Geoff Raicer

iTrader: (7)

yes, they are rated at 58lb/min - they look to be shipping in 2 weeks

Geoff Raicer

iTrader: (7)

the most recent update i received from Hajo's TS S200SX had great video footage of the car on the circuit:

n2oiroc

iTrader: (33)

great vids! that gt3 owner had to be pissed!

Joshs EVO

iTrader: (46)

Nice video!

R/TErnie

iTrader: (32)

hahaha. great vids Thanks for sharing Geoff.

Geoff Raicer

iTrader: (7)

glad you enjoyed the vids, its pretty impressive that a stock bottom end evo with the smallest T4 twinscroll turbo that BW manufactures and 272 cams tuned on stock ecu can hang with two of the fastest cars in the world - plus walking away from them on the top end

EDIT: FIXED! thanks hajo

Hajo

Its all right, but we use 272 Kelfords

Geoff Raicer

iTrader: (7)

I asked my high altitude (5800ft) subaru buddy to do some more high altitude dyno comparisons since he has the 88-75 on his car with some free time this week:

He found a solid gain in spool and midrange power going to the .91 from the 1.00. All (4) combinations are shown here:



these are comparing:
83-75 in .91 a/r AND 1.00 a/r

VS

88-75 in .91 a/r AND 1.00 a/r

A simpler view of his (2) favorite configurations are overlayed here:
83-75 in .91 a/r
88-75 in .91 a/r



For some reason I never tested the .91 a/r 88-75 on my RB26 but after seeing this i wish i had!

RSMike

iTrader: (1)

wow Geoff, those are some interesting results.
300-350 RPM improvement for spool @ 400hp mark and no loss in top end for different exhaust housings. Very nice.

Geoff Raicer

iTrader: (7)

agreed, plus a healthy bump in peak torque!

Talonboost

That is really interesting, that once the power curves for the bigger and smaller housings come together, they stay together the rest of the way to the right.

Ok now that I have a headache from trying to sort out all those curves on top of each other, I want to put in a wish that everybody from now on would have their power curves and tq curves on separate plots. An overlay of a few different power curves would be easy to look at. But throw torque curves in there on the same plot and it's a mess.

R/TErnie

iTrader: (32)

Geoff,
Have you found that the twin scroll turbochargers are more sensitive to the turbine housing A/R's being mismatched than say the standard open housings?

RSMike

iTrader: (1)

power curves are solid colour, the torque curves are faded.

STi*guy.kiev

SO the 0.83 T4 divided housing will have the corresponding benefit over the 1.00AR USING the super-responsive S200SX 75/70 PLATFORM? There isn't a 0.91 housing for the s200sx right?

Are the housings on the s200sx and the s300sx the same dimensions/flow? (given equal AR). If so must be that the 1.15 HAJO-RS Spec would be more "mismatched" for the spool and especially the transient response judging from this HIGHER GAS FLOW test using the larger s300sx platform and 2.5 AVCS engine.

I'm building an open class rallycar which I'm also planning to use on the Nurburgring, and I was torn between the HKS 7460 ball bearing (spool ~before 2k) and CBRD's billet blue with CUSTOM forward facing manifold and SD 3" headlight intake; but I know that the ported T4 s200sx will have less bottlenecks than the turbo factory layout at its not giving me sleep .
I've been in a twinscroll 3586hta car and it was a dog before 4k. I really like to push the car a feather the throttle in slippery conditions, but its almost impossible in any large turbos like the 35 and so on..



GEOFF, do your magic, enlighten me! This s200sx turbo is soo well priced I can get a forward facing twinscroll manifold as well for the cost of either stock location turbos mentioned above.

PM please price of revised s200sx with full race ported and coated hotside, evo fittings, 2 purple mvs gates with 1.1 bar springs, titanium turbo blanket and tial Q with 11psi spring (purple is avail). SHIPPING TO NY

Geoff Raicer

iTrader: (7)

those are some great questions. For an open class rallycar, i agree that the S200SX 75-70 would be an excellent choice to produce the powerband you are after. The 1.00 a/r and 1.09 a/r are what i recommend if you can give up some top end for quicker throttle response. Of course every application is different so it may be wise for you to try out a couple different A/Rs and go with the one that best suits your application.

A/R literally means Area / Radius. In the case of the S200 vs S300 i can tell you this:
-an S200 has a smaller Radius than S300
-a 1.22 a/r in S200 is about the same as 1.00 in S300.
-a 1.09 S200 is about the same as .91 in S300

i do not understand what you are saying about Hajo's evo, but i believe his 1.15 a/r is a perfect match considering his setup and 272 cams. if you want to rephrase the question i will do my best to answer


we're always learning, and whatever i can share i am happy to do so

not more sensitive but certainly different. The biggest thing ive found is that every turbo has a "Sweet Spot" for both style hsgs AND that sweet spot moves around depending on altitude and engine configuration (cams, boost level, etc).

With regards to twinscrolls - if you run too small of a housing they dont spool faster than the next size up, and obviously dont make more power. Each respective turbo can only do so much, beyond that you have to look at ways to improve the turbine wheel -- ie different blade aero and/or different materials, etc.

dont forget he is at 5800ft altitude! most of the sea-level testing weve seen indicates the .91 gives up top end flow and the 1.00 will spool the same and gain at top end.