I am going to be purchasing a exhaust cutout for my car and am wondering if anyone has done before and after dyno pulls. I'm planning on running a 3" downpipe with a 3" cutout. I'm keeping my 2.5" exhaust but wanted a little extra flow for the track but was curious to know if anyone has some dyno results to compare it open and closed. I searched a bit and couldn't seem to find any dyno results.
from what i hear the better the flow of exhaust the happier the turbo is.
On my n/a ecotec it got me down 2 tenths in the quarter. I ran better times consistantly with worse launches
2.4 S/C, 220 hp at 6200 RPM with it closed. 226.5 hp at revlimit with it open. It was still climbing when the limiter kicked in.
So with a 2.4 turbo with 300+whp it should make a difference then.
Oh yeah. Make the turbo spool faster as well
Well ill give you a little example of my open vs closed cut out.
At the GM bash last year I ran it closed, temperature was 97 degrees outside. I ran a 14.6 at 110mph.
I ran the car again but with the cutout open in August, temperature was 72 degrees outside and I ran a 13.0 at 109mph.
So, not sure if the temperature had THAT much affect on my times, or if it was because my cutout was open that I ran better times. Im betting a little bit of both.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
The cooler temps probably helped a bit but your mph didn't change a whole lot but it would appear that it worked better as a second and a half is quite a difference, unless your 60 fts was cut by a significant amount.
From what I understand you have to tune for it being open then tune for it being closed. That just what I heard anyway. I was wondering the same thing since I purchased a cut out for my Saab setup.
I questioned an old friend of mine on cutouts. He said the electronic one's don't last very long, being attached to the exhaust an such. Could anyone elaborate on the reliability?
SLO CAV (the autoxing one) wrote:From what I understand you have to tune for it being open then tune for it being closed. That just what I heard anyway. I was wondering the same thing since I purchased a cut out for my Saab setup.
I believe you are supposed to tune with it open, and accept the small problems that will come about when having it closed. You can create two files, but it will be a PITA to switch between two tunes like that all the time.
Shane Reid wrote:I questioned an old friend of mine on cutouts. He said the electronic one's don't last very long, being attached to the exhaust an such. Could anyone elaborate on the reliability?
I'm getting a manual cutout...its only got 3 wing nut bolts to undo and at least I know the motor won't go bad. I've heard the eletric ones are not that reliable and I don't want to have it open and not be able to get it closed.
My electrical cutout's solonoid didnt last long at all. I turned it into a manual one.
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
Electric ones are a PITA, gears always stripping out or solenoid dying. Get a manual and stick with it.
my QTP electronic one worked flawlessly for quite some time untill I bottomed the motor out one to many time and smashed it.
WHITECAVY wrote:Well ill give you a little example of my open vs closed cut out.
At the GM bash last year I ran it closed, temperature was 97 degrees outside. I ran a 14.6 at 110mph.
I ran the car again but with the cutout open in August, temperature was 72 degrees outside and I ran a 13.0 at 109mph.
So, not sure if the temperature had THAT much affect on my times, or if it was because my cutout was open that I ran better times. Im betting a little bit of both.
It wasn't just the heat and the closed cut out. That track was garbage.
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
^^Yep, that too lol
~2014 New Z under the knife, same heart different body~
______________________
WHITECAVY no more
2012 numbers - 4SPD AUTOMATIC!!
328 HP
306 TQ
Anyone use DMH Performance's cutout? That's the one i've heard is nice. 4yr warranty too
I have been looking around for the best deal on a cutout and I found this one. Wondering if anyone has a place they got theirs from that is a better deal.
Link
On an NA, doesn't the exhaust cutout confuse the computer?
My wife's 2003 Ecotec 2.2 liter Sunfire:
* 2 1/4 inch in and dual 2 inch out muffler Trans Am muffler
* 2 1/4 piping to a very long 2 1/4 inch resonator
* 2 1/4 inch catalytic converter
* an AEM true cold air intake NOPI edition
* 8 gauge ground wire kit
* Toyz front strut brace
* Russell stainless steel brake lines all around.
Mike85220 wrote:On an NA, doesn't the exhaust cutout confuse the computer?
no it won't. The comp doesn't know if the exhaust is on or off. You can run open header if you want and the compute doesn't know the difference.
I wonder if with the cut out before the cat, if enough exhaust fumes would make their way to the downstream O2 sensor for the computer to still think you had a cat...
Paying someone to install parts and bragging about it being fast, is like watching someone bang your wife and being proud to raise their kids.
I'm probably getting rid of my cat this year. Looks like I will need a boost controller if I decide to go with a cutout. I guess the change in flow can make a significant difference in performance and the guy tuning my car said he has seen motors go bad because of cutouts. He has seen 50-100hp gains with a cutout and said I would need to limit boost with the cutout closed in order to be safe. I'll have to wait and see what happens, guess if I want the extra powert of a cutout I'll need to find a cheap manual boost controller or maybe buy hp tuners and have two separate tunes.
A friend got a '87 GN from a reputable dealer. A week later he took it back because the catalytic-converter was plugged-up (Not his fault!). They replaced it with a test-tube that contained a dump with a removable cap. Whenever he went to race, he uncapped it. It ran quicker uncapped, but oddly it was noisier inside the car while it was uncapped than it was outside!
Go beyond the "bolt-on".
50-100hp? Call me crazy but that's seems too high.
