Bronco Forum - Full Size Ford Bronco Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
I just took my exhaust off yesterday and its runnin open headers. how bad could this be for it? have a built 400 with rv cam and ported heads
 

·
Registered
Joined
·
2,091 Posts
Could be bad for your wallet if the cops in your area adhere to strict noise violation laws. On top of that, you'll be burning up valves.
 

·
Registered
Joined
·
461 Posts
You know already that it's loud. Otherwise it's fine. There are an awful lot of very expensive race engines that run unbaffled; there is no risk to the engine. The "backpressure" argument stems from a misunderstanding of the relationship between exhaust restriction and scavenging. Scavenging is good, backpressure itself is never good unless it happens to come with enough scavenging to offset the ill effects of the restriction. I'm not sure why everyone wants to believe this backpressure business; I guess we are attracted to the counter intuitive like "Could water boils faster than hot water". It sounds so strange it just might be true. With a good set of longtubes you are getting about as much scavenging as you ever will, so before anyone suggests you'll make more power with an exhaust on there, I'll say you're fine... except for having to live with an obnoxiously loud truck.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #4
I was thinking its fine because friends have ran open header for a long time but just wanted some opinions. Im probably gonna put an exhaust on it but just straightpiped.
 

·
Registered
Joined
·
2,091 Posts
You know already that it's loud. Otherwise it's fine. There are an awful lot of very expensive race engines that run unbaffled; there is no risk to the engine. The "backpressure" argument stems from a misunderstanding of the relationship between exhaust restriction and scavenging. Scavenging is good, backpressure itself is never good unless it happens to come with enough scavenging to offset the ill effects of the restriction. I'm not sure why everyone wants to believe this backpressure business; I guess we are attracted to the counter intuitive like "Could water boils faster than hot water". It sounds so strange it just might be true. With a good set of longtubes you are getting about as much scavenging as you ever will, so before anyone suggests you'll make more power with an exhaust on there, I'll say you're fine... except for having to live with an obnoxiously loud truck.

I'm probably one of those guys that doesn't fully understand the difference, but have read pros and cons to both sides. However, I've heard/read enough horror stories to not be willing to take the chance with something so easy to 'theoretically' prevent. Not to mention, I figure if there were absolutely zero negative affects, there would be alot more folks running open headers and Ford would have made open headers an option.
 

·
Registered
Joined
·
461 Posts
I'm probably one of those guys that doesn't fully understand the difference, but have read pros and cons to both sides. However, I've heard/read enough horror stories to not be willing to take the chance with something so easy to 'theoretically' prevent. Not to mention, I figure if there were absolutely zero negative effects, there would be a lot more folks running open headers and Ford would have made open headers an option.
I ran a 78 with open longtubes for a couple years and the problem is that it's just deafening, at WOT it could be heard for miles. Not even remotely legal for street use. Also if you aren't getting exhaust out from under the car it tends to make its way inside.
 

·
Registered
Joined
·
125 Posts
I've also heard that it is bad for valves. If your exhaust is letting loose under the truck and is left like that for a long time you'll und up with rust/corrosion problems. There's a lot of water vapor and corrosive stuff in exhaust that is not good for sheet metal long term.
 

·
Registered
Joined
·
7 Posts
I've got a 400m that I just rebuilt also. Running open heads is cool if u like the loud motor but if u have noise restrictions you'll get stopped. You loose a lil HP tho since u don't have any back pressure. I'd recomend atleast putting some kind of muffler on it for the back pressure. I got flowmaster super 40s on mine and it's still very loud and has that old school muscle car idle. And if u want it louder like open heads, u can put some straight pipes on it. Cherry bomb has some really nice straight thru mufflers which are pretty much like straight pipes that I'm looking into myself. But definetly put the headers and mufflers back on it!
 

·
Registered
Joined
·
773 Posts
I ran open long tubes on my 67 mustang with a built 289....for a while. I say it like that because I could only take it so long and so did the local PD. If I got on it you could literalliy hear it a mile away. Cruzin the local hang outs was cool at first but not being able to talk to my passengers and the everyone getting out of the car smelling like exaust got old quick. Ran straight pipes on it and dumped them out in front of the rear tire. Still plenty loud but managable.
 

·
Registered
Joined
·
2,248 Posts
open headers will not hurt the engine

you cause more damage from running without headers or manifolds that is were the ruining valve comes from as the extreme tempature diffference from what is coming out of the cylinder and what sucks back in as the valve closes

even open manifolds wont hurt the engine and they are the shortestt dump you can get

will you gain more power no, will you attract unwanted attention you bet
 

·
Age. Fac ut gaudeam
Joined
·
3,881 Posts
Just watched some Open Header youtube videos... Gawd, I have a stiffy...

I want to take my exhaust off. XD
 

·
trying to go fast!!
Joined
·
1,083 Posts
i run open on my 302 all day everyday music to my ears!!
 

·
trying to go fast!!
Joined
·
1,083 Posts
Can you post a sound clip, of it outside?

I'd like to hear a 302 Bronco open headers. :p
ya man ill see if i can get that for ya sounds sick! just like a Fox body stang!
 
1 - 19 of 19 Posts
Top