3in exhaust on jrsc?

[MADDracer]

anyone got one?

by the way i got a greddy sp for sale. make me an offer

[waveoff]

A 3" exhaust won't do you much good unless you have a turbo. Sure the 3" will make more noise but don't be fooled...it'll be making LESS power. I'd stick with your GReddy or better yet go back to the stock exhaust.

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Fred G.
'97 Civic EX supercharged http://www.geocities.com/motorcity/track/4059
Beech 1900D driver...2,558 shp, 10,000+ ft./lbs. tq., top speed 331 mph

[cpa]

I'm in the same exhaust decision dilemna for the JRSC. It seems no one has any reliable, real world results isolating data on exhaust options . I have a stock exhaust now and the torque falls off quickly at the top end. I think freeing up flow will help, but what size piping and/or which exhaust seems anyone's guess.

[Zeus]

3" would even be good for 6psi, maybe not mandatory...but beneficial...basically anytime you force more air though your engine, you have to move more air out...sorry to be so simplistic, but people need to move out of this 50's style thinking when it comes to exhaust back pressure. In any application you want the biggest exhaust you can get without decreasing exhaust gas velocity. I'm too old to flame so I hope no one takes it that way...I don't have the energy for it. However, as the dynamics of the modern small displacement engines have changed, the masses of "street class" hotrodding minds have moved forward very slowly...hell, 10 years ago a 60mm exhaust(Greddy SP for example) was thought to be to huge for a NA small displacement engine...now the fastest small displacement engines are being run with quote-unquote huge primaried open headers...go figure. It depends on what you want to "tune" for...yes it can be argued that some torque can be lost down low, however, I really don't think that to be an issue as the average SC'd Honda owner hasn't learned to control their "new found torque" off the line (or light) anyway... I'd be willing to bet that most people would be disappointed in their boost gauge after "opening up the exhaust" header back. All things being the same, you would "lose" a pound, maybe two of "boost pressure"(excessive back pressure is more like it) on the gauge, but the dyno and more importantly, the speed at witch your engine accelerates through its power band would sing a different tune. Now if you look at my sig. below, you would think me a hypocrite. Remember that my wife?s SC?d GSR was built fast enough to land her with adjudicated probation...I quit building on it when she couldn't control her right foot...If she can be good for a while, I?ll pick back up with the fuel issues and a full exhaust including a 3? section from the rear of the header back...

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1998' 4dr GSR, 8psi JRSC w/hand ported plenum, Walbro HP fuel pump, valves set to .005i/.006e, MSD BTM, B&M CommandFlo regulator(working it out), stock intake w/resinator cut off at fenderwell for "cool air", Greddy sp exhaust, Tokico Illumina 5-ways, Neuspeed springs(sux!), Skunkworks 22mm rear swaybar, ES motor mounts and front swaybar bushings, Yokohama AVS 205/50/15's, Metal Master brake pads(KVR Carbon Fibre pads sitting on work bench) ,B&M fuel pressure gauge, Autometer sport comp A/F gauge in dimmer location...

YLW 00' ITR #00-1011 with AEM CAI and 143db triple air horns

Honest officer, I had no idea how fast I was going...the speedometer only gos to 150...

[Marc]

IMO, a 3" exhaust is overkill on a supercharged engine. An aftermarket exhaust has proven to be benficial over the stock exhaust. It all depends on how restricitive the factory parts are will determine how much of a gain aftermarket products will show. I think a 2.5 inch is more than ample for a blown motor. I run a 60mm Greddy exhaust on my car.



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Marc
1997 Civic EX, Supercharged

[Holden]

Don't forget that there's no point in running a 3" exhaust if you still have the stock cat.

I have RSR 4-2-1 headers, stock cat and a Greddy PE (60/70mm) and I STILL see over 8psi on the boost gauge with my 6psi setup.

I've seen people with my same setup but a Random Tech cat and they only see 6.5psi.

Soon I will be getting one. I'd get a straight pipe, but the thought of exhaust work every year to pass inspection and the risk of breaking O2 sensors in the process makes that idea not worth the ponies.

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Greg Holden
96 GSR, JSRC, I/H/E, yada yada yada...
My JRSC Install Site

[lundgren]

I have an RS-R exhaust, stock header and cat, I see 8-9 psi max and I run an 8psi pulley.

I do think the right header can help, and that a 3 inch exhuast would help also.

Think about it this way, cars making 220 at the wheels have larger, or sometimes dual exhausts. If you take the entire cross section of exhaust, you'll find that it is equal or larger than 3 inches.

[plumvtec]

Usually guys that have a 6 PSI kit and see higher boost pressures is a result of a choked up exhaust. It's basically back pressure the blower is creating with a restrictive exhaust.

Upgrading your exhaust: Cat. muffler,pipe ID should reduce back pressure and ultimately lower your boost readings. You will in essence get a more accurate reading on your gauge.

A 2.5" ID should be fine. The cat. is probably the most restrictive part in the System. IMO.

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'96 JR6 GSR Sedan (black currant pearl)
'93 Honda CBR 900RR
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[Zeus]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Holden:
Don't forget that there's no point in running a 3" exhaust if you still have the stock cat.

<HR></BLOCKQUOTE>

Sorry Holden, that was supposed to be an unstated "given"...



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1998' 4dr GSR, 8psi JRSC w/hand ported plenum, Walbro HP fuel pump, valves set to .005i/.006e, MSD BTM, B&M CommandFlo regulator(working it out), stock intake w/resinator cut off at fenderwell for "cool air", Greddy sp exhaust, Tokico Illumina 5-ways, Neuspeed springs(sux!), Skunkworks 22mm rear swaybar, ES motor mounts and front swaybar bushings, Yokohama AVS 205/50/15's, Metal Master brake pads(KVR Carbon Fibre pads sitting on work bench) ,B&M fuel pressure gauge, Autometer sport comp A/F gauge in dimmer location...

YLW 00' ITR #00-1011 with AEM CAI and 143db triple air horns

Honest officer, I had no idea how fast I was going...the speedometer only gos to 150...

[phatcivic97]

the other thing to consider is- how big is your dump on your header, i doubt it is 3 inch. prolly 2.5. no point in going bigger than that, if you could find a quiet muffler you could go 3 inch on the openings to aid on flow. cuz i hear the straight thru on a sc is really loud.

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