legacycentral bbs

I was thinking (planning) of porting the inlet to my VF12 before I install it, but don't know how far to go (diameter wise).

Is the up-pipe outlet diameter close to the diameter of the up-pipe to turbo gasket? I would use a gasket as a guide, but want to know if it is 1mm oversized, 5mm, or ???? compared to actual hole.

Or, does anyone know the actual diameter of the up-pipe outlet? that would work too.

Thanks!
Chad

So I found that the WRX up-pipe outlet is 41mm. I am going to assume, for now, that the Turbo Leg up-pipe is the same.

I measured the VF12 inlet to be 44.5mm...

Now that it looks like there will be no opposing lip in the exhaust path I will just leave it as is. I imagine that it would work best if the up-pipe had a matching diameter so there was no step at all, but I'm not sure that porting the outlet side to match the turbo would be the right thing to do. I don't think there is any material there to remove anyway (it's just a pipe).

But if anyone can confirm that our up-pipes have 41mm outlets, I would appreciate it.

Chad,
I've got one off a car right now. I will check for you...

Cool.

Thanks man

-Chad

What kind of increase are you trying to get. If I remember right, in general, if you increase the diameter of the uppipe, your turbo will not spool as fast because of a lower air velocity, and increase your top end horsepower.
-Max

My original goal with the port matching as to get spool as fast as possible (by removing any flow restrictions in the up-pipe to turbo junction), but it looks like the VF12 has a inlet that is larger than the stock up-pipe outlet so I won't have to do anything.

And yes, making the up-pipe too large could increase time to spool. I can imagine if you're running a giant turbo, the a larger up-pipe would be good, but not in a mostly stock setup.

anybody have that up-pipe outlet diameter confirmation?

My silicone tubing and clamps are on order and I plan on installing this baby on 3/17.

Thanks!

Well, the VF11 inlet is 44.5mm as well.

The stock up-pipe outlet is 41.5mm.

I'll post a whole VF12 as-measured thread soon. I took some pictures, but they were with a 35mm cam (wife has the digi out of town) so I'll have to scan.
But in brief, the 12 is considerably larger than the 11. Not stupid huge, but for example - the compressor inlet of the vf11 is 41mm, and the vf12 is 50mm - that's ~25% larger.

And oh, yeah the install looks TITS (but no, it's not quite done - stupid job! )

-Chad