Bob Rawle

Bit early to be absolute, another 600 miles or so and I can start to really assess it, only covered just on 1000 miles, so far impressive though, its quick out of the box, don't forget you will need a different downpipe as well as the turbo as the GC8/early GDB ones don't fit, the std downpipe is well thought out being a cast open kneck design instead of the traditional flat plate. I don't have the C spec but the version with all the electrics etc and the VF36, the ecu maps are identical to the C spec car though which indicates that both the VF36 and VF37 have the same or very similar compressor maps indicating the only difference may be the bearings (and its titanium).

edited to add maps are identical except for the wastegate solenoid duty values to cater for the turbo difference.

[Edited by Bob Rawle - 8/2/2003 8:39:18 AM]

greasemonkey

As per the header, anyone know what the details on this turbo are? I presume that as it's ball bearing it's an IHI product, but if anyone knows any more, I'd much appreciate a heads-up!

submannz

The pipes run two seperate header exits to the turbo, it keeps one exhaust pulse from reversing back to the head on the inlet stroke of that cylinder (as is with the single scroll design), so efectively the turbo can spool up faster, earlier & less lag because of more even exhaust pulsing.

A very minimal design improvement would be to have a quad scroll design, similar to the reason people have 4 into 1 extractors

The 2003 model incorporates AVCS (Active Valve Control System) and new for this Twin scroll turbo is the titanium wheel.


If you don't understand then I will try to re-word

[Edited by submannz - 7/30/2003 10:57:41 PM]

john banks

john banks

submannz

AVCS optimizes the timing of the intake and exhaust valves according to engine revolutions, which results in better fuel efficiency and optimal torque output.


[Edited by submannz - 7/30/2003 11:24:20 PM]

greasemonkey

Cheers gents, know all about the theory! Trying to assess the feasibility of putting one of these things in my Classic (throttle response gains sound worthwhile), so trying to find out as much as I can about the actual turbo used, before I spend serious energy trying to source one (and the matching headers).

Do either of you know what the full (IHI or Subaru) part number of the turbo in the '03 Spec C is? I presume it's still a VFxx, any ideas?

Am I correct in thinking that the two of you have had a look under the bonnet of the Spec C? If so, does the physical positioning of the turbo look like it'll present any problems when mated with the late Classic induction tract?

Presume also that the new STi headers and up-pipe will be a direct fit on an EJ205 block, and that the downpipe flange area on the turbo will be sufficiently different in shape to the older VF's that a new downpipe will be needed. Any comments, one way or other?

submannz

VF36

greasemonkey

Cheers chap. Anything else you can tell me?

submannz

No not really, can't find any Subaru details on this at all

VF36 - Twin Scroll, Not Ball Bearing
VF37 - Twin Scroll, Ball Bearing

[Edited by submannz - 7/31/2003 5:25:52 AM]

roodog

http://www.i-club.com/index.php check through this site there are suppliers of twin scroll turbos vf 37 and 39, i think you can get a up pipe to fit the standard headers, i think the vf34 and a good set headers and zorst plus a after market ecu will have quick and low spool up... just a small comment from down under... good site

AJbaseBloke

well, there's lotsa opinions on turbos, but apart from the header, the oil pan is a bit different too

I good ball bearing Garret, funnily enough from down under (a place called AVO - natch other places do them too) will get a similar or better result without all the futzing with oil pans, too IMHO.

Edit to fix the cryptic bit about Oz...

[Edited by AJbaseBloke - 7/31/2003 4:22:02 PM]

greasemonkey

Grrr about oil pan. Take it the only difference is to make space for the headers?

Bob Rawle

Right about the oil pan, the headers are incased in a rather large set of heat sheilds as well, so much so that they have had to use a smaller oil filter as well (Forrester I think) although I managed to get the larger item to fit ok as I installed the STi guage pack which has an interface adaptor for oil pressure and oil temp that fits betweeen modine and oil filter. The pan has to be different to accomodate the centre feed of the right bank.

bob

greasemonkey

Hmmm, so if the headers were wrapped in tape rather than the standard shields, d'ya reckon the standard filter and oil pan would do the job?

Any idea about the shape of the downpipe flange as well Bob? Will an open neck DP designed for the older turbos fit/do the job properly, or is something new required?

Bob Rawle

Filter will be ok but not the oil pan.

bob

greasemonkey

Thanks Bob. Looks like I'll have to add a pan to shopping list then!

As a matter of interest what do you think to this turbo setup? Looking for great throttle response and adjustability rather than outright power, plus, it's different from all the TD05/VF2x equipped cars out there. Comments?

hypoluxa

You could use a 4-2-1 equal length manifold (as long as it's 1 with 2 and 3 with 4) and replace the '1' section with an extended '2' section with appropriate flange for the twin scroll.

Not sure about the down pipe flange, but the wastegate design is different (opens like a catflap).

greasemonkey

Cheers gents, was working on the assumption that new DP would be needed. Now to get hold of the bits...