Stillen Headers Installed

[XPLORx4]

Why are you using 93 octane? Headers or no headers, the 3.3L engine is designed to use 87, so you're just wasting $4 per fillup.

Edited June 6, 2007 by XPLORx4

[dernt]

Why are you using 93 octane? Headers or no headers, the 3.3L engine is designed to use 87, so you're just wasting $4 per fillup.

 

It pings like crazy on low octane fuel. I get premium at a local station that sells it for the same price as mid grade on Fri and Sat. It costs 0.10 more per gallon than 87 octane on those days. So it costs me $1.80 more per fill up. With the cost of gas now, the difference in price is neglible.

[dernt]

Is it a 3.3L engine? Assuming so, since it's a 98. Loosen off the distributor, and give it a turn. Same as the WD21 Pathfinders.

 

So then what happens to the fuel timing vs. ignition timing once I do this? I might try it next dyno pull, but i suspect it is already somewhat advanced due to the pinging mentioned in my prior post. I'll stick a timing light on to check.

[turbopath]

Do you still have oe cat's and exhaust out from the headers? That would explain the low gain. The printout you have is likely sae corrected hp and tq and the computer file is actual. My experience on headers on my other vehicles was a slight change of powerband with a factory exhaust, and a noticeable gain with nice open exhaust. BTW, leaner AFR's like that don't hurt hp on a NA engine. I made peak hp on my other car with an AFR of 14.1:1....that's the hottest and leanest I could go without knocking and it showed about a 5hp gain over 12:1. Obviously you don't want to run that lean for daily driving though. You may want to try out a safc to see if you can richen it up just a hair, but I think you may have something else going on with your car. The fact that you require premium should say something. Check your fuel filter/injectors.

Edited June 6, 2007 by turbopath

[Simon]

Well, that's ignition timing. If it's advanced, that could definitely cause your pinging, and it's probably helping your horsepower numbers a touch, though, is also probably hurting your torque output, at least, at lower RPM's. Try putting a timing light on it, and running it at stock timing (15 degrees BTDC, IIRC) and see what happens.