Exhaust Diffusers - Na Housings

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09-09-2003, 01:31 PM

#11

mazdaspeed7

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Join Date: Sep 2002

Location: Savannah, Ga

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Quote:

Originally Posted by BigTurbo74' date='Sep 8 2003, 09:52 PM

haha i guess i never checked back, nice

you would need a sleeve in there to have your car operate correctly. you can remove them by tig'ing the roll pins on the side of the housings and pullin them out.

Why do you say that? My car runs great with them out. I posted pics in the porting practice thread a while ago. But its not for everyone. It moves the powerband up, and makes the car very loud. When I had a stock engine, my car was barely louder than stock. With the same exhaust, and those exhaust ports, my car is almost as loud at redline as my friends gxl was with a stock motor and NO mufflers. He had headers, and a straight pipe. You cant hear the person next to you at WOT.

Basically, if you wouldnt drive a BP, then keep the sleeves. Its loud, and the powerband is high.

09-09-2003, 03:58 PM

#12

turborotor

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Join Date: Nov 2001

Location: LA, USA

Posts: 1,622

You have to take the sleeve off and keep them off if you want to truely port the exhaust. The benefits of them is to have good heat transfer into the exhaust. With them is a restriction and not a true port job.

09-09-2003, 07:03 PM

#13

88IntegraLS

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Join Date: Feb 2003

Location: Corvallis, Oregon

Posts: 223

Ha! True port job!

I'm a wannabe engineer. I am building an engine for a compromise (dual duty) role: civilized exhaust volume but able to flow to match the street ported intake ports. If you mean true race car or full race car, forget it! This will be my daily driver and weekend autocrosser.

I got a pair of TII sleeves on the way thanks to a want ad on the evil forum. I'll smooth them out and open them up a tad, and open the exhaust port a couple mm lower than stock but that's it. I want a decent midrange.

09-09-2003, 09:06 PM

#14

BigTurbo74

Senior Member

Join Date: Jul 2002

Posts: 2,315

huh i was always under the impression if you had no sleeves your housings would become too hot while driving... but if you run no sleeves, wouldn't you have to make a custom header to "port match" the exhaust port to the exhaust pipe?

09-09-2003, 10:43 PM

#15

mazdaspeed7

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Join Date: Sep 2002

Location: Savannah, Ga

Posts: 2,763

I had to grind the hell out of my RB headers, and its still FAR from a nice transition. Im in the process of making some custom headers to alleviate this though.

I never have had a problem with heat, in 12K miles in the blistering coastal Georgia heat. But, I did ceramic coat the inside of the exhaust ports, and on the motor Im about to put together, Im ceramic coating the intake ports also.