98 Cobra tune and exhaust leak questions

[JDUB348]

So last night I helped a buddy install his new exhaust setup for his 98 cobra. He went with a BBK X pipe along with an SLP cat back.

First question is how does he go about addressing the exhaust leak he has? The exhaust leak is coming from the passenger side exhaust manifold. We tried to loosen and re tighten the two bolts, but the leak was still there. When I was running my old Mac Pro chamber for my terminator (for stock manifolds) I could swear there was some kind of exhaust gasket that went between the mating surfaces. Is there something like this for his 98?

Lastly, what does he need to do for the car to run properly? I was thinking he may need a tune from deleting the cats?

The car is 100% stock other than the new exhaust setup

 

[cbrown9064]

There is a one time us crush gasket on the passenger side. Get a new one. Sometimes you get lucky and can reuse it. Also, make sure and put AntiSeize on the studs. It will help to lube the threads. Make sure you the nuts go on all the way onto the studs without the pipe on. You could be jamming up before tightening the gap.

 

[JDUB348]

So how about tuning? Does he need a tune from deleting the cats?

 

[Deceptive]

Did he get an x pipe for the 96-98? Contrary to popular bullshit, a 96-98 mid pipe for stock manifolds is slightly different than 99-04.

 

[JDUB348]

Yes he did. He's running a BBK mid pipe for stock manifolds

 

[cbrown9064]

Also, I think there is a slight difference between the 96-98 Cobra and GT mid pipes. Brute force can make a GT mid pipe fit, but they are slightly different.

As far as a tune, there is no performance gain by deleting good cats on a stock motor (although it does sound much better). A mod to the EEC is required to prevent the Rear O2 sensors from tripping the Check Engine (MIL) light. The rear O2 sensors are there to check the state of what should be catalyzed exhaust. Without the cats the EEC says "whoa, your cats are not doing their job" and trips the light.

So, getting someone with the proper tools (Binary Editor among others) to go in and turn off the rear o2 sensors is what is needed. It is not really a "tune" but is considered one because the programming has been modified.

I have no experience with the hand held units (SCT, Diablo, etc...) but think they can modify this setting. I see conflicting advice on this. Binary Editor modifies all settings, but there are a couple ways to get the EEC to use the new data. Fun stuff for sure...