divided log manifold?

[rbryant]

All,

I was thinking about changing my log manifold for the SRT4 engine slightly to actually share only the 1/2 and 3/4 runners into the turbo flange. This isn't of course a true header but it does atleast keep the direction of the flow always toward the turbo rather than 180 degrees opposed...

Would this be better or worse?

Or if that is too much perhaps just a little triangular diverter would work as in the bottom of the picture...

It would be something like:

11891


Thanks,

Rich

[BadAssPerformance]

If you have 2 and 2 you definitely would not want them flowing at eachother without some sort of a "Y" like that.

Do you just want to make one to make one? There are so many 2.4L header choices

http://www.turbo-mopar.com/forums/showthread.php?t=9739

For a 'log' the AGP cast one is supposed to work well:

http://www.slowboyracing.com/img/sbr%20srt%20manifold.jpg

The OBX has been ok on mine so far... (and might be for sale soon)

http://www.racingpartsdepot.com/pictures/TH10747b.jpg

I may have an RT Ernie one like this for sale as well... with GT35R ;)

http://www.project-neon.com/PN2006/10162006001.jpg

[rbryant]

I was looking at it so that I can put the turbo in where it fits best in an lbody...

I should have the engine in shortly so after that I will have a better idea of whether or not it is really necessary. I also already had a hybrid Garrett with a chrysler flange and the TU 3" swingvalve so I was going to use that but with the manifold options I might just swap to a holset or a standard flange turbo.

I was starting to think that it would fit best in the middle and then I realized why none of the log manifolds put the turbo in the middle...

That -> <- flow just isn't good.


-Rich

[turbovanman²]

I am no expert by all means but I would think your idea wouldn't work due to the firing order??? it could cause reversion or maybe bad flow????

[OmniLuvr]

i have a stainless log manifold with a wastgate port, and turbo in the middle, for a t3 flange. i agree its not the best flowing, and its for the neon head not the srt 4. i got it as part of a purchase, do you already have a manifold? you could buy a bigger ford style t3 turbine housing on ebay at a good price for that hybrid garret, but you could also get a holset for pretty cheap too.

[rbryant]

I am no expert by all means but I would think your idea wouldn't work due to the firing order??? it could cause reversion or maybe bad flow????

Hmm I guess if they are 1-3-4-2 like the 2.2/2.5 then 3-4 on the same runner would be back to back.

Now does it matter?

-Rich

[turbovanman²]

Hmm I guess if they are 1-3-4-2 like the 2.2/2.5 then 3-4 on the same runner would be back to back.

Now does it matter?

-Rich

No idea, experts??? :eyebrows:

[rbryant]

No idea, experts??? :eyebrows:

I would think that keeping the flow in the same direction is what is important.

The header tube will still be shared anyway and the time between pulses isn't much different from back to back pulses to every other pulse anyway... Especially if you have basically a steady flow at high RPMs.

I do see honda log manifolds with the turbo simply put right in the middle aswell and that can't possibly be good.

-Rich

[OmniLuvr]

i think the mitsubishi eclipse header is setup up SIMILAR (not the same) too, the turbo diesle dodge truck is the same, but i dont know if its a split housing or not?

[8valves]

We used a cast log on a Honda H motor that was shared 1-2 and 3-4 and they aimed in center like one of your pictures. Worked great!!!

[BadAssPerformance]

We used a cast log on a Honda H motor that was shared 1-2 and 3-4 and they aimed in center like one of your pictures. Worked great!!!

Same 1342 firing order?

[rbryant]

We used a cast log on a Honda H motor that was shared 1-2 and 3-4 and they aimed in center like one of your pictures. Worked great!!!

Was it fully divided or just with a triangular diverter? I imagine that fully divided would be the way to go but it seems like anything is better than 180 opposed....

-Rich

[BadAssPerformance]

Yeah, whatever you can do to direct the air flow... The center two should point directly into the turbo if it is centered anyways so the flow from the outer two is what you need to 'direct' towards the turbo inlet.

[8valves]

Was it fully divided or just with a triangular diverter? I imagine that fully divided would be the way to go but it seems like anything is better than 180 opposed....

-Rich

JT, yup, H22 motor with a 1342 order.

Nope, not fully divided. The casting just had a peak in the center that came abotu halfway to the turbine flange face. That car made just a tick over 400 WHP on just 8.5 psi. Pretty good stuff for a log manifold car! It was a nice and simple piece.

Wastegate pulled off of the right side of the casting, only cylinder 1-2. I wasn't big on that, but the plugs always looked very similar from the other cylinders comparatively.

[rbryant]

JT, yup, H22 motor with a 1342 order.

Nope, not fully divided. The casting just had a peak in the center that came abotu halfway to the turbine flange face. That car made just a tick over 400 WHP on just 8.5 psi. Pretty good stuff for a log manifold car! It was a nice and simple piece.

Wastegate pulled off of the right side of the casting, only cylinder 1-2. I wasn't big on that, but the plugs always looked very similar from the other cylinders comparatively.

Cool thanks. It sounds like I am in the right ballpark then.

I might just put it over the #3 anyway which avoids this problem because then all of the flow is in the same direction. Basically 3 and 4 get their own flow and only #'s 1 and 2 are shared. In that case atleast #4 and #1 aren't flowing against each other as was previously stated.

It is one of those cases where I suddenly realized why the log manifolds tend to be on the #2 or #3 cyl rather than in the middle of #2 and #3!

It is good to know that if needed a hump in the middle should solve most of the problem if things lend to putting the flange in the middle.

-Rich

[rbryant]

Same 1342 firing order?

When you think about it, all possible firing orders have the same issue.

The only firing orders you can really have in an inline 4 are 1-3-4-2 (almost everything) and 1-2-4-3 (most fords).

They have to alternate outer and inner banks because of the connection to the crank unless you want something strange like a "big bang" engine which I hear is sometimes used on bikes but that is another story...

-Rich

[Ondonti]

We used a cast log on a Honda H motor that was shared 1-2 and 3-4 and they aimed in center like one of your pictures. Worked great!!!

But would it make a difference compared to the srt style manifold...
h22's are monsters regardless.

I would use a divided t3 flange and roll with the punches :P