mr_mbuna

Hey guys,

I have a full Comptech bolton system: Icebox, Header, Carsound Cat, and Catback Exhaust. I was just given a Comptech Exhaust Silencer for Christmas (a message there???). From the looks of it, it seems the silencer restricts the exhaust to stock-diameter at the exit point. Does adding a silencer erase the performance gains I have added from my exhaust system and turn the entire package into a very very expensive cosmetic mod? Or does it have no effect on performance somehow? Or, oddly, does it have a beneficial effect on performance (one guy posted that it increased his torque w/o decreasing his hp)?

Thanks,
Ben

mildly.interesting

I've got the plug in my N1, and it does increase torque...not to mention it sounds almost stock

Tweakmeister

I don't know how it could ever increase torque...that's a myth haha (backpressure).

If the sound gets attention or bothers you then plug it. Not much use for a "performance" part on the street...not legally anyway.

Lysawy

its odd but i notice little better mid range with silencer

mr_mbuna

After doing some research on Team-Integra.net as well (the best Integra site out there, sorry Honda-Techers), I've found out that the silencer actually improves performance on mildly modded B18B1's! The consensus over there "is that with the smaller tip, peak volumetric efficiency was occuring at an earlier point. You can see that after 6300 rpm, the non-silencer setup begins to show slight increases over the silencer for the last 500 rpms. On a vtec engine which breathes much heavier at the higher rpms, the power loss in the higher rpms (6000-8000) would have been more substantial." -BlueTeg


Dyno run was for a B18B1 with i/h/e
Red line was with the silencer 123whp, 117tq
Blue line was without 123whp, 112tq
Dyno sheet courtesy of BlueTeg of Team-Integra.Net

Ben


[Modified by mr_mbuna, 5:40 AM 1/4/2003]

Tweakmeister

that's the B18B1, and what exhaust?

Those gains are hardly definitive

mr_mbuna

That's the same car, same day, consecutive runs, Integra LS with Comptech Exhaust, with and without Quiet Tip Insert. No need to be skeptical.

"Conditions:
105 degrees, sunny, 29.84 in. Hg (1010 hPa)

Run1: AEM CAI, Comptech header, Comptech exhaust, Comptech quiet tip insert (exhaust silencer)
123.1 whp 116.8 lb/ft tq

I was disappointed w/ my power output (I was hoping for at least 130whp) and decided to do a second run and remove the silencer in the hopes that it would free up some exhaust flow and get me some more whp.

Run2: same mods as run 1, but I was curious as to how much whp the exhaust silencer was sacrificing, so I removed the silencer and ran with the straight thru exhaust.
123.1 whp 112.2 lb/ft tq

Peak power was the exact same on both runs which surprised me......but what surprised me even more was when I looked at the dyno plot and realized that I had actually lost power when I removed the silencer. When they overlayed both runs on one graph, you can clearly see that the car showed increases in whp and tq across the board execpt for the last 500 rpms where the non-silencer setup gained 1-2 whp.

Whats even more interesting is that in the midrange, at the "aem hump", there was a very noticeable spike in whp and tq w/ the silencer installed. Almost 5 whp and 5 lb/ft of tq!

Even though I was fairly dissappointed that I wasn't even putting 130whp to the ground w/ my mods. I'm glad that I ran the car w/ both setups. I was concerned when I bought it that the silencer would rob the car of some whp, especially in the higher rpms where the engine really needs to exhale. Who would have thought that I would have actually gained power throughout the midrange and nearly the entire top end!

Next stop for the BlueTeg and 150 whp project......carsound hi-flow cat, and some Crower 403 cams w/ all the fixings! " -BlueTeg's post

mildly.interesting

w00t! I was right!

NVMYSi

Why do you need a silencer? I have a header, testpipe, comptech cat back, ITR CAI, ect... and its not that loud. That is one of the beauties of comptech, it looks almost stock and isn't loud until you hit the really high rpms.

mr_mbuna

Well now that it seems a silencer increases performance on a bolton B18B1, there is a benefit there. In addition, at times the Comptech is really "rumbly" and I'm going to see how it is with the silencer.

Ben

Tweakmeister

What you're basically saying is the Apex'i N1's piping is too big for the engine output when stock or with minor bolt-ons.

acydphryck

get it...you have everything else...

HuskerHybrid

what diameter piping is this dyno based off?

mr_mbuna

AEM CAI and Comptech Headers and Exhaust

Ben

HuskerHybrid

2.25,2.5,3.0?

mr_mbuna

If I'm not mistaken the Comptech system is 2.25" straight-through design.

Ben

mr_mbuna

Well the silencer is on... and the exhaust is returned to near-stock noise levels. It feels at least as powerful as before, but who knows how true the butt-dyno is.

Ben

joshalee

I just got the comptech exhaust for my 98 GSR yesterday. Sounds good. A little loud for me and I ordered the silencer. Anyone have pics? Soundwise, what should I expect? Will I get a lower rumble still?