Let's clear-up that 3" vs 2,5" Catback thing for the LSJ.
11-09-2011, 10:04 PM
#102
I am liking the Bad mab because it seems to get good results for you lsj guys and is a bolt on to the stock downpipe. So I dont have to take it to a exhaust shop to do any welding.
I think I will be going the 2.5" route. If I get to the level that it cant support the power im making then so be it but I doubt itll be the hold back to my build.
Unless im off on this lol. Hard to tell from this thread. Seems to be a 50/50 split lol
11-10-2011, 07:06 AM
#103
Just curious...
Cause im currently on the fence on what to get.
But guys are making gains with a 3" over a 2.25 on a n/a cav eco.
Now im supercharged and plan on eventually going with the tvs...basically shooting for 300whp. Can I get away with a 2.5 and retain a somewhat good sounding exhaust or is the 3" going to make the difference?
The plan is a Bad-mab header, zzp catless 2.5" downpipe, cat, longest resonator I can fit, superturbo muffler.
Cause im currently on the fence on what to get.
But guys are making gains with a 3" over a 2.25 on a n/a cav eco.
Now im supercharged and plan on eventually going with the tvs...basically shooting for 300whp. Can I get away with a 2.5 and retain a somewhat good sounding exhaust or is the 3" going to make the difference?
The plan is a Bad-mab header, zzp catless 2.5" downpipe, cat, longest resonator I can fit, superturbo muffler.
His exhaust mods are as follows:
-Stock manifold
-2.5" catless downpipe
-2.25" GMPP catback
You should be fine.
11-10-2011, 07:31 AM
#104
Maybe this can be of some help...
tunes were the same for both.
I didn't post max values, instead here's temperature and humidity.
End result: 16whp gain
note: (2.5" was catless, 3" was with a high flow cat)
Don't see an issue with the noodle having an effect on the power band here... then again it's a mere 15.5 psi.
tunes were the same for both.
I didn't post max values, instead here's temperature and humidity.
End result: 16whp gain
note: (2.5" was catless, 3" was with a high flow cat)
Don't see an issue with the noodle having an effect on the power band here... then again it's a mere 15.5 psi.
Last edited by 100% METH; 11-10-2011 at 07:52 AM.
11-10-2011, 07:57 AM
#106
Wsfrazier's graph:
TVS, stock manifold, 2.5" catless downpipe, gmpp 2.25" catback
Smaller than stock piping seems to flow well enough for this kind of horsepower output, and airflow....
This is why the debate of "what size exhaust" will never really come to an end.
TVS, stock manifold, 2.5" catless downpipe, gmpp 2.25" catback
Smaller than stock piping seems to flow well enough for this kind of horsepower output, and airflow....
This is why the debate of "what size exhaust" will never really come to an end.
Last edited by Staged07SS; 11-10-2011 at 08:18 AM.
11-10-2011, 08:40 AM
#107
^gotcha...buy one and stick with it.
Now it comes down to sound I suppose. Is the 2.5" going to sound better?
Reason I ask is I already have a 3" superturbo I bought when I was going turbo but if its going to sound better being a 2.5 ill sell it and buy 2.5" parts.
*** and like you said. in two posts I get info supporting both sides lol.
Now it comes down to sound I suppose. Is the 2.5" going to sound better?
Reason I ask is I already have a 3" superturbo I bought when I was going turbo but if its going to sound better being a 2.5 ill sell it and buy 2.5" parts.
*** and like you said. in two posts I get info supporting both sides lol.
11-10-2011, 08:46 AM
#108
^gotcha...buy one and stick with it.
Now it comes down to sound I suppose. Is the 2.5" going to sound better?
Reason I ask is I already have a 3" superturbo I bought when I was going turbo but if its going to sound better being a 2.5 ill sell it and buy 2.5" parts.
*** and like you said. in two posts I get info supporting both sides lol.
Now it comes down to sound I suppose. Is the 2.5" going to sound better?
Reason I ask is I already have a 3" superturbo I bought when I was going turbo but if its going to sound better being a 2.5 ill sell it and buy 2.5" parts.
*** and like you said. in two posts I get info supporting both sides lol.
100% Meth posts good data for his particular setup. Not everyone will see those kinds of results though.
You can make a 3" sound decent with the proper muffler and resonator combo. A 2.5" will more times than none be quieter than a 3" setup.
11-10-2011, 10:52 AM
#110
I don't know the full details of his tune either (timing, AFR, ect.), but he is still making impressive power with such a small diameter exhaust.
I am by no means promoting using a small exhaust, I just don't want some of the members to think bigger is always better.
There are a lot of factors that govern using a certain size exhaust for a particular application that many do not account for.
Last edited by Staged07SS; 11-10-2011 at 11:19 AM.
11-10-2011, 11:57 AM
#112
It could have been due to a number of things.
I do feel though that a car that is flowing the kind of air a TVS or MP90 can produce should run a larger exhaust.
I'm just trying to post some power examples to show what people have made with smaller than 3" exhaust setups.
Wes's was the only one I could really think of off the top of my head.
Last edited by Staged07SS; 11-10-2011 at 01:17 PM.
11-10-2011, 04:03 PM
#116
I'm sure fuel plays a big role here
Below is a comparisson of a TVS and MP90 on the same dyno. Over here our torque curves peak way sooner.
Note: I've substantially improved the advance table since my days on the dyno with the MP90.
TVS | 2.6 PULLEY | ZZP INTAKE | METH 21gph | PORTED HEAD | BADMAB HDR | 2.5" DP & CATBACK | 25-28* advance, knocked post 6500 rpm unfortunately. I'm pretty sure I've found the limits of water injection... If you throw a lot of timing at peak cyl pressure, the water injection can only do so much.
MP90 | 3" PULLEY | ZZP INTAKE | METH 19gph | STOCK HEAD | BADMAB HDR | 3" DP & CATBACK | 18-25* advance
Maybe I'm going about this all wrong...
Figure with a aggressive head port, ATI Dampener, NB shafts or delete, supertechs springs, a set of stg2 zzp cams or similar, and a 8k redline.
I think thats a winning combination most should aim for, taking full advantage of our small displacement. Rather than throwing a million degrees of advance at it and 20+ PSI.
Below is a comparisson of a TVS and MP90 on the same dyno. Over here our torque curves peak way sooner.
Note: I've substantially improved the advance table since my days on the dyno with the MP90.
TVS | 2.6 PULLEY | ZZP INTAKE | METH 21gph | PORTED HEAD | BADMAB HDR | 2.5" DP & CATBACK | 25-28* advance, knocked post 6500 rpm unfortunately. I'm pretty sure I've found the limits of water injection... If you throw a lot of timing at peak cyl pressure, the water injection can only do so much.
MP90 | 3" PULLEY | ZZP INTAKE | METH 19gph | STOCK HEAD | BADMAB HDR | 3" DP & CATBACK | 18-25* advance
Maybe I'm going about this all wrong...
Figure with a aggressive head port, ATI Dampener, NB shafts or delete, supertechs springs, a set of stg2 zzp cams or similar, and a 8k redline.
I think thats a winning combination most should aim for, taking full advantage of our small displacement. Rather than throwing a million degrees of advance at it and 20+ PSI.
Last edited by 100% METH; 11-10-2011 at 04:39 PM.
11-10-2011, 05:50 PM
#117
Well I know for myself somewhere north of 300 is the eventual goal. I plan on getting there with either a tvs or a mp90....whichever is available to me at the time.
But it maybe 2 years before I get there.
Unfortunately I don't have the luxury of e85........best I got is 94 octane and meth.
But it maybe 2 years before I get there.
Unfortunately I don't have the luxury of e85........best I got is 94 octane and meth.
11-11-2011, 12:22 PM
#122
Maybe I'm going about this all wrong...
Figure with a aggressive head port, ATI Dampener, NB shafts or delete, supertechs springs, a set of stg2 zzp cams or similar, and a 8k redline.
I think thats a winning combination most should aim for, taking full advantage of our small displacement. Rather than throwing a million degrees of advance at it and 20+ PSI.
Figure with a aggressive head port, ATI Dampener, NB shafts or delete, supertechs springs, a set of stg2 zzp cams or similar, and a 8k redline.
I think thats a winning combination most should aim for, taking full advantage of our small displacement. Rather than throwing a million degrees of advance at it and 20+ PSI.
https://www.cobaltss.net/forums/2-0l...blocks-264562/
11-13-2011, 12:43 AM
#124
Senior Member
Thread Starter
Join Date: 07-22-05
Location: Quebec City, Quebec
Posts: 1,591
Likes: 0
Received 0 Likes
on
0 Posts
Back to exhaust talk ...
About the new 2012 Buick Regal GS Turbo with "only" 270 BHP at 20 PSI of boost:
"A three-inch-diameter exhaust system provides reduced back pressure, resulting in higher engine power"
"A three-inch-diameter exhaust system provides reduced back pressure, resulting in higher engine power"