The one in the link wasn't, but BW does have twin-scroll housings available for the S256.

 

the actual Borg-Warner S256 is a twinscroll turbo. The t3 housing that bullseye makes converts it to a single scroll unit. singlescroll 30R vs single scroll S256, 30R will win no question. Twinscroll 30R vs twinscroll S256 you could see interesting results.

 

a GReddy 25G kit would make about 425whp on pumpgas. not a BB turbo but will last twice as long as a BB turbo...

 

There are single scroll housings available from BW. We used a .70AR Single Scroll housing that we modified to fit our needs.

I have yet to see a 30R hit 502whp/501wtq.

We use both turbos and so I have 0 bias but I'll take the longevity of the BW over a 30 anyday.

just my $.02

 

Come on Geoff, let's hear more about those "interesting results".

 

I still find it funny that everyone uses Garrett turbo's as the guideline for making power, when in all honesty the boost preasures it takes to really make the 4g63 engines shine you are generally past the garrett turbo's efficiency point. While BorgWarner and Turbonetics both make compressor wheels designed to be more efficient at higher boost lvls. My opinion between the GT30r vs. the S256 I would bet you will see higher torque #'s from the S256 and more stable HP's in the higher rpm due to cooler air charge. We compared the S472 against Garrett's t6 frame 72mm inducer on our race car and the air temps at the compressor outlet were averaging 40-50 degree colder from the S472, and we all know cooler air means we can run more timing and fuel and that translates to more power.

 

which t6 frame 72mm garrett are you referring to? I have never seen this turbo? we compared the 4294R to borgwarner 71.095mm S400SX, borg warner ate up the 42R on the track and the dyno

 

Geoff we do not use off the shelf turbo's on our race car, you can't seem to stay ahead of the pack that way. for the past 2 yrs we have been using GT4708 with the compressor wheel cut down to 72.5mm and the compressor housing sleaved then remachined to the same contour of the compressor wheel. All said and done we spend abot 4k on a garret with all the extra machine work and the Bullseye S472 made more boost with less air temps and made a droader torque curve, and that was off the shelf unit plus it spooled faster then the garrett even though it had a 1.36 exhaust while the garrett using a 1.14.

 

^ Wow, see it's not often youll get people telling you things like that.


I wonder what the HTA could be using?

Propietary wheel cut down or cut to fit?

Scorke

 

we use a standard gt4708 wheel that gets cut to fit the new contour of the housing after it gets modified then they all get flow tested to make sure the compressor will still be efficient for our application. Our new turbo for this yr is the new Precision Billet 116mm we will be running outlaw drag radial.
What alot of people don't understand about turbochargers and engines is that old saying of there is no substitution for cubic inches is not allways true, sometimes you go with a bigger motor and now you can be outside the boundery of the turbo's capability to fill the cylinders efficiently. Just to test the theory seeing our old class rules allowed us a max of 72.5mm inlet and we were running a 360cid engine we built a 310 engine and used the same turbo setup. We ran 4 mph faster with the small engine and we all know mph is what shows HP, ET just shows how well the car is set up and how well the driver can drive.

 

damn you are cutting an 88mm inducer down to 72.5mm! now this is basically a completely different compressor wheel with a completely different compressor map. That combined with the displacement of the engine changing makes the compressor operate at a completely different efficiency area on its own map. This is obviously what you need to do when you cant go bigger than 72.5mm on the inducer, go massive on the exducer to make every bit of that 72.5mm work lol. The borg warner will have the advantage in an application like this becuase the 88mm wheel you had was a 6 blade, the borg warners are 7 or 8 blade, moving more air for the same size inducer.

I agree that more disp isnt necessarily good, but with the "little" 4 cyl motors we use, its apples and oranges from what youre doing. More displacement is almost always better. A lot more dispalcement to us (Stroker motor) is adding .2-.3L. This might shift the operating area on the map a little bit, but when you are considering your application which is a difference of .9L and a wheel that is cut down 16mm you are in a completely area on a completely different map. i can see in your application where you have massive displacement and cant run bigger than the 72.5mm inducer, but if you had an 80mm or bigger inducer you would likely want the extra disp.

 

Geoff we have also tested with a straight GT4708 with both engines and the smaller engine still posted higher mph then the big engine it basicly used the 88 more effectively then the 360 did, I am not so sure the smaller engines work the same way.

 

which turbine housing did you test with?

 

on the dyno we have tested with the .96, 1.08, 1.23, 1.39 and the bullseye we only tested 96mm exhaust wheel with the 1.32 housing but what we were doing on the dyno was logging for backpreasure changes with the .96 on the garrett we were getting 49 lbs of backpreasure we finalized with the 1.23 as best with 26 lbs of back preasure the bullseye had 24.5 lbs of back preasure, and too much back preasure is lost HP.

 

theres been alot of testing with the borg warner turbos on the srt-4 forums. but since i havnt seen many proven numbers i say dont try to be a pioneer unless ur rich or own a shop- just run a gt3071 for low boost or 3076 if u want to run high boost