Twin scroll t4 vs a single scroll on the 3076?

 

There is no need for a 5k rpm power band. . . our gears are not that long. Power from 4-7k is more than enough to keep you permanently in boost/power band

 

For drag or street yes but on track there usually is a corner or straight that will cost you time with small range.
Edit: mine won't spool like that graph its 2.3 mines 2.0lr so loose a little. Happy at 4k of full boost

 

Yes , old 3076 was a open scroll T3

 

Is this car running the 1.05A/R Divided T4 or the 1.45A/R Divided T4? Or did I say too much?

Nice work JB. Did you drive it?

 

Not sure how long ago this happened but the EFR7163 maps are up on the matchbot program. Looks like the EFR71 packs a bit more airflow then the GTX71. Looks like the whole map is shifted right about 2-3 lb/min, more flow, more surge. Other then that, it's efficiency is lower only at boost levels we'd never care about.

Could just be a generic approximation, but I really hoped to see a signifigant difference in the turbine map for the mixed flow turbine but it's not really there. All it shows is that the 63mm turbine flows the same as the 64mm wheel while using a slightly smaller A/R housing. I guess I had hoped for massive flow and spool, but it still has to conform to the basic laws of thermodynamics.

Seemed like the SAE papers I had on it suggested a pretty decent bump (~10% range) in low flow thermal efficiency (down where the turbine is in the low 60% range) with a 1-2% bump at high flow rates. None of that would show up in the maps on there but should make for a nice improvement on response.

I wonder if there is any way to pick up the weld on turbine housings used by the IRL teams? For some reason, a "turbofold" with a good turbo and an efficient manifold layout seems like it would be pretty awesome as it eliminates a bolted connection that always seems to be trouble.

 

^ Im sure there are a few people you could ask to see if they've fallen off any trucks recently. or see where BW is at with the 1.45 commercial t4 housing.

 

If you think people are having trouble with a bolted connection, just wait until they try welding a cast turbine housing to a stainless collector. It takes experience and skill to do it right. I doubt BW would be willing to release a part that has such a high risk of being improperly installed.

 

Of course they wouldn't. That's not the point.

 

1.05...the 1.45 hasnt been released yet though I have called a few time to get one backordered

 

Yeah definitely wasn't thinking it would be something everybody would want. That said, it seems like with it being investment cast it would likely weld better?

The trend in OEMs seems to be turbofolds and I can see the benefit. It would be kind of cool to mimic something like the dual wall BMW turbofold but with a 500HP turbo and an emphasis on flow.

 

It will weld just fine. They've given it to all the INDY teams as a weld on piece (as I think we're all aware of) most cast pieces that I've welded I just paid close attention to pre-head and cool-down procedures. Slowly elevate the entire weldment in temperature to 500 deg F (aka Broil ) Weld piece with proper filler rod... Place weldment back in oven at 500... let it slowly cool.

Of course I realize that it should be heating them to higher temperatures for the heat up and cool down, but realistically not many of us have kilns at our houses. It's better not best. But I also bet that the INDY guys don't even pre-heat the housings before they weld them.

I would start asking your Motorsport friends if they have any friends that work in INDY... and find a used one where the manifold failed or such. INDY only uses the 9180 or a pair of the smaller units... smaller than 7064's IIRC. For the 7163 or the 7670 I think the T4 1.05 A/R is about the right size.

I got my 8374's turbine housing extrude honed.... amazing! per Khiem that should be good for a point or two improvement on the turbine efficiency.

Mike,
After driving a ton of the Garrett turbo's GT2871, GTX2867, GTX3071, GTX3076, GTX3576... I can say with extreme confidence that the transient response of the 7670 was significantly better than the smallest of the bunch... GTX2867. I honestly think the 8374 will still have better transient response in comparison than the 2867... which I can actually log both and compare...when my car runs again! lol

 

Yeah, this is kind of saying what Dave W and 03White said, in different words. The welding would take specific knowledge and skill to do right.
I've been frustrated a couple times, talking to local professional welders, who didn't seem to have a clue about welding stainless steel. They both told me they would use the same filler rod (or wire!) that they use to weld ordinary mild steel. When I started trying to tell them about chromium dilution and carbide formation with the chromium, they didn't want to talk to me anymore. Fine.

 

I'm having a nightmare about some cheap kid taking his ebay T3 manifold and EFR weld-on turbine housing to the local muffler shop. NOOOOOO!!!! (wakes up in a cold sweat) lol

But seriously, why not a V-band housing? It maintains the round shape from the collector down into the volute, offers interchangeability, adaptable to almost any platform, less risk of messing up the install, etc.

 

the 7163 was shown at 2012 SEMA (i know..) with an aluminum CHRA and a v-band turbine housing. So it's already been done and they're slowly moving forward with it.

If you're wise enough to find a weld on turbine housing for one of the EFR's.... you'll be smart enough to take it to someone who knows how to weld. We aren't kids buying manifolds off ebay!