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Hi: new to Forum. My 91 2.8L just failed the safety inspection due to rust hole in the muffler and exhaust. While I'm underneath changing things, it would be a great time to upgrade the exhaust system as a whole.

Are there any supliers of performance exhaust components for the 2.8L? For that matter, is there anything to gain by upgrading the exhaust (say in conjuction with a better TBI)?

In particular headers, hi flow cats, or exhaust? If so, can anybody recommend a vendor? Has anybody tried to use the Chevy S-10 2.8L Headers from Pacesetter on the Trooper? Thanks, mfp
 

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A 2-1/4" cat and exhaust will give noticable gains. Plenty Trooper Folks have been using the Dynomax Super Hemi Turbo for less restriction and good sound (not too noisy either). Summit Racing has these for a good price and also good deals on generic replacement cats.

If you ever plan on putting a 3.4 in your rig for a huge increase in performance (and you can make it emissions-legal, too !), put a 2-1/2" exhaust in. If you have a good muffler shop, have them open up the exhaust "wye" to splice in the 2-1/2" pipe, as the exit of the "wye" is quite small and would give a large restriction in the line. Also have the muffler shop custom-bend the exhaust piping to take out some of the unnecessary, restrictive 'kinks' in the Trooper's exhaust system, aft of the cat and muffler. There's a few bends back there that really don't need to be there.

Doubt that S-10 headers will fit, some have made custom-fit headers out of a set of those but don't expect a bolt-on fit. Obviously they'll bolt up to the motor but there are clearance issues with various parts of the vehicle.

If you do decide to mess with headers, don't use Edelbrock T.E.S. headers as they have unequal-sized runners from one side to the next; this was supposed to be used in conjunction with their carbureted Performer manifold which also had unequal-sized runners. Obviously in a TBI-equipped motor this won't work well!

You may be able to find some special "block hugger" type of headers which then could have downpipes mfr'd to fit.

Also, the Camaro 3.4 stock exhaust manifolds have 2" outlets vice 1-7/8" of the 2.8. You could fit these and have 2" downpipes coming into a 2" dual-inlet-to-2-1/2" single-outlet "wye" and have a true free-flowing exhaust.

Of course this is WAY more than your 2.8 really needs, especially with no other mods.

You'd want to bore your intake and install a larger TBI to take advantage of the freer-flowing exhaust.

A set of 1.6:1 roller-tipped rockers will "juice up" your motor too. You'll want to do mods to the air cleaner for better flow, as the stock setup is quite restrictive. I'm running a K&N filter in mine and also spliced in another "snorkel" into the air cleaner body, it breathes better, retains the stock air stove valve, and is much quieter than flipping over the air cleaner lid or drilling holes in the lid.

BTW, if you haven't done so, just flip the air cleaner lid over and see how much more responsive your motor is at midrange & up. You'll likely be amazed.

Of course, the ultimate power increase is a 3.4 swap. You just can't believe the difference in power and torque levels between these 2 motors. I had a highly modified 2.8 in my old Trooper, the 3.4 with the same mods is just incredible. If you're interested drop me a private mssg and I can forward a load of info on the swap.

Here's a good article on Power Mods at the Outdoor Wire Isuzu site:

http://www.4x4wire.com/tech/60degreeV6/?

HTH and have fun...........ed
 
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