The Official Cutout Thread

[D-Speed 2.5]

After having my electric exhaust cutout for almost a year and a half, I figured I would start a thread that can help others in their decision to go with an exhaust cutout. Many other members on this site have cutouts and they should also share their experiences in this thread.

A LIST OF COMPANIES THAT MAKE ELECTRIC EXHAUST CUTOUTS:

EDIT (6/1/08): DON'T BUY A BADLANZ CUTOUT! He has never been able to create a cutout that is on par with the other alternatives out there. If I were to do over again, I would spend a bit more for a QTP, DMH, or ATP.

While all cutouts leak, the Badlanz cutouts seeming leak worse/quicker than others.

QTP: http://www.quicktimeperformance.com/QTEC/index.php
BadlanzHPE: http://badlanzhpe.com/
StreetPro: http://www.streetpro.us/
McCord: http://www.mccordcg.com/mpp/order.htm
ATP: http://www.atpturbo.com/root/releases/release091004.htm
DMH: http://www.dmhperformance.com/
(I know there are more but these are all I can think of for now)

There are many threads about the subject on nasioc. Some of which are listed below:

I think this thread has the most information:
http://forums.nasioc.com/forums/show...ghlight=cutout

Here are some others:
http://forums.nasioc.com/forums/show...ghlight=cutout
http://forums.nasioc.com/forums/show...ghlight=cutout
http://forums.nasioc.com/forums/show....php?t=1136340
http://forums.nasioc.com/forums/show...ghlight=cutout
http://forums.nasioc.com/forums/show...ghlight=cutout
http://forums.nasioc.com/forums/show...ghlight=cutout

SOME BASIC THINGS TO KNOW:

1. Cutouts are welded into the downpipe
2. Cutouts are insanely loud! Take the loudest Subaru exhaust you have heard and multiply it by 3. Cutouts make Harleys sound tame. It will make your ears ring.
3. Cutouts will spit flames out under the car
4. Cutouts are almost unbearable to use in stop and go traffic because of the fumes.
5. Cutouts will leave a lot of soot under and on the sides of your car.
6. Electric cutouts will all eventually leak from being over torqued over time. The leak sounds like a baseball card in bicycle spokes. If you already have a medium-loud catback, you won’t hear it. I have a STi axle back, thus I can hear my leak.
7. Electric cutouts MUST be sealed around the motor with silicon or something similar. My cutout failed to corrosion after only 6 months due to rust. Since sealing the motor assembly, I haven’t had a problem.
8. There is usually ground clearance issues associated with cutouts so make sure you have properly test fit where your cutout will sit once installed.

MY SETUP:

ERZ DP w/ BadLanzHPE cutout welded in:
-$150 for BadlanzHPE cutout
-$100 for welding and installation (included wiring)



A pic to show how much fuel collects in the cutout (hence flames, I was running rich):



Also, in the top left corner of that pic, you can see how the motor rusted out because I didn't seal the rubber boot that protects the motor with silicon. You must make sure this part of your cutout gets sealed with silicon or something similar!

PERFORMANCE:

UNTUNED: My performance observations were (stock turbo):
-Boost came on about 200 rpm sooner
-Power felt much more linear with it open (smoother power delivery)
-Gained about .5-1psi of boost (depending on gear)
-The car felt much stronger at the top of the rev range (boost seemed to hold on longer)
-Never saw a single CEL

Untuned, the car was easily faster than stock STis and stage 2 WRXs. I felt that much of my power was coming from my cutout. While I was happy with my car, I wanted more power thus I finally went in for an EcuTEK tune from Harvey at Super Rupair in Boulder, CO.

TUNED: (much of this is what the tuner said)
-“Wow this car spools quickly with that thing open”
-“This car reacts really well to changes in boost”
-“Power holds really well until redline”
-“It seems as if the whole curve has moved to the left”


TUNING NOTES: I went for 20k miles on my cutout untuned, stock turbo, stock ECU. I was running rich as hell, 10.0:1. Closed it would creep up to 10.5:1. When I came in for my tune (EcuTEK), my tuner was pretty surprised by this. For my baseline run, cutout open, I put down 200whp (6,000ft above sea level)which is what most stock turbo guys leave at fully tuned from the same dyno. After a couple of hours, I left at 227whp and 225wtq. My car did not respond positively from changes in timing since I think the ECU was so used to the cutout already. Instead, the car made big power from additional boost and leaning out the AFRs to 11.0:1.

HOWEVER, ALL CARS RESPOND DIFFERENTLY! Just because I was running fine for 20k, doesn’t mean that the next guy will. It was really odd that my car was running rich on the stock ECU but I think that may be a rarity.

My dyno charts (sorry, I don’t have an open vs. closed comparison):

Stock STis put down 215whp on this dyno:




A friends dyno chart (different dyno) that shows a comparison between open and closed on his ’04 WRX:



Keep in mind that this is uncorrected, 100+ degrees in the dyno room, and at about 5,500 ft in elevation. Its hard to see but peak change in power was 17whp and peak change in torque was 25wtq. These were back to back runs with no additional tuning.

CONCLUSION:

Cutouts are not for everyone. Most do not like the noise, I however do. I also really enjoy the added power. However, I mostly enjoy the ability to go from super loud, to super quiet at the flip of a switch. This is really nice for those who have girlfriends or wives who hate the noise that an aftermarket exhaust brings.

I hope others will contribute their experiences as well so that all questions can be easily answered in the future.

Thanks for reading,

-D-Speed

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[9vapors]

Nice informative write up D-Speed 2.5, Thanks!

[InfamousDX]

I loved my cutout for the year or so I had it.

[Unabomber]

Damn nice thread buddy. Please add this: http://forums.nasioc.com/forums/show....php?t=1136340

You get sticky!

[McBain_TP]

It seems I post in every thread about cutouts, but I don't think I can bring myself to whore my dyno chart again. I have the QTP cutout, and picked up 10-20 hp and ft/lbs from 4-6.5k, though no peak hp. That was with my old 18G, and using the same map for open and closed. In a few days I'll have my car back with the new QTP electronic controller (along with 2.5l, cams, 20G etc.):

Features:
Controls up to 2 QTECs
Calibrates each motor independently and synchronizes their position
Automatic close at power up
Digital status displays shows butterfly position
Manual pushbutton operation for open, close or partial open
User configurable partial open position
2 Memory preset partial open settings
Short circuit protection on motor drive electronics
Fault detection and reporting
Automatic open or close by grounding or not grounding the trigger wire
LED butterfly position status
0-100 0=Closed and 100=Wide Open

The valve is connected to a sidepipe exiting under the left rear passenger door, with an exhaust tip from an Audi RS6.

[D-Speed 2.5]

Originally Posted by Unabomber

Damn nice thread buddy. Please add this: http://forums.nasioc.com/forums/show....php?t=1136340

You get sticky!

Thanks man! I added that link in the group of links (its the third one down).

[D-Speed 2.5]

Originally Posted by McBain_TP

It seems I post in every thread about cutouts, but I don't think I can bring myself to whore my dyno chart again. I have the QTP cutout, and picked up 10-20 hp and ft/lbs from 4-6.5k, though no peak hp. That was with my old 18G, and using the same map for open and closed. In a few days I'll have my car back with the new QTP electronic controller (along with 2.5l, cams, 20G etc.):
The valve is connected to a sidepipe exiting under the left rear passenger door, with an exhaust tip from an Audi RS6.

That's a sick setup. You have the silver wagon right? Please show your dyno charts as well.

[McBain_TP]

^^^18G, TMIC, no cats, Borla Hush, ~21 psi

I'll take some pics when I get my car back, but here's one with the old setup, which was a little more crude and dumped under the front passenger door. That location didn't comply with the rules at my local dragstrip, so it was moved back by taking some of the angle out of the pipe before the cutout.

[AZScoobie]

Great post.. My favorite is the Boost activated one From ATP turbo.

http://www.atpturbo.com/root/releases/release091004.htm

It uses a wastegate actuator to open the gate. This way its instant and automatic.. Cruise around under 8 psi and the cut out is closed. Pass 8 psi and its open. Its adjustable so you could set it to 10,12, or what ever.. This one made 12whp on subiechicks car.

CT

[D-Speed 2.5]

Originally Posted by AZScoobie

Great post.. My favorite is the Boost activated one From ATP turbo.

http://www.atpturbo.com/root/releases/release091004.htm

It uses a wastegate actuator to open the gate. This way its instant and automatic.. Cruise around under 8 psi and the cut out is closed. Pass 8 psi and its open. Its adjustable so you could set it to 10,12, or what ever.. This one made 12whp on subiechicks car.

CT

Added it to the list

[scubyslacker]

Yo, I'm the one with the 2004 wrx that D-Speed 2.5 mentioned in the opening post. It was D-Speed that convinced me to go with the cutout. For reference, I'm running a Super16G, ssautochrome tmic, hpebadlanz cutout on a txs full tbe, and utec.

The dyno chart D-Speed show'd was with my cutout open and closed, obviously, on my most aggressive map. I was running around 2 psi more with the cutout. As was already stated, I gained around 17 whp and 25 wtq. Also, my tuner tweaked my setup and maps so that I don't have to change maps when I open or close my cutout, so the two runs with the cutout open and closed was on the same map, the only difference is whether the cutout was opened or closed. As you can see, for me at least, the cutout really helped.

The cutout is definitely super loud, but if you get an electronic one, then you can open and close it at will. I don't run my setup open nearly as much as D-Speed, but its great to have if you want that extra power or just want to literally ROAR.

[McBain_TP]

Originally Posted by InfamousDX

I loved my cutout for the year or so I had it.

Yes, you did!
http://youtube.com/watch?v=yX3DAxpVd4k
http://youtube.com/watch?v=rClayYgqzDA

Other cars:
http://youtube.com/watch?v=AwZzcjme4s0
http://youtube.com/watch?v=bsgOVy1_8R0
http://youtube.com/watch?v=jcfPVXsJH40
http://videos.streetfire.net/search/...5fa49845bd.htm

I really need to get mine on video.

[intence]

i have a DMH cutout
http://www.dmhperformance.com/

[FWD WRX]

my cutout motor is broken so it's manual now meaning i have to get under the car and flip it by hand lol

[shineynitelite]

will you have to buy a complete unit, or just the motor?

what brand do you have?

[D-Speed 2.5]

Originally Posted by intence

i have a DMH cutout
http://www.dmhperformance.com/

Added

[D-Speed 2.5]

Originally Posted by FWD WRX

my cutout motor is broken so it's manual now meaning i have to get under the car and flip it by hand lol

Is it a BadlanzHPE? If so, PM me.

[Force]

Hey D-speed, is it ok to open and close the cut-out while the car is driving? I heard somewhere that it is only good to open/close it when the car is at idle or completely off. What's your opinion about this? Any ill effects to the turbo/performance if it is opened while driving?

[D-Speed 2.5]

Originally Posted by WRXG0N

Hey D-speed, is it ok to open and close the cut-out while the car is driving? I heard somewhere that it is only good to open/close it when the car is at idle or completely off. What's your opinion about this? Any ill effects to the turbo/performance if it is opened while driving?

It is fine to open it while you are under lower RPM conditions. I open mine all the time while driving. However, opening under high RPM conditions will put undue stress on the cutout motor which will cause leaks over time. This is due to the high amount of exhaust flow putting resistance on the faceplate of the cutout while you are trying to move it.

[McBain_TP]

The ECU adjusts timing when the cutout is open, so if you've had it open for a while, then close it and go WOT, you may get knock. It happened to me when pulling out of a gas station on a long trip.

I got my car back last week, with the new Q-Tec electronic controller mounted under the ashtray. I now only have to press the button once to fully open it, rather than holding down a switch for a 5-count (which can over-torque the valve). It can be programmed to open it partially, but I doubt I'll bother with that. It also can control two Q-Tecs, and I may find a use for it...

Controls up to 2 QTECs
Calibrates each motor independently and synchronizes their position
Automatic close at power up
Digital status displays shows butterfly position
Manual pushbutton operation for open, close or partial open
User configurable partial open position
2 Memory preset partial open settings
Short circuit protection on motor drive electronics
Fault detection and reporting
Automatic open or close by grounding or not grounding the trigger wire
LED butterfly position status
0-100 0=Closed and 100=Wide Open

http://quicktimeperformance.com/Controller/

[Force]

Originally Posted by D-Speed 2.5

It is fine to open it while you are under lower RPM conditions. I open mine all the time while driving. However, opening under high RPM conditions will put undue stress on the cutout motor which will cause leaks over time. This is due to the high amount of exhaust flow putting resistance on the faceplate of the cutout while you are trying to move it.

Thanks! I'll be looking into a cut-out very soon...cops don't like my RFL around here in the suburbs....even if I am just cruising normally, damn melon-launching can catches their eye. Cut-outs are more sleeper anyways...

[subikid]

What about manual cutouts, for those who can't afford e cut outs? Any suggestions? They seem less "cool" but may be more reliable?

Thanks,
Kevin

[D-Speed 2.5]

You can do a manual cutout by simply getting the cutout Y-pipe from Summit and manually take the cap on and off.

[subikid]

What about the ones with the cable to open/close them? Have any info? Sites?

[McBain_TP]

Originally Posted by subikid

What about the ones with the cable to open/close them? Have any info? Sites?

The only one I could find is 2.25": http://www.jcwhitney.com/autoparts/P...012733/c-10101

Here's a 3" universal fit exhaust cutout: http://www.jegs.com/webapp/wcs/store...9799_-1_458953