Exhaust vacuum - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Parag · 10-26-2011, 12:09 AM

I am trying to settle an argument with my roommate. Will creating a mechanical vacuum in the exhaust of an engine increase or decrease hp? Has anyone tried it?

SnoopyAce7 · 10-26-2011, 12:12 AM

id say neither since its not redirecting it back into the intake

JoshBobGuptaMarley · 10-26-2011, 12:20 AM

Isn't this what turbos and superchargers do, ram air through the engine? I'm gonna say this is done but long befor the air gets in the exhaust. A vacuum in the exhaust would just add weight in my opinion.

14pilot · 10-26-2011, 12:27 AM

The answer is...

It will increase power. A great set of Tri-Y headers well matched to the engine package can create a pull on the exhaust port of -5psi.

Nascar has done this for years. Dragsters are just recently starting to use this setup.

Russell James · 10-26-2011, 06:59 AM

It's not going to be a yes or no answer. Going to depend on many factors. Especially with computer tuning/calibration. Drastically change the exhaust backpressure characteristics and you might throw the engines AFR so out of whack that the computer cannot react enough - loss of power. Or maybe an old school carb'd engine might gain power on the top end, but lose tq on the low end because of no back pressure.

I think the answer needs to be qualified as - it most likely will increase peak hp as long as the vehicle's fuel/tuning system can appropriately adjust for the increased exhaust flow.

Work on curing cancer instead. The world already knows how to design good flowing exhaust systems.

10-26-2011, 12:09 AM	#1
Parag Drives: 2010 camaro 2SS LS3 Join Date: Aug 2011 Location: Denver Posts: 1,334	Exhaust vacuum I am trying to settle an argument with my roommate. Will creating a mechanical vacuum in the exhaust of an engine increase or decrease hp? Has anyone tried it?

10-26-2011, 12:12 AM	#2
SnoopyAce7 (ʘ‿ʘ) Drives: The one with a roof rack Join Date: Dec 2009 Location: Northern Virginia Posts: 1,221	id say neither since its not redirecting it back into the intake __________________

10-26-2011, 12:20 AM	#3
JoshBobGuptaMarley Emerald Coast Camaros Drives: '12 2SS/RS LS3 GBA Join Date: Sep 2011 Location: PanamaCityBeach,Florida Posts: 1,375 View My Garage	Isn't this what turbos and superchargers do, ram air through the engine? I'm gonna say this is done but long befor the air gets in the exhaust. A vacuum in the exhaust would just add weight in my opinion. __________________ Muffler Delete, Cold Air Inductions intake, Technostalgia Sequential LED Tail Lights, Vmax CNC Ported TB, RX Catch Can, AAC LED Interior Lights (Aqua)

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10-26-2011, 06:59 AM	#5
Russell James Drives: '15 SS 1LE, '69 Z28 drag car Join Date: Dec 2009 Location: Mich Posts: 4,482	It's not going to be a yes or no answer. Going to depend on many factors. Especially with computer tuning/calibration. Drastically change the exhaust backpressure characteristics and you might throw the engines AFR so out of whack that the computer cannot react enough - loss of power. Or maybe an old school carb'd engine might gain power on the top end, but lose tq on the low end because of no back pressure. I think the answer needs to be qualified as - it most likely will increase peak hp as long as the vehicle's fuel/tuning system can appropriately adjust for the increased exhaust flow. Work on curing cancer instead. The world already knows how to design good flowing exhaust systems.