turbo manifold tube sizing

[chrisdoesitsideways]

Im gonna be running a single Turbo on my 1uz and im curious to hear everyone's opinions on what size tubing I should use for my manifolds. I currently am planning on running 8 pounds. So I have two different sets of 3/8 SS flanges. One has 1.75 ports and the other 1.5 inch ports. Im thinking im gonna go with the 1.5 inch primaries into a 1.75 inch. This will be a log style manifold just because of lack of space. So the two 1.75 tubes will connect together from each side of the motor and up to the Turbo. The other option is the 1.75 primaries into a 2 inch to the Turbo. Any opinions? Im guessing the 1.5 inch to 1.75 will flow at higher velocity just because of the smaller tubing which would mean faster spool up versus the slower more open pipe which would be better for a higher boost application? ? This is my opinion.

 

[Alan Whitaker]

Hi,
I an going for 1 5/8 primary's to a 4 to 1 collector to 2 1/2 inlets to the turbo's, I have only just started so will be a few weeks before I can post pictures

Alan

 

[chrisdoesitsideways]

That doesn't sound to bad. Unfortunately I have to go with a log style. I think im gonna try the 1.5 - 1.75 to the turbo

 

[stevieg]

I'm running 1.5" primaries into 2" logs then up to 2.5" piping to the sine turbo. 570whp without an issue

 

[chrisdoesitsideways]

Im assuming your running a single Turbo? So your using the 2.5 inch where the two sides come together to the Turbo? 570hp that would be nice. Im shooting for the 350ish range so im gonna do 1.5 runner to a 1.75 log with probably 2.5 to the Turbo should work well with my goals

 

[XR8tt]

Imo the smaller size and concentrate on better design as in
angle into log .. 90* is best to be avoided..
At modest power levels..
Not too many turbo manifolds don't work...

 

[stevechumo]

I've been using 1.5" for the 4 holes on each bank and merge into 1.75" into a single pipe. That's for each manifold on each side. Then both sides merge together in 2.5" before the single turbo. I've been boosting fine ever since and make near 400 rwhp. There's still lots of boost left.

Since this is a turbo thread, you may want to move it to the Forced Induction section, where you can get more responses.

 

[XR8tt]

Since this is a turbo thread, you may want to move it to the Forced Induction section, where you can get more responses.[/QUOTE]
Done..

 

[chrisdoesitsideways]

here is what i went with 1.5 primaries to 1.75 log gonna go 2.5 to the turbo (see attached picture)

 

[XR8tt]

YES Sideways..
Simple and well flowing for log style..
It's not F1 tech but we're not looking for F1 power..
Like the merge into log...Picture is worth 1000 words..

 

[stevechumo]

That's what I built for mine. With correct angles and less turns along with big turbo & good tuning, you can make at least 500 rwhp plus.

 

[Alan Whitaker]

Just an update on my twin turbos, headers now done, will have them ceramic coated next week

 

[cribbj]

Alan, your exhaust looks much too nice to go on that lump!

It looks to be in need of some serious TLC

 

[Alan Whitaker]

Hi.
Been a long time to get this far, I have the body fully sanded ready for the body shop, I have had the engine running, it started first time after sitting in the shed for 2 years, hope to be on the road in the new year.

Alan