AWDer thread - S200 - DSport test

[garywerner]

For those of you watching AWDer's tech thread on the Borg-Warner S200 series of turbos:

AWDer says "My only problem I am having is really slow spool up. I am not hitting full boost in third gear until around 4800 RPM -- "

I am not surprised because this lines right up with what DSport got with an S200 on one of their project cars, a Subie STI. Their STI reached full boost at 4500 rpm. This is in the July 2007 issue of DSport - issue 55, on page 43.
They published a nice graph of boost vs RPM and of course hp and torque. They were limiting boost to about 23 psi.

Anyway, this is on a 2.5 liter engine with some nice bolt-ons and tuning done by XS Engineering. I don't see anything wrong with their setup, and neither did they. I just think that the S200 turbos are not the spool monsters some people say they are. Flow yes, High PR yes, spool - no. Too bad. That's my take anyway. With the lack of info and user experience on these turbos maybe I'm wrong.

I wanted to post this DSport info a few days ago in AWDer's thread but found out I couldn't post in the tech section because I'm a "Newbie". I'm a Mechanical Engineer and I've been a car nut for longer than most of you guys have been alive but I can't post in the tech section because I'm a newbie. Very funny! Anyway, the B-W turbos are interesting and I hope AWDer can figure out a way to get quicker boost with his.

Thanks for your posts!
Gary Werner

 

[absolute_DSM]

With a mechanical engineering degree and some participation in the forum, youll be off newbie status in no time.

 

[steel_3d]

Without comparing specs, it seems to make sense that a high PR turbo would have a large exducer diameter, which translates to a larger moment of inertia with all else being equal, which resists spooling.

Good info though, at one point I was considering that turbo as an option. Settled on an fp3052 instead, which is known to spool pretty well.

 

[We're on Boost]

Ok, here's some interesting info on the DSport test. They were using a .76 A/R turbine housing on their Borg Warner. That is not what you would want on that turbo for quick spool. Dan and David (at Bullseye) say they should have been using the .55 or maybe the .70 housing for that test, but at the time they didn't know - they thought the 2.5 liter STI might be good with the .76 A/R. But it was pretty laggy. I think the fancy stainless housing is only made in .55 anyway, might as well get the looks AND the spool while you are at it.

David Buschur confused the heck out of everybody by testing what was apparently a Borg Warner S256 with a mitsu-style internal gate housing, getting bad results, then refusing to give any details about the turbo so we don't really know what he tested. That's on evolutionm.net. back about Christmas time.

Dan and David at Bullseye say that Sean Glazer (Extreme Motorsports) tested a .55 A/R S256 and got good results. Sometimes Sean answers the phone, I'd say give him a call if you're interested. Don't know if Sean tested with an internal or external gate, or T3 housing, or what.

Will be interesting to see what AWDer comes up with.

 

[We're on Boost]

Finally! Here are some 4g63 S256 dyno results, published by a good shop, and lots of supporting info so you know what the heck you are looking at!
Two turbine housings tested, the .55 and the .70 a/r:

BorgWarner S256 Dyno Results! - evolutionm.net