Exhaust Cut-out [Merged 8-9] cut out bypass

[eyebrowski]

First hand experience here as well. The QTP cut out WILL fail, mine lasted just over a year as well as a hand full of other people I know as well.

This cutout offers a 4 year warranty:
http://www.dmhperformance.com/

DSMJim: A restrictive exhaust will actually hurt gas mileage. It's not as efficient.

That WG cutout is flawed in design. When the cutout is closed you will be running a smaller exhaust while the turbo is spooling, this will kill spool up time and hurt performance. How about during a shift...the cutout will close and if you are running a large enough turbo it is very likley you will fall out of your turbos effective RPM range do to the increase in spool time. The only way I can see to avoid this is with a complex set of solenoids and at that point why not just go with an electric cut out?

 

[dre99gsx]

i think most people who are posting here didnt read the article which this thread is about... an idiot who put a couple 9/16 holes in his flapper and put it INLINE with his exhaust: bad idea. however a cutout used correctly: not such a bad idea

That idiot is... me... I did that writeup, and it is undergoing testing.

Thus far, 2 9/16" holes give me enough throttle response to do some light passing (2-3 lbs of boost), long uphill climbs, cruising at 80-90mph and easy city driving.

Making the holes bigger will increase sound. 3.5" exhaust piping, 4" muffler, don't do much to muffle sound.

I don't like a cutout. I like to have some quietness when going WOT. The less attention you grab, the easier you can go under the radar.

"I have to agree that this is probably not the greatest idea. It brings to mind how motors get killed by clogged cats..."
Right.. clogged cat + WOT = devestation. 2 9/16" holes and no more than 2-3 psi boost should not hurt anything. For cruising and light throttle, there isn't that much flow out of the motor.

"it hurts my ears to drive by other cars because of the sound reflecting back"
That is partly what I am also trying to avoid.

": A restrictive exhaust will actually hurt gas mileage. It's not as efficient."
Correct, if you drive WOT quite a bit. Thus far, I have almost 2 weeks of data of gas mileage, before and after. For almost 6 months, I've average 230-260miles per tank. With the valve closed, doing my normal driving, no boosting, keeping rpms below 4500rpm, just daily driving, I've maintained 230-260 miles per tank. I can still hit 260miles, so that is a good sign.

 

[SexyDSM95]

Okay, so maybe I won't be doing this....

 

[rsunahar]

First hand experience here as well. The QTP cut out WILL fail, mine lasted just over a year as well as a hand full of other people I know as well.

This cutout offers a 4 year warranty:
http://www.dmhperformance.com/

DSMJim: A restrictive exhaust will actually hurt gas mileage. It's not as efficient.

That WG cutout is flawed in design. When the cutout is closed you will be running a smaller exhaust while the turbo is spooling, this will kill spool up time and hurt performance. How about during a shift...the cutout will close and if you are running a large enough turbo it is very likley you will fall out of your turbos effective RPM range do to the increase in spool time. The only way I can see to avoid this is with a complex set of solenoids and at that point why not just go with an electric cut out?

What part failed on yours--the motor, the valve?

 

[eyebrowski]

What part failed on yours--the motor, the valve?

The motor itself failed. From either heat or shock or a combination of the two.

 

[rsunahar]

The motor itself failed. From either heat or shock or a combination of the two.

Looking at the other link you posted, I don't see how that other brand cutout will hold up any better than the quicktime pipe.

Do you think there's a way to install either that will increase life expectancy?

 

[eyebrowski]

There are people that have had it installed on their cars for over 3 years with out failures from what I hear on NABR. From what most people have said you will be lucky if the QTP lasts a year, it just barely did for me. I'm not sure if the components are different or what but the warranty backs the product up.

 

[Jehu]

I have the DMH and it's worked well for almost a year now. I'm never seen the Quicktime piece but the DMH cutout is a very well made item.

 

[highintenzity4]

Hey guys Ive been thinking about doing this but is there any downside to this? Im fearing that the sensor is going to throw my cel and slow me down. I recently bought the dsmlink would it fix that problem?

 

[JessesTalon]

If you have a 1g you wont have to worry about a CEL because there is no rear o2.


If you have a 2g you still might not get a CEL because some air still goes through the stock exhaust but you should get a 3" dp and cut out right after the downpipe and since it is before the cat and rear o2 and muffler so it will be huge performance gain.


I'm thinking about doing it for my car

 

[highintenzity4]

I have a 2g and I already have a 3 inch downpipe. Thats a good idea about doing it right after the downpipe but what about my rear o2 sensor? Is it going to throw a cel? If it does can the dsmlink disable that? Thanks.

 

[jim97gst]

Removing the rear O2 sensor or diverting exhaust gas around it may or may not throw a CEL. On my 97, the rear O2 sensor is not in the exhaust stream, but not unplugged either. It is tied up with some wire underneath the car. I guess it's happy breathing fresh air, because it has not thrown the CEL like that for 2+ years.

If it does throw a CEL, dsmlink you can turn it off. However, if your state does emissions testing with the OBD2 port, and you simply disabled the CEL with dsmlink, it will still show up in their scan and you will fail.

The CEL for a bad reading on the rear O2 will not slow you down. It's just meant to send you to the dealer so they can sell you a new cat, and to let you know if you will pass emissions depending on your state. The only downside, not including the emissions stuff, to the CEL coming on for this is if some REAL problem occurs, but you're ignoring the CEL because you think you know why it's on.

 

[goofynick6]

I've used the electronic mccord powerplate cutout, just like the Qtec but a little better. It was pretty much the shit, except with almost all cutouts on FI systems, they can't seem to handle the pressure that well, and within a month they start to leak. The shaft gets loose and the plate rattles a little and it leaks a little at idle. Other than some issues like that, there's nothing like hitting the switch at a stoplight and getting reactions.

Nick

 

[BREW]

Hey now: http://www.vfaq.com/mods/O2bypass.html

Brew

 

[Defiant]

Hey guys Ive been thinking about doing this but is there any downside to this?

Any cop who spots it in the US will impound your car.

 

[definitiveno]

Any cop who spots it in the US will impound your car.

thats what I call a downside

 

[PieTSI]

I doubt they will impound your car, I've been to many car shows and there was a lot of old muscle cars leaving with exhaust cutouts. None of the cops there seemed to care. May depend on your state laws tho.

 

[definitiveno]

defiant is from californie where the laws are stricter than most, but he is also a police dispatcher. In cali they won't hesitate.

 

[goofynick6]

Cutouts are legal as long as they are kept closed on the highway (in virginia at least)

Nick

 

[DragGSX]

For the people who keep bringing up getting impounded and caught by cops....(in this thread an the other thread with the same topic) I highly doubt that there gonna have these cutout open all the time (and if they do there ignorance was bound to catch up with them) So the only time it SHOULD be open is when your at the track or racing on the street...and if a cops close enought to hear it, your screwed anyway because your Drag racing on city streets...And if thats the case, when you see the red and blue's..CLOSE IT. then when and if he mentions it say that was the other guys car, and rev your engine Then tell them no way would you want your car to sound lika POS honda(..make it belivable, how does he know)

As for emmision, at least in Tucson, AZ they take a quick look with a foot mirror to see that the cat is installed. Now if the Y isnt plainly hanging down you shouldnt have a problem...Ive read that some of you guys plan or have installed it at the end of your DP...thats great but when its installed there u need to aim the Y down to avoid the exhaust gasses hitting the vehicle if your smart..Now if it was installed in the middle of the sweep in the 90 of the DP kindof vertical then it would allready be pointed down and theres no way they could see it....EVEN COPS....i hardly think there going to take that good of a look and get under your car(honestly can u picture a cop lieing on his back in the street lookin under your car?a cop getting dirty hahahaha now thats funny)...and from under the hood the turbo and Rad. Fans block the veiw...Just my two cents

 

[FLIPTION]

I was wondering if there are any fitment issues w/ putting on a 2.5" downpipe w/ an electric cut out at the flex section in a 2g. Will it fit?

 

[FourG63 97GST]

You need a flex or you'll break shit, when you engine moves the downpipe moves, the flex takes up some of that movement. unless you want your exhaust beating on the bottom of your car

 

[FLIPTION]

i mean not exactly at the flex section.. after.. would it fit?

 

[GSTinCO]

It should fit, but you will need to put it in a straight section of pipe unless the cutout unit is bent. Right before the cat should be fine.

 

[BluemeanieTSi]

u need a flex or u'll break shit,unless u want your exhaust beatin on the bottom of your car

no it doesn't and um....no it doesn't. if your exhaust is moving that much you got motor mount issues. poly mounts and no flex section for 3 years track raced it, autoxed it, never thumped or broke anything and i don't even have a brace on the downpipe. my 3.5" doens't have a flex either