When we were doing the turbos for GM Racing's Ecotec program for NHRA Sport Compact, we found that TS allowed the use of less boost builder when on the line. The engines started lasting longer as a result, since they weren't being worked so hard on the line. Boost builders are not gentle.

There was no penalty in trap speed as a result of using TS here.

 

Martin, I agree completely with that as doing a straight analytical comparison of housing vs. housing.
Now I took the point of this discussion to be which kit, flatout, performs better. I would take that to be pushing each of them to their given limit on a given fuel ona spec motor with the most evenly matched manioflds. If one creates more back pressure and starts to limit VE in the top end and more timing is needed than that is the downside of that turbo. Then again that makes for more variables to question the testing done.
So to be completely fair, I guess same A/F, timing and boost pressure would be the most straight forward test. Also as you well know timing will effect your A/F, so would you lock the timing map down and adjust a/f based soley on fuel...but then again fuel energy has been shown to help spool turbos. Regardless trade offs will be made in the testing.
In cylinder pressure monitoring would be the best way to monitor the testing...makes me wish I did the fiberoptic in cylinder pressure gasket as my senior project now

Oh, and how is the FSAE resume hunt going

-Micah McMahan

 

ill post tomorrow, im too damn tired. jkav is on point

 

[quote=Ted B;4691371]It's funny how both of my setups also showed roughly the same thing when looking at the spool curve on a dyno chart. However . . . quote]

However your open volute was a T3, 35R and the TS was a T4 37R.
Maybe there is something to this TS thing

 

nope... nothing to it... spools the same but loses top end

 

I know you guys have seen my dyno sheet but this is a full twin scroll setup. Looks like to me that this is a perfect combo for drag racing.

 

There it is, right from the source


No really, Ted has already presented the question that needs answering. The only way to do it is to do testing. Geoff, send me over one of those twin scroll housing

 

Nice!

Paul, what was my advice when you called about which turbine housing to use? I want you to tell it so these guys don't think I'm biased towards one housing.

 

It was to go to a 1.28 divided housing. You where very adamant that going from a 1.02 to a 1.28 would make more power and maybe lose 100rpm to 200 rpm in spool I do feel with the 1.02 housing the most we could have gotten is 950 whp on better cams maybe 55 psi of boost.
After talking to TedB i really am thinking about ordering the 1.44 divided housing to see if i could make the same or more power with less boost and timing plus keep my spools about the same.

 

See guys

Thanks Paul. I also recommended the twin scroll over the open scroll as I wasn't convinced either way which one is better. I also think the twin scroll is a good option for the GT42R. I've made more peak power on the open scroll HKS housing compared to the 1.28 A/R divided housing on our drag car but our header is completely different so it's hard to equate the power differential. Maybe the 1.44 will make the power and still provide better spool, it's something worthwhile to try. Paul, throw that 1.44 on there and let us know how it does.

 

Ah, but having observed a few things prior to this, I was advising him to go straight from the 1.02 to the 1.44. He stopped at the 1.28 because you advised him to not to get the 1.44.

Me thinks you need a spanking.

 

Baby steps Ted

send me some damn absinthe!

 

+1 for that

 

I do find it interesting that most of the turbo ALMS cars, Rally cars, CHAMP CAR, use a an open scroll housing. I would figure that Audi with such a huge budget for the R10 TDI would use the best technology possible. Maybe the rules limit then to what they can run? Jason, you'd have some more insight then the rest of us on this one.

 

You'll shoot your eye out.


WRC cars use a small, restricted turbo. The problem they face is high rpm power. Already the cars make peak torque around 3500 rpm (and 40 psi of boost at that speed).

While TS isn't a new concept, it seems to me that the use and understanding of it for the type of applications we consider is relatively new and not widely understood. After all, Garrett only very recently revised the recommended engine displacements for their larger turbos, having seen us do things they never expected or would have recommended with their products.