Just wondering if anyone has any dyno numbers of their car with an open downpipe, then #s it put down after putting the full exhaust on. If I can be picky, I'd like to see full 3" dp & 3" catless w/dual resonators.

I just got my full 3" all done, and it seems to have had a bigger power drop than I was expecting. I'm not too sure if the noise before made seem faster, seeing as how I've only had 200 miles on boost to tune/play with it. Its either that or the fumes from before, I always smelled like exhaust before.

 

I was just having this discussion the other day about how louder cars seem faster.....

So i too would like to see some info backing this up.

 

I'd like to see this also.

My car picked up around 16 whp/20 wtq when I was running a 60mm Apexi exhaust (slightly smaller than 2.5"). However, I'd imagine that 3" with a really good flowing muffler would not make such a substantial difference.


Modified by tthame1 at 9:12 AM 6/23/2006

 

Hmmm waiting to see some results

 

What kind of power level are we talking? How well is the 3" exhaust made? Crush bent with a crappy muffler, or mandrel bent with a nice muffler?

 

this is 2.5 inch crush bent exhaust vs. a 3 inch stainless mandrel exhaust i made.
no other changes

 

those are some insane gains

 

yeah but he also went from crush bent which really sucks ***

 

id like to see some also...

 

my car at the track, i ran full 3" turboback, no cat, no res just a magnaflow muffler... I trapped 118mph. On my next pass i disconnected my cat-back so i ran sraight DP and trapped 119mph.. Didn't do anything different... 1 freakin MPH lol.... Not worth the sound at all. I hooked up my exhaust after that and trapped 119mph..... So Open DP doesn't do jack on my car

 

i have 2.5 no cat. when i run the cut out i gain 1 to 2 mph 103 goes to 104-5. wow

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo-charged &raquo;</TD></TR><TR><TD CLASS="quote">this is 2.5 inch crush bent exhaust vs. a 3 inch stainless mandrel exhaust i made.
no other changes
</TD></TR></TABLE>

thats a VERY good comparison!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1Quikgsr &raquo;</TD></TR><TR><TD CLASS="quote">id like to see some also... </TD></TR></TABLE>

 

LS turbo, 12.9 PSI

Stock Exhaust VS. Open 3inch downpipe

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eastcoast_ej6 &raquo;</TD></TR><TR><TD CLASS="quote">Went back to the dyno tonight to up the boost, 12.9lbs
final run with open DP(red) & with stock exhaust(blue)
</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eastcoast_ej6 &raquo;</TD></TR><TR><TD CLASS="quote">My stock LS-T

Meutek cast mani
t3t04e 57 trim .63 ar
2.5" charge piping
SSAC Precision 350 knock off intercooler
35mm WG
monza SSQV BOV
precision 525cc sat injectors
Motorola 2.5 bar map
adjustable cam gears
Apexi TT
LC-1 wideband
3" dp
3" DMH cutout (running stock exhaust when closed)

Tuned on Crome Pro @ JD racing
Need to get some more time on the dyno, have to do some cam tuning and raise the boost a bit.
dyno sheet was on 10lbs











Modified by eastcoast_ej6 at 6:39 PM 7/1/2006</TD></TR></TABLE>

 

so anyone else want to offer some dyno's, from open to full exhaust.. Perfered 3" Dp and cat-back

 

bump! good question you have going here.

im currently running an ecut but thinking of going full 3" no cat. i honestly dont think the difference between the 2 will be substantial. as some others have said, we are talking in the 1mph range

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackeg &raquo;</TD></TR><TR><TD CLASS="quote">bump! good question you have going here.

im currently running an ecut but thinking of going full 3" no cat. i honestly dont think the difference between the 2 will be substantial. as some others have said, we are talking in the 1mph range</TD></TR></TABLE>
Yeah i even made a 4" catback for my car but i took it off cause i was thinking a while back if i only trapped 1mph more from a open 3" DP then i see no point in going 4"... So im going to redo my 3" catback with some nice v-bands.... I think if your pushing over 650-700whp it would be good to step up to a bigger exhaust....

 

yea 650-700 is a lot of power, id probably want to run at least 3.5" on that.

good call on the vbands, makes it much much easier

 

all this 4" hype is getting out of control.... Some guys see 4" Dp on race cars, so they make it cause they think it will be better.... 3" is more then enough for the street. I mean if you have over 550whp on a FWD car its already pointless unless you have some nice tires.....

 

If you guys can wait until next Saturday (August 5th), I'll post back with a full 3" exhaust (Thermal R&D) vs. open downpipe. Tuning is next saturday so that's why.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AF-P Dunc &raquo;</TD></TR><TR><TD CLASS="quote">If you guys can wait until next Saturday (August 5th), I'll post back with a full 3" exhaust (Thermal R&D) vs. open downpipe. Tuning is next saturday so that's why.</TD></TR></TABLE>

im interested to see your results. What is your setup?

 

interested as well, I also like the sleeper factor of the cutouts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by moops vs moors &raquo;</TD></TR><TR><TD CLASS="quote">the main reason open dp makes more power than a full exhaust system is because of the extra boost pressure open dp adds on an internal gate anyways...</TD></TR></TABLE>


If thats happening then you have poor manifold design or an undersized wastegate. so ya know.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo-charged &raquo;</TD></TR><TR><TD CLASS="quote">this is 2.5 inch crush bent exhaust vs. a 3 inch stainless mandrel exhaust i made.
no other changes
</TD></TR></TABLE>


well that helped make my decision on whether to run my current 2.25" exhaust or change to a 3"


Modified by civicskater at 2:12 PM 7/30/2006

 

Turbo exhaust theory is simple. Its about high and low pressure zones. A larger exhaust will create a lower pressure zone so the air will want to travel from the manifold through the turbine due to the fact air flows from high to low pressure zones. The low pressure zone post turbine will also reduce back pressure on the turbine wheel allowing it to function more efficiently. In short, you will always gain some torque with a larger exhaust, how much depends based on the individual system