Has anyone installed manual cutouts on NPP Exhaust - Page 2

sworn · 03-15-2017, 12:13 PM

Even though I'm sure it's not going to be a huge gain. What do you guy's estimate the HP increase would be by running cutouts? Would there be any at all, or just marginal?

buckbadfish · 03-15-2017, 03:02 PM

Had this over at the I4 Turbo crowd forum. Looks to be an excellent manual cutout design. Best breathing one anyway. https://youtu.be/3Ch4hCTPTZw

parish8 · 03-15-2017, 03:14 PM

The issue I see with the npp valves tied in before the muffler is they are on the small side. It will get louder but won't flow as much air as a 3" cut out would.

buckbadfish · 03-26-2017, 12:13 AM

I think on the Turbo motors it would be a nice gain. Especially if they had a tune to take even more advantage of the extra exhaust flow. Turbos don't want anything in the way of exhaust. Actually no fuel motor wants anything in the way of the exhaust, but you do have to keep the exhaust velocity up and have the right fuel metering to take advantage on N/A cars.

TrickracenLS3 · 03-28-2017, 11:50 AM

Quote:

Originally Posted by Atomic Ed

It will still be quite when you close the NPP valve. Just like normal.

Put the NPP valve in a T or Y before the muffler and re-route the pipe out the back. You should cover the pipe hole coming out of the muffler also. Again, take a look at the NPP valve/muffler arrangement. Simple mod with control of the NPP valve as your cutout valve.

Should be a simple job for a muffler shop.

Unfortunately this is wrong, think about it, you are relocating the NPP valve, before the mufflers in this scenario which would make the car like it was always open, and to the position you say to move it to would just make it louder. Closing it at the new location, you still have a free flowing exhaust system as if the system was open. and that answers your question as to why people are installing them.

Burly · 03-29-2017, 05:58 AM

I love my cutouts so much I'm going to put the NPP fuse back in.

03-15-2017, 12:13 PM	#15
sworn Drives: 2019 Camaro SS Join Date: Jan 2017 Location: Chicago Posts: 138	Even though I'm sure it's not going to be a huge gain. What do you guy's estimate the HP increase would be by running cutouts? Would there be any at all, or just marginal? __________________ 2019 Camaro 1SS. Crush. Mishimoto Catch Can, BMR Strut Tower Brace, Oracle Side Markers, ZL1 Side Skirts, Blade Spoiler W/ZL1 Addons Wicker Bill, Exhaust Cut Outs, BMR Front and Rear Cradle Braces, Cold Air Inductions CAI. ZL1 Rims 285 Fronts and 305's Rear. Speed Inc Tune PCM & TCM.

03-15-2017, 03:14 PM	#17
parish8 Drives: 17 SS a8 Join Date: Feb 2010 Location: omaha Posts: 1,678	The issue I see with the npp valves tied in before the muffler is they are on the small side. It will get louder but won't flow as much air as a 3" cut out would. __________________ dropped a valve in the 6.2. now running a drop in rods and piston 5.3 best et 5.83@121 with the 5.3 http://www.camaro6.com/forums/showthread.php?t=465472

03-15-2017, 03:02 PM	#16
buckbadfish Drives: Toyota Camry Join Date: Mar 2017 Location: Ca Posts: 6	Had this over at the I4 Turbo crowd forum. Looks to be an excellent manual cutout design. Best breathing one anyway. https://youtu.be/3Ch4hCTPTZw

03-26-2017, 12:13 AM	#18
buckbadfish Drives: Toyota Camry Join Date: Mar 2017 Location: Ca Posts: 6	I think on the Turbo motors it would be a nice gain. Especially if they had a tune to take even more advantage of the extra exhaust flow. Turbos don't want anything in the way of exhaust. Actually no fuel motor wants anything in the way of the exhaust, but you do have to keep the exhaust velocity up and have the right fuel metering to take advantage on N/A cars.

03-29-2017, 05:58 AM	#20
Burly Drives: 2016 Camaro 2SS Join Date: Apr 2016 Location: Spotsylvania, VA Posts: 724 View My Garage	I love my cutouts so much I'm going to put the NPP fuse back in.

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