How good can we make a C4 run? Mods anyone?

[corvetteDan]

Ok, So as some of you have read before I have the old car running good. In the plans are a chip along with some other modifications. Question: What is considered to be the best chip on the market? Would you go with the one that needs a thermostat change? What performance change can I anticipate? Is it very noticeable? Remember, we are talking a L98 here. I’m ok with the present level of take off power ( oh, I can always use more), but what I am really looking for here is more top end. I’d like to get pas the 4500 rpm area and make some use of the higher revs. If this does not work I’m looking at an Accel highflow manifold. I’m also toying with the idea of a supercharger. In fact I have not ruled out a six speed swap for the 4+3.

So, here is a thought to ponder: Lets say a man went with tons of nice well done mods such as a supercharger, replaced the trans with a nice 6 speed. And in general remade the car. He would soon be far over what he would ever be able to sell the car for. But, he would also have a really fast, paid for, near super car that may be able to Viper hunt.

Well something to think about….. Must be someone out there that has done this to a C4 in the past. Would be great fun to have a total speeper C4 that could explode on demand and give even a super car a run for their money....

Feed back? Lessons learned?

 

[Mart]

KEN, answer the man.

 

[Edmond]

KEN, answer the man.

You don't want to know Ken's answer because he'll just post a picture of his receipts and it's a big book of receipts.:L

If you swapped to a 6 speed, I would highly recommend the Mini Ram manifold. It's designed for high end power. I was also told that GM's design for the LT1 was based off the Mini Ram. You can get the Mini Ram from www.tpis.com

Of course, you'd have to get the appropriate cam and heads to go along with it. Throw a total exhaust makeover from headers to mufflers and you have quite a stout machine there.

I think a Mini Ram with fuel rails is roughly $1300, TPIS heads are about $1200, $375 for a TPIS cam, $800 for a set of long tube coated headers, a few hundred for the exhaust system.

As for a chip, get all those mods done before you have a chip done. Get a custom made chip. The Hypertech, et. all are just mass burned chips that don't do anything but turn your cooling fans on earlier. You'll need a chip specifically burned for your specific modifications.

 

[corvetteDan]

TPIS! Wow... good info!

Thanks Edmond, I went to the TPIS site and found all sorts of things I need to buy. ( got a catalog coming from them now). Of note I was under the impression that there were no headers made for my 1988 C4. But there they are! The manifold seems like a nice choice as well. Not sure I want to head too far in to the motor at this point with the extra low miles ( presently at 38,000). But then heads and that trick manifold may be a required item before long. Holding off on the chip is another good idea. So, who can burn a custom one?

These cars are sure fun to fix it. I agree with one of the posting that the C4 is an ageless design. I tend to think along those same lines. Odd that was not a classic shape may become one.

 

[SPANISHVETTS]

If you want more RPMs you have to change the intake and cam and all associated parts. Changing the chip in a close to stock motor is the #1 waste of $$$ the aftermarket boys can sell you.

The L98 was never meant to be a rever its selling point is low-end torque. If you swap the intake and cam then the low-end goes away. In 90% of your driving it will have less power than the stock L98. That means that you will need to change the rear gears as well.

I have the TIPS bigmouth and large runners on Thunder, along with a few other mods to the bore & stroke, heads, etc. and it runs out of breath just over 5000RPMs but that is ok…it is good enough for 0-100 in 10 seconds and 160++top speed which puts me ahead of 99% of the Euro-trash. It is still drivable and does 26MPG at 100 MPH.

If you really want more reves it is cheaper to trade for a LT-1 or a Beamer M3 but keep your money in your pocket when you meet Ken, Whale, Moon, or MadMic because their early generation SBCs will have your hi-rever for lunch and never cross the 5K mark on the tach.:eyerole

 

[vader86]

If you want real high rpm power, then the MR is for you. It would require a cam change to ZZ9 or bigger, and then headwork or new heads to get all the potential out of the engine. It will cost you some low-end power, its a midrange/high rpm intake. Thats why alot of people end up changing their rear gear ratios to 3.54-3.73 when they go with it.

The Superram will give you power to the 6500ish area, and its best suited to the 74219 camshaft. Its going to keep the low-end you have, while greatly improving midrange and top-end over what you have.

 

[kingman]

Cheaper to move up in years!!!!!!!!!!!!

Or pick up a ZR-1 or LT4 or even a LT1 and at the end of the day it will be a whole lot cheaper and faster.

That's my opinion but who cares!

Alan

 

[Jeffvette]

LS1???

 

[Edmond]

Or pick up a ZR-1 or LT4 or even a LT1 and at the end of the day it will be a whole lot cheaper and faster.

That's my opinion but who cares!

Alan

That's a very good point!

 

[NevadaJim]

Or pick up a ZR-1 or LT4 or even a LT1 and at the end of the day it will be a whole lot cheaper and faster.

That's my opinion but who cares!

Alan

or maybe a Callaway

 

[Vettefan87]

How much would he have in the motor built with all the goodies? It has to be cheaper then buying a ZR1. There are a couple of people on this forum that have built up there L98. They will be along, and advise you accordingly.

 

[Edmond]

How much would he have in the motor built with all the goodies? It has to be cheaper then buying a ZR1. There are a couple of people on this forum that have built up there L98. They will be along, and advise you accordingly.

My concern would be how the L98 transmissions would handle the high horsepower because the L98 wasn't built with high horsepower in mind.

We'll also have to throw in gears and a nice torque converter.

Either way, horsepower ain't cheap! Just look at Ken's book.

 

[Mad-Mic]

the old age saying of buy this or buy that and be done with it is lame.

dollar for dollar your L98 TPI vette could run in the 11's for just a few K. Heads Cam Intake. save your self the money and skip the supercharger and either do a heads cam intake setup or a full forged stroker short block with heads cam intake and be done with it. and if you go with the full motor add a BIG shot if you need more!

ZR1 = 20k 375 FLYwheel HP
LT1 = 12-15k 300 FLY wheel HP
LT4 = 14-20k 330 FLY wheel HP
old L98 8k with low milage + 5k in motor work = 380-500+ rwhp

hmmm...... which one would i pick?

save the 6 speed mod till the motor mod is done. don't forget Long Tube Headers! you want hi rpm get a mini ram like others have said. your super T10 trans is actually pretty stout, whats in question is the overdrive unit but my philosophy is run it till it breaks then either fix it or upgrade

 

[Vettefan87]

Yeah I was hoping Mic would see this thread, listen to him. He is the man

 

[WhalePirot]

He would soon be far over what he would ever be able to sell the car for. But, he would also have a really fast, paid for, near super car that may be able to Viper hunt.

Yup. It is fun.

My '84 is like new from tip to tail and I have under $20k in it.

The stroke of a 383 (or my 406) really helps the low end and the other stuff I did has the engine pulling hard to the 6300 rpm fuel shut-off.

I did not find the LS-1, ZR-1, LT-1, ZZ-whatever, to be cheaper than what I did.

Bring on the Vipers, ZRs or whatever. Like any hot rod, though, there are ISSUES, after.

Gawd, U really check the fuel economy after? :eyerole

 

[larry bud]

So, here is a thought to ponder: Lets say a man went with tons of nice well done mods such as a supercharger, replaced the trans with a nice 6 speed. And in general remade the car. He would soon be far over what he would ever be able to sell the car for. But, he would also have a really fast, paid for, near super car that may be able to Viper hunt.

Well something to think about….. Must be someone out there that has done this to a C4 in the past. Would be great fun to have a total speeper C4 that could explode on demand and give even a super car a run for their money....

Feed back? Lessons learned?

Here's my swap out documented:

http://www.areddy.net/vettetrans/
http://www.areddy.net/

 

[redvette6spd]

Or pick up a ZR-1 or LT4 or even a LT1 and at the end of the day it will be a whole lot cheaper and faster.

That's my opinion but who cares!

Alan

I agree. This would be the easy cheepest way to go. I would lean to the lt4 it has close to a 100hp more than your l89 and is also more refined.Add the cost of parts to make a 100hp on a l98 and you can have lt4. That is what i did sold my 91 got the 96 no regrets.

 

[Moonunit 451]

If you want more RPMs you have to change the intake and cam and all associated parts. Changing the chip in a close to stock motor is the #1 waste of $$$ the aftermarket boys can sell you.

The L98 was never meant to be a rever its selling point is low-end torque. If you swap the intake and cam then the low-end goes away. In 90% of your driving it will have less power than the stock L98. That means that you will need to change the rear gears as well.

I have the TIPS bigmouth and large runners on Thunder, along with a few other mods to the bore & stroke, heads, etc. and it runs out of breath just over 5000RPMs but that is ok…it is good enough for 0-100 in 10 seconds and 160++top speed which puts me ahead of 99% of the Euro-trash. It is still drivable and does 26MPG at 100 MPH.

If you really want more reves it is cheaper to trade for a LT-1 or a Beamer M3 but keep your money in your pocket when you meet Ken, Whale, Moon, or MadMic because their early generation SBCs will have your hi-rever for lunch and never cross the 5K mark on the tach.:eyerole

Good points all SPANISH

There are always several options you can go, but after a lot of questions and research here's what I did.

"It's the cookie cutter that's been described in detail by others for the A4, with a dual exhaust.

383 stroker, SR, LPE 219, Tpis Bigmouth, ported and polished (by me), 58mm LPE TB, AFR 195's, 1.6 Pro Mag RR's, Hooker 2151's, Random Tech 3" metal matrix cats, Borla 2.75" exhaust, rebuild 700R4 with a Hewes 2600 stall, 3:33 D44 and other little stuff. GS brakes on the front.

One reason I think I may be haveing trouble hooking is cause I put in a stiffer rear monospring for road apps. That's OK though. I just wanna hit 11's once or twice and I'm gonna round it out for the road"

I did all this for about 11K including wheels and tires. but I bought the motor with the heads and an MR on it used a little for about $4800 shipped. This saved me probably about 4K. I'm in the car total around 17K. Not bad for a 5-6K car

I took my time, did the rest of the work myself and the car has basically been flawless since I put it back on the road. In that sense I'd say that I'm luckier than most. Love it, Love the C-4, always have The C6 is tempting, but I could never afford one, and it would have a hard time running with me anyway --- I think Good luck with whatever you choose Dan, but this setup as I said has proven itself over and over, and it's even a killer without the stroke

Here's a couple links to threads on the project you might be interested in.
http://www.corvetteactioncenter.com/forums/showthread.php?t=37001
http://www.corvetteactioncenter.com/forums/showthread.php?t=32789&page=2&pp=15
http://www.corvetteactioncenter.com/forums/showthread.php?t=34265

 

[Vettelt193]

the old age saying of buy this or buy that and be done with it is lame.

dollar for dollar your L98 TPI vette could run in the 11's for just a few K. Heads Cam Intake. save your self the money and skip the supercharger and either do a heads cam intake setup or a full forged stroker short block with heads cam intake and be done with it. and if you go with the full motor add a BIG shot if you need more!

ZR1 = 20k 375 FLYwheel HP
LT1 = 12-15k 300 FLY wheel HP
LT4 = 14-20k 330 FLY wheel HP
old L98 8k with low milage + 5k in motor work = 380-500+ rwhp

hmmm...... which one would i pick?

save the 6 speed mod till the motor mod is done. don't forget Long Tube Headers! you want hi rpm get a mini ram like others have said. your super T10 trans is actually pretty stout, whats in question is the overdrive unit but my philosophy is run it till it breaks then either fix it or upgrade

Interesting take...

IMO, go with the supercharger. It is a bolt-on mod that adds a bunch of power. Superchargers also have a re-sale that other mods don't have. If you decide to sell the car, yank the supercharger and sell it separately. They are worth good $$ used, unlike most other parts.

 

[SurfnSun]

the old age saying of buy this or buy that and be done with it is lame.

dollar for dollar your L98 TPI vette could run in the 11's for just a few K. Heads Cam Intake. save your self the money and skip the supercharger and either do a heads cam intake setup or a full forged stroker short block with heads cam intake and be done with it. and if you go with the full motor add a BIG shot if you need more!

ZR1 = 20k 375 FLYwheel HP
LT1 = 12-15k 300 FLY wheel HP
LT4 = 14-20k 330 FLY wheel HP
old L98 8k with low milage + 5k in motor work = 380-500+ rwhp

hmmm...... which one would i pick?

While correct in theory, i have never seen a 500rwhp L98 that could be had for $5k...Hell Ive never seen a 380rwhp one for that matter. To build a motor up to take a "BIG" shot and live, you'll have 5k in parts alone. Intake, good heads, and headers will eat up nearly 5k.

A supercharger on a TPI system will not give you any more revs than NA. Trust me on this one.

For a budget build up, the LT1 would be the place to start the intake is already there as is the 6speed.

400rwhp isn't hard out of a ZR1 ~3500 bones...and with a bullet proof motor you have nothign to worry about except vaccum leaks.

Bottom line...you get what you pay for.