pros and cons of straight pipes

[greasemonkey060]

before i weld up a new exhaust system i was wondering iof someone could give me the lowdown on straight pipes... something about warping valves..

for awhile i was gonna run straight pipes from the headers to right angle bends out under the bed in front of the rear wheels.. ive also noticed a popping sound when trying to slow down in a low gear at high speeds..

can someone fill me in on whats going on?????

-brandon

[68F250]

Headers and straight pipes exiting in front of the rear wheels:

I would worry more about your ears than the valves.

[bwc302]

the popping is from back pressure being released through the exhaust
it will also change your air/fuel mixture (if I remember correctly it will cause the vehicle to run a little rich).

noise will be a huge factor in running open exhaust and depending on where you live could also get you a ticket for it.

[heep70]

LOUD I did that when I was younger. I got sick of it after about a week. Couldn't here anybody in the cab while running down the road. Sounded good though.

[willowbilly3]

If you do it run them on out the back. Some cars are more forgiving than others. One friend picked me up in a cherry 85 Elky with flowmasters and after 5 miles I was ready to walk. Another buddy has headers and straight pipes on a 305 in his 48 F-1 (out the back) and it isn't bad to ride in at all.

[Nefarious67]

Warping valves Occur from running NO headers or exhaust manifolds. when you have an exaust system heat is transfered from the head into the manifold or header. When the enging cools off it allows things to cool evenly since everything is warm and there is warm air up next to the vavles. If you run No headers or exhaust and you shut the engine off cool air can be sucked back into the head and cause the vavles to cool at a faster rate than the head and crack them. This is what i was told since i have never run an engine without manifolds as I was advised to never do it.

opps forgot----if you are running egr ( which im 99% sure you arent) straight pipes will mess it up. Egr has to have back pressure to help it work and with straigth pipes, well less backpressure is the point! unless you count just being noisy

[crazy larry]

i too have heard in the past that open headers will burn or warp exhaust valves, but in all my 33 years, i've never actually MET ANYONE who could prove this.

PRO= loud as hell.
CON= loud as hell.

[greasemonkey060]

Warping valves Occur from running NO headers or exhaust manifolds. when you have an exaust system heat is transfered from the head into the manifold or header. When the enging cools off it allows things to cool evenly since everything is warm and there is warm air up next to the vavles. If you run No headers or exhaust and you shut the engine off cool air can be sucked back into the head and cause the vavles to cool at a faster rate than the head and crack them. This is what i was told since i have never run an engine without manifolds as I was advised to never do it.

opps forgot----if you are running egr ( which im 99% sure you arent) straight pipes will mess it up. Egr has to have back pressure to help it work and with straigth pipes, well less backpressure is the point! unless you count just being noisy

thanks a lot! now i wont worry as much..

[greasemonkey060]

PRO= loud as hell.
CON= loud as hell.

haha good point

[berad357]

Back in my hot-rod days, an old flat-head guru told me this about exhaust. Keep 'em straight as possible. If you elect to install glass packs or mufflers, paint the exhaust pipes and let the paint dry. Then go run the truck like you intend break the sound barrier. After 20-30 minutes shut it down, let it cool and see where the paint stopped burning off. Where it ends burning off is the best place for the muffling device to begin. If you intend to go open with side exits use sweeping angle. No tight bends. I do miss my hearing.
Brad Burns

[greenbank]

How come loud pipes are fun when they're your vehicle but annoying as hell when they're someone else's? I try to remember the latter when deciding about the former.

[boots]

well your pretty much doing what I just did ( Pictures in my gallery ). I dont know if you read my other thread but I straight piped it and kicked it out infront of the back tires. i like like the sound alot, but i have only run it in the garage ( with the doors open of course ) beucase im waiting for some drop brackets for my front i-beams, so it cant go anywere. If it is just too loud when i get the chance to run it outside, then ill go ahead and put some mufflers on it.

[boots]

by the way, does anyone know if backfire can hurt your truck in any way?

[rjewkes]

depends on where it comes from. If from The carb the worst i personally know of is the carb can catch fire and atleast get gummed up.If out the pipes i have no idea. I thought i had been told that backfire in the exhuast can cuase head damage but i don't think i have had it proven to me.

[68swb]

i have headers and stright pipes running out the back of my 68 and it is loud. but i love it . and always say if you cant hear it is it really running. one thing to think about is if you put the exhaust in front of the rear tires the fumes and gases that come out the exhaust will turn you wheels black over time. on 97' f150s that is how the exhaust was run stock and it turned the wheel black and took a little extra time cleaning that wheel.