AusS2000

I am considering developing a turbo kit for the S2000. Where my aim differs from most is that I am happy with the top end of the S2000 and concerned about reliability and longevity.

What I would like to achieve is a top end similar to the Comptech SC, but more boost and hence torque down around 3500 to 4000.

I make the following assumptions based on the Comptech SC.
4-6 psi doesn't require ECU alterations.
Ghost Booster required
No intercooler or aftercooler in basic form
Uprated fuel pump
Uprated fuel pressure regulator.
Oil supply and return.
Possible relocation of oil filter
Fits LHD and RHD (turbo mounts high)

The idea is to reach reasonable boost by 3500 but then to cap it at 6psi all the way to 9000 rpm using wastegate, bypass, blowoff valve.

I am looking for discussion on the feasibility of such a system, and in particular what turbo to use. I'd like a very efficient low end turbo that doesn't suffer at the high end and is freely available in the US and around the world.

xviper

Why do guys with innovative ideas have to be clear across the other side of the world from me? (Big SIGH!)

AusS2000

I'm only an e-mail away.

This idea is a commercial venture and is targetted firmly at the US market. Ok, so it's actually a way of paying for a mild turbo for me, but don't tell either my GF or accountant.

AusS2000

Also, I intend to provide this as a kit with everything required except the turbo itself. The reason being that the turbo will probably be cheaper to source in the US than here and it is a substantial weight and risk to ship.

So we would manufacture the manifold, return pipe to cat, charge plumbing, intake, oil lines etc and supply a FPR, fuel pump and GhostBooster. The intake would be a box about half the width of the current air box with a drain chamber below the filter. The opening would be in the same place and the same size as stock. Why? I love the Spoon/Mingster CAI

My question is what are the specs of a turbo best suited to this? I guess it would be a ball bearing unit for quick spin up. I doubt it would be excessively big because the top end is not important.

Also, for the powerheads out there, I wouldn't do anything to limit the possibility of upgrading this system. An alternative spec turbo is an option. An intercooler would be possible, or even and water/air after cooler like the ones Vortech make. Piggy back or replacement ECU's to adjust timing and A/F, and a boost controller to amp it up. But that's all way in the future.

Penforhire

Have you looked closely at our members' published dyno plots for the SpeedCraft turbo? Looks to me like they're spinning up by 3500-4000 RPM and they are easily limited to 6 PSI if you wanted to...

AusS2000

Exactly. I'm looking at a system with a low-end like speedcrafts, but without the expense inherent in producing their top end. A top end like the Comptech. I'm looking at a system that I can provide for $3500 sans turbo.

Spend another $1000 on a decent turbo and you've got Speedcrafts low end, Comptech's top end, and all at Comptech's price.

Whitelightning

I don't know everything, but from what I know, the bigger the turbo, the more time it takes to build to it's power charge.... The SpeedCraft turbo is AWESOME, but it is a far sized T-60.. if you tried like a T-40 would it help you with the 0-60 lack of REAL get up and go??? Please don't bash me, I am still learning... I think a turbo would help more from 0-60 though, because it uses the exhaust instead of the flywheel, which the flywheel must get spinning in order to spin the s/c I would love to chat with you sometime if you have extra time to get a better understanding of everything... But in about 6-8 months after I turn 16, I am HOPING to have the money for a turbo ($7000)

AusS2000

I guess the considerations are: What sort of turbos pins up nicely at 3-4K, but doesn't mind the exhaust speed of 9K.

And what to do with the excess pressure? Bleed off, or avoid altogether with an exhaust bypass (wastegate?). From my early experience with old Garret Turbos I suspect that if you had good pressure at 3-4K and then a pressure activated wastegate opened it would divert exhaust, but by 9000K with the old small wastegates you'd still have enough exhaust flow to overrev the turbo.

Elistan

This is pure speculation, but you might want to see what comes with the VW/Audi turbos. My mom has a 1.8T Jetta, and it is absolutely impossible to tell it has a turbo - it simply feels like a smooth, large 6cyl. Absolutely zero lag. I have no idea how it would handle the exhaust volume at 9000rpm, though.

naishou

External wastegate.

By the way I think your 3-4krpm spec for spoolup is pessimistic. The turbo in my WRX is at full boost at 2800rpm, and full boost is 14psi held to 7000rpm. I'm sure you don't need anything like its capacity. Try looking at the specs for the first turbo used in the Liberty (Legacy for US) B4. It's a sequential jobby and I think the smaller one might be somewhere near what you need.