I just purchased a 96 LT-4 that is stock with the exception of the exhaust system. I am interested in in any bolt-on mods that will improve performance. I just want to be able to take full advantage of this great engine. I have been told things like replacing the "chip", new MAF sensor, Throttle body, cold air intake, fuel regulator etc.. I was planning at the very least to install a K&N air filter but at 75 bucks I thought I would do a little research first. As you can see from my sig, I am no stranger to rebuilding things as I have done all that myself but I am not looking to go down that road here. However, I am a stranger to this new concept call fuel injection...

 

Congrats on your LT4, great car.

There is no "chip" in the 96, the PCM is reflashed instead of a chip replacement. Its not worth replacing the MAF sensor, Throttle body, cold air intake, or fuel regulator. The ones you have on are pretty good, very little room for improvement.

What I would recomend is a cam change to a "Hot cam" or simular cam.
Headers, 4.10 gears, and a retune of your PCM.

Anything more will be getting the heads worked on.

 

Thanks!

What are the stock rear gears?

 

3.45

 

It all depends on what you want the car to do.
If I were to do it all over again I would have gone heads,cam,long tube headers,corsa cat-back,dyno tune,and call it a day.I would even be in favor of doing heads only on the stock cam and gears for more power with awesome driveability.

 

Yes, I am trying to hold back on the temptation.

 

IMHO 4.10 gears and a Hurst shifter should be every LT4's first two mods!!

 

LT4 Hot Cam with matching springs...it's one of the few things that are cheap for this car...and its a direct bolt in....uses the stock computer...passes smog easily, even in California. It was originally developed when the factory raced, and dominated, showroom stock racing. You'll see crate engines ads from back in the day that claimed as much as 425 hp at the flywheel for this combo in an LT4.

There are a ton of other cams out there, but none (IMO) that match the bang for the buck.

Next call Jon at FIC (Fuel Injection Connection) for a set of new, modern Bosch III injectors matched to your engine. They are a huge improvement over the factory Multitek injectors that can't be rebuilt and probably not even worth cleaning; The price is very reasonable; they plug right in; it'll be the easiest thing you ever do to your engine.

And don't forget (or try to avoid) doing a good ignition tuneup.

good luck and enjoy.

 

He already has an LT4 cam.

 

If your looking for a quick and cheap add on, get a intake air foil. There only about 25 dollars and they take about 5 mins to install. You can find them at ecklers or mid-america. They just go on the front of your throttle body. Says it adds up to 11.8 HP and 12 ft/lbs, I doubt thoughs numbers but either way an easy cheap investment that's worth the money to me.

 

4.10s are the best mod for an LT4 by far. Next, get it dyno tuned and put an electric water pump on it. I ran low 12's with that combination and sticky tires all day long.

 

He said is car was stock, HotCam isnt.

Ditto on making sure the car is in good tune to start with then make a plan and budget (est cost x2 wll be safe)

 

 

Tune? Hmmm.... I am guessing that will require someone with a computer. I am used to doing all that stuff myself on the C3, I wouldn't know where to begin on a C4. I think there is a local speed shop here that does that. They have a dyno as well. I am so impressed with the performance, I am considering putting fuel injection on my C3 along with some better tires. I did my own rear-end rebuild on the C3, is there anyone here that does C4 rear ends?

 

I'll disagree with some of the above.

First, switching from 3.45's to 4.10's out back doesn't make any sense to me. I already spin the tires (285/40/17's) on my LT-4 too much with the 3.45's. With the 2.68 first gear in the ZF-6 tranny, we have more gearing in our LT-4 Vettes than my 69 Z/28 with 4.10's and a M-21 Muncie (4.10 x 2.20 = 9.02 vs. 3.45 x 2.68 = 9.25 for the LT-4 Vette). And the Z/28 (302 cid) will spin to 7500 RPM. The LT-4 will never see the dark side of 6500.

My opinion; the 3.45's are perfectly fine.

Secondly, I think the first mod would be exhaust. Ditch the choking cast-iron exhuast manifolds for some long-tubes and you'll see real results. The exhaust is almost always the first place to look for HP.

Lastly, once your exhaust can breath, I think the Hot Cam is poor choice. It's a great selection if used with a stock exhaust system because it has exceptionally long exhaust duration (228 @ .50 on the exhaust side vs. 218 @ .50 for the intake).

But, now that you have (will have) long tubes, that extra exhaust duration would cost some power as ALL dual pattern cams will. Dual pattern cams are designed to compensate for poor exhaust systems and/or inferior heads (BTW, LT-4 heads are pretty darn good!).

More here on dual pattern cams:

http://www.camaros.net/forums/showth...rn+cam+cabbage

I think after you've installed a free-flowing exhaust system, there are much better cam choices than the Hot Cam.

Good luck with your 96!

 

Recommended Headers? I assume Hooker, Hedman etc all make ceramic coated headers for C4's? The previous owner installed a pair of Magnaflow mufflers which sound nice.

The rear gear feels fine to me...at least for the moment.

 

I think for the money you will have more fun with gears. An LT4 with 3:45's hit's 51mph in 1st gear at redline which is wayyyy to tall IMO. Gears if you took the diff in to a shop to get set up would be $500. Headers with cats would be closer to double that. Ideally do both. Exotic Muscle seem to be the header of choice for cost and quality.

 

I agree.

Also, if you like the idea of keeping something like 25-33 mpg on the highway, don't diddle with the rear gears. If you just want neck-snapping acceleration and burning rubber, then mess with them.

Jay

 

You will lose very little if any highway mpg with 4.10 gears in a M6 LTx car. I have ~375 rwhp/4.10's and still get 26-28 highway mpg.

 

I disagree with most if not all of this post!! Ask "jonecap" how the 4.10 gears and the Hot Cam are working with his LT4, pretty sure he also has headers.