Dual straits on a diesel?

[Possum]

I have a 89' diesel (7.3L international) and i have a 5'' straight run out on the passenger side and it will rattle winders and just sounds D@m good. I'm wondering if puttin a "Y" on it and runnin "duals" (yea i know that aint true duals but i'm goin the cheap route) would it make any considerable difference in the sound ?

 

[dragogt]

Should, big rigs run that all the time..

 

[A_G]

Should, big rigs run that all the time..

on big rigs its defintely useless just for style.

i know way back when big rigs did have a V style cylinder configuration, but now all are inlines....so they have one header, there not true duals at all.

i was always a fan of the tractor muffler (yes they do sound good) or no muffler, dumped with a 90* turn down somehwere under the truck.

when you do get the black smoke (over fueling) it looks like a black smoke clound is rising round the rig....but if you ever tow a white campr on any sorts. get tall stacks. i see it all the time. white 30+ ft towable rvs with black smarks all over them...

either they dont do stacks tall enougvh or there pointed right at the camper...its funny

 

[6L PWR]

I always wanted to get nice 5" chrome stacks, but run them like old side pipes along the sides under the doors. With 45 turn downs at the end.

 

[73F100Shortbed]

I always wanted to get nice 5" chrome stacks, but run them like old side pipes along the sides under the doors. With 45 turn downs at the end.

That would look cool. I did that for a guy with a chevy dually truck but it only had a 350 in it. The bad part was the way he put the inlet to the pipes the exhaust I had to run from the engine almost to the rearend then back to the front to connect to the pipes. The exhaust actually made a u-turn under the truck. I was laughing the whole time I was bending the exhaust. He refused to re-do the inlet for me to do it right. But it was his $600 he wanted to waste in pipe and labor lol. If it is done right it would look cool. I was going to do this on my truck (with smaller stacks of course) but decided against it. On a diesel it would look awesome though.

 

[dragogt]

]on big rigs its defintely useless just for style.[/B]

I'm gonna have to disagree w/ ya there, yeah part of it is for aesthetics but it also gives the exhaust a secondary way out..

More air out lets more air in.. At least Paraphrase'd thats how it was explained to me when I worked as a tech....


i know way back when big rigs did have a V style cylinder configuration, but now all are inlines....so they have one header, there not true duals at all.

i was always a fan of the tractor muffler (yes they do sound good) or no muffler, dumped with a 90* turn down somehwere under the truck.

when you do get the black smoke (over fueling) it looks like a black smoke clound is rising round the rig....but if you ever tow a white campr on any sorts. get tall stacks. i see it all the time. white 30+ ft towable rvs with black smarks all over them...

either they dont do stacks tall enougvh or there pointed right at the camper...its funny

That ant no lie, but the boss would have had our *** if we let a truck roll out like that..

 

[Skandocious]

More air out may let more air in (though of course there is a bound on how much air you can bring in), but Anthony is saying that most big rigs with dual pipes are really just a single pipe off the head that splits into 2. Splitting into 2 pipes surely wont allow the engine to breath much better.

But i DO submit that it would divide the soot content in half between the two pipes and would therefore reduce the chances of blackening the trailer that you're towing.

 

[F 150Cobra]

courtesy of SBFtech!

* Backpressure = high torque down low < BULL Sheizaa
* There is no such thing as "too big" of an exhaust system. When such a claim/observation is made it literally translates to a "too small of an intake" air and fuel wise.
* Key component in the exhaust = header (long tube) and collector + extension design.
* Exhaust system is one that requires pulse tuning NOT VELOCITY.
* Exhaust system is one that requires free flowing characteristics after the headers NOT VELOCITY.
* Characterization of full exhaust systems sizing based on engine HP categories is wrong.
* This is an area in which erring towards the too big side is better. Rather than trying to correct such an error by restricting the exhaust, it's always more productive to correct the exhaust via increasing the engine's intake capabilities.

 

[dragogt]

Well when you have a "vacuum" (lack of a better word) being created by the exhaust being "pulled" out the stacks it empties the cylinders better and helps create a draw so you get More air in the cylinders...

Edit to add* Jurgen is correct, and tks for the assist ..

 

[Skandocious]

Well when you have a "vacuum" (lack of a better word) being created by the exhaust being "pulled" out the stacks it empties the cylinders better and helps create a draw so you get More air in the cylinders...

But if the duals split from a single pipe then that vacuum will be bottled necked by the smallest portion of the pipe, which will be BEFORE the pipes split into two. You cant pull any more air out of the tips of the two pipes than you can pull out of the single pipe that their splitting from, otherwise you've just magically created more air between the split and the ends of the pipes.

 

[dragogt]

Speed...

Faster out = More in

 

[Skandocious]

Speed...

Faster out = More in

Right but I'm explaining to you that splitting a single pipe into 2 pipes is not going to dump any more air that a single pipe that is not split.

 

[dragogt]

http://sbftech.com/index.php/topic,19160.0.html <-- you have to have at lest 10 posts there to see it, but for those that dont..

Joel5.0: Here is something a few people compare and look at the principle's applicability in 4-cycle engines. If a bigger exhaust pipe past the collector affects negatively the scavenging pulse....... how come increasing the exhaust pipe volume to enhance the scavenging pulse is exactly what is done for 2-cycle engines?...... a reduction in the exhaust pipe is then placed at a specific distance to generate a sonic pulse and control the fresh A/F charge that reaches the header by the scavenging...... using the exhaust to "supercharge" the intake by making the exhaust system an extension of the intake pulse and intake volume.......

Joel5.0: Now.... 4-cycle engines do use valves to control flow and timing........

Make more sense??

 

[Skandocious]

No, not at all. That idea only applies to 2-stroke engines.

Edit: Not to mention it has nothing to do with your argument. It's making the point that a 2 stroke system would utilize a strategically placed pipe reduction to send a sonic pulse back towards the engine and force some escaped intake air back into the combustion chamber. How is that related?

 

[dragogt]

Right but I'm explaining to you that splitting a single pipe into 2 pipes is not going to dump any more air that a single pipe that is not split.

Take a straw and try and breath through it.....




Now add one more....

No, not at all. That idea only applies to 2-stroke engines.

Edit: Not to mention it has nothing to do with your argument. It's making the point that a 2 stroke system would utilize a strategically placed pipe reduction to send a sonic pulse back towards the engine and force some escaped intake air back into the combustion chamber. How is that related?

B/c it a tuned system, apply the same principles to a 4 stroke engine

 

[TexasNomad]

Weeeeeeeee, round n' round

 

[Skandocious]

Take a straw and try and breath through it.....




Now add one more....

That analogy pertains to TRUE duals, meaning two exhaust manifolds each with their own dedicated exhaust pipe. Splitting 1 pipe into two, like we're talking about here, would be more analogous to: breath through a stray, then cut a hole in the straw halfway through and punch another straw through that hole. Easier to breath? No, the volume of air moving through the straw is bottlenecked by the one straw in your mouth, before the split.

B/c it a tuned system, apply the same principles to a 4 stroke engine

A 4-stroke engine has no use for such a principle, the valves prevent scavenging.

 

[dragogt]

That analogy pertains to TRUE duals, meaning two exhaust manifolds each with their own dedicated exhaust pipe. Splitting 1 pipe into two, like we're talking about here, would be more analogous to: breath through a stray, then cut a hole in the straw halfway through and punch another straw through that hole. Easier to breath? No, the volume of air moving through the straw is bottlenecked by the one straw in your mouth, before the split.



A 4-stroke engine has no use for such a principle, the valves prevent scavenging.

How do you figure that one???

 

[Skandocious]

How do you figure that one???

You dont know how a 4-stroke engine works?

It's designed to never open the intake and exhaust valves at the same time. Theoretically impossible for fresh fuel/air mixture to escape through the exhaust valve.

 

[dragogt]

Sorry bud, But I have to call BS on that one...

Delay Exhaust valve closing and extend Intake valve opening... Now with all that air rushing in start the compression stroke w/ the intake valve still open......

Do you really think all that air is going to turn around and rush back out the intake valve?????