Pinched Exhaust... Really?

mspeed1LE · 05-13-2018, 12:56 PM

Had the car up in the air the other day and was shocked to see the exhaust pinched the way it is. Why did this have to be done? Certainly not for clearance. I can only see this as being a restriction... for what?

Glen e · 05-13-2018, 12:59 PM

Tests published here have found it does not restrict horse power or torque. I believe on of the most recent test was by phasetek.

Magnum922 · 05-13-2018, 01:02 PM

My 72 corvette original exhasust was pinched exactly like this.

trohde78 · 05-13-2018, 01:04 PM

I think there is a debate as to why it was crimped, but it was proven in dyno testing to have little to no effect on power.

https://www.mishimoto.com/engineerin...he-crimp-myth/

Gunkk · 05-13-2018, 01:17 PM

The only thing the pinch affects is your mind...

https://youtu.be/azPKIjxmmdU

mstgeer · 05-13-2018, 01:18 PM

I also had the convertible in the air for the 1st time this weekend and the exhaust is crimped after the axle to clear the rear cross bracing.

samr350 · 05-13-2018, 02:52 PM

It's crimped because the convertible has bracing there and it needs the extra clearance since the convertible and coupe use the same exhaust. On a stock and lightly modded car it's not restricting power.

Hyper RS · 05-13-2018, 03:37 PM

as stated earlier...It is crimped in order clear the convertible braces. It saves GM money to make a "fits all" exhaust vs. making different ones for Coupe and Convertible.

Iroc_Z28 · 05-13-2018, 03:43 PM

I've also heard that the crimp acts as a crumple zone for the exhaust, so that if the car is hit in the rear, the exhaust will break off there, rather than transfer the force upwards damaging the cats/manifolds... not sure the validity of that though.

lt4camaro · 05-13-2018, 07:08 PM

If you want max flow and sound, install the Borla mid pipe that deletes the the secondary unmonitored cats and the crimped pipe area. Better flow and sound = more power. Now you will have the car that always seems to run just a little bit better in a race, be on the strong side instead of the weak side.

Hyper RS · 05-13-2018, 11:01 PM

Quote:

Originally Posted by lt4camaro

If you want max flow and sound, install the Borla mid pipe that deletes the the secondary unmonitored cats and the crimped pipe area. Better flow and sound = more power. Now you will have the car that always seems to run just a little bit better in a race, be on the strong side instead of the weak side.

True....unless you have a convertible!

lt4camaro · 05-14-2018, 08:20 AM

Quote:

Originally Posted by Hyper RS

True....unless you have a convertible!

Because I am a automotive tech, I would have to see a convert on a lift to see just how much clearance is really needed.. I have removed many factory exhaust parts with factory crimps/restrictions on GM cars over the years to make the system flow better with out issues.

MrChrisLS3 · 05-14-2018, 09:55 AM

The biggest, and main power robbing restriction in the system is the primary catalytic converter. As long as those are stock and in place, the restriction from these crimps in minimal, if at all.

mspeed1LE · 05-14-2018, 10:07 AM

Great feedback! Thanks all! Might make some changes down the road.

05-13-2018, 12:56 PM	#1
mspeed1LE Drives: ZL1 1LE SUMMIT WHITE Join Date: Feb 2018 Location: VANCOUVER ISLAND Posts: 318	Pinched Exhaust... Really? Had the car up in the air the other day and was shocked to see the exhaust pinched the way it is. Why did this have to be done? Certainly not for clearance. I can only see this as being a restriction... for what?

05-13-2018, 12:59 PM	#2
Glen e Retired from Car mfrs.... Drives: 2LT RS/HR-V Join Date: May 2013 Location: /Fort Lauderdale Posts: 10,048	Tests published here have found it does not restrict horse power or torque. I believe on of the most recent test was by phasetek. __________________ Glen CLICK HERE for detailing a new car: detailing for non detailers CLICK HERE for how to rinseless CLICK HERE for EASY wheel sealant

05-13-2018, 03:37 PM	#8
Hyper RS Drives: '19 Corvette Stingray Convertible Join Date: Jul 2016 Location: Rochester NY Posts: 141	as stated earlier...It is crimped in order clear the convertible braces. It saves GM money to make a "fits all" exhaust vs. making different ones for Coupe and Convertible. __________________ '19 Corvette Stingray Convertible M7

05-13-2018, 01:02 PM	#3
Magnum922 Drives: 2017 Camaro 2SS, A8 Join Date: Aug 2017 Location: North carolina Posts: 336	My 72 corvette original exhasust was pinched exactly like this.

05-13-2018, 01:04 PM	#4
trohde78 Drives: '17 Red Hot 2SS 6MT Join Date: Mar 2018 Location: Chicago Suburbs Posts: 346	I think there is a debate as to why it was crimped, but it was proven in dyno testing to have little to no effect on power. https://www.mishimoto.com/engineerin...he-crimp-myth/

05-13-2018, 01:17 PM	#5
Gunkk Thank you Al Oppenheiser! Drives: Red Hot A10 ZL1 Convertible Join Date: Jun 2017 Location: Sarasota, FL Posts: 4,978 View My Garage	The only thing the pinch affects is your mind... https://youtu.be/azPKIjxmmdU

05-13-2018, 01:18 PM	#6
mstgeer Drives: '17 2SS Vert H50, A8, F55, NPP Join Date: Jan 2018 Location: NW PA Posts: 179	I also had the convertible in the air for the 1st time this weekend and the exhaust is crimped after the axle to clear the rear cross bracing.

05-13-2018, 02:52 PM	#7
samr350 Drives: 2017 SS 1LE Join Date: Jan 2018 Location: Southern NH Posts: 138	It's crimped because the convertible has bracing there and it needs the extra clearance since the convertible and coupe use the same exhaust. On a stock and lightly modded car it's not restricting power.

05-13-2018, 03:43 PM	#9
Iroc_Z28 Drives: 2017 1SS 1LE Join Date: Sep 2014 Location: Canada Posts: 408	I've also heard that the crimp acts as a crumple zone for the exhaust, so that if the car is hit in the rear, the exhaust will break off there, rather than transfer the force upwards damaging the cats/manifolds... not sure the validity of that though.

05-13-2018, 07:08 PM	#10
lt4camaro Drives: 2021 LT1 10 speed auto Join Date: May 2013 Location: Connecticut Posts: 2,343	If you want max flow and sound, install the Borla mid pipe that deletes the the secondary unmonitored cats and the crimped pipe area. Better flow and sound = more power. Now you will have the car that always seems to run just a little bit better in a race, be on the strong side instead of the weak side.

05-14-2018, 09:55 AM	#13
MrChrisLS3 Drives: 2018 1SS M6 Join Date: Nov 2014 Location: Houston Posts: 2,617	The biggest, and main power robbing restriction in the system is the primary catalytic converter. As long as those are stock and in place, the restriction from these crimps in minimal, if at all.

05-14-2018, 10:07 AM	#14
mspeed1LE Drives: ZL1 1LE SUMMIT WHITE Join Date: Feb 2018 Location: VANCOUVER ISLAND Posts: 318	Great feedback! Thanks all! Might make some changes down the road.

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