I wish I had done some big single setups so I could add some input on the larger turbos...I've never done anything huge, but the twins on my VR-4 don't spool until the high 3k range but when it comes on it comes on FAST...I'd love to see what the extra .3L the SVX has does to that number. This is going to be a FUN project.

I don't think that the 4094 will be THAT laggy on the EG33.... I have seen dyno sheets and videos of EJ25's that have a GT40 series turbo and they are hitting 16-18psi at 4k I think it was. With an extra .8 liters of displacement I would like to think that I would be able to hit 20psi @ 3700-4000. With a redline of 8k I think we would be okay.

With an extra .7L tacked onto the 3kgt engine, our guys have seen their boost about 1000RPM sooner (and being that the 3.0 is a larger engine to start with, we've got a much greater % increase in displacement in your scenario). I think it will be a very nice setup if those spool numbers are accurate that you found on that 2.5

Well if you're bumping the redline to 8K+ it won't be as bad as you'll have more usable RPM once that snail finally gets moving. Compared to any well developed setup, 4000K rpm is damn laggy. Even the old GTP cars from Porsche that used huge KKK turbos(non BB CHRA I might add) still saw 1.5 bar of boost before 3700rpm. I highly recommend using a divided housing and manifold setup if you plan on making this any car other than a straightline 1320 slut. It's only going to help you in the long run. I've track raced cars with 40+ larger spools making 200WHP more than my 911 with the GT35R and I whoop them on the track. they just don't get into boost quick enough to make use of it.

1/4mile or highway run car it's the way to go if you're looking for stupid power and don't care about the twisties.


Again I'm not trying to sway you to one decision or another, just trying to help you get the most of of what you're doing. I do this stuff for a living and just want to give you clear cut info on what I know and deal with making and developing setups that you're looking to do on the SVX.

I would really like to see how you do this. I might give this a try some day. Should be pretty easy to do with the stock headers.

Sorry. I've been around, just busy with all that is going on in my life. I'm still waiting to get my block back from the shop. They finished semi closing the deck, but I needed them to groove the deck material a bit so I can get good coolant flow to the heads. When I get it back I'll take picks and show you what I mean. I have the heads back. When I get everything back I'm going to take Mike's advice and cage all of the bearings just to verify clearances. Then I'm going to check the crank with a dial gauge to make sure its good. If you are in town this weekend give me a shout. I'll probably be watching the SEC championship game, even though the gators are not playing:(

I ran OK for about 3000 miles on about the same level of boost and the stock setup. I think it is just a matter of time though. I was running about 3 psi of boost with the more aggressive maps Mike had. I was also using 550 cc/min injectors with the Tec II. No audible knock. I also have knock sensors.

I think it is worth trying high boost on the stock motor. I would just expect to have to replace the pistons someday. Tom and I have both had the experience of blowing ring lands. In fact this is a common problem with the Imprezas as well. The good news is I didn't have any major sleeve damage as a result.

Our motors will spin to 8k safely, but I will be shifting at probably 7200-7400 when I am dragging the car. I agree 100% about you beating cars with 200+more WHP than you. Sounds like a Supra with a huge turbo that will put down 800+whp and still run a 11.4-6 1/4 mile. I am going to go back and really look at what 4094r's were hitting for boost at different RPMs. I would like to have full boost (20psi) by 3500rpms with a turbo eg33.

Also, boxer6, please just keep talking/ posting too. You obviously know what you are talking about and have a lot of experience. My S/C was my first real endeavor with forced induction and now to be looking a the new world of turbos........ Yeah, a lot to learn.

That won't be a problem at all since this manifold design will only work on my 962 chassis and not an SVX engine bay(not worried about people copying it :) ). I will not be using the OEM manifolds as a true divided setup matches exhaust reversion pulses together in sequence with the stock manifolds don't do. Look at Full Race's 2.5 divided setup and you'll see what I mean where the joining of cylinders on opposite sides of the motor are needed. The turbocharger will be a centrally located unit, so I'll be able to design and tune this header system on Solidworks within 1mm of equal length well :)




HAHA :lol: yeah what's the running joke about the difference between a 600, 800, and 1000hp supra?.......about 2 tenths in the quarter :lol:

Ok so you ARE planning on building this as a drag car system.....then yea the GT4094 will probably suffice for your needs. Sure as heck would be too large for a circuit car like I build but for a drag car once it's spooled it's inertia will keep it up there which is perfect for a drag run.

EG33 spinning out to 8K rpm with stock valvetrain and PCM???? Elighten me on that one as I'd love to get even a 72-7500rpm limit on this 962. If not stock valvetrain, what the hell are you using up top for springs and retainers? Who remaps the stock PCM to up the rev limit? I'm not aware of any open source tuning for the EG33 PCM....but then again remember I'm a Porsche guy and don't know the Eg33 like you guys do ;)

I looked at the setup http://www.full-race.com/catalog_ima...fold-5_jpg.jpg

I don't really see how this would layout would translate to a 6 cylinder twin scroll compressor housing application, but it would seem to me the best and easiest way to mimic this on a 6 cylinder would be to use the stock manifolds and run two equal length headers to the turbo. Would probably require a special fitting to properly plumb the two pipes into each scroll of the turbo to keep the lines separate.

I am far more interested in auto-x'ing and doing open track days (Lime Rock is very close to my house) than drag racing. The valvetrain is the valves and springs from ecutune. You have any recommendations on a header layout/design? Also, what do you think about using the stock intake manifold (heavily ported and ceramic coated) vs. a custom manifold?

To piggyback sicksubie, on the intake question; is it even possible for our intake to be extrude honed? I know all the z32's did that as the only option, but they also didn't have a iris in their intake.

That picture was just to show how the pulses are kept separated as long as possible before going through a collector. Doesn't matter if it's a Subaru flat 4 turbo, or a Porsche flat 12 turbo. The benefit of a divided housing is to keep the exhaust pulses isolated from one another as long as possible before the turbine. This delivers more energy to the turbine for faster spoolup. The EG33 stock manifolds will not work well for this as they mash the exhaust pulses together too soon to be effective in any sense in a twin scroll housing. Plumbing the exhaust from the OEM manifolds into a divided housing would just be a restriction and more than likely reduce power on the top end. You need to separate the pulses longer to make the system effective and use all the benefits of a divided setup. That's the reason why the FR twin scroll setup in the picture you linked to pulls each pair of runners from opposite sides of the head as the firing order of an EJ25 is 1 3 2 4....again keeping the pulses separated as long as possible(cylinders are grouped as 1+2 and 3+4).

Another thing to remember with a twin scroll manifold design is the primary diameter is normally smaller than that of a standard housing setup as you're looking for exhaust velocity and low expansion until the exhaust reaches the turbine. Using a typical primary size of a standard setup and you'd lose that velocity, gaining nothing in the end. If you're going for all out power a divide housing is not in your best interest. If response is your game, so is twin scroll.

You most definitely can use the OEM manifolds for a standard turbine housing though and I'd go that way as it's cheap and easy and the reversion in those manifolds has been "tuned" by subaru's R&D. No need to mess with that too much. Just match an appropriate A/R and turbine to your needs and you're set.

I doubt that I will be using the stock manifolds. I may be speaking to early though.