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Discussion Starter #1
My car seems to be ~8-16+ hp low compared to other cars w/ the same mods. The CE light bulb was removed by the previous owner when he installed an o/r H-pipe. No MIL eliminators were installed. I have changed H-pipes four times since I've owned the car. Right now I have BBK LT's and o/r X-pipe installed without MIL eliminators.
Would not having MIL eliminators or having bad o2 sensors cause timing to be pulled or something like that, causing me to lose some hp and/or torque?

My mods are...

Underdrive Pulleys
BBK Longtube Headers
BBK Offroad X-pipe
Borla Cat-Back
80mm C&L MAF w/ K&N filter
FRPP Single Blade Oval Throttle Body
4.56 gears
Carbon Fiber Driveshaft
Autologic Chip dyno tuned by Cerra Racing(pre LT's and o/r X)

My numbers are 285.4hp/281.6tq. Before the LT's and o/r X I had 282.7hp/273.7tq. My max numbers didn't increase as much as I had expected them to, but my best gain was at 5400rpm where I gained 10hp/17tq. Both dynos were Dynojets.

-Misc. info-
*Most '96-'98 Cobras w/ similar mods seem to be putting down 293 to 301+ hp.
*I've done a compression check and it was good w/ all cylinders beween 180-190.
*The chip was tuned w/ stock exhaust manifolds and a hi-flow catted H-pipe. Would a retune increase my numbers? Cerra now does data logging which I guess they didn't do back when they burned my chip.
*I haven't cleaned the IMRC's and have been thinking about just deleting them this winter while the car is in storage. With the gears, I don't think I will notice any low-end loss.
*If it's not o2 sensor related, what could it be?

Thanks!
 

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Only if your front O2 sensors are bad.....

The rear sensors will just trip the light but do nothing to affect performance. If your front sensors are bad though, they could be the the cause of a powerloss (timing pull, etc...).

Your tune is definitely part of the problem. When you change the exhaust as much as longtube headers affect the exhaust flow then your tune is not optimized for your setup now.

Tom Crews
 

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Travis,
front o2 sensors change the a/f ratio, the rear ones just check to make sure the cats are working. Just buy some MIL's and put the Check engine light back in, ya never know, you could have a code for something.
 

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Discussion Starter #4
Tom, are you saying that both front sensors would have to be bad to cause a power loss? Do you think I should just replace the front o2 sensors to prevent the possibility? I will get a retune eventually, but I'm wanting to wait until I get a SSR intake, probably next year sometime. I have to drive 900 miles each way to Cerra Racing. I don't think there's any better Autologic tuners closer to North Dakota.

Guido, I'm not sure how he disabled the light exactly, he may have cut the trace wire to it. I'm not too sure about removing the instrument cluster either, so I'd kinda rather just leave it as is.

Thanks for the replies, guys.
 

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Removing the guage cluster is easy, the only ***** is getting the headlight knob off. I broke mine but got a piece from UPR to match my radio anyways.
If I were you I'd get some kind of autotap or something so you can see what your computer is up to. Ya never know, you might have an IMRC MIL and you'll never know.
From a performance stand point I ran 13.8 @ 103mph on a 2.15 60' with 4.10's and catted X pipe
With my IMRC check engine light on I ran 14.1 @ 101mph on a 2.2 60'
Just to give you an idea of how much performance I lost from my computer pulling timing and dumping some fuel (I think the IMRC's werent staying closed, just not opening all the way).
 

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Discussion Starter #6
Well, I ran a 7.94 1/8th mile, which is about a 12.4 1/4, and I have my IMRC's set to open at 2850 and can feel it, so I know that's not the problem. I may pull the instrument cluster apart. Got any good write-ups on doing it?
 

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http://www.superstallions.com/tech/elect/96-98shiftlite/96_98shiftlite.html

It's a tech article on installing a shift light (From Bill Tumas) but it's pretty detailed on getting the cluster off the car. If you need any help just pm me but I had no problem doing it so I doubt you will.

BTW, why did you open the IMRC's at 2850? Did you dyno any improvement in a powerband by doing that?
 

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Discussion Starter #8
No, Mike just asked me if I wanted to change it, so I did. No dyno proof of anything. I have two settings on my chip. I think it's stock on the other setting.
 

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i'm pretty sure, i think the rear o2 codes would be say something about a catylyst, not 100% sure though
 

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Discussion Starter #15
Plugs were changed right before the dyno both times. Fuel filter was changed ~2.5years/5,000 miles ago when I bought the car.
 

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Discussion Starter #17
Does Checkers charge to use the reader?

Heard you got a new car, John. Did you pick it up already? Sounds like you got a pretty good deal on it.
 

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I think they charge to rent it, but it is just a refundable deposit. I know some people up there, so I just take it up there and use it there. I got a new car. Come by and check it out. I have a new job, and get off at 4:30 every day!
John
 
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