I just got long tubes and 3 inch duals on my stock L03, now it idles around 1000 RPM all the time.

Im trying to figure out how exhaust would affect the volumetric efficiency, but I suppose it could? I did some searches and people were saying it WOULD. Maybe some of the old exhaust stays in the chamber when the new intake charge comes in?

The engine isnt going to stay in the car for too much longer. I know its way too much exhaust for the L03 and itw ouldnt have gone in if I didnt have an engine swap planned, but I was curious as to how much of a difference this has made. The 02 sensor is in the collector, but Im sure it's giving fairly different readings now too since it's so much farther downstream. In fact, I've got an Air/Fuel ratio gauge (narrowband) and I can see exactly what the ECM sees and it's definitely looking very different.

Was wondering if you guys had any experience with this and what you thought. Ijust want to make sure that driving it for hte next month or so isn't going to blow it up or something. I'm just worried about it going lean and causing problems.

Sounds fantastic though!

 

If this is the one wire stock O2 sensor then your problem may be that in its new location its not getting hot enough to work properly and its giving bad values to the ECM, causing the high idle. You may need to go to a 3 wire heated O2 sensor. I doubt the VE changed caused by the exhaust system is causing the idle problem.

Paul T.