88hybrid.com

nismopu · Posted: Tue Sep 30, 2008 6:23 am Post subject:

http://www.youtube.com/watch?v=uPt4ku4t_PI

it sounded like michaels but alot quieter IMO.
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my280

My DD ^, currently getting a 5 speed for traffic.

michaelp · Posted: Tue Sep 30, 2008 6:06 pm Post subject:

I used to run a 2 1/4" with the stock cat, no muffler and a resonated tip, sounded ok, but mostly like my car now only quieter...
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1984 300ZX NA2T, K&N filter, MBC, intercooler...WIP
1974 Datsun 260Z Project

Twisted`Z · Posted: Tue Sep 30, 2008 11:32 pm Post subject:

I know I need to pull my cat off because the exhuast is starting to smell funny, but I know if I pull the cat off, its gonna make the car sound like shit... I could always replace it with a new cat...
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1984 NA - 86T Front end conversion, intake, 2" exhuast w/ Apex'i Type R Muffler, 87T wing, clutch damper mod, e-fan conversion, 203,XXX miles
1985 NA - 4Sale, rolling chasis $200
1987 NA - Slicktop, build-up starting soon!

ZpassionZ · Posted: Sat Dec 27, 2008 11:06 am Post subject:

I have an n/a too but my exhaust works great! if i want to keep
the pressure for torque then upgrading seems useless....
would the best thing just be upgrading the cat only?
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1986 300zx N/A stock

DeleriousZ · Posted: Sun Dec 28, 2008 10:03 pm Post subject:

are you still digging up old threads?
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GT35 1988 300zx turbo: in hiding.

michaelp · Posted: Mon Dec 29, 2008 12:21 am Post subject:

FlyingT · Posted: Mon Dec 29, 2008 2:59 pm Post subject:

michaelp · Posted: Tue Dec 30, 2008 12:57 am Post subject:

1stcar86z · Posted: Fri Jan 16, 2009 5:55 pm Post subject:

back pressure is not a bad thing. I went with a2.5 straight back no cat w/ a can on it. It was slower than stock untill I upgraded my Throttle body, Built an Intake system and Bored the plenum elbow. In my opinon it depends on how much air your intake side can move. Go from that to design your exhaust. You want bigger intake than exhaust for sure. And size doesnt matter on the exhaust side flow matters. If you have steps and areas that open up at the exhaust that are no chaphered you are limiting the size on the pipe by creating air turbulence there is less useable flow area. As well as bends. even mandrel bends cause turbulence just no as much. This turbulence helps add to the raspyness of the exhaust because the air is bouncing around in the pipes instead of flowing smoothly. i am no pro but my friend is a mechanical engineer and this is how it was explained to me.
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My poor little NA Smile

phxZ31 · Posted: Fri Jan 16, 2009 7:32 pm Post subject:

DeleriousZ · Posted: Fri Jan 16, 2009 7:35 pm Post subject:

http://www.z31performance.com/forum/viewtopic.php?f=15&t=13866&hilit=backpressure

hate to link to outside threads but read up, and learn 1stcar86z

michaelp · Posted: Fri Jan 16, 2009 8:30 pm Post subject:

85_300ZXT · Posted: Sat Jan 17, 2009 6:20 pm Post subject:

http://videos.streetfire.net/video/Flybys-of-a-300zx-turbo_201460.htm
i have a turbo tho
but its a 3" no cat no muffler
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84 300zx Turbo 5speed GLL
85 300zx Turbo Auto GLL
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michaelp · Posted: Sun Jan 18, 2009 12:14 am Post subject:

http://www.howstuffworks.com/question172.htm

1stcar86z · Posted: Tue Jan 20, 2009 1:35 am Post subject:

okay so like i said i am no pro but this is how stuff was expained to me i was appartently wronge and i have since read the post article. But my car was defiantly slower with the 2.5 no cat, stock intake side (except for a can filter).
And mike you forgot to ask questions. so i will, were did your 2.5 start and did some of your y piping have to be replaced when your cat was removed? Did you have vac lines remove or were you stock on the intake side?
And i am sorry but the high end only made alot of noise after replacing the exhaust. I couldnt even keep up with my friends civic any more. Although i do agree that it increased the low-end torque a little.
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My poor little NA Smile

michaelp · Posted: Wed Jan 21, 2009 1:33 am Post subject:

1stcar86z · Posted: Wed Jan 21, 2009 2:50 am Post subject:

yeah mine was cut off half way down the y pipe and was replaced with 1.5 to a new y to 2.5 so maybe the loss of back pressure/flow velocity was the difference in mine and yours and the reason mine. plus i had the full shitty intake w/ a pos can untill i built the new intake for it. ill post some pictures of the new intake. on the project area soon i have no pictures of my progress though.
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My poor little NA Smile

michaelp · Posted: Wed Jan 21, 2009 3:03 am Post subject: