ptuomov

Right now, it's about 14.7+32 psi at worst. Which is too much.

Here's the new turbine housing, pre surgery, next to the old one. It's going to flow more with less exhaust manifold pressure. The only problem is that the turbocharger unit needs to be cut and welded in three spots to fit in the space available. The old smaller turbos only needed one cut and weld...

U-928

So you're re-designing with external wastegates then? Or somehow modifying the one on the left to an internal something-er-other? Is that even possible!?

ptuomov

Me? I wouldn't even try that kind of welding project? ;-)

The turbos that I have now were already cut and welded on the compressor side by John's welding expert. This is a more challenging project, cutting that stainless steel housing in two places, adding an "internalish" wastegate, adding a flange that fits in the space, and then welding the jig-saw puzzle together again. Like putting humpty dumpty together again (to be remachined). Rest assured that I could not do any of that. I am focusing on understanding what is happening, and that is a challenge enough.

We will find out soon whether it is possible. So far, John is batting a thousand on turbo cutting and welding.

U-928

Granted, I don't know the details or engineering specs of the setup, but would it not be "easier" to just run dual external wg's? I'm guessing space is really of the essence and that probably isn't an option at this point. I'm confident whatever you do, will. be. awesome.

ptuomov

Yes, it's all about real estate. "Location, location, location."

If this surgery works, it'll be awesome.

If it doesn't work, I'll be sad. But when I'm sad... ;-)

ptuomov

We're proceeding with a proof of concept with these slightly larger turbos. If the proof of concept is successful, I'll post more data. Both the turbine wheel and compressor wheel are larger. The challenge is to modify the housings to fit the available space and to integrate a wastegate to the exhaust housings.

Special thanks to Todd Tremel for additional motivation! ;-)

U-928

Mmmmmm Billet compressor wheels

ptuomov

The fender mounted intercoolers are good, but not that good...

blau928

Tuomo,

I'd be interested in seeing a pic of complete assembled turbine and compressor section if you care to share... I think I see the ext WG mount, and the faces of the comp/turbine seem clockable in portions of 72deg. I like the idea of V bands, and am curious about the compressor exit. Seems like a 3076 modified setup, but I can only guess from here... Interesting....

Best,

Thom

32psi of back pressure for 20psi of boost make a ratio of 1.6, which is not perfect but far from excessive IMO. Spool must be excellent, but this is obviously missing the point since we don't need that much torque low down with a 5.0 engine.

That new turbo looks like a GTX3582R. I'm pretty sure the largest 1.06 A/R housings will work best with what you want to achieve.

ptuomov

Here's the groom for the shotgun marriage between the turbine housing and the wastegate:

ptuomov

There's some progress to report on this topic. The new turbos are about to be hung. After all sorts of surgery, these GTX 3576Rs will fit without modifying the car chassis. Let's just say that this wasn't possible with components available year ago, and even with the newly available housings it's still a custom job.

Here are some photos and in the end there's a video link:

Roy928tt

Hoo Yeah that is big, It wasn't till we could see the turbo in situ to get some scale to realise just how sizeable the growth has been.

Best wishes guys, look forward to seeing the results.

Iwanna928

You have done an amazing job on that 928. Simply beautiful. That wheel looks awesome and the video was great! Good luck!

ptuomov

It's about 40% more capacity on the compressor side. The turbine side is also a big bigger. We're hoping that this combo will no longer be maxed out on the stock engine so it makes sense to put in the hot-rodded low compression engine that Jim Morton built for me. If you are maxing out your turbo or supercharger, more cam or lower compression isn't really going to help. We'll see, there are a couple of risky operations still that need to succeed before these turbos can be used.

It's 99% John at this point. With these new turbos, I've basically done nothing except a little bit of math.