Straight Pipe?
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Straight Pipe?
What size/kind of pipe do I need to use. I am gonna cut my cat. converter off, and weld straight pipe all the way back and finish w/ dual tips. Thanks
Colby
Colby
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Car: 82' Z28 IROC Clone (SOLD)
Engine: 355
Transmission: Built TH-350
Axle/Gears: 3.73 Moser 12 bolt
No Cats and straights is gonna be loud as ^&^#$%. I had 2 1/2 inch straights with no muff or cat on my truck...You could hear me 3 miles away and it sounded like I was right in front of you....4 tickets in 3 days!!! Atleast get a bullet muffler... I'd say 2 1/2 inch for the pipe....
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Car: 1989 Iroc Z L98
Straight pipe = straight ghetto
unless you are running an over the top motor you will lose all your back pressure and that means on a street motor no torque, and if your motor doesnt have a lot of top end kiss bye bye to any fun at all.
unless you are running an over the top motor you will lose all your back pressure and that means on a street motor no torque, and if your motor doesnt have a lot of top end kiss bye bye to any fun at all.
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Originally posted by unknown_host
...you will lose all your back pressure and that means on a street motor no torque...
...you will lose all your back pressure and that means on a street motor no torque...
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Car: 1989 Iroc Z L98
Originally posted by five7kid
well then five7 kid, i am listening and would love to hear your explaination about why running no mufflers is great for street motors. dont forget to mention that running straight pipe for long periods of time can warp exhaust valves, oh and the whole lack of back pressure on a street motor and how that affects torque. looking forward to it.
#6
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yea...ive had my exhaust come off for some unknown reason. it was hanging from the middle of the exhaust system and i tell you...i felt a huge power loss both tq/hp. i needed that back pressure. unless your running some motor with good hp, your goin to have a loss.
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Car: 1992 Camaro RS
Engine: Yet another 350 TPI
Transmission: Borg Warner 6 spd
Axle/Gears: 3.73
I have disconnected the exhaust pipe after the catalytic and turned the car on just out of curiousity before to hear how it sounds. It felt as if it had MUCH more bottom end torque with the muffler disconnected, and it would rev considerably more freely. Thats just my experience though.
By the way, unknown host....how does running a straight pipe for long periods of time warp exhaust valves? I'm curious.
By the way, unknown host....how does running a straight pipe for long periods of time warp exhaust valves? I'm curious.
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Car: 1989 Iroc Z L98
Originally posted by 92blue
I have disconnected the exhaust pipe after the catalytic and turned the car on just out of curiousity before to hear how it sounds. It felt as if it had MUCH more bottom end torque with the muffler disconnected, and it would rev considerably more freely. Thats just my experience though.
By the way, unknown host....how does running a straight pipe for long periods of time warp exhaust valves? I'm curious.
I have disconnected the exhaust pipe after the catalytic and turned the car on just out of curiousity before to hear how it sounds. It felt as if it had MUCH more bottom end torque with the muffler disconnected, and it would rev considerably more freely. Thats just my experience though.
By the way, unknown host....how does running a straight pipe for long periods of time warp exhaust valves? I'm curious.
as for the exhaust valve thing, i hear it everytime this comes up. i have heard that since there are no mufflers on the car the exhaust valves are exposed to greater temperature changes, not sure if this is the actual reason but there is a scientific reason i have seen.
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Car: '85 Z28
Engine: 305
Transmission: WC T5, 3.23 posi
Backpressure (aka restriction) is never good...
I have 3" duals on my 305 and it runs fine. I get plenty of low end tq.
I have 3" duals on my 305 and it runs fine. I get plenty of low end tq.
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Car: 1989 Iroc Z L98
Originally posted by kfoley
Backpressure (aka restriction) is never good...
I have 3" duals on my 305 and it runs fine. I get plenty of low end tq.
Backpressure (aka restriction) is never good...
I have 3" duals on my 305 and it runs fine. I get plenty of low end tq.
I am not saying corking your exhaust and having tons of backpressure is good, I am saying slight backpressure is a good thing to have as it helps scavenge the exhaust.
A real world example:
My friend has a little beater pickup, we hacked the exhaust off before the catalytic converter and put a glasspack there, the exhaust ended basically underneath the passenger's feet hehe. no backpressure. he got sick of the drone and decided to get a dynomax turbo muffler and run pipe back to the axle. suddenly, his truck is torquey again and fun to drive. i think that if you put dual 2.5" or dual 2 1/4" on your 305 you would feel a lot more torque. 3" is too big for 90% of 350's.
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Car: '85 Z28
Engine: 305
Transmission: WC T5, 3.23 posi
Yes I do have mufflers, though not much (you can see tight through them... ) I know 3" is way overkill for a 305, but soon I will be dropping in a 383 or 400, so that's why I decided on 3".
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When I had my lg4 I had no muffler and removed the cat and definately got a seat of the pants difference for the better. The reason you got the good ol was because backpressure is always bad. It costs you both power and torque. The thing however is your exhaust has to scavenge. That means that you have to have a well designed exhaust. The thing about warping the valves. I dont think you will really have much of a problem with that unless you are running open headers, because it takes long enough to get that cool air to them through the pipes that they should be fine. Search backpressure and scavenging and you will find some interesting information and debates.
Ben
Ben
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I bet it would still be loud but it might move some of the loud toward the back instead of coming out right in front of the driver(you). I think I would like it, but a lot of people on here dont seem to like the sound of straight pipes although that may just be because their motors aren't built enough to sound good on their own.
Ben
Ben
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Do you like the way it sounds with open headers? If so I would think you would like it with straights on it also. What kind of power are you making anyway?
Ben
Ben
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Originally posted by unknown_host
straight pipe sounds ghetto and nasty, you like the fact that when you let off it backfires and pops? or do built motors not do that
straight pipe sounds ghetto and nasty, you like the fact that when you let off it backfires and pops? or do built motors not do that
Ben
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