2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

exhaust.?

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Old Nov 30, 2005 | 09:42 PM
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exhaust.?

ok i used the search and its acting up for me and saying no results found etc.

i have a 87' turbo





if i go with this exhaust

what all do i need to know installation wise.. and about the ports etc.?
thanks

http://cgi.ebay.com/ebaymotors/RX7-T...16919444QQrdZ1
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Old Nov 30, 2005 | 09:44 PM
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you dont need to know anything to intsall it, just unbolt your old exhaust and put that one on. And what about the ports? If you refer about the 5th/6th ports, turbos DO NOT have them.
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Old Nov 30, 2005 | 09:46 PM
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ugh...
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Old Nov 30, 2005 | 09:47 PM
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ok sry bro... i kno about cars etc.
but i just picked up my rx-7 and still learning everyhting bout rotarys and there whole setup.
THANKS MAN
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Old Nov 30, 2005 | 09:49 PM
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well... he says it all
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Old Nov 30, 2005 | 11:00 PM
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with this exhaust system would i need to port the wastegate etc?
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Old Nov 30, 2005 | 11:03 PM
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port the WG if you open the exhaust up....
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Old Nov 30, 2005 | 11:07 PM
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wut do u mean by open the exhaust up???
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Old Nov 30, 2005 | 11:10 PM
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Originally Posted by cls6888
wut do u mean by open the exhaust up???
if you run without a catalytic converter=open exhaust.
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Old Nov 30, 2005 | 11:16 PM
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If you install that exhaust your boost level will almost certainly rise to the point where fuel cut is activated (8.6psi) because the S4's wastegate is too small to control boost properly once you increase exhaust flow. You need to remove the turbo and port the wastegate as big as possible to prevent this. This will allow you to keep boost below the point of fuel cut. If you want more than 8.6psi you need to install a fuel cut defender (FCD), but you should not do this without at least upgrading the fuel pump.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/serious-s4-wastegate-porting%85-343788/
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Old Dec 1, 2005 | 05:41 AM
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well , would it b recommended to port wastegate even if i kept the cat...?

cuz im trying to stay away from porting at all possible becuz , im not 100% knowledgable with the rx7 yet and i dont really want to have to take apart my turbo and engine just becuz of exhaust.
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Old Dec 1, 2005 | 06:13 AM
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You don't need to touch the engine, just the turbo. See the link I posted.

The cat might keep boost low enough, but it might not...
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Old Dec 1, 2005 | 11:59 AM
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Originally Posted by NZConvertible
You don't need to touch the engine, just the turbo. See the link I posted.

The cat might keep boost low enough, but it might not...
If it's not a HF cat, it should be fine, should'nt it? Don't qoute me on this guys, it's actually more of a question than a statement.
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Old Dec 1, 2005 | 06:55 PM
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^ is this true???
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Old Dec 1, 2005 | 10:33 PM
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Depends on the rest of the exhaust as well. If you have a hi-flow cat, and a really restrictive exhaust it'll control it. Just depends on your exhaust flow overall. cat's will severly screw some exhaust flow up. Therefore keeping boost under control. . Just port out your wastegate. Pretty easy. Find a write-up around hear somewhere and follow it. Completely fool-proof.
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Old Dec 2, 2005 | 11:57 AM
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ok well say i were to get the dual exhaust that i posted off ebay...

would i need a diffrent cat or will that "race cat" restrict it enough?
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Old Dec 2, 2005 | 12:04 PM
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Good lord, no. What is that, 80mm? If you get that your gonna need some wastegate portage, no?
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Old Dec 2, 2005 | 01:24 PM
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seriouslt thats a nice exhaust system and all but i know from experiance that the doul exhaust setup is way to damn heavy for these cars and in the long run more restrictive because it has a y pip set up .. so its more cosmetic thaNanything .... i know from experiance that a free flowing exhaust with 3 inch pipe racing beat header and freeflow ractive apex i muffler both saves weight and adds hp and lbft of tq .... i had a dyno slip of my car and with the simple exhaust mod im pushing not 210 hp and 200 to the wheels .... dont ask how .. oh and i have k&n ... but with stok intake .. so not much difference ...
so my point is ... jst go custom single 3 inch and ull be happier
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Old Dec 2, 2005 | 02:00 PM
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Originally Posted by cls6888
ok well say i were to get the dual exhaust that i posted off ebay...

would i need a diffrent cat or will that "race cat" restrict it enough?
They advertise it as a race cat, but its not a cat at all, just a muffler or presilencer. So yes port your wastegate.
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Old Dec 2, 2005 | 02:12 PM
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wel lim goin for looks and power and i dont really wanna go with single exhaust for the fact id have to fill the other exhaust hole on the bumper and then repaint it becuz i dislike the loook of single exhaust with a extra hole in the bumper.
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Old Dec 4, 2005 | 06:15 AM
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Originally Posted by rotary downshift
seriouslt thats a nice exhaust system and all but i know from experiance that the doul exhaust setup is way to damn heavy for these cars and in the long run more restrictive because it has a y pip set up...
Oh great, another completely ignorant post about dual (doul?!) muffler exhaust systems.

Way too damn heavy? The weight difference is well under 1% of the car's total weight. If you think you'll notice that you're kidding yourself. You add several times more weight than that filling the gas tank.

More restrictive? You need to learn about how pipe sizing affects flow far more than a Y; specifically how two correctly-sized pipes car easily outflow a single pipe.
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Old Dec 4, 2005 | 09:55 PM
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after reading through the forums a good amount it seems like a decent amount of people r putting exhaust on the turbo II and not porting the wastegate or putting a fcd on right away atleast...
is this a must need...? as u can see i really want a new full exhaust system but AS OF RIGHT NOW, i wanna stay away from having to port the wastegate and install a fcd and fuel pump.

??????żżżżżż
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Old Dec 4, 2005 | 10:40 PM
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If you NEVER drive it hard, you will be fine without a FCD/wastegate port. However, first time you hit the gas hard in the upper rev range, especially in 4th or 5th gear, you are going to hit fuel cut, which is rather unhealthy for your engine. If you are not comfortable doing the WG port (and it is really easy, and this is coming from someone who had never used a die grinder before I di my WG), just rig up the FCD, as that is quite easy to do. However, that brings about a whole new series of potential engine hazards, as it is easy to end up with more boost than you have fuel with just the FCD.
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Old Dec 4, 2005 | 11:04 PM
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Originally Posted by cls6888
after reading through the forums a good amount it seems like a decent amount of people r putting exhaust on the turbo II and not porting the wastegate or putting a fcd on right away atleast...
If you leave the stock DP and TID in place (i.e. cat-back exhaust and pod filter only) you'll be okay, but upgrade either of those and you will hit fuel cut. If you then add a FCD you'll find you're boosting too high to be completely safe with a stock fuel pump.
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Old Dec 4, 2005 | 11:26 PM
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To sum up, you can just install the exhaust, but you run the risk of doing serious damage to the engine, especially if you just put on the FCD. Don't you think its worth the little extra money and effort to avoid the huge money and effort of a rebuild?
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