I purchased a 97 Z28 about a year ago. I knew it had some modifications and I was able to identify a few of them. However, recent events requires me to install a new clutch. In the process I keep finding more and more that looks modified. One was a sticker in the engine compartment with the name "Hypertech". This would indicate to me chip programming was likely done.

One issue is that all I have read about a stock engine indicates that programming will likely NOT improve performance, and may HINDER performance. So there is a chance that either this is what is happening or further mods were performed. So far here is a list of the things I know...

1) After Market exhaust (research indicates to me SLP Loudmouth but no absolute proof).

2) K&N CAI

3) Daytime running light bypass (I read that 97 had DRL).

4) Skip shift bypass (This I believe has disabled my E-brake like. I have to turn the car off to pop the trunk... )

5) Hypertech sticker in engine compartment

What I am asking is: How to identify certain parts that may be stock and may be after market. I will be doing an overall tuneup so will be able to prope into the nooks and crannys. Things like MAF will be easy to note, but other things like headers, cam, injectors, etc will be hard unless I know what to look for.

Any assistance in what to look for on stock parts or on some of the most common after market parts would be greatly appreciated.

 

stock exhaust manifolds come up and are a rusted iron color with an aluminum heatshield cover 80% of them.

Most headers have individual primary tubes that go down first.

You can also easily see the sparkplugs in most cases with headers.

 

Ok thanks. I have stock exhaust manifolds. And yes, they will make changing the sparkplugs a PAIN! Hopefully having the tranny dropped will make that job a little easier. (doubt it though).

 

the skip shift mod will disable the E-brake and not let you pop the trunck unless you kill the car. thats what mine did until i got the pcm programmed and pull the skip shift elimator out.

 

Where is the skip shift mod? I have been looking at the wiring diagrams for the parking brake light and the skip shift module. I think it could be fairly easy for someone with EE background to bypass the skipshift and NOT disable the parking brake light. I would like to remove the skip shift but not sure where it is normally added.

Thanks for the help.

 

My skip shift hasn't been disabled and I have to shut my car off to pop the trunk!

 

Does your "brake" light come on when you pull up the e-brake? If so, you should then be able to pop the trunk (with the e-brake light on).

 

you will definitely know if you have a Loudmouth exhaust...its considerably louder than stock and doesn't have a muffler to it! (just some resonators in the pipes)

If you have Hypertech programming you could be somewhat screwed...you will either need to fnid the original programmer from the guy that did it, get a new PCM, or send it to someone to have it programmed out...

 

The previous owner though most likely reprogrammed the PCM back to stock before he sold the car so he could either use the programmer on another car or sell the programmer. Because if he left the stock programming in the hypertech programmer then it doesn't do the owner any good without your car. The hypertech programmers only work on one car at a time.

 

My trunk pops up sometimes when running and sometimes I have to turn it off....

 

Thanks! This is good to know. I will cross my fingers then and hope that the guy was smart and put it back (the car didn't come with the programmer).

 

yea u would know if u had a loudmouth

yea that sucks if you dont have the programmer that your car was programmed with...i'd probably get a new pcm. not that expensive. check the FS section

 

Wahoo! While dealing with all the broken things, I found that the MAF is a nice after market one. Free flowin', no choppin' done!

Any way to identify a stock exhaust? This thing is WAY too loud to be stock.

Also, any way to check stock cam, TB, intake, etc? Headers are stock so my guess is this kind of work is unlikely, but I'm still curious.

 

really? weird