QTP Exhaust Cutout

[bigdaddy]

So My buddy recently had his done on a 1984 El Camino 305, and I love the way it works. Did a little research, and found an MS3 with one. YouTube it.

I just wanted some input on this. Do you guys think there are any negative aspects of doing this? Im not sure about it, and probably wont end up doing it, because I dont think it sounds that good, I just wanted to get feedback.

h ttp://www.youtube.com/watch?v=ZVRDSqnGgMA&NR=1


delete the space between h and t

 

[Sport6]

Did I miss something saying that linking to youtube was a no-no?

Well with the turbo seal/downpipe issue, a cut out could escalate the turbo seals blowing because even less back pressure. But aside from that it shouldnt be a problem unless you are running a flash tune and its tuned with the cut out shut (running through the entire exhaust) you could overboost with it open.

 

[bigdaddy]

ok so you want me to take the link out? why is it such a big deal
and i decided I dont want to do it. I'd rather save the money, or go with a DP

 

[Sport6]

ok so you want me to take the link out? why is it such a big deal
and i decided I dont want to do it. I'd rather save the money, or go with a DP

No just saying that i don't see what you didn't actually link to it rather than putting a space in it.

 

[RuZec]

what is this cutout you two are speaking of?

 

[SBSPEED3]

a cut out is a device you put at the end of a Y-pipe in line with your exhaust. one leg of the Y goes through the normal cats, resos, muffler and tail pipe. the other leg of the Y is attached to the cutout. when the cut out is closed exhaust flows through smog and muffler equip normally. when the cut out is open the exhaust takes the path of least resistance and largely bypasses the standard exhaust route preferring to dump out ASAP. this effectively is the same as putting the car on straight pipes whenever you want.
QTP is a company that makes electric cutouts (its basically a solenoid attached to a butterfly) so that you can have straight pipes at the flip of a switch.
pretty cool idea, for restrictive exhaust systems if you want the stock sound for DD but it to be louder at the track or something.
i had a QTP cutout on my truck (2000 f150) and it really made it sound nice when open. however the motor burned out on the first one within a week, and the gears in the motor stripped on the replacement after about 2 weeks. QTP was great about returns and everything, but it got annoying to keep replacing them.
there are other designs out there where instead of a butterfly there is a plate that slides over the end of the Y pipe, this seems like a better idea to me. electric cutouts are not cheap though, and (at least in my truck) you lose a noticeable amount of torque due to loss of back pressure . i ended up leaving the Y pipe in and just putting a butt plate on the open end of it. when i wanted a louder exhaust i undid 3 bolts. this is a much cheaper way to go, although getting under a truck is a bit easier then crawling under the MS3...
$0.02
-Nick

 

[clos561]

i thought about it but without good tune and something to control spike, car may go boom. people spacing out youtube links lol

 

[MSMS3]

I don't see how it would produce much gain if anything for our particular application - the MS3. A lot of noise yes. The restriction is upstream in the sharp angles and poorly shaped downpipe and that first cat. You might eliminate some restriction from the second cat by putting the cutout there ahead of it, but it's easier and cheaper to just put in a test pipe or race pipe.

The stock cat back exhaust flows extremely well, in fact, better that the flow rate of the output from the K04 turbo's exhaust side.

Now if you had a bigger turbo and turbo manifold and larger piping all the way from the air filter, maf housing, intercooler, compressor side of the turbo, etc, so that flow was much higher, then you might exceed the cfm flow rate of the stock CBE. Then and only then, IMHO, would you really see any power gain from a cut out.

Without serious mods elsewhere greatly increasing the ability of the engine to pump a lot more exhaust out of the stock turbo, I don't think you'll see any change other that the ability to make a lot of noise.

There is some evidence that cutouts might make a little (maybe 5 horses) on the Mazdaspeed 6, but only because they have a more restrictive exhaust than we do.

If you need the cats, you'd be better off with an aftermarket DP/RP combo with one high flow cat somewhere in the system, and keep the stock CBE. That attacks the problem where it exists, upstream of the CBE.

Just one opinion.

 

[SxySpd3]

I was thinking about putting a QTP cutout on my ms3, does anyone have it on an ms3 already? If so, have you seen much improvement? Does anyone know the diameter of the stock downpipe on the ms3?

 

[cudaman]

Exhaust cutouts on turbo cars will reduce your torque on the low end and give you more HP on the top end. Typically you want to open them up only when you are moving fast already. They will make your ride noisier and be careful of the QTP cutout butterfly plenum screws backing out over time... or at least they used to.... McCord makes a cutout as well, but I'm not sure for the MS3. McCords used to have motor burn-out or gear stripping issues over time on the plenum actuator though.... so, pick wisely. If you aren't going to track the car, it may not be worth the time and expense.

Stuff I picked up in 2007 regarding them:

McCord Power Plate: http://www.mccordcg.com/mpp/mpp.htm

McCord directions seem to have more "plate flex" and gear issues that may cause leaks


http://www.mccordcg.com/mpp/installation.pdf

(See the precautions and usage over time that requires RTV)

It does however have a TIG welded butterfly. And it has circuitry to stop the motor at full open and close without watching the LED and preventing damage from holding the switch down too long.....That microswitch that senses the "divot" in the rod and stops the motor.
Motor appears to be a bit smaller and less powerful than QTP model though.

Excerpt:

Plate seems to leak air:
• Severe nitrous backfires and forced induction backfires can damage the plate. Check butterflies
for damage.
• The butterfly is sealed with RTV high temperature silicone before it leaves. As the plate
experiences thermal growth from a variety of exhaust temperatures, it may leak. You can reapply
the RTV around the jams as well as where the shaft and butterfly meet to close off any pinhole
leaks.
• Overtightening the plate can warp the main body and cause the butterfly to not seat against the
jam. Per the installation instructions, you should not apply more than 28 ft-lbs of torque to the
bolts. A warped body, if not too severe, can be sealed with additional RTV.
• Occasionally, as the plate settles onto the exhaust system, the fully closed position of the butterfly
falls off the drive side of the final gear in the gearbox. As a result, the plate will flex back when
the button if released. If this is occurring, loosen the screws that hold the motor to the body and
rotate approximately 2-3 degrees to put it back on the gear drive side. This will effectively take
out the backlash in the gearbox. Be sure and use loc-tite on the screws when retightening and do
not overtighten the screws

QTP E-cutout: http://www.quicktimeperformance.com/

Has the QTEC controller for memory, or one-touch open/close/partial setting ($110)

http://www.quicktimeperformance.com/Controller/

See all the details there...