Honda D Series Forum banner

1 - 20 of 103 Posts

·
Banned
Joined
·
1,875 Posts
Discussion Starter #1
I've been researching the Hytech manifolds, and apart from being -very- different from every manifold made for a honda, it doesn't seem to have equal length runners as a priority in manifold design. Seems more that packaging was more important.

How important are equal length runners in a turbo manifold?
Is it as important to have EL runners as it is hyped out to be, with exhaust pulses reaching the turbine at the same time?


Yes, I understand the basic theory behind the manifold design, and that's not what I'm asking.
 

·
Registered
Joined
·
2,539 Posts
How important are equal length runners in a turbo manifold?
Is it as important to have EL runners as it is hyped out to be, with exhaust pulses reaching the turbine at the same time?]
Theoretically atleast equal length will produce more of a peak. Different length primaries/runners will "spread" the power over a slightly larger portion of the powerband.

This is what ive read in a few books. Never tested it myself, Im sure a few others can chime in if that is incorrect or not
 

·
Registered
Joined
·
10 Posts
just thinking of flow, if thats the exact manifold your going to run i would be worried about that tight 90 right infront of the turbo flange? i dont think equal length makes much of a difference unless your going for record numbers or close to it! just my 2 cents.
 

·
Registered
Joined
·
2,340 Posts
Well Subaru STI's run un-equal length headers, thats what gives them that distinct sound. They have great power band and tunability. However there also almost a full liter higher in displacement. As far as Hondas are concerned. I have no clue.
 

·
FYB or FIU tune, pick 1
Joined
·
560 Posts
Well Subaru STI's run un-equal length headers, thats what gives them that distinct sound. They have great power band and tunability. However there also almost a full liter higher in displacement. As far as Hondas are concerned. I have no clue.
this is what i was about to say, go read up on subaru and porsche boxer design engines
 

·
Well.......
Joined
·
2,488 Posts
Well Subaru STI's run un-equal length headers, thats what gives them that distinct sound. They have great power band and tunability. However there also almost a full liter higher in displacement. As far as Hondas are concerned. I have no clue.
maybe its the lack of sleep but i thought they got there distinct sound due to the firing order and how it is... correct me if im wrong
 

·
Banned
Joined
·
1,875 Posts
Discussion Starter #8
Theoretically atleast equal length will produce more of a peak. Different length primaries/runners will "spread" the power over a slightly larger portion of the powerband.

This is what ive read in a few books. Never tested it myself, Im sure a few others can chime in if that is incorrect or not
I've read this when it comes to designing NA headers.

But the primaries are also 30"+ long (in NA apps), so two runners being 3" shorter is only 10% difference in length; in a shorter runner manifold, where some runners are only maybe 12% long, it's like a 25% difference, so idk if makes a difference.
 

·
Registered
Joined
·
2,340 Posts
maybe its the lack of sleep but i thought they got there distinct sound due to the firing order and how it is... correct me if im wrong
Nope, cause porsche uses equal length headers to control this sound in the newer models to control said sound. And i have personal experience with STi's with equal length and they lose that signature sound.
 

·
Registered
Joined
·
2,340 Posts


Which runner is the longest? Which is the shortest?


Seemingly unrelated question:

What is the firing order of a Honda 4 cylinder?
Honda is 1-3-4-2 im pretty sure and it looks on that header that the second from the left is the shortest.
 

·
Well.......
Joined
·
2,488 Posts
Nope, cause porsche uses equal length headers to control this sound in the newer models to control said sound. And i have personal experience with STi's with equal length and they lose that signature sound.
o ookie thanks for the info +REP
 

·
Formerly weebeastie
Joined
·
904 Posts
i dont think equal length makes much of a difference unless your going for record numbers or close to it!
This turbo manifold appears to be going for record numbers for a short ram design from what I can see. Very well designed


I've been researching the Hytech manifolds, and apart from being -very- different from every manifold made for a honda, it doesn't seem to have equal length runners as a priority in manifold design. Seems more that packaging was more important.

How important are equal length runners in a turbo manifold?
Is it as important to have EL runners as it is hyped out to be, with exhaust pulses reaching the turbine at the same time?


Yes, I understand the basic theory behind the manifold design, and that's not what I'm asking.

I'm sure packaging was a consideration because it has to fit into a certain chassis, but this manifold is designed like this for a reason.

Read Acid Beavers post, then reread it until you understand why #2 exhaust runner is the shortest and why #1 is the longest.


Sorry my spoon is broken
 

·
Registered
Joined
·
984 Posts
Read Acid Beavers post, then reread it until you understand why #2 exhaust runner is the shortest and why #1 is the longest.


Sorry my spoon is broken
I reread it and I still am a bit uncertain... I'm sure I'm not alone. This is an oppurtunity for some useful knowledge/information here.
Someone get this man a new spoon.
 

·
Registered
Joined
·
2,539 Posts
I reread it and I still am a bit uncertain... I'm sure I'm not alone. This is an oppurtunity for some useful knowledge/information here.
Someone get this man a new spoon.
The way im reading his post is, the lenth of the tubes goes with the firing order to time the exhaust pulses to the turbo.
 

·
Registered
Joined
·
984 Posts
The way im reading his post is, the lenth of the tubes goes with the firing order to time the exhaust pulses to the turbo.
I see that but it doesn't make since to me. It seems by doing that 1 and 2 would be "arriving" at the turbo closer together instead of a consistant rhythm.
 

·
Registered
Joined
·
2,539 Posts
I see that but it doesn't make since to me. It seems by doing that 1 and 2 would be "arriving" at the turbo closer together instead of a consistant rhythm.

:bigok:
 

·
Registered
Joined
·
1,757 Posts
EL is most important on NA builds. The EL runners help you take the most advantage of your exhaust velocity, and also help you capitalize on the stoke of your motor, just like VL Intake runners.

Depending on the length and diameter or the runner, size of the collector, they will make peak power at different Rpms, because of pressure pulses traveling up and down the exhaust to help with flow. The longer the runner the longer the pulse takes to travel, so the lower the RPM it will be most efficient at. the shorter the runner, the faster the pulse can travel, so the Higher the RPM it will be efficient at. Since your looking at a turbo manifold, it wont make MUCH of a difference. Most important thing in a turbo manifold is going to be smooth transition from Exh. ports to the exh. turbine of the turbo.
 

·
Registered
Joined
·
984 Posts
OK.... researching pulse vs equal length now. I just dont see it yet. It seems that 1-3-4-2-1-3-4-2-1-3-4-2 in a rhythm kinda like a speed bag in boxing, would be more beneficial, smoother and thus more effecient than 12----34-----12---34----12 ect ect.... I know this is a bit crude and exaggerated but its the only visual I can come up with lol.
 

·
Registered
Joined
·
2,539 Posts
OK.... researching pulse vs equal length now. I just dont see it yet. It seems that 1-3-4-2-1-3-4-2-1-3-4-2 in a rhythm kinda like a speed bag in boxing, would be more beneficial, smoother and thus more effecient than 12----34-----12---34----12 ect ect.... I know this is a bit crude and exaggerated but its the only visual I can come up with lol.
Im thinking that 12---34----ect. would produce a stronger pulse, slightly less often, than 1-3-4-2...

I could be way off tho lol
 
1 - 20 of 103 Posts
Top