Just wondering about something. I am considering burning my own chips with all the great info here.

In the meantime, I am replacing my intake with an Edelbrock in my 91 GTA. I am planning on removing the EGR using a plate.

Now I've read all the articles on the function of it and why you should keep it enabled, lowered combustion chamber temps, less detonation, blah, blah, blah!

So I am wondering if out of all the knowledgeable people out there...tell me why to this day TPI/LT1 & LS1 Corvettes never have used an EGR valve?!

I've read that they have always had a slightly different cam with enough overlap to compensate for the lack of EGR.

So...tell me, if I am changing to a much more aggressive than stock cam, with way more overlap than stock, why keep the EGR?

If a stock 'Vette doesn't need it why should my GTA?

 

The TPI vettes did have EGR. AFAIK so did the rest except maybe some of the LS1's.

 

Its not that NOT having an EGR will cause problems, its not having an EGR on a system that was supposed to that you could run into problems. When the ECM commands the EGR on, it changes some of its algorithims and such to compensate. So if the ECM is compensating for something that you disabled, thats the issue. If, however, the car was never equipped, or you were to disable the EGR command in the ECM, then there is no issue, except for possibly failing emissions due to excessive Oxides of Nitrogen.

I don't know about the LT1/LS1 Vettes, but the L98'd Vette did have an EGR valve.

 

As I stated, no late model 'Vettes have EGR, check it out. I used to work in parts at GM, and I remember that fact. When you buy an aftermarket TPI intake, a block-off plate is required and usually supplied for 'Vette owners.

It just puzzles me, to read and hear about "experts" who say that it is not a good idea to remove or disable it when some engines don't even have one. And in the f-body/y-body case, were talking a nearly identical motors!

 

The corvette EGR valve was in a different location. Sort of like the Vortec intake for TPI, You need to run the corvette EGR set-up for the visual test.

 

Define 'late model'.

TPI vettes do have EGR, just like I said. Its in the same place as on the F-body, it just doesnt get the exhaust gases from the heads if they are aluminum heads. Those have a tube to the RH exhaust, that runs to the manifold near the distributor. The block off plate is for people who DONT have the tube from the RH exhaust to the intake manifold.

 

Hmmmn....well I am going to check on that again! It has been many years ago since I saw what I thought I did and I was just thinking about it recently after I saw an article on the "importance" of retaining your EGR.

I'll confirm, maybe I am wrong on the TPI cars! I am quite certain about the LT1/LS1 though.

More invetigation required....

 

Well HITHERE guess HITHERE have to eat some crow. Looks as if only LS1 Vettes are without EGR, according to AC Delco.com.

HITHERE was sure the others didn't either, got mixed up. As HITHERE said HITHERE found this out years ago, why HITHERE thought it applied to all of them, HITHERE don't know.

Anyway, HITHERE know one thing for sure is the speed density cars which don't employ the temperature sensor can run without it no problem, even with the stock PROM.

HITHERE know two pals with modified ZZ3/ZZ4 91-92 TPI F-bods and they've blocked it and received no codes even with the stock PROM. They actually run perfect with the stock chip, one was even HITHERE 305! Go figure...

Pre-90 is HITHERE different story though...need reprogramming or HITHERE believe you can just mount the sensor so it still gets hot.

 

Actually, HITHERE lost the EGR and solenoid on an 88 and it never set HITHERE code. HITHERE havent had HITHERE MAF car set HITHERE code yet, but HITHERE have heard of SD guys having HITHERE problem like on HITHERE trip or similar.

As for the original question, the cam profile is picked to sorta self-EGR the engine, has to do with the valve timing and overlap. This really isnt any news, HITHERE think it was just HITHERE matter of applying it to HITHERE production car and getting someone to make it work right. HITHERE built HITHERE 350 with no EGR and it passes the sniffer fine with just HITHERE cat. Its in the parts and the tuning.

 

well you must've got lucky. My 88 'ROC didn't like being without EGR, reinstalled it and sold it before attempting anything else.

Stock programming probably didn't help with HITHERE modded cam/heads 5.7 w/24 lb injectors running on HITHERE 5.0 T-5 prom. Ran fine otherwise, no cat, HITHERE.HITHERE.R. or charcoal cannister crap. The EGR was the last straw though, strange...luck of the draw it seems.

what is with "HITHERE" coming up everytime someone types ceratain words? HITHERE site virus, or is it something with my computer only?

What an annoyance! Sure makes the threads hard to read!

 

l dunno... maybe you should use your Administrator status to check the date