Depends on what's trimmed, if it's just to reduce mass then it would spool quicker but have the same top speed due to the turbine profile.

Remember a turbine is driven by exhaust gass so it doesn't flow so much as it's driven by gas velocity.

from what i've read its just the edges that tend to be cut back to allow the exhaust gasses to escape at higher rpm thats why i assumed it would increase lag as some of the exhaust gasses would escape at lower rpm when u need them all to spool up the turbine wheel

Ideally you want as small a turbine wheel as possible before it starts to strangle the top end.

I think there is a difference between having a smaller turbine wheel and cutting back the blades to reduce back pressure.

I will update this post when i get it mapped by flea on the 31st oct!
anyone care to guess the bhp and torque it will produce!
spec below.

20VT LE 6 speed 87k, fsh, 2 owners seems v healthy serviced yesterday at motormech when fitting

Superpool hybrid t28 turbo
evo 6 front mount intercooler
+ full 3 inch blueflame exhaust and downpipe with decat
greddy boost controller
ram air filter (no sip) yet
forge uprated dv
std fuel pump with wireing mod

errrrmmmmm 286bhp and 270lbft of torque

3" blueflame ? I thought they were 2.75" ?

I would guess around the 280bhp area. What are you using for boost control?

Greddy boost controll. I'm sure its 3 inch not 100 % but its the biggest one put it that way.

Nice although a huge exhaust isn't really needed for the superspool, it will run out of puff long before the benefit of a large exhaust comes in to play. It will sound nice though

what kind of rpm do superspools hold there torque to before they drop off, know its about 5000rpm with the standard

Looking at my rolling road graph, the torque rises very quickly at 2500rpm where it holds an almost flat line up to 5800rpm where it starts to drop off.

that's a fantastic spread of torque, do you know if your turbo has the cutback turbine blades jimbo or just standard blades

Doug, you have to remember Jimbo has C&B Fast Road cams, a 2.75" exhaust so the top end is going to flow a little more. Realistically I wouldn't expect the turbo to give more than 280-290bhp on it's own.

http://www.torquestats.com/Jimbo

cheers flea, didn't realise jimbo had the additional mods

Flea/Doug, that was my rolling road print out before the C&B cams.

http://i2.photobucket.com/albums/y5/James_Hardwick/DSCN0532.jpg

My mods at the time were,superspool, gtec2, chargecooler + smic, blueflame exhaust.

The C&B cams have improved the figures by around 20bhp and the same torque but the graph is quite similar.

I have one of the first superspools, I'm not sure on the exact spec of them but I remember talking to TurboDynamics who mentioned a cut back turbine but the turbo was ordered through Barbz so it was his spec.

Thats still pretty good for setup before the cams!

so 291 before cams! thats a good result surely.

It is, although the power was corrected to 278.5bhp due to the ambient conditions:

Intake temps: 6.8c
Ambient temps: 4.7c

Temperature really makes a difference on all boosted cars.

Yep, it was a freezing cold November morning at Powerstation

BMCu, you need to look at the corrected power, as Leighton said the cold temps give a bit of a high reading.

That was running the chargecooler that I found gave a healthy spread of torque and power on the little superspool, I think it struggles with the FMIC as it's quite a bit more area to pressurize.

Here's the graphs after the C&B cams and FMIC so you can see the difference
Torque before and after unichip mapping.
Power again before and after mapping.

You can see the difference the cams and FMIC have made on the before mapping results. It looks like it has all just moved further along to the right ?

Jimbo, I thought the benefits of cams is only prominent with headwork?

the torque curve before the cams is really impressive in that it spools up really quickly, thats as quick as a standard turbo but holds it a lot longer, do you prefer the car before the cams and FMIC or after

Blimey, thats a tough question and so much has changed since getting the turbo and exhaust fitted.

If I'm honest, I don't like the FMIC, I think it's probably great for larger turbo's but not so great for the superspool, it was the FMIC that spoiled the torque curve or thats how it felt after it had been fitted.
I think it's because it's such a large area for the little turbo to pressurise that it takes a little bit longer to come on boost.

The chargecooler/SMIC combination has the same length induction as a standard car and give or take a small amount has the same volume so the turbo isn't struggling.

The cams will work with a standard head but will work better with a worked on head, it's hard to tell from those two prints as the one from powerstation uses Nm for torque where the other is in ft/lbs but the area under the torque curve is now much greater than it was so the car does feel quicker, the torque curve is dropping off at 6500rpm now but still at a higher level than it used to be.

As for spool up and the rapid increase of torque from the early graph, if anything it's more manageable driving the coupe now, with the rapid surge of power it was very easy to spin the wheels, it's still easy to do it now but not as bad.

My goal was always to have a driveable car that would give instant ooomph when I put my foot down, I'm not interested in power figures or waiting for the turbo to spool up before I can overtake. Thats pretty much what I've got and I'm happy with it, if I could turn back time though, I would have saved some cash, not fitted the FMIC and kept the chargecooler.

jimbo what fmic did you fit?
the one i have fitted is a evo6
my 2 mates have pro alloy, i think there's fits a bit better.

still a good spread of torque low down though, i have a chargecooler on mine at the mo as didn't want to go down the FMIC route due to possible lag issues and also didn't fancy chopping the front bumper at all although that is largely due to the fact i have no mechanical skills at all lol, have you thought about going back to a chargecooler

It's a Pro Alloy, don't misunderstand me, the Pro Alloy intercooler is brilliant and not restrictive in any way, it's just the size of them that I thinks an issue.

No, I sold my chargecooler to help pay for the intercooler and you never know, I may have a change of heart and rebulid the engine with forged internals and a bigger blower one day

yeah i think if i went over 300 bhp id prefer to play it safe and have forged pistons etc.
my friend is contemplating a gt28rs set up but id worry if running around 340 about blowing the engine up.
Is 350 is the limit on std internals to run safely?
i hear anything over 330 is gonna strain it if so if he wants 340 on std internals he is risking it surely.

I'm not really a big power tuning expert to be honest but I believe the weak point on the internals is the piston ring lands.
So long as the fueling is correct and your not running high boost then you should be ok, saying that, increasing the performance of the engine is always going to effect longevity.

It's not as simple as that - there are loads of threads on this in the tuning section if you search for them.

Yeah I guess, well my friend is buying a gt28rs and doesn't seem interested in spending loadsa money on forged pistons etc, so if its fine if done properly 340 bhp is what he is after he may not need to get his internals done then !

Well the results are in...