Does anyone know which I.I. or HTT turbos have the largest internal wastegate area? Do you have to get a certain turbine option to get the large gates?

I'm under the impression that the SS HTT housings have bigger gates.

JH

 

I have only seen one of the SS housings. The gates were huge compared to the same companys 12 and 14 housings.

Dave

 

the 62/13 has a huge gate, ill dig around the shop and take a better look this weekend

 

I've had a standard 14cm HTT housing and a 13ss apart and the standard cast ones are like dual 5/8" and the SS are about dual 1" gates.

 

there ya go, now i dont have to dig around this evening.

 

If you plan on going crazy with the gas, none of the internal wastegates will flow enough to give you longevity. You will need an external gate.

How many high HP gas applications have you seen with internal gates?

 

Not trying to be argumentative here, but what is the difference between a 40mm internal gate and a 38mm external gate?

I can understand if that gas has to enter the turbbine section it may become slightly compressed by drive pressure, but that will also allow it to move easier through a smaller port.

Again, nit trying to call anyone out, I just want to understamd the difference.

Dave

 

I know externals are the way to go but I think those HTT ss housings could really flow some drive pressure while sprayin with their extremely large wastegate ports, and also the overall thickness of the stainless housing was much thicker than a cast. Just for durability sake of not cracking so easily.

 

Personally, I now hate internal gates after having my external setup the way I do. Turn a dial to the pressure I want (minus spring pressure, of course) and there I go. No checking pressures, the numbers are right on the dial. AND, I could go as low as 20psi, and as high as I dared

Chris

 

There's more to it than just how large the gate is in diameter. How FAR it will open matters as well. It's all about the "window" size-- which is a combination of area and opening. Just like an engine valve will breathe better if it's larger at the same lift, or lifted higher at the same size (at least until the window area equals port area, but I digress).

IN favor of an external gate is the precision of boost control, total gate flow (generally) and reduced turbulence (not that important).

In favor of an internal gate you have reduced heat loss (important when driving a primary) and simplicity (huge advantage).

Though a SS62 with the 13ss housing is laggier than I'd like, the simplicity of using it in a twins application and the large internal gate force me to consider it.

If I could get something like the SS62 but in the smaller HTBG size with the 65mm turbine, that would be almost ideal. I'd have the faster spoolup of a "BD super B" type S300 (or is it S257? anyway..) and the large WG and SS housing that I'd want.

Too bad HTT doesn't seem to think there's a market for SS housings for the smaller turbos.

Justin

 

Drive pressure is drive pressure as far as I can see. If you have 50psi in the manifold where your external is, you'll have 50psi in the turbine housing where the internal gate is.

Of course, we model this is being steady state, but the reality is that you have pressure pulses that might be as high as 70-80psi at the peak, and as low as 20psi in the "trough" when the gauge shows 50psi.

Justin

 

http://www.htturbo.com/Feature.htm According to their website you can get it with the 65mm wheel.
Joe

 

You can. There's a guy on compD with a stainless steel htbg

 

My gut tells me that an internal gate could possible transfer the pressure pulses "more" intact than an external gate could. This is just based upon the geometry of the tubing and the valve itself. The typical internal is a flapper vice the external which is a plug and seat. Then again with the volume of the hot pipe, it might not matter in the least. Other than that I agree with Hohn.

Anyone actually tested this?

Jim

 

I think I may Jim.

I have a buddy that could use some work on his truck and maybe we'll mock it up both ways and then lock 'em out one at a time.

As my truck could use a few changes, this would be a good chance to measure with gauges any net effects.

Dave