[Turninconcepts.com]

Originally Posted by IGoFast1589

How do you know when the inlet and outlet of an aftermarket pipe is TOO big? I still believe that at this point in time it would not be worth if for me to do an up-pipe but, in the future for sure. I have to make some more money and do some other mods first.

At the point where you cause a lip or step in line with the flow of the system.

There are two concerns on the step:

1) When you go from small bore to big bore.
2) When you go from big bore to small bore.

Number one causes a low pressure zone as air "falls" off the small step into the larger space. This will cause turbulence, but is really not as bad as the next situation.

Number two when you go from large bore to small bore, and this is when we're talking about a sharp edge step, not a gradual over a long distance tapering. The flow basically hits a wall and backs up the gasses. This causes a lot of turbulence and causes the air to stall.

The ideal best solution if you want to go from one bore size to another is a smooth taper spread out over an long a distance as you possibly can.

[IGoFast1589]

Originally Posted by Turninconcepts.com

At the point where you cause a lip or step in line with the flow of the system.

There are two concerns on the step:

1) When you go from small bore to big bore.
2) When you go from big bore to small bore.

Number one causes a low pressure zone as air "falls" off the small step into the larger space. This will cause turbulence, but is really not as bad as the next situation.

Number two when you go from large bore to small bore, and this is when we're talking about a sharp edge step, not a gradual over a long distance tapering. The flow basically hits a wall and backs up the gasses. This causes a lot of turbulence and causes the air to stall.

The ideal best solution if you want to go from one bore size to another is a smooth taper spread out over an long a distance as you possibly can.

That makes perfect sense. Thanks

[all4bspinnin]

please make this a sticky!!

[avi1777]

is the improvment in spool relevent also for a 2.0 engine(20g)?
and finaly-to wrap it?
great thread

[avi1777]

anybody?

[Turninconcepts.com]

Originally Posted by avi1777

is the improvment in spool relevent also for a 2.0 engine(20g)?
and finaly-to wrap it?
great thread

Originally Posted by avi1777

anybody?

Sorry, didn't see until now. Good flow to the turbo is absolutely important even on the 2.0.

Are you using the JDM motor? If so did you get the twinscroll setup at the same time or did you convert to single scroll?

[avi1777]

thanks
my set up in single scroll,i know twin is better but im runnig a bolt on,
since i put the headers and up the car is lazyer,i hope once wraped the spool and response will come back.
my motor is stock but soon i'll go stroker2.2

[Turninconcepts.com]

Originally Posted by avi1777

thanks
my set up in single scroll,i know twin is better but im runnig a bolt on,
since i put the headers and up the car is lazyer,i hope once wraped the spool and response will come back.
my motor is stock but soon i'll go stroker2.2

If you're using JDM heads then you need something better flowing than the stock headers. I would think about porting the ends, going with a crosspipe, and doing a nicer UP.

I believe I have a graph around somewhere that shows the JDM STi heads outflowing the USDM STi heads by a decent margin. I'll see if I can find it.

Oh, and if you're gonna spin that 2.2 stroker about 7K then you definitely want as free flowing an exhaust pre-turbo as possible (heck, I guess you could just say that about any of these setups).

[modaddict]

Originally Posted by Turninconcepts.com

I believe I have a graph around somewhere that shows the JDM STi heads outflowing the USDM STi heads by a decent margin. I'll see if I can find it.

OH! PLEASE find that! I'd like to see it.

[RFFG]

Subscribed

[avi1777]

[quote=Turninconcepts.com;1590029]If you're using JDM heads then you need something better flowing than the stock headers. I would think about porting the ends, going with a crosspipe, and doing a nicer UP.
you mean porting the heads of the stock headers?
beacuse i allready put the perrin eql,bigger up and ewg and moved to otronic engine manegment from ecutec.
for now(maybe beacuse its not wraped and dont boost beyond1.4bar)i dont feel any improvment on my car what so ever,sad.it even spool slower
and in israel thing coast twice than the states so imagine how i feel

[avi1777]

sorry i ment porting the stock ends(not heads)

[SCOOBYTRAP]

Originally Posted by BoostJunkie

This is why I ordered the new Grimmspeed uppipe. It only has a single bend, 10mm flanges, the ID is a perfect match to my GT52 (I will port the outlet on the manifold accordingly), and the flex section is at the bottom, minimizing turbulence at the point where the exhaust enters the turbo. I think it's the best piece available right now.

I ordered a grimmspeed upipe from TIC and it definitely has 2 bends. bends are more like the first one pictured here:
http://www.grimmspeed.com/images/pro...tors_500_1.jpg

Here's a pic of a PRODUCTION Grimmspeed. Its a nice piece but def 2 bends.

[Rasz's STi]

Thanks for all the info in this thread, I was waiting to do the 'before' turbo set up, but now I am convinced that this would be a good next step. By the way, if any has read it, Modified mag did an article (January 2008) by AMS on an STi. The following numbers where for what they did on the dyno:

4wd Dynojet

Stock VF39 (14psi): 258whp / 261ft lbs
Remap (19psi ~ 15/16psi by redline): 285whp / 317ft lbs
AEM CAI (19psi): 295whp / no torque reading
Turbo XS Downpipe: 301whp / 337ft lbs
Manual boost controller remap (19.5psi): 311whp / 355ft lbs
TGV Delete: 318whp / 360ft lbs
Remap (21psi ~ 15psi at redline): 328whp / 370ft lbs
Vibrant header + up-pipe (19.5psi~15 at redline): 343whp / 404ft lbs

Gains over stock: 85whp / 141ft lbs

These numbers all had dyno graphs, and this was done with the stock VF39 turbo, fuel pump and injectors.

[Dirty Bird 15]

ooo, that 404 looks tantalizing.