Lets Playyy, Find That Restriction!

[Harey]

On a separate note, I was told by the precision guys that a .82 T3 open housing flows the same as between a .58 and .68 T4 open housing. Can anyone confirm? Sounds quite dubious.

That does sound VERY dubious. Why would the fact it has a T3 or T4 flange change the flow unless the T3 flange was actually limiting flow??

Whereas a twin scroll T4 turbo for example has 2 smaller separate paths for air to flow all the way through the turbo, not just at the flange.

My understanding is the flange just has to be big enough so as not to be a restriction in comparison to the flow the turbo can deliver.

I dont know of any rb30s with precision turbos. What do 2JZ supras with precision turbos run?

[ST240]

That does sound VERY dubious. Why would the fact it has a T3 or T4 flange change the flow unless the T3 flange was actually limiting flow??

Whereas a twin scroll T4 turbo for example has 2 smaller separate paths for air to flow all the way through the turbo, not just at the flange.

My understanding is the flange just has to be big enough so as not to be a restriction in comparison to the flow the turbo can deliver.

I dont know of any rb30s with precision turbos. What do 2JZ supras with precision turbos run?

There may be some merit in his comment no? A T4 of the same a/r when compared to a T3 by definition should flow more; more area, larger nozzle = more flow. He did also agree with what was mentioned above in that a divided housing would flow roughly equal to one size lower in open flange form (not that i didnt believe that )

Here's an interesting 2JZ auto dyno with a 6262 .68. However even his seems restricted. 19 psi run (im choking hard on 15). Source: http://www.clublexus...-automatic.html

Edited August 18, 2011 by ST240

[Rolls]

That looks like a horribly mismatched turbo, full boost at over 5k on a 3L and torque starts dropping off straight away and it only makes ~320rwkw?

What a heap of shit lol. A gt3076 on 18psi would be on song by 3.3k and make ~300rwkw on the same boost on a 3L

Edited August 18, 2011 by Rolls

[R31Nismoid]

Like i said I have a divided manifold with the appropriate runners in each port. What I lack is dual wastegates.

On a separate note, I was told by the precision guys that a .82 T3 open housing flows the same as between a .58 and .68 T4 open housing. Can anyone confirm? Sounds quite dubious.They also told me they dont offer any larger turbines because they "feel you should be moving to a 6265 if youre flowing that much". Lol. Guess the GT35R with a 1.06 is a silly idea then .

Don't happen to have a sensor bung at all you could measure the pressure with in the exhaust manifold?

That would give you the answer very quickly.

Also done runs without the exhaust on the car? (dump only etc?)

[ST240]

That looks like a horribly mismatched turbo, full boost at over 5k on a 3L and torque starts dropping off straight away and it only makes ~320rwkw?

What a heap of shit lol. A gt3076 on 18psi would be on song by 3.3k and make ~300rwkw on the same boost on a 3L

You aren't the first person to say this. Another member on here ran a Precision 5557 on his 25det and had similar results; lots of boost and not a lot of power. Define horribly mis matched? It has almost the exact same specs as a GT35R! I'm really starting to wonder about Precision.

Don't happen to have a sensor bung at all you could measure the pressure with in the exhaust manifold?

That would give you the answer very quickly.

Also done runs without the exhaust on the car? (dump only etc?)

I was thinking of doing this thru my egt port but figured it was kind of moot as per this discussion and nistune load tapering off . What is it again, backpressure equalling 2x your boost means its restricted? I have not tried dump only.

Edited August 18, 2011 by ST240