I did the 3.1L to 3.4L swap on my 92 Camaro RS and now have about 35,000 miles on the swap and rebuild. When I did the swap, I just used the original 3.1L ECU as is with no change but did get a new cam listed for the 3.4L engine. The performance has been good over these miles but the gas mileage was a bit less than with the original 3.1L engine. For much of those miles I was driving in Denver, CO so high altitude. I replaced the 3.1L air cleaner with the air snorkle out of a 5.7L so increased the air flow due to the thinner air. I would get about 26 to 28 mpg in Colorado (my 3.1L was getting 28 to 30 mpg originally) but now that I am back in the Pacific Northwest and about 500 feet altitude, the mileage is more like 22 mpg. I am typically running mid grade gas since that was recommended for the 3.4L (from a 94 Camaro donor car) but would like to run regular if possible. So, I am wondering if I should get a custom chip for the 3.4L swap to improve the gas mileage without affecting performance too much since gas prices are killing us in Washington State?

Opinions and experiences are appreciated.

Thanks....

 

Why not tune with $88 ?