You don't need the fuel until you've got the air - look at the boost curves.

Bryan, that's a nice looking collector - what is the outlet diameter? For a cross sectional area provided by 1.75" tubing x 3, an outlet of 3" would seem optimal just crunching the #s but that seems like overkill preturbo and would probably hurt velocity. Also I would think that smaller diameter tubing would increase velocity and spool but decrease top end. So not sure how increased spool with your headers would equate to top end flow. Perhaps it's more a matter of equal length tubing more evenly spacing out pulses that is contributing to the earlier spool. Thinking in terms of pulses is another reason perhaps a 3" outlet is suboptimal. Would love to hear your thoughts on the design decisions that went into the headers - really a sweet looking piece.

 

Raj, our headers outlets are 2.25, the equal length is key, remember that the cylinders are 120 degrees apart, so that there is always capacity in the collector. The header woks the same in FI as in NA, as it produces more scavenging than the OE manifold (lots more). the scavenging produced for an NA car sucks air through the heads by creating a "vacuum". same effect for a turbo car except there is pressure there and a path for it to escape. The equal length primaries reduce the amount of back pressure.

I'm not the guy who designed them, but there was a lot of CFD analysis that went into the design, I'll get that data from R&D at a decent hour tomorrow and post it up

 

the collector outlet diameter would not need to match the area of all three primary tubes because only one cylinder is firing at a time on each bank. i would want the outlet diameter to match whatever hfc/test pipe i had to keep turbulence minimized and velocity up. well, i should say that in reverse, i would want the hfc/test pipe diameter to match the collector outlet diameter i guess. all imo tho.

edit, previous post wasnt there when i typed this. that outlet diameter is perfect considering most hfc and test pipes use that 2.25". how much are these headers? pm me please if necessary to stay on topic. great thread

 

please check our website for prices and dealers

 

well this points out something i thought about when he first posted the graphs. the 8psi was on the box tune, from what ive heard very conservative timing, and the blue line was a "Final tune" more aggressive timing would also speed up the spool considerably.

 

agreed, should be equal tunes to be apples to apples

i wonder if it would be worth a shot to cut up the stock manifolds, work the inside of them to get everything open and smooth, then weld them back together..... sounds ghetto, but if it works, i prefer oem looking parts anyway

 

WHAT?

With the number of header brands out there why would you do that?

It would cost yo more to get the OEM headers cut/gutted/welded than a decent aftermarket header, and you would still be left with a shi..ty OEM header that has now been welded.


Here is your cut up OEM header:









8" long section of this:



You can see how long that 1.5" section is:

 

i guess i was thinking it would cost less than 100$ but maybe youre right, i was just thinking out loud anyway

 

that wasnt thinking out loud. That was ignorant thinking

 

call it what you want, i dont care. but thinking outside the box is what leads to good finds. i get tired of no one having an open mind to trying different things.

 

yes, you are right, i was thinking that collector was closer to 2" with the outside material. im out of town now so i cant go out in my garage and look at the ones sitting there. but looking at the pictures, it seems that even if a guy was able to clean out that long collector, the part where the primaries merge does NOT look like a good arrangement to promote scavenging anyway. i fail

 

Thomas Edison understood the profound secret that to succeed you have to be willing to fail and fail fast. To Edison all failure provided valuable information that he could use to correct his course, and lead him to eventual success.

I fail often too. its all in how you look at it.

 

Not to let this drop, I've asked R&D for the data, and he'll get it to me later today Monday.

 

cool, so now thats its been beaten to death, how about someone actually get this kit installed properly with all the necessary add-ons and make some good numbers There are supras to clown

 

I am working on it.

I believe that this kit is capable of some very good numbers with the 67mm turbo.

 

still no tuners explained the diff in fuel graphs. comparing a 8 psi to a 10 psi seems dumb, then add the fact that one is a complete tune and the other is a bolt on and hit the gas tune makes it a even more usless comparison. sorry.

 

that wasnt very good thinking to be brutally honest with you. oem was designed for emission purposes, not performance (even though this is a performance car)

people have open minds here, and use them, as witnessed with multiple products, kits, companies, etc. that all had great success and followings. this outside the box thinking, when used well, will produce successful results, as witnessed with momentum and boosted performance. but what you stated made almost no sense. now go with the outside the box thinking, and work on developing a header kit that produces numbers, and market them. we always could use a wider selection of parts.

 

i have all the needed mods! I just keep running into crap with the dyno then the housing being small, etc etc.

i do'nt think there is a supporting mod left to put on my car (that would alter engine performance)

 

BP - Since your ST bolts up to the factory manifold, wouldn't it be pretty simple to put on a set of DC or any short style headers and test the hypothesis? If you see hp gains at higher rpm, then that pretty much proves the restriction.

 

I am in the process of doing this amongst other things. This spring (or as soon as I can drive the car) I will put tubular headers on, a 6265 T4 .81 BB turbo, and a bunch of temperature/pressure sensors all over the place to see what I come up with.

In the mean time, I am looking at headers, clutch, and a larger FMIC, although a 7” and 9” core will be tested for thermal efficiency.