brnrbr247

This is my first post and have several questions about this 1996 lt-1 6sp z-28 i just bought. It was a former GA state patrol car. What perfomance upgrades can i do and still keep stock programming and fuel injection? I am using this as my daily driver because it gets alot better gas mileage than my Z- 71 Tahoe and its fun as hell to drive any help or suggestions would be great.

Injuneer

Let's move this to "LT1 Based Engine Tech".

There are several "bolt-on" (external) modifications you can do that will not require computer programming, or exceed the capability of the stock fuel injection components. The fuel system is good for about 350HP at the flywheel.

Consider:
-cold air intake
-catback exhaust system
-throttle body coolant bypass
-1.6X roller rockers
-headers

Don't forget that upgraded engine power requires upgrades to the drivetrain and suspension. While going to 3.73 or 4.10 rear gears won't increase HP, it will give the car a significant performance boost off the line. Changing rear gears does require computer programming to correct the speedometer.

Don't be afraid of a PCM reprogram. Even a stock engine will gain 10-15HP with a reprogram. You can get a "mail order" reprogram for a reasonable price.

brnrbr247

these upgrades sound great .....when i do the headers what are a good choice and will i need to modify the smog lines...the car now has the a 3.42 gear in it and im not sure if it has already been reprogrammed or not since it was a highway patrol car. I have already ordered the harland sharp rockers.should i dyno the car before i do changes or just go by the seat of my pants and the feel.also it already has a flowmaster on it but i think the only gain was sound thanks again for all the advice

Injuneer

The "highway patrol" car is simply a Z28 without the badges - same engine, same programming, same trans, same rear axle ratio. Search on option "B4C". All M6 cars from 94-02 had 3.42:1 rear axle.

From the 4th Gen FAQ:
What you need in the way of smog depends where you live, and what kind of emission checks you have. If they just plug into the computer and look for trouble codes, you can delete the AIR and EGR connections completely, and have the resulting codes "programmed out" as part of your mail-order tune. If you live somewhere that they rigidy enforce FEDERAL regulations, you may not be able to do much at all. In states like CA, you need a CARB-EO emissions authorization tag welded on to the headers by the manufacturer. The dual cats on your 96 will have to be kept i the stock locations, AIR and EGR must work.

In between, are locations that just run tailpipe tests, and don't care how you pass. You will need cats, but they won't care if you have relocated the cats, for example, to allow the installation of long-tube headers. AIR is only used to heat up the cats on cold start, to that's not an issue on a tailpipe test. EGR reduces NOx emissions, so if you delete that, you might have a problem passing a tailpipe test.

brnrbr247

i live in the land of NO CAR INSPECTIONS which is called South Carolina ,so the long tube headers are my choice.I think i have beginning game plan now with all your help .I have the rockers(1.6) ordered and now I'm going to order the cold air intake and start shopping for headers.I have a buddy at a local junk yard thats going to get me a spare computer so i can send it off for retune after parts are on.might try and do the msd dist and wires while i have it tore apart putting headers on.Your advice has been great and thank you for all the help.

moparman

I'd think twice about the MSD opti. Search around the forums about the MSD. Seems to be hit or miss on the quality.

brnrbr247

i will do that ....thanks for the warning will really do some homework on it and see what i can find out do you have any suggestions?

moparman

An OEM opti seems to be the best choice. Made by Delphi.

CamDriver

i know a guy in the local impala club thats running high 10's with a stock opti... summit racing opti's ar garbage and msd dont work no better than a stock one

brnrbr247

the car had the stock opti replaced a year ago with new water pump and seems to work great was just curious if their was something better .Did some research last night with the internet and jegs and found alot of the recommended parts at great prices. has anyone tried the edelbrock aftermarket intake ? I have decided to do all my upgrades in one job,so as i order the parts i will stack and collect them then do the job at one time. another question is will i see a benifit from the intake with stock heads and do i need to change the throttle body also or will stock be good enough? Thanks again guys for all the advice and insight!

Procharged94Lt1

I've run MSD opti for 4 yrs now with no problem as opposed to every other year at best with the OEM unit, but that was just my luck so far..others have claimed to have or heard of horror stories. But its just like everything else- people remember the bad and post stuff like my "brother's uncle's dad knew a guy whose friend's brother heard about a guy who read about this guy who had a friend's MSD that failed". When it comes to the Opti- install it correctly and it shouldn't be an issue.

BTW- I just spent 30 minutes trudging thru old posts and on Google and what I found about the 'MSD problems' was 95% of the time the post said something like "I've heard of MSD Opti's having problems..." Couldn't really find anything that was concrete on the problem. I would venture to guess that a lot of the problems could be linked to either incorrect dowel pin length or not double checking the rotor screws to insure they are tight- both of which you should do on ANY opti. Perfect example- one individual didn't install the seal that came with it and it failed within 800 miles. Got a second one under warranty and again didn't install the seal, this time got 1200 miles out of it. I'm no expert, but cursing the MSD Opti because you failed to install it correctly is hardly enough reason to put a nation-wide hate ban on it.

The Edelbrock intake is a little different but for the money I would spend it elsewhere- you are halfway to getting some port work on the heads which will yield much better results.

I would get a decent cam for what your end goal is. Give Lloyd Elliot a look-up. He is very good to work with and will set you up top to bottom on what you need. For a couple grand-ish you could easily have a reliable 400hp car.

Guest47904

A few suggestions. If the opti works, DON'T MESS WITH IT.

Another is: Don't do all the mods at one time. Very few of the things you want to do are "overlap" items. If you do too many things at one time and have a problem, it may be hard to trace which one caused the problem. If you limit what you do at a time, it will probably be easier to find the cause of a problem.

Remember what are considered tune up items: Plugs, O2s, coil, both filters, distributor cap and rotor (yes even on an optical distributor).

An aging F body will give you fits. It's a good idea to invest in a good scanner that gives you both DTC's and real time sensor data.

Last one to bore you with. If you do headers, run them and get them hot with OUT having the O2s in place. Then after they cool, put the O2s in. Over the years, there have been several people that supposedly damaged their O2s by burning in the headers with the O2s installed from the beginning.

Just my $.02

And oh yeah, congrats on the "fun ride". I hope it gives you many years of entertainment without problems.