lt4 computer question
 

i was wondering what the difference between the lt4 computer and the lt1. ive always asumed they were the same with different programing.
im wonderiing because im goign to do egr deleate and it will set off my ses light . so im going to deleate egr with lt1edit. but in dallas they check for that as part of emmisions. if i had a true lt4 how would th eemmisions not pick up the egr

Your assumption is right. The LT4 computer is the LT1 with different programming. LT4s dont have EGR. The LT4 cam negates any need for an EGR system.

so how is the egr deleated in a lt4 computer
the reason im asking is because if i deleate the egr in m y car the smog computer will show that i deleated. how would i make it think i had a lt4

I don't beleive the computer will pick up that the EGR has been unprogrammed. It doesn't here in GA. LT1 edit turns off the EGR and the trouble code.

The LT4's installed in the Corvettes definitely did not have an EGR system. But I'm not so sure they deleted EGR on the 120+ F-Bodys..... maybe someone who actually owns one can tell us.

The LT4 F-bodys still had EGR, and the stock LT1 ecu (and programming).

Scott Settlemiere also told me that they have the LT1 cam as they wouldn't pass emissions with the LT4 cam.


I'll check an LT4 Vette file and see what they have the 'diagnostic test/set ses' set at.

While the LT4 SSs and Firehawks do have the stock f-body LT1 ECM tuning, I have never heard anything about them having an LT1 cam. They do have the LT1 fuel rails and injectors, but I'm pretty sure they have the LT4 cam, not that it's a big difference. The LT4 cam is really not much different than the stock LT1 cam:
LT1 205/207 117
LT4 203/210 115
The big difference was in the heads, intake and 1.6 Roller Rockers. The LT4s in the SS and Firehawk were also blueprinted and balanced by SLP, but I honestly don't think that makes a huge difference. Stock LT4 Vettes usually put down 300RWHP and most LT4 f-bodies that have had the ECM retuned put down the same thing, so the balancing and blueprinting might be making a few extra ponies and compensating for the more restricted f-body exhaust.