Cut-out/Y vs. True Duals
Thread Starter
On The Tree
Joined: Feb 2004
Posts: 185
Likes: 0
From: Atlanta
Cut-out/Y vs. True Duals First off I will say that I love the sound/performance of my true duals. But I have always wondered how a dyno comparisson of an open cutout y-pipe setup would compare to true duals. I've heard that the peak HP numbers are similar, but the duals make better power under the curve. Anyone have back to back dyno numbers?
The reason that I'm asking is I'm planning on lowering my car soon and am extremely worried about clearance issues with my 3" TD's. I live in Atlanta, with some of the worst roads ever, and have already scraped the duals a few times on stock ride height. I'm thinking I need to go to a cut-out/Y/cat back system or perhaps 2.5" duals.
The reason that I'm asking is I'm planning on lowering my car soon and am extremely worried about clearance issues with my 3" TD's. I live in Atlanta, with some of the worst roads ever, and have already scraped the duals a few times on stock ride height. I'm thinking I need to go to a cut-out/Y/cat back system or perhaps 2.5" duals.
yes i did back to back runs. but this was over stock exhaust. gained 11/13. but at the track, did nothing for the 1/4 mile. but did change what happened in the quarter. it moved the power curve upwards. look at the 60ft and 1/4 mph.
cutout closed ----- open
60ft - 1.987 ------ 2.074
1/8 - 7.902 ------- 7.912
mph - 93.20 ------ 93.97
1/4 - 12.102 ----- 12.080
mph - 117.12 ---- 118.06
cutout closed ----- open
60ft - 1.987 ------ 2.074
1/8 - 7.902 ------- 7.912
mph - 93.20 ------ 93.97
1/4 - 12.102 ----- 12.080
mph - 117.12 ---- 118.06
Originally Posted by mrr23
yes i did back to back runs. but this was over stock exhaust. gained 11/13. but at the track, did nothing for the 1/4 mile. but did change what happened in the quarter. it moved the power curve upwards. look at the 60ft and 1/4 mph.
cutout closed ----- open
60ft - 1.987 ------ 2.074
1/8 - 7.902 ------- 7.912
mph - 93.20 ------ 93.97
1/4 - 12.102 ----- 12.080
mph - 117.12 ---- 118.06
cutout closed ----- open
60ft - 1.987 ------ 2.074
1/8 - 7.902 ------- 7.912
mph - 93.20 ------ 93.97
1/4 - 12.102 ----- 12.080
mph - 117.12 ---- 118.06
I wouldn't exactly call that nothing in the 1/4 mile dude, you gained some nice trap speed uncapped.
My first setup was the Pacesetter ORY with dual cutouts. Lemme tell ya, that thing took away alot clearance.
I'll have pics this afternoon of 2.5" TD's lowered with the Eibach Prokit..
I'll have pics this afternoon of 2.5" TD's lowered with the Eibach Prokit..
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Originally Posted by LS1LT1
So this was just a Y pipe with a cut out closed versus open right? No duals involved I assume?
I wouldn't exactly call that nothing in the 1/4 mile dude, you gained some nice trap speed uncapped.
I wouldn't exactly call that nothing in the 1/4 mile dude, you gained some nice trap speed uncapped.
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Originally Posted by mrr23
yes i did back to back runs. but this was over stock exhaust. gained 11/13. but at the track, did nothing for the 1/4 mile. but did change what happened in the quarter. it moved the power curve upwards. look at the 60ft and 1/4 mph.
cutout closed ----- open
60ft - 1.987 ------ 2.074
1/8 - 7.902 ------- 7.912
mph - 93.20 ------ 93.97
1/4 - 12.102 ----- 12.080
mph - 117.12 ---- 118.06
cutout closed ----- open
60ft - 1.987 ------ 2.074
1/8 - 7.902 ------- 7.912
mph - 93.20 ------ 93.97
1/4 - 12.102 ----- 12.080
mph - 117.12 ---- 118.06
Originally Posted by Jorday
When I switched from a y pipe to true duals I only gained approx .1 ET and a mph or two.
that all could play an important role in the gain from one to the other
10 Second Club
Joined: Nov 2001
Posts: 1,724
Likes: 0
From: Fenton, MI
I had macs with off road pipe and an SLP dual/dual catback with a cutout,
I switched to thunder LT headers with an all 3 inch true dual system with x pipe, bullet mufflers and turndowns.
I didn't use cats on either setup.
I switched to thunder LT headers with an all 3 inch true dual system with x pipe, bullet mufflers and turndowns.
I didn't use cats on either setup.
Originally Posted by Lucian
do you think that the longer ft times would be due to a traction problem. So possibly if you were able to hook the tires up a little more then you would have a little better time. Just my opinion from looking at the numbers w/out seeing the actual track run
Last edited by LS1LT1; Sep 2, 2004 at 09:30 PM.
TECH Senior Member
Joined: Apr 2004
Posts: 6,157
Likes: 1
From: Texas
Who has ran both cutouts with y AND true duals in two different setups? Which gives you the lowest times? I have true duals and im thinking to switching to cutouts with y pipe. Will I gain any time/power?
Launching!
Joined: Jun 2004
Posts: 234
Likes: 0
From: san jose,CA
no a y-pipe doesnt net you very much flow....the x-pipe however gives more velocity,therefore yielding more torque(under-the-curve)which is something you always want. 
duals flow more freely,and ive heard that a crossflow muffler;especially Slowmaster,only support up to 350-horse.....maybe your making more but couldnt get it through that muffler....TD's ALL THE WAY! 
plus when i open my cut-out's i LOSE power! it sucks;i guess my exhaust is already free-flowing enough,that the c/o doesnt gain me any flow.it saps the low-end hard and doesnt really yield you much more top-end...sounds sick,though.
duals flow more freely,and ive heard that a crossflow muffler;especially Slowmaster,only support up to 350-horse.....maybe your making more but couldnt get it through that muffler....TD's ALL THE WAY! plus when i open my cut-out's i LOSE power! it sucks;i guess my exhaust is already free-flowing enough,that the c/o doesnt gain me any flow.it saps the low-end hard and doesnt really yield you much more top-end...sounds sick,though. 
Staging Lane
Joined: Jul 2004
Posts: 55
Likes: 0
From: Bartlett, IL
Can u open electric cutouts in the middle of the run? How bout trying to get the best of both worlds. Start out with it closed and then open it bout halfway down the track. I have FLP's w/ory and a gmmg but am thinkin of gettin the TexasSpeed True Duals but here's the question, if i get a cutout then would i be making the same power as true duals or something minimal or would it be a good difference.
Originally Posted by Lucian
do you think that the longer ft times would be due to a traction problem. So possibly if you were able to hook the tires up a little more then you would have a little better time. Just my opinion from looking at the numbers w/out seeing the actual track run