I went to the track last night to test out the new headers and my time is in my sig., with a 2.07 60'. The ET is the same as before last night, but I gained 1 MPH.

The car has never been "tuned", but my SES light will not turn off. Even after my mech. turned it off, it came on an hour later. My car went w/o rear O2s for a while before I ordered extensions. They're plugged in after both cats in my y-pipe. Could their location possibly be harming performance? The car feels a little stronger on the highway and around town. Is my engine a dud, or is this a normal time for my car's setup? The dyno number is from a long time ago too.

 

you shouldnt need a tune anyway with just those mods. is the rear o2's the only code being thrown? may have another issue your unaware of. lt's are also not going to be too noticable on your 60', so dont expect to cut a 1.8 with that addition. take it to the dyno again to see if you did gain anything, and who knows, could have been a sh*tty track night. around here same track from hour to hour can give everyone +/- .2 (englishtown nj)

 

Yeah, I didn't think I'd need a tune.

It's got to be the rear O2s, they're probably not in the best location and that's probably what's throwing the codes. I've heard sometimes that a car's O2s can hold back performance if they're not functioning to their full potential.

My previous best time (before the LTs) was a 13.3@105 with a 2.0 60' as well. I didn't expect to lower my 60' with the LTs, but I did expect to gain more than 1 MPH and reduce my ET, with pretty much everything else being as equal as my previous time out.

 

The O2 sensors are only used for cruising and light-moderate acceleration when the car is in closed loop.

When the engine is under full acceleration, the O2 sensors stop measuring air/fuel and the car goes into open loop, where it uses programmed fuel/timing tables from the computer.

The O2 sensors are not the problem.

Mike

 

Also, you didn't mention if the car is a 6-speed or an automatic. Obviously the driver can come into play if it's a 6-speed.

You may want to get your car dynotuned once you finish your bolt-ons. You'll probably pick up around 10-15 rwhp.

 

I was always under the impression that a tune would be needed when you get headers. From what I have read the OBDII computer will automatically adjust things to bring power levels back to stock if you put on parts that inhance airlow and exhaust flow. However, I have read differant on here many times.

 

Wow. That statement couldn't be any more wrong.

Mike

 

3.23 gears = A4

Maybe my trans. is holding me back.

 

I think a higher stall is in order. You don't list that in your mods.

 

Here's what I had read that told me that. It's from a Hot Rod build-up of a 96 Camaro, the first to have OBDII.


They continue to bolt on intake and some shorty headers, then say they don't gain much, attributing that to the OBDII (although it could just be that they used shorties )

They never got a tune till they installed heads and cam.

I coupled that along with the posts made on here that people pick up decent power when they get a tune after installing headers or their car's running funky after installing a set and came up with my reply.

Then again, I have yet to install headers on this car, and you have.

 

Ugh, that's why I stopped reading Hot Rod and the other magazines that make for silly build-ups, along with Horsepower TV and their marketing bull**** that put retarded parts on cars.

It's just not true. The computer isn't going to "return back to normal". There's a set of fuel/timing charts that's programmed from the factory that the computer reads from during open loop driving and no o2 sensor feedback. The only thing it's going to do is retard timing if it hears knock. Maybe you won't get as MUCH of a gain as you would from a tune, but you surely wouldn't "Return to stock." That's ridiculous

Mike

 

Thanks for setting me straight I learn something new all the time from this site.

 

My car still has the stock converter.

Would it be a waste for me to get drag radials without a higher stall? I'll probably get a nice set of DRs in a few months, they're a necessity.

I just thought I'd run at least a 13.1@107 with headers. About $1,600 for all of this and there's barely an improvement, you don't know how I feel.

 

It's not a waste if you're car is spinning off the line

I wouldn't worry about MPH increases too much with an automatic and bolt-ons. They aren't going to be the same as a 6-speed car because you have more drivetrain loss. Focus on getting a nice converter (I'd say a 3600 minimum) and pulling a wheel during a great 60'......something a 6-speed can't due....converter torque multiplication

Mike