So I was running my stock tbi with a 14in k&N, xstream top, and a drop base. It ran great. Tonight I removed the tbi spacer and used a flat base. I think it ran better at low rpm but there were two flaws. It ran hotter and when running down the road at high rpm ( near govenor) it would sputter and have little power. Why would this simple change make it run worse and not better.

 

Vac leak ? Does it idle same RPM?

 

I dont think its a vac leak, it idles the same and it ran normal when i switched back. I think the issue was the air coming in from the side of the injector rather than coming in from top to bottom of the injector.

 

Thats the main reason of going to a flat base is to allow more airflow. my guess would be its leaning out at higher rpm's, its now not getting enough fuel for the amount of air coming in. If you aren't already running an adjustable fuel pressure regulator, get one. my car stock was at 11.5 psi and i now have it at i believe 13 or 13.5 psi. This should fix your high rpm lack of power with the flat base.

 

Sounds like a good thought and wouldnt be a bad idea. What regulator would you recomend?