sicivic12

Hey guys-

I bought a thermal R+D exhaust for my turbo setup, but am now considering going the supercharger route. Can I use that exhaust for the JRSC?

SleepyEG

You sure can. Assuming we're talking about a cat-back, there's no such thing as a "turbo only" exhaust. You can use that exhaust on your car, turbo, supercharged, whatever. Heck, you can use it on your lawnmower, your snowblower, etc.

Usually companies use "turbo" just as a gimmick, but in many cases a "turbo" exhaust will be a bigger diameter than other options. (Possibly 2.5" rather than 2.25")

EX R8ED

I'm pretty sure the Thermal "turbo" cat-back is 3" but don't quote me on that.

I'm sure there was a debate on using a 3" exhaust on a JRSC with stock boost somewhere. So my point is, it depends on how much boost you're running. Atleast thats what I took from that thread. Do a search on "JRSC exhaust"

SleepyEG

3" whatever, it doesn't matter. There is nothing to debate about. It will work fine. 3" is big, and it will be loud, but the question was will it work? Yes it will. Will it be the perfect exhaust, probably not.

hadboosttroy

3 inch with a jrsc will be obnoxiously loud if you ask me. unbearable if it is a daily driver!

SiR Kid

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hadboosttroy &raquo;</TD></TR><TR><TD CLASS="quote">3 inch with a jrsc will be obnoxiously loud if you ask me. unbearable if it is a daily driver!</TD></TR></TABLE>

There's an ITR with a 3" Thermal exhaust, a JRSC and a Hytech header running around... IT'S STUPID LOUD. He hated it.

MADEINIRAQ

i have thermal 3in with my jrsc.. yes unbearably loud.. haha.. i put a cat on and now its pretty tame unless you really get on it.. but not too bad.

95GSRTT

So getting a 3" TRD exhaust and carsound 2.5" to 3" cat would be really loud with a turbo set up? What would you guys recommend for something more quiet but 3" for the turbo?

bxsi

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SleepyEG &raquo;</TD></TR><TR><TD CLASS="quote">3" whatever, it doesn't matter. There is nothing to debate about. It will work fine. 3" is big, and it will be loud, but the question was will it work? Yes it will. Will it be the perfect exhaust, probably not.</TD></TR></TABLE>

not exactly true, superchargers don't necessarily want a 3'' exhaust like turbo cars. Some back pressure is needed with a supercharger, trust me i've been there done that. I made 248whp with a full 2.5inch exhaust setup no cat, made 245whp with stock 00 civic si rear section, no cat. made 235whp with open downpipe. All those combos were with 9.5psi. I'd say if your gonna go above 6 psi stay with a 2.5" , going 3'' will lose some low end torque. If you know the basics of how turbos work then you will understand how the "The best exhaust is no exhaust theory" doesn't apply to jrsc or na motors.

95GSRTT

Well since I do have turbo, a 3" exhaust would be best if I plan on running around 10-15 psi?

Since with my turbo I want no back pressure so the turbo can spool quicker right?

MachAF

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bxsi &raquo;</TD></TR><TR><TD CLASS="quote">

not exactly true, superchargers don't necessarily want a 3'' exhaust like turbo cars. Some back pressure is needed with a supercharger, trust me i've been there done that. I made 248whp with a full 2.5inch exhaust setup no cat, made 245whp with stock 00 civic si rear section, no cat. made 235whp with open downpipe. All those combos were with 9.5psi. I'd say if your gonna go above 6 psi stay with a 2.5" , going 3'' will lose some low end torque. If you know the basics of how turbos work then you will understand how the "The best exhaust is no exhaust theory" doesn't apply to jrsc or na motors.</TD></TR></TABLE>

No matter what your setup, you don't want back pressure.

An optimal setup will flow the greatest volume at the highest velocity. If you go too big velocity will suffer, if you go to small volume with suffer.


1. Larry Widmer of Endyn on Exhaust Backpressure:


quote:
--------------------------------------------------------------------------------


"from 21st Century Performance Book

Few tests have been done that clearly show the effect of changing back pressure. Most muffler and exhaust comparison tests change more than one parameter simultaneously, making the identification of exhaust back pressure as a culprit difficult.

However, Wollongong (Australia) mechanic Kevin Davis has done extensive testing of varying back-pressure on a number of performance engines.

These range from turbocharged Subaru Legacy RS flat fours to full-house traditional pushrod V8s. In not one case has he found any improvement in any engine performance parameter with increased exhaust back pressure.

The tests came about because Kevin has developed a patented
variable-flow exhaust that uses a butterfly within the exhaust pipe. He initially expected to use the system to cause some back pressure at low loads 'to help torque.'

However, he soon changed his mind when any increase in back pressure proved to decrease torque on a properly tuned engine. What increasing the back pressure does do is dramatically quieten the exhaust.

One of the engine dyno tests carried out by Kevin was on a modified 351 4V Cleveland V8. Following the extractors he fitted a huge exhaust that gave a measured zero back pressure. Torque peaked at 573Nm (423 ft-lbs) at 4700 rpm, with power a rousing 329 kW (441 hp) at 6300 rpm. He then dialed-in 1.5 psi (10.4 kpa) back pressure.

As you'll see later, very few exhausts are capable of delivering such a low back pressure on a road car. Even with this small amount of back pressure, peak torque dropped by 4 per cent and peak power by 5 per cent. He then changed the exhaust to give 2.5 psi back pressure. Torque and power decreased again, both dropping by 7 per cent over having zero back pressure. These results were achieved on a large engine with a large overlap cam - one of the type some people suggest is 'supposed' to like back pressure.


If, in fact, power does increase with increased exhaust back pressure, it is most likely the air/fuel ratio and/or ignition timing that are no longer optimal for the altered state of engine tune."