scorke

iTrader: (18)

No, not really, too big of a turbo to really appreciate the difference as there's nothing that big in single scroll format that you would want to drive.

Scorke

scorke

iTrader: (18)

Yes there is a benefit of going with a larger twin scroll unit over a smaller single scroll unit that can produce 400-450 whp. If your producing the same power on a bigger turbo with similar spool characteristics your usually going to be operating more efficiently in terms of heat and air flow.

Scorke

03whitegsr

iTrader: (8)

Huh? How about I drove the car without a divided manifold and it spooled almost 1000 RPM later and was a complete dog? I'm well aware of the benefits of twin scroll when the car has terrible spool. That's not my concern though. My point is, on a setup that already has great power and response, is there any benefit.

Efficiency being higher on a larger turbo is not always right as smaller compressors can easily produce high efficiency along with lower turbine demand from reduced rotating weight and aerodynamic drag. Case in point, the GT3076R maps out to 74% efficiency accross almost the entire engine operating range I'd be looking for. The GT3582R is off the map for much of the rev range and finally comes up to 72% efficiency by 6500 RPM. Bigger is not better in this case.

I just don't agree with it being a one size fits all solution like its being pushed.

If it was superior in all ways, you'd see it being used in all forms of racing almost exclusively, but it's not. Almost every top level racing organization allowing turbocharging is dominated by single scroll turbo setups.

EvoDan2004

iTrader: (94)

Lots of casting flash and if u look at the divider inside where the turbine wheel is you can see how inconsistent it is. Sometimes on some castings the divider does not even loop all the way around.

scorke

iTrader: (18)

Your question is one that cannot be answered because its subjective. Your asking, if a car is responsive and powerful can twin scroll make it better? The answer is yes. The smaller turbos HAVE to have lower turbine demand ( some of which is from ) reduced rotating weight because they aren't using the exhaust gasses as efficiently.

It's not being pushed as a one size fits all solution, people are just saying that a properly designed and sized twin scroll setup seems to offer more power throughout the rev range than a similarly sized single scroll one.

When you reference other top level racing organizations allowing turbocharging which ones are you specifically talking about?

Scorke

03whitegsr

iTrader: (8)

If the smaller turbo is more efficient on the compressor and turbine (which on the turbo I am interested in, it is more efficient on both accounts) how is it not using the exhaust gases more efficiently? Yes, it's subjective and that was my point, that's all.

CART/IRL, Lemans, WRC, TurboF1 all seem to have used single scroll setups at their pinnacle. Many WRC teams were using twin scroll setups until Garrett produced the TR30, which is a single scroll turbo similar in size to a GT30. The TR30 was also used in IRL and Lemans. I believe it has been replaced with a next generation of turbo though, but it's still a single scroll arrangement.

Joshs EVO

iTrader: (46)

What HP do you think a TS GT4088 will max out at? When will it run out of breathe on a 2.3. Would there be a certain Psi that once it goes by it won't be making any more power?

EvoDan2004

iTrader: (94)

i never really see the HP climbing with them on a 2.3 past 7500rpm. the HP levels i have seen are around 750 to 800 HP but this is race fuel and high boost.

Philthy748

iTrader: (21)

I'll have an answer to this in a couple of weeks... We made 640whp @ 27psi on 93 pump gas, so 750whp on Q16 with more boost seems doable...

Ted B

iTrader: (6)

Actually, the pinnacle of turbo F1 saw BMW's turbo motor using a twinscroll setup to deliver up to 900bhp/L. The Zakspeed engine used TS as well. The V6 engines were twin turbocharged, so they ostensibly didn't/couldn't use TS.

03whitegsr

iTrader: (8)

I could be mistaken, every picture of F1 from the 80s I've come across has been single scroll. But realistically, the pictures are few and far between and often of poor quality, so I could easily be off.

Ted B

iTrader: (6)

Here are a few clear photos from these amazing turbo F1 engines:

BMW F1

The twin ducts from the TS manifold to a single WG are apparent:






Zakspeed

Same arrangement as the BMW engine:






These TS setups were delivering 1000+bhp with 4-5+ bars (60-75 psi) of boost and 11-12k rpm with 1.5L. That's impressive even by today's standards.

Geoff Raicer

iTrader: (7)

you could try out a twinscroll w/ dual flapper internal WG, although there is the potential for creep. this is what im running on my R14 right now, but modified it to T4 inlet and 4" EWG outlet in 42R position

03whitegsr

iTrader: (8)

That is what I've been considering too, a thin wall manifold with FP HTA Green. Still pretty light weight, compact and simple. Probably total weight very similar to the Tial housing GT30 and MV-S setup. Done with a modified 2-port actuator it should provide pretty solid boost control with a good range of boost levels.

Just very spendy on the turbo, but without buying the wastegate, helps offset the price.

Does BW have internal wastegate housings that flow well?

Geoff Raicer

iTrader: (7)

you are definitely mistaken -- easy to see at the Penske Museum here in scottsdale, there are many generations of turbocharged race cars there on display with the engines easily visible for anyone to check out, now that they are ancient history in the racing world.. many of the best turbocharged examples are twinscroll, where applicable IE V8 if the firing order allowed it.


yes, but i dont know how well the wastegate would flow, or how well the internal would fit an evo.