Dual cutouts-HP GAINS DYNO PROVEN
03-12-2007, 10:36 AM
#1
Dual cutouts-HP GAINS DYNO PROVEN OK...for all the haters out there that think its not worth doing dual cutouts or even single cutouts....I went to the dyno yesterday and saw something extremely impressive. I didnt think there would be this kind of difference, but honest to God, this is the truth.
My car...mods in sig.
Dual cutouts closed : SS catback with Magnaflow muffler = 440 rwhp
Dual cutouts opened : Cutouts right after Pacesetters = 461 rwhp
(before Tuning)
I finished with 465rwhp....My tuner is awesome and the only gains over his street tune were with getting the timing lined out since thats one thing you need a dyno to see for sure if it helps or not. ALL my friends that went were like "Now lets see the truth...you say the cutouts closed affects the car alot, lets just see how much so there is no more bitching about having them closed!" Well, lets just say I SHUT THEM UP!!!
My car...mods in sig.
Dual cutouts closed : SS catback with Magnaflow muffler = 440 rwhp
Dual cutouts opened : Cutouts right after Pacesetters = 461 rwhp
(before Tuning)
I finished with 465rwhp....My tuner is awesome and the only gains over his street tune were with getting the timing lined out since thats one thing you need a dyno to see for sure if it helps or not. ALL my friends that went were like "Now lets see the truth...you say the cutouts closed affects the car alot, lets just see how much so there is no more bitching about having them closed!" Well, lets just say I SHUT THEM UP!!!
03-12-2007, 12:27 PM
#2
thats awesome cause i did the same thing when my exhaust was out with the motor. i will only open mine at the track so looks like it wasnt a bad move.
congrats on the nice power.
congrats on the nice power.
03-12-2007, 12:40 PM
#3
Originally Posted by moeZ28
OK...for all the haters out there that think its not worth doing dual cutouts or even single cutouts....I went to the dyno yesterday and saw something extremely impressive. I didnt think there would be this kind of difference, but honest to God, this is the truth.
My car...mods in sig.
Dual cutouts closed : SS catback with Magnaflow muffler = 440 rwhp
Dual cutouts opened : Cutouts right after Pacesetters = 461 rwhp
(before Tuning)
I finished with 465rwhp....My tuner is awesome and the only gains over his street tune were with getting the timing lined out since thats one thing you need a dyno to see for sure if it helps or not. ALL my friends that went were like "Now lets see the truth...you say the cutouts closed affects the car alot, lets just see how much so there is no more bitching about having them closed!" Well, lets just say I SHUT THEM UP!!!
My car...mods in sig.
Dual cutouts closed : SS catback with Magnaflow muffler = 440 rwhp
Dual cutouts opened : Cutouts right after Pacesetters = 461 rwhp
(before Tuning)
I finished with 465rwhp....My tuner is awesome and the only gains over his street tune were with getting the timing lined out since thats one thing you need a dyno to see for sure if it helps or not. ALL my friends that went were like "Now lets see the truth...you say the cutouts closed affects the car alot, lets just see how much so there is no more bitching about having them closed!" Well, lets just say I SHUT THEM UP!!!
Woops EDIT: I see you run an ORY.
03-12-2007, 12:41 PM
#4
Well, you have a TRex cam, though. I've read that it loves to breath like no other and hates backpressure. Your results will no doubt vary from others with dissimilar cams.
My car with a stock cam feels like it loses a **** load of power all over the range with my dual cut-outs open. Not doubting at all. It may gain, I'm just saying that's what it feels like.
My car with a stock cam feels like it loses a **** load of power all over the range with my dual cut-outs open. Not doubting at all. It may gain, I'm just saying that's what it feels like.
03-13-2007, 12:32 AM
#5
Yeah it does like to breathe, but I knew before it was gonna make more power. On my old motor with a hotcam and ls1 intake, I made 15 more rwhp with the duals open over an SLP loudmouth 1 exhaust system. I think any car with a cam can benefit from this. It may only make a few more ponies than one cutout, but it makes a **** ton more than goin through the catback. I look at it this way, where else you gonna get 21 horsepower from $60 or less and all you have to do is take off 6 nuts and 2 plates.
03-13-2007, 03:40 AM
#6
Well, you are not going to have a backpressure problem on an LS1. It may make more peak horsepower....actually that would make sense. Open headers are higher power, but usually drop some on tq numbers. Notice how he is only 388rwtq? Can you post up your dyno sheet? Surely you did a pull with them open and one with them closed to see the real difference in tq as well. Not just HP here. I want to see the tq curves.
03-13-2007, 09:42 AM
#7
No sheet for the the closed run...it was just to shut up a friend who was there at the dyno with a bunch of us who was like "now lets see..." I am pretty sure the torque was only in the 370 range though. My car has no ***** down low at all. Torque peaks at 5700, hp at 6700. Thats why I am gonna change cams and get more usable power. I posted this up b/c a few people lately have been asking about gaining horsepower from dual cutouts.
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03-13-2007, 10:23 AM
#10
Those are some nice gains. I went from 320 to 328 rwhp and from 365 to 373 rwtq with my dual cutouts open (mustang dyno). I think Pat G said I would gain more with a bigger cam and your post shows that to be true.
On my graph the torque looks higher down low with the cutouts open. I do know I have a tougher time launching it without spinning the wheels be it may just be because of all the noise.
On my graph the torque looks higher down low with the cutouts open. I do know I have a tougher time launching it without spinning the wheels be it may just be because of all the noise.
03-13-2007, 06:39 PM
#12
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Question for you.
Did you tune the car with or without the cutout open.
I'll be willing to bet if you tune the car with the cutouts closed, you'll have your gains with them closed. And if you tune the car with your cutouts open, then your higher numbers will be with cutout open.
I had my car tuned with cutout open. Closed the cutout and there went 20rwhp. However, I went from 12.5:1 AFR to an 11.5:1 AFR.
If we leaned her out a bit to get back to the 12.5:1 range, that "could" have gotten me my power back with the cutout closed. I say "could" because we didn't try lol.
The next person that goes to tune their car with a cutout should try this and let us know!
Dave
Did you tune the car with or without the cutout open.
I'll be willing to bet if you tune the car with the cutouts closed, you'll have your gains with them closed. And if you tune the car with your cutouts open, then your higher numbers will be with cutout open.
I had my car tuned with cutout open. Closed the cutout and there went 20rwhp. However, I went from 12.5:1 AFR to an 11.5:1 AFR.
If we leaned her out a bit to get back to the 12.5:1 range, that "could" have gotten me my power back with the cutout closed. I say "could" because we didn't try lol.
The next person that goes to tune their car with a cutout should try this and let us know!
Dave
03-13-2007, 06:55 PM
#13
It says that the car was untuned.... The reason for the gains is probally b/c you still have the factory piping with a muffler. If you were to get a whole magnaflow exhaust system your gains with the cutout would not be that great. Still good numbers
03-13-2007, 07:02 PM
#14
Launching!
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Originally Posted by Starz T/A 17
It says that the car was untuned....
Last edited by Arcolog2; 03-13-2007 at 07:09 PM.
03-13-2007, 09:35 PM
#16
Originally Posted by gi8e7oi825
I gained something like 8 rwhp and 6 rwtq with the GT2-3, stock heads, and no tune on an '02 f-body with dual cutouts right after the headers.
That's it? You get more than that on most stock cams. Not that the cam you have is too far from stock....but still.
03-14-2007, 12:47 AM
#18
I had it ran with 3 inch piping, mandrel bends. It had a stock muffler in place, then I added the Magnaflow a couple weeks before the dyno. The car was ran with cutouts closed, then open, then tuned and ran till the tuning was done. My tuner is awesome...his street tune with a wideband was almost dead on, the only thing that he played with was timing on the dyno.
OH, and I forgot to mention that my stock auburn posi unit is fucked and all of this was done through one tire b/c thats all that the car will turn, which is probably taking away power as well. The car did spin the tire on the dyno though, which was really ******* cool!!!
OH, and I forgot to mention that my stock auburn posi unit is fucked and all of this was done through one tire b/c thats all that the car will turn, which is probably taking away power as well. The car did spin the tire on the dyno though, which was really ******* cool!!!
03-14-2007, 11:12 AM
#19
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Originally Posted by orangeapeel
That's it? You get more than that on most stock cams. Not that the cam you have is too far from stock....but still.
03-14-2007, 11:24 AM
#20
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I had my car tuned with the cutouts closed. Made 349.5hp and 362.4tq. With the cutouts open it made 349.1hp and 366.5tq. (lid,85mmMaf,bellows,fast 78tb,qtp hvmc longtubes, tsp TDs under axle CME)