911

As title, power/torque/smoothness/max boost/stability etc etc?
Have an Sti v3 with mods and 20g @ 407 bhp.
If I fit an 18g and remap (Apexi) what might be the outcome?

Graham.

stevebt

iTrader: (8)

18g might give you better mid range, i know of someone who has swapped his 20g for an 18g and he thinks his car is faster, obviously not top end but thru the mid range

911

Better as in more torque?
Mid range as in 4000 to 7000 rpm
Any ideas on what else was done to the car's engine?

You know my spec, so just looking to change the turbo to 18g and Andy re-map to max it out.

Graham.

Graham.

alanbell

iTrader: (6)

Ninnybobs has one on his bugeye, He is just over 400bhp , top speed over ,150mph, and runs 12s at elvington, you will find him in northern thread , TTs, cheers , Alan.

stevebt

iTrader: (8)

his engine has been fully rebuilt with much stronger internals and he will be running more boost than a standard engine can take, i think the difference is betwen 3000 and 5000 rpm. a fully ported 18g would be good to get. plus it depends on when you make full boost as i remember alanbell asking if he should swap his turbo and andy told him that it was not worth doing as his car spooled up very quickly, as does mine so i wouldnt bother with an 18g. i would go bigger

gussy

iTrader: (2)

Steve sorry to disagree with you but ninnybobs is running bog standard internals he does have tho a lightweight flywheel fitted.

Peanuts

iTrader: (15)

similar spec engines between myself and ColinC, both at WRCtech (albeit on deifferent daysand with different mappers).
I made about 5bhp more than Col from the charts,

stevebt

iTrader: (8)

im not talking about martin im talking about someone else who had a 20g fitted then went to an 18g

Pavlo

The big difference on the 18g is it can run more boost at low RPM without getting any surge. SO you can use a boost profile that develops max torque with say 1.7bar of boost and then tapers off steadily to the redline. If you do things to improve breathing before the turbo on the 20g it can get VERY bad surge will is real bad news, especially for a MAF based ECU. The 18g on the other hand seems much much better, and also has a higher boost "envelope" on the compressor map.

When I purchased Andy's old car with a 20g on it, it surged very badly, I couldn't run more than 1.1 bar of boost at 3000rpm. I had to wait till about 4500 before running full boost. Much if this is probably down to the large and very straight inlet to the turbo.

Paul

911

Paul:
Any idea what torque the 18g can muster and at what rpm?
I think you know the engine spec of my Sti v3.
Graham.

Pavlo

I don't have an exact value. I do know (roughly speaking) it spools up mretty much like a td05 but flows more, I should think it will make high 300s around 4000rpm with enough boost, but the whole setup needs to be looked at. Airbox, inlet pipe, boost control, headers, cams, exhaust, dumpvalve and mapping are the only things that will affect it

Paul

stevebt

iTrader: (8)

it seems so simple

gussy

iTrader: (2)

Sorry about that steve misread the thread.

911

Stevebt:

LOL!

Too true; I only want to go faster
Thanks for the feedback Paul.

Graham.

Pavlo

Stick with the 20g for a while first I think, and concertrate on the setup of the car overall. I've been playing with the simulator, and I think that 1.85-1.90 64ft time is definitely acheivable on your tyres, but would represent about the best you could reasonably expect.

Paul

Danny Boy

iTrader: (2)

Graham

I managed a 1.974 60ft time today at the pod when the lauch all hooked up and that was on normal pirelli road rubber on 17inch wheels.
I think with your setup what paul quotes should be readily achieveable with a bit of practice.

Dan.

Pavlo

Those times are with zero roll out.

911

I'll try harder tomorrow!
2 runs todat:
4500rpm blipping = 2.30 for the 64 feet
5500/6000 and dump the clutch = 2.30!

Still never seen a road tyre shod car better 1.95 for the 64 feet (EVO 5 on D7's)

Graham.