Offset H-Pipe
Thread Starter
|
Senior User
Joined: Apr 2009
Posts: 115
Likes: 1
Offset H-Pipe
Since many trucks require the exhaust to be run down one side of the truck, is there any advantage to putting an H-pipe over on one side of the truck? I have understood the theory to be that the exhaust has "even" 90 degree timing on an 8 cylinder engine, so every 90 degrees of rotation there is a pulse to the whole system.
Anyone have any input? Should I try to get a crossover before the turn to the passenger side?
This is a 1977 F150 with a 460, 2wd, street driven, headers, ported heads, right around 450 hp.
Thanks!
Anyone have any input? Should I try to get a crossover before the turn to the passenger side?
This is a 1977 F150 with a 460, 2wd, street driven, headers, ported heads, right around 450 hp.
Thanks!
Moderator
Joined: Aug 2002
Posts: 6,104
Likes: 384
From: Southern California
To actually achieve that you would have to install a 90 degree header system- similar in NACSAR where the header pipes actually run onto the opposite sides of the exhaust exit/tail pipe to take full advantange of the pulse waves (actually they use a 180 degree system, but the same principle applies). The H or Y pipe is there to equalize pressure imbalances, on a street vehicle, the easiest way to find the correct location is to take some good ol paint (houshold, etc., paint a thin line on the side of the pipe where you think the "area of confusion" is, drive the vehicle for about 15 minutes, then crawl under neath and look for where the paint has blistered.....that's the area of confusion and where the H or Y pipe should be installed.
Now on a street, stock truck that is turning 5K, is there real benefit...minimal at best. On an engine turning 6K on the street, well, some benefit but it is really minor, not enough to really make any difference. On a race type engine...you bet because if you are turning less than 5K...you need to call AAA because you are lost and can't find the track (grin)
Now on a street, stock truck that is turning 5K, is there real benefit...minimal at best. On an engine turning 6K on the street, well, some benefit but it is really minor, not enough to really make any difference. On a race type engine...you bet because if you are turning less than 5K...you need to call AAA because you are lost and can't find the track (grin)
Freshman User
Joined: Dec 2010
Posts: 33
Likes: 0
H PIPE --THANK YOU
Beechkid, thanks for your response regarding H/Y placement. I'm in the process of installing Hedmans on 300 with Offy DP/Holley 390 setup and was wondering about exactly the same thing with a slight twist. I posted in the six cyl forum yesterday. Due to the front and rear collectors being offset 18 inches on the 6, I was and am now even more confident that I want and need an H and that it also needs to be attached to the pipes at the same distances from respective collectors and you verified that. Since the 300 is all about torque, not HP, I want the benefit to peak at cruise speed rather than to create max HP out at 4500 RPM etc. Can you confirm that as engine speed changes 2000 VS 3000 as an example, will the turbulant distance shift up and down the pipes or will it be in a stable location? In 6 cyl post I had asked for formulas etc but the paint trick is "in application on the actual vehicle" THANKS for the tip
Bob the Treeman
Bob the Treeman
Moderator
Joined: Aug 2002
Posts: 6,104
Likes: 384
From: Southern California
Beechkid, thanks for your response regarding H/Y placement. I'm in the process of installing Hedmans on 300 with Offy DP/Holley 390 setup and was wondering about exactly the same thing with a slight twist. I posted in the six cyl forum yesterday. Due to the front and rear collectors being offset 18 inches on the 6, I was and am now even more confident that I want and need an H and that it also needs to be attached to the pipes at the same distances from respective collectors and you verified that. Since the 300 is all about torque, not HP, I want the benefit to peak at cruise speed rather than to create max HP out at 4500 RPM etc. Can you confirm that as engine speed changes 2000 VS 3000 as an example, will the turbulant distance shift up and down the pipes or will it be in a stable location? In 6 cyl post I had asked for formulas etc but the paint trick is "in application on the actual vehicle" THANKS for the tip
Bob the Treeman
Bob the Treeman
Thread
Thread Starter
Forum
Replies
Last Post
RAY1986F150
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
4
Jan 29, 2013 02:56 PM
jniolon
1948 - 1956 F1, F100 & Larger F-Series Trucks
7
Mar 12, 2004 05:18 PM
