I think each scroll is typically designed to be the same A/R. So, because the divider wall is angled, the scroll closer to the turbine exit effectively has a smaller 'R' which is the radius to the centriod of the 'A'rea. Therefore, to keep the same A/R, the area is smaller for the scroll closer to the turbine exit.

Borg Warner does the same on their twin-scroll turbo on the old GM 2.0L Ecotec:


IHI JDM STI turbo:


Honeywell Turbo BMW M5:

 

I'd have to look at my numbers again, but I beleive the A/R was not the same between the two scrolls.

Just as a general comment, "A/R" seems to be a pretty useless number as it tells you nothing specifically about the housings flow capabilities in an absolute sense. I like the scroll area method used by Mitsu and others a lot more. You know a 12cm^2 housing is going to flow more then a 10cm^2 housing regardless of the family size (TD05 vs TD06 for example) even though the A/R of the 12cm^2 housing could be smaller.

 

I agree. The whole A/R and trim nonsense that people who don't have a clue quote all the time annoy me. Neither number is meaningful on its own. The area of the volute makes much more sense.

 

Well guys I pulled the trigger on a twin scroll kit 6466 1.15 AR on my 2.0 long rod with a ams intake manifold and 75mm throttle body
Let's see what I got my self into

 

Check this out.


http://www.escortrscosworth.com/foru...t=36731&page=5

 

READ THIS: http://www.hindawi.com/journals/ijrm/2012/589720/

Due to increasingly higher demands for improved fuel economy of passenger cars, low-end and part-load performance is of key importance for the design of automotive turbocharger turbines. In an automotive drive cycle, a turbine which can extract more energy at high pressure ratios and lower rotational speed is desirable.

efr... twin scroll.. tial... good for mid range part throttle... clasic sigle scroll for top end

 

^^^ Hot Damn!

I thought it was a paper I had already read when I opened it originally. Second look though, it is not the same paper and it is EXCELLENT reading material.

The last section in particular of TiAl turbine wheels is of particular interest. I do believe the EFR turbos have approached this slightly differently though and have increased wheel size for a given airflow capability. I think this helps offset the efficiency loss due to the blade design change to accommodate the material properties. Even with a larger wheel, the material density helps reduce inertia. As I said pages ago though, how much (if any) reduction in inertia for a given airflow capacity is the question.

Thus far though, it seems qualitative reviews of the EFR turbochargers are saying it works.

 

been updating data in my head for last few weeks looking for all the results I can find. funny that thread has the best data available for running 4g63 with EFR. I think now I am finally convinced these turbos are indeed special when setup correctly. the two that seal the deal for me are the 500tq at 3500 on 2.0 engine (7670- 3rd gear) and that 9180 94lb turbo spooling faster than nice 35r setup.

EFR came out three years ago. Those in the know over hyped them without results to back them up. impossible to get for two whole years. most just lost interest. now secretly for the last year people are quietly getting them into action with great results. but few are watching or waiting at this point.

 

EFR for my track car (finally) gets here next week ^_^

I'll have some more EFR results to post soon enough

 

will this be going on the car in you sig? replacing the 6266. cause that would be very interesting. your setup was spooling really fast for single scroll. be interesting to see what you end up with. which EFR did you get?

 

That's serious. Link me?

 

It will be going on one of the cars in my sig. Not the one with the 6266 though. The other one should be an even faster spooling set up (lighter rotating assembly/custom cams/custom headwork/custom intake/port matching etc etc)

 

I haven't seen 3500 on a 2.0 but there are several close to that on 2.3's.

Here is an Evo 6 2.3 7670 (post #446)

http://www.lancerregister.com/showth...343977&page=30

Here is an Evo 8 2.3 7670. It is one of the first 7670 evo set ups

https://www.evolutionm.net/forums/ev...yno-graph.html

 

If you read all the posts in those links and the linos in those lancer register threads you will se the graphs are a bit of because of the loading method on dyno.. the were held at more than 300p rpms for or 4 sec... turbo full boost and than run... if you check latest buit the evo 3 wit M.A.D engine you will se it actually spolls just like a 3076 and hits fool boost at 4500 ... but it seems to respond better at part load and transitional regimens... that can be atributet to slighter less weight of EFR chra package...... at the time there are no conclusive results on these.. is more like a diffrent setups rather the turbo itself.. don't get me wrong.. i live in germany i have been arond twin scroll and vgt .kkk/ borg warner for years now.. the tial turbines are nothing new.. mitsu has ben using them on evo for at least 15 years.. others maibe 20.. there is nothing magic just a better package.. i really want a turbo that responds well transitional for the hill climb and rally cars i build.. but until now only garett has been able to take the beating on als.. i know everybody looks at nemo and other time attack cars results.. but those cars rarely drop under 4500 5000 rpm... it is not a good example of what it can do down low..and thei dont run als as you would run on a rally or hill climb car where you have hairpins where you drop rpm under 3000...the most unbiased results are the tests that perrin did efr vs gtx.. minimal difference.. and 8 belive gtx will do it if someone like tial would make a propper twinscroll housing.. v band or t3/t4

 

Anyone know if the 1.45 A/R came out for the EFR 9180 or the EFR 8374 yet?