Markp

Well yes I understand your point about the wheel, although at 5000 RPM I suspect that there might be enough flow. Especially when you raise the velocity. It would be interesting to know where that point is and what reducing the A/R would accomplish in this case... all academic of course and not 100% practical.

Mark

jwarriner

WTF are you talking about? Do you have any clue how A/R is calculated?

A/R is calculated by dividing the turbine discharge diameter's cross-sectional area by the distance between the center of the wheel's shaft and the center of the measured inlet.

Blocking a port on a twin scroll turbine is the stupidest idea ever, won't work like you think it will and discussing it is not worthy of this forum. I can't even believe I'm reading that blocking part of the turbine inlet (which is what you're doing regardless of whether it's twin scroll or not) will help spool. Not to mention, if it worked like you thought it did the A/R would INCREASE, not decrease. Jesus.

That turbo belongs on a tractor. Otherwise it's a paperweight.

EDIT: Sorry to be harsh but it's early and I couldn't take it anymore.

lazzer408

iTrader: (1)

Splitime

iTrader: (24)

If anyone wants to hybrid their t3... i have an entire t4 coldside ready... housing/backing plate and compressor wheel.

Markp

Now wait a second.... I almost was tired enough to concede your point but then my brain actually turned on, it's obvious that you are still a few cups of coffee behind.

If you have a cross sectional area of 1.00 and a radius of 1.00 we have an A/R of 1.00. Agreed?

If we reduce the cross sectional area of the port by 50% it is now 0.50
Over the radius which remains 1.00. Are we following along still?

Then if we divide A/R, 0.50/1.00 = 0.50 A/R

Now I am just a ******* psychology student, not a ******* engineer, but tell me where did I go wrong?

Not to be harsh, but the math seems fairly straight forward.

Mark

PS - I don't think you are being harsh, if I fucked up as bad as you say. Despite being a psychology student feel free to take me to task when I am wrong, you won't hurt my feelings and I might learn something new... which would be great.

lazzer408

iTrader: (1)

Mark your logic is correct, however, the design of the housing wouldn't allow it to be as efficient as a "real" .50 a/r housing. The size of the wheel alone takes much more cfm to turn it then the smaller wheel found in say a T3 .48. But it would look cool. =)

Markp

I realize that it would not be as efficient as a real .50 A/R housing. I was more writing it down to think about the effects than I was suggesting that someone actually implement it.

We agree that the turbine wheel is simply too big for the application here. It would still be interesting to see the effect. People are right in stating that I have no idea how a twin scroll housing works, I never said I did (Remember Mark the Psychologist, Not Mark the Engineer!). All I know about twin scroll divided tang housing is that you can get them to spool earlier than the identical non divided tang housing.

Mark

cjernigan

iTrader: (13)

Well how well do you guys think this would work with a .48 turbine T3? The .48 would spool fine I'm sure. But would it pull to redline is more what I'm interested in? I have no problem hybriding the two turbos just wondering how well they might work together.

lazzer408

iTrader: (1)

What psi are you planing to run? My T3 (.42/.48) would pull hard into redline running 12-14psi. I'm planing on 15-25psi to reach 300-400hp on the new engine. Hence my need for the larger compressor. The .42/.48 will get you at least 10psi by 3000rpm. If not check for a potato in your tailpipe.

Are you planing on using the T4 compressor? If your goal is only 250hp a T3 should be fine.

jwarriner

You are wrong because the "inlet" by which A/R is measured is actually the nozzle area of the turbine scroll, not the inlet of the turbine housing itself. If you were correct then everyone who ever ported a turbo would be changing their A/R, which they are not. If you block half of the turbine inlet then your turbo will spool up slower. Period.

Markp

Ok, paint me a bit of a picture here, because as I stated, I am not an engineer. While I understand that you are saying changing just the inlet size will not change the A/R (or will it because the A/R would no longer be constant and it should be according to Garrett.) where exactly does the nozzle area begin.

Once again, try to understand I don't have an engineering background but would love to know exactly how this is calculated so I don't have to guess at how it works. I know a little about turbos and I can pick a decent turbo to match my goals but that doesn't make me an expert. So feel free to share your knowledge, I am willing to learn something new today.

Thanks,

Mark