsDude55

I'm looking to buy a C4 in the next month or two. My plan is to put a forced induction setup, haven't decided exactly what yet, leaning towards a rear-mount STS setup. My questions are basically what I should be looking for. My current plan is to build the engine to a forged 383 set-up, aiming for around 600 hp(12-16psi or so).

I am leaning towards a convertible, although I know they're not as structurally sound as a coupe. I think I would put a rollbar for stability, but I've heard C4's are too cramped to easily fit a safe rollbar. Is this a bad idea? Would a coupe be a much better idea?

I definitely want a 91-96, leaning towards a 96 so it can be OBD-II (would be nice to install a blutooth OBD-II monitor so I can view information on phone or laptop etc). Is it useful to have OBD-II for anything other than the kicks and giggles of looking at engine stats on my cellphone?

Is the LT4 much better for forced induction? Would it be best to replace the heads anyway, so does it matter if its an LT4 or LT1?

I want to lower it, and have the best suspension setup I can reasonably have, and want it STIFF. What should I look for as far as stock setups go, or what is easy to mod/improve etc.

I know the setup will not be cheap, although I don't want it to become extremely expensive. This will also be a street car, not a track car, so I want it to be reliable. Is 600hp on forged internals and stock block a reliable and reasonable set-up? Basically, I don't want to replace the stock 6-speed and rear D44, but I can deal with replacing the clutch every 20K miles or so.

I plan on doing most of the work myself.

Sorry about all the questions! Thanks for your help.

Bjh

I have a roll bar in my 1988 corvette, it was easy, but it was custom made by my father. I'll post some pics. Z51 has stiffer springs and i think bigger sway bars. The z51 is the best cornering suspension from factory. Also, I have a l98 that is supercharged and has 175 shot of nitrous(wet shot) and they weren't to hard to do. Either motor you go with the l98 or the lt1 or the lt4, they all have great potential just depends on your preference.

http://s1125.photobucket.com/albums/...3DIMG_1198.jpg

http://s1125.photobucket.com/albums/...3DDSCF0651.jpg

Bjh

http://s1125.photobucket.com/albums/...t=IMG_1134.jpg

http://s1125.photobucket.com/albums/...3DIMG_0920.jpg

PhysicsDude55

Thanks for the input! Your rollbar is EXACTLY what I had in mind. Looks great.

Not too many C4's go for sale, so as always, I'll probably just keep an eye on craigslist and just see what kinda deal I can find. Everytime I find one I like, I find out its an automatic!

drjimmy

Thats because for the C4's they only made less than 20% manual. And if it was 84-88, you didnt want the 4+3 manual.

Bjh

Yup 4+3's suck thats why you swap in a richmond 6 speed or just get later models with a zf(which would be a lot cheaper). I bought my car with it already done at a low price. Also, when putting in the roll bar you have to cut u some fiberglass and then put t back together, but if you no the basics of fiberglass you can easily do it. I think it cost me about $50 to do the entire roll bar.

dizwiz24

get a zf6 car. dont know about turbo's but I can tell you about S/C.

Im not sure about the l98 cars, but greg @ blowerworks is the expert for the c4's.

He knows how to route a dedicated 8 rib drive S/C belt system in there that wont slip.

All the procharger kits, while making a superb head unit, all have slip issues with their single belt setup.

The issue with single belt(on an ltx c4) is you have accessories on the left half of the car and the blower on the right. So you dont get good >180 degrees of wrap around your crank pulley. Slip occurs at the crank pulley (not s/c drive pulley as many probably believe.)..

If you go stock bottom end, Id limit max boost to about 10 psi.

Also, somewhere you mentioned going to new heads. Id be careful with this on a stock bottom end. Id hate to see you a put a lot of money into expensive ported heads only to have them get destroyed if a stock bottom end, under boost detonates and comes apart.

No matter what you do, go with a meth injection kit (50/50 methanol/water) in place. These will help you make more power (can run a tad more timing without detonation) and keep things safe.

The c4 doesnt have a good spot for a front intercooler. the procharger c4 intercooler is worthless and a boost restriction. When I removed mine, I picked up 3.5 psi boost while still spinning the same size S/C pulley !

Bjh

Couldn't have said it any better and I have a l98
Do you have any pics of this 8rib pulley setup, i have 8lbs on my car and its already slipping like mad.. Zfs 6 speed is the best tranny stock for the c4 manuals for sure.

dizwiz24

heres a video of it when I still was running the restrictive procharger intercooler and stock size throttle body.

Now, there is the vortech curved discharge pipe between the supercharger outlet and intake in place of all the complicated, restrictive procharger intercooler piping.

The vortech curved discharge pipe has the meth injection nozzle bung welded in the bottom. But again, thats not in this video.

http://forums.corvetteforum.com/c4-f...-build-c4.html

Bjh

Beautiful car by the way

Lemme

I have an 87 I'd like to supercharge. I would be very interested to know more about what you have done, costs etc. Why did you do NOS and s/c? Why didn't you change the intake?

RVY

I may have available most of what your looking for. At least an honest 600 rwhp vert. What is your planned budget and where do you live. Send me an E mail.

RVY

I'm curious as possibly a few others may be regarding costs. After you buy the car (1996 C4) and make a major investment in outdated engine technology as well as necessary add ons to the car in the form of gearing, fuel system, transmission, etc what do forsee as your bottom line expense? Not what you budget but what you actually expect to spend. We all usually go over budget. I wouldnt be surprised to see you spend $28,000 to $30,000.

Bjh

Sorry I haven't been on for awhile. The total cost of my supercharger kit was 1300, but thats because it was bought used off ebay. I took a chance on it and so far its been great. That cost is with out a tune also. I did all the work on it so if you had someone else do it, it would cost a lot more $$$$. I like the tune port itake, Everyone says its crap, okay yeah a mini ram or stealth ram puts out more hp but I don't want to take my motor to like 6500, also I like the drivability of the tune port intake, lots of torque and I like going to the track and everyone says "its a tune port car it won't run".. The nitrous was on the car before the s/c, I sprayed 175 shot, I just left it on because I'm about done with my 355 build (which is for the s/c and some NOS ). NOS is way cheaper to do obviously but you run out of juice, unlike the s/c. ALso it all depends on your preference. And no it won't cost you $28,000 to make a mid 11 second car if your smart. I'll have about 15k in my car (including purchase) , MOST of that money is in interior, speakers, suspension. I'll have about a $3500 motor and the parts aren't junk..(Srp pistons, comps cam, Steel crank With sply caps, Lunti rods, GM fast Burn heads, ect). To make a cheap build you have to get deals on parts.
Regards, Brandyn

If you have any questions about prices or information feel free to private message or respond to the Post.

Lemme

Where did you mount the NOS bottle?

Bjh

I currently have it the passenger side compartment bin. I didn't want to mount it in the back of the car with brackets drilled in the floor . But that's just me.

PhysicsDude55

I live in Dallas, but my job takes me all over the country......

My current plan is to take an 92-96 LT1 (LT4 if I can find one) bore/stroke it to a 383 stroker and put in forged pistons and crank (I can do all this myself in the garage)

Then, a turbo set-up. I plan on running pretty high boost (as high as I can run on a stock block without reliability issues - 14psi or so?) and try to keep supporting mods to a minimum for money reasons (obvious new ignition/bigger injectors/fuelpump, etc) anything that is necessary to make the turbo(s) work.

I want to reach 600hp, but 500ish would also be OK. I don't want to replace the 6 speed, and I don't want to replace the rear D44.

I still have a lot of research to do, but thats my current plan. I'm hoping to keep the project to about 20,000, depending on the vette I buy, I anticipate about 10K for the car and 10K for the mods (including new tires, some interior work, rollbar, audio system, maybe spoiler, etc.)

Any input is appreciated.

Thanks,
-Paul

Bjh

Okay let's see what we got here.

-you are able to put the motor together in your garage so that cuts costs

- You want forged pistons and a steel forged crank, I'd add sply caps for the boost pressure

- do you want to keep the stock intake? Or heads?

-It has to be and lt1 or lt4(you could easily make an lt1 an lt4 with lt4 intake)

-roll bar is cheap if you do it with yourself, suspension can get costly fast but so can everything else(I dont have much expierence with suspension)

-you might want to go with an intercooler for the turbo to cool that hot air. also is it going to be rear mounted or in the engine bay. You have to provide oil for the bearings in the turbo
Now 600rwhp is a ton , there is a blown lt1 car with 498hp that runs high 10s, 600hp would blow the wheels off the car so bad That it would make it kinda hard to drive around town but that's just my input.

PhysicsDude55

Thanks for the input. I have seen a lot of C5's run 600-800 horsepower and are supposedly pretty street-able. But if I can't get traction in 2nd gear than the extra HP is kind of a waste.... So maybe 500hp is a better goal (~600hp at the crank).

I do plan on running 315 wide tires in the rear, some with minimal tread lines, so that I'm not totally screwed in the rain, but that have some good grip.

There is a frontmount turbo system for sale on this forum, and if its still for sale when I get my vette, I'll probably get it, but most likely I'll be looking at a rear mount twin turbo set-up. I do plan on running a front intercooler. I also want to keep my A/C, so rearmount is probably preferable.

I am planning on sticking with stock heads, if I end up with an LT-1, I'll look into an LT-4 swap if I can find them for relatively cheap.

BigC4

I haven't driven mine yet, but after riding in another C4 with the roof out I had to stiffen up the chassis. I have some finishing up to do, but I am putting a 12pt in mine.

http://trevorroebuck.com/Cars/default.asp

If the bar is too close I will lower the seats with a different set of mounts. I too will eventually go turbo (7.4L) and you will definitely want a six speed.