Are 89 exhaust manifolds the same as 92?

The RH manifold shows as a different number from 89 - 91 vs. 92 - 93, but the left side manifold is the same number. The main difference may only be the 92 - 93 manifold for the R/S probably doesn't have a hole for the EGR tube connection, since 92 - 93 did not have EGR. So with 89 manifolds, just putting a plug in that hole may be all you need to get it to work.


cheers
Ed Nicholson
SCCoO
 
Would you recomend the porting of the exhaust manifolds or for me to put headers on? Would there be a big diference or would I just be wasting my money on headers?

**Main question: Can I put on headers / ported exhaust manifolds without generally dissrupting my engine compartment, or will I have to start pulling the engine apart, or even pull the engine?
 
Headers are definitely NOT a waste of money.

If you ever get a chance to compare the stock manifolds to headers (as we did last month at our tech meeting) you'll have no doubts.

Of course if you're not going to open up the rest of the exhaust, why bother with either option.

I think you'll find that the 1st thing to do with these babies is uncork the exhaust, THEN the intake and fuel. Especially if you want to keep your HG's intact.

Lee
 
The deal is that I am looking at taking out the current system, running new custom downtubes to two high flows, through an "X" pipe, and out through two Borla's. I don't want it crazy loud, just mild and rumbly. What do you think of the set-up I have in mind. I also thought about using 2.25" pipe? Any suggestions out there?

Also, leaving the engine intact? Anyone done this and care to comment?

Many Thanks.
 
That exhaust with headers are probably good for about 20Hp.

The intake (sound box and 55mm TB) is pretty restictive.

Hi flow intake with 70mm TB and 73mm MAF cal'd for and install 36lb injectors should double the exhaust mod's. Anything more than that and I'd think about increasing the fuel pump.

The next big gain in 1/4 times, or street racing would be to change your rear end gearing.

After that, real gains are going to take some engine dis-assembly.

It's tough to stop after you've started. :p

Lee
 
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6 of 1, half dozen of the other.

To do it from the bottom, dropping the crossmember helps - or having tiny hands and flexible arms.

From the top - yeah the IC tubes have got to go.

Lee
 
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