Straight pipes-when do they help

[Anonymous]

I was wondering, When does a motor gain performance from the lack of mufflers? I heard that back pressure is necessary for the motor to run right. Another question, Where would we get the setup to drop the mufflers off while driving? Is this an impractical application for our cars?

TX Steve

 

[LaGrasta]

"Straight pipes", often referred as "drag pipes" are useful in exactly that application. When you are full blast on the pedal. lower speeds, they rob power and torque (and add a lot of noise).

 

[Anonymous]

u can buy things that u can attach easily between your exhaust pipes...basically its a small push/pull operated Y pipe...so u can have it running through the exhaust at one time or if u want u can pull the nob and run straight pipe.

 

[Anonymous]

u can buy things that u can attach easily between your exhaust pipes...basically its a small push/pull operated Y pipe...so u can have it running through the exhaust at one time or if u want u can pull the nob and run straight pipe.

Exhaust cut outs

 

[BB6Mustang]

Backpressure is never desirable in an exhaust system. What you do want, however, is high exhaust gas velocity to help with cylinder scavenging. You need to size your pipes for your engine size, RPM range, and driving style so that you keep your exhaust velocity up while providing as little backpressure as possible, and ideally you want a muffler with as little backpressure as possible while still providing the sound suppression and tone you desire.

The greatest gains from lack of backpressure come at high RPM WOT (where we have the greatest volume of exhaust gas). You can run straight pipes, if they are properly sized, with no performance loss. The only thing it will hurt will be your ears (and maybe your wallet if you get a ticket).

 

[Lazy JW]

As BB6 notes, no internal combustion piston engine needs back pressure, BUT the cam timing/gas velocity needs to match the particular operating conditions. Just slapping a set of straight pipes on without due consideration of the entire system is no guarantee of more power. If mufflers made more power you can bet that Top Fuelers would run them. So would the WW2 fighter planes. JC Whitney used to sell exhaust cutouts, I don't know if they still do.
Joe

 

[Anonymous]

Thanks for the help guys. A few more questions, though. With the exhaust cut outs, could I easily drop them at any time while I am driving, for example, when I gun it or just when I hit higher RPMs? I have 2 1/4" duals. Is this a good size for my 200 if I want to get the cut outs? The size of my pipes and type of mufflers, as well as the header setup, control my exhaust velocity, right? How do I know what is right if I want the cut outs?
Again, thank you all.

P.S. Does anyone have cut outs on their I six?

 

[Anonymous]

http://www.jegs.com/cgi-bin/ncommerce3/ ... rmenbr=361

http://www.jegs.com/cgi-bin/ncommerce3/ ... rmenbr=361

This is prolly what you want...
http://www.jegs.com/cgi-bin/ncommerce3/ ... rmenbr=361

 

[addo]

SSM, as to when you can run the cutouts - whenever you can stand the noise and risk of a fine! I've thought about hooking up a set to the accelerator pedal, so WOT opens them.

Adam.

 

[Anonymous]

WOW!

That is exactly what I wanted, 76 Maverick. Thank you for the links. After I first put my header on, I had to drive the car like 20 miles with no exhaust and I fell in love with that monster truck sound, but it IS a bear on the ears. Adam, Joe, BB6, LaGrasta, Placid Warrior, Thank you all.

Steve

 

[Asa]

Steve, check this site out too
http://www.quicktimeperformance.com/QTEC/

it's along the lines of the last one 76Mav posted, but a step up
more expensive, but they're nice

my room mate has a set on his 454SS truck, they're cool

 

[Falcon62]

I have 2 1/4" duals. Is this a good size for my 200 if I want to get the cut outs?

Too big for a 200. For dual out you should have nothing larger than 2" and something a tad smaller would be even better. 2 1/4" would be ok for a single outlet.

 

[Anonymous]

i have a 170 with dual headers with the Y collector to have single tube, here known as 6-2-1 (because here they dont make single headers).

it has no muffler, just free exhaust in 2,5" the sound is awesome, the engine have no modifications, the engine runs better now at high RPMs, at low rpms is the same than before, original header and turbo muffler...

i have some friends with 221, hot cam, worked sp head with 3 or 3.5" single exhaust (free).

totally deaf but the BRRROOOWOOOOOOOOAAAMMMMM is awesome 8)

 

[Anonymous]

I think I will save my money for the QTEC cutouts. The others seem like too much work. I just want to drop the exhaust any time and close it up whenever without waiting for the exhaust to cool. I read somewhere else on this forum that going too big with exhaust (2.25 dual on a 200) wont hurt, it just wont help after a certain point. Aside from that, I can't afford to replace my brand new exhaust to decrease the size.

Steve