QTP cut-out
Thread Starter
Intermediate
Joined: Oct 2012
Posts: 33
Likes: 0
QTP cut-out
Hi,
I wanted to install QTP electric cutouts on my C6 Vette, but someone told me that the "low profile" version (which is the only one fitting the C6) has big problems of overheating which makes it breaks after a few months.
And it seems to be quite difficult to install under the Vette.
What do you think ? Does someone has it ? Is it reliable or not ?
Thanks !
Olivier (from France)
I wanted to install QTP electric cutouts on my C6 Vette, but someone told me that the "low profile" version (which is the only one fitting the C6) has big problems of overheating which makes it breaks after a few months.
And it seems to be quite difficult to install under the Vette.
What do you think ? Does someone has it ? Is it reliable or not ?
Thanks !
Olivier (from France)
Intermediate
Joined: Nov 2012
Posts: 47
Likes: 0
From: Virginia Beach VA
I had QTP low profile cutouts right where the pipes meet the axle backs. never had a problem with them other than I didn't have turndowns on them and they were cooking my trans. For the cost and the fact I never closed them I went with bullet axle backs on the current vette. Cutouts are cool at first then the feature gets old and you ended up spending a lot of money on parts and fabrication for just a straight pipe. I'll see if I still have pics of them.
Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
Please bring me up to speed on the thought process here.
All your back pressure is at the cats, so if you are going to do any good, then they need to be before the cats/ after the headers.
If you are running high flow cats, or even no cats with a straight through muffler design, then the QTP are doing nothing more than making the car sound like a trash truck alone.
All your back pressure is at the cats, so if you are going to do any good, then they need to be before the cats/ after the headers.
If you are running high flow cats, or even no cats with a straight through muffler design, then the QTP are doing nothing more than making the car sound like a trash truck alone.
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Race Director
Joined: Dec 2013
Posts: 12,502
Likes: 3,629
So no gain in power, and pretty much the same as just putting a playing card in the spokes with a close line pin.
Ditch the QTP idea, and just install NPP mufflers instead (can get a set off Craigslist on the cheap).
You can pull vacuum from the intake, through a wild to mild type switch in line, to the mufflers, and when you want the extra noise (that sounds good, and not like a dump truck with open pipes), just hit the switch to open the straight through valves on the mufflers.
Instructor
Joined: Aug 2013
Posts: 145
Likes: 5
From: Raleigh, NC
Go for Fusions if you want to switch between quiet and loud. Gen 3 specifically. I have them, love them. May end up trading with someone local for Bullets though... I just never run them closed, and the Mrs has gotten used to the sound.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
I've had QTP cutouts for 8 years now. They are very reliable and because they direct the sound below the car, rumble in the car sounds awesome and different from other cars. I love my qtp cutouts. Here is my thread from long ago with video.
https://www.corvetteforum.com/forums/c6-tech-performance/1628234-installed-cut-outs-on-my-c6.html
https://www.corvetteforum.com/forums/c6-tech-performance/1628234-installed-cut-outs-on-my-c6.html
Had QTP cutouts installed by Florida Performance in Fort Lauderdale. Overall very pleased with the job Rob, the shop owner, did. This was his first C6 and he found a great place to put them and made the custom mandrel bent Y-pipes to maximize flow from the cutouts. We found no way to put them right after the collectors but they fit well by the trans. I have the DTE brace too but it wasn't in the way.
Installed the wiring myself along the drivers side rocker panel, behind seat then out the wheel well under the carpet. Removed the rear inner fender and drilled a small hole in the wheel well then ran the wire down to the cutouts. Hardest part is finding a hot wire when the ignition is on on these C6's. I ended up tapping the seat heater fuse as others here have done.
They are loud and DEEP when open at idle. I've actually heard louder exhaust though, I was kind of surprised they are not louder. I think it is because of the turn downs and the fact that I have cats and the pipes are pretty long before the cutouts. On the track they have a nice race car sound - I'd say like Borla Stingers plus 25%. When you open them at a stoplight you will turn heads, that's for sure.
I did not see any track gain with them so far - but we had an unusually cold day at the track Saturday (negative 230 DA and 53 degrees and 70% humidity) and I could not get any grip at the line, spinning every time.
I did notice on my HP Tuners logs at the strip I was running lean so I added some fuel, but I can't say if that was because the cutouts or the cold weather but I will find out soon. We don't stay cool long.
Overall happy with the mod, it gives me quiet during my morning drive but loud when I'm at the track which is what I wanted.
Here is a video of idle with cutouts open and closed. The gain on the mike makes the closed sound much louder than it is, it's really quiet with factory mufflers even with my cam.
Here are some pics:
Installed the wiring myself along the drivers side rocker panel, behind seat then out the wheel well under the carpet. Removed the rear inner fender and drilled a small hole in the wheel well then ran the wire down to the cutouts. Hardest part is finding a hot wire when the ignition is on on these C6's. I ended up tapping the seat heater fuse as others here have done.
They are loud and DEEP when open at idle. I've actually heard louder exhaust though, I was kind of surprised they are not louder. I think it is because of the turn downs and the fact that I have cats and the pipes are pretty long before the cutouts. On the track they have a nice race car sound - I'd say like Borla Stingers plus 25%. When you open them at a stoplight you will turn heads, that's for sure.
I did not see any track gain with them so far - but we had an unusually cold day at the track Saturday (negative 230 DA and 53 degrees and 70% humidity) and I could not get any grip at the line, spinning every time.
I did notice on my HP Tuners logs at the strip I was running lean so I added some fuel, but I can't say if that was because the cutouts or the cold weather but I will find out soon. We don't stay cool long.
Overall happy with the mod, it gives me quiet during my morning drive but loud when I'm at the track which is what I wanted.
Here is a video of idle with cutouts open and closed. The gain on the mike makes the closed sound much louder than it is, it's really quiet with factory mufflers even with my cam.
Here are some pics:
Thread Starter
Intermediate
Joined: Oct 2012
Posts: 33
Likes: 0
Thank you very much Joe G, your thread gave me a lot of useful informations.
I guess you used the "low profile" version too, because of the lack of space.
And knowing that you are still satisfied for so much time is reassuring.
I guess you used the "low profile" version too, because of the lack of space.
And knowing that you are still satisfied for so much time is reassuring.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
Glad it helped. I really like my qtp cutouts. As you could perhaps tell from the video it gives me the best of both worlds; stock quiet or racecar loud.
I have the standard units, not low profile. They are a high quality product, standing the test of time.
I have the standard units, not low profile. They are a high quality product, standing the test of time.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
Racer
Joined: Dec 2013
Posts: 419
Likes: 5
From: Bel Air Maryland
I've had QTP cutouts for 8 years now. They are very reliable and because they direct the sound below the car, rumble in the car sounds awesome and different from other cars. I love my qtp cutouts. Here is my thread from long ago with video.
https://www.corvetteforum.com/forums...-on-my-c6.html
https://www.corvetteforum.com/forums...-on-my-c6.html
Drifting
Joined: May 2008
Posts: 1,505
Likes: 7
From: Jacksonville FL
So no gain in power, and pretty much the same as just putting a playing card in the spokes with a close line pin.
Ditch the QTP idea, and just install NPP mufflers instead (can get a set off Craigslist on the cheap).
You can pull vacuum from the intake, through a wild to mild type switch in line, to the mufflers, and when you want the extra noise (that sounds good, and not like a dump truck with open pipes), just hit the switch to open the straight through valves on the mufflers.
Ditch the QTP idea, and just install NPP mufflers instead (can get a set off Craigslist on the cheap).
You can pull vacuum from the intake, through a wild to mild type switch in line, to the mufflers, and when you want the extra noise (that sounds good, and not like a dump truck with open pipes), just hit the switch to open the straight through valves on the mufflers.
For what its worth I had my cats on my 4.6L Mustang swapped out with resonators and pulled the mufflers. Sounded deep and agressive. I loved the sound of the exhaust hitting the ground under the car.
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08