gettin exhaust upgrade need help!!!

I have an 88 xj, 4.0 straight 6. Want my truck to be much louder but still be able to pass California smog regulations. ANy suggestions about how to achieve this? i noticed that Borla sold a cat-bak exhaust kit for $340 online. Any good?

i have a magnaflow muffler on it now that came with the truck, it sounds decent when idling and when its started up, but when i really get on it, the sound seems to diminish. Im looking for a little more throat to it. something deep

flowmaster muffler with a turndown tip will be plenty loud and sound like a nascar when yuou get above 3k rpms.

I have a long body magnaflow on mine and i love the low rumble without all the screaming noise. try getting an exhaust shop to put a turndown tip on the end of your tailpipe, it will make it twice as loud to you without pissing off everyone else.

x2 on turndown. My XJ came with a turndown after stock muffler from PO. I now have a 14" 4x9 oval maggy. I love the way it sounds. No drone, due to straight-thru design.

Be careful here, I failed smog this year due to high NOX. RENIX has a Vacuum Transducer between the EGR Solenoid and the EGR. The Transducer acts as a regulator for the vacuum to the EGR, it works on exhaust Backpressure, it requires 1 to 2 psi of Backpressure to open. If it does not open there will be no EGR which will give you high NOX. Mine was 1650ppm with no EGR and 250ppm with EGR. I had installed a Borla header, 2 ½” Cat, 2 ½ pipe and 2 ½ Flowmaster 50.

Turn downs may sound neat but have you every fallowed anybody that has one on a dusty trail? They blow straight down in to the dust and raise a cloud. You will look like Pig Pin from Charley Brown driving around in a cloud of dust!

Not to mention you have to be very careful about *how* it turns down. A couple of SoCal guys have had the geometry work out that their exhaust cooked the rear diff on the highway.

I have a 2.5" header, 2.5" high flow cat, flowmaster 40 and 2.5" to the tailpipe. It growls, is almost TOO loud, and passes smog fine.

cal said:

Not to mention you have to be very careful about *how* it turns down. A couple of SoCal guys have had the geometry work out that their exhaust cooked the rear diff on the highway.

I have a 2.5" header, 2.5" high flow cat, flowmaster 40 and 2.5" to the tailpipe. It growls, is almost TOO loud, and passes smog fine.

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Hey Cal what year is your XJ?

had an 87, now i have an 88. similar setup on both.

cal said:

had an 87, now i have an 88. similar setup on both.

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Good to know. I don’t want to highjack this thread so I am going to start a new one to discuss Back Pressure

cal said:

Not to mention you have to be very careful about *how* it turns down. A couple of SoCal guys have had the geometry work out that their exhaust cooked the rear diff on the highway.

I have a 2.5" header, 2.5" high flow cat, flowmaster 40 and 2.5" to the tailpipe. It growls, is almost TOO loud, and passes smog fine.

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who makes your header?

i have a high flow cat, muffler, i plan to get the down pipe and tail pipe bent up. i just cant find a 2.5" header that is 2.5" at the collector.

505's 2.5" header:
http://www.shop.505performance.com/product.sc?productId=250&categoryId=23

I've always wanted to work out a side exit exhaust right in front of the rear tire.