Power Junkie

iTrader: (1)

Hi All..
I need a bit of advice, so here is the spec.

Sti V5 Type R
Full De-Cat
Unichip (304bhp@1bar)
HKS fcd
Knock-Link(to be fitted)
SX regulator(to be fitted)
Walbro pump(to be fitted)
Defi gauges

ok I want to up the boost but until I get an electronic controller I was thinking along the Dawes route.
Would I be able to run at 1.2bar with the same Map but with higher fuel pressure? any point in doing this..
If the Dawes was in front of the boost solenoid would I get the natural tail off at the top end? (crazy idea but thought I would ask) so I could run a bit higher lower down..

Thanks for any advice

Mark...

john banks

Entirely depends on if the Unichip is mapped up to 1.2 bar. I would assume not. If not deliberately mapped, at best it will be rich and retarded on the higher boost, at worst you could hit fuel cut or have lean fuelling or too advanced timing.

Turning up the fuel pressure will richen it, but perhaps not as much as you think. 10% raise in fuel pressure will give approx 5% raise in fuel flow, assuming your fuel pump can keep up. And then there is nothing done about the ignition, and your ECU can't be at all trusted to sort the detonation out that may result.

A Dawes will generally taper off a bit on a VF28 sort of size of turbo if you run 1.2 bar midrange anyway. If you run the Dawes between the turbo compressor outlet and the T-piece it will raise the boost a bit unpredictably - you have the ECU (I presume that is still controlling the boost on yours?) trying closed loop to fight the situation. You'll probably end up with a poorly controlled spike.

As stock your car is shooting for 15.7 PSI midrange anyway - they often overboost a bit beyond that when driven hard in the cold in a high gear or with breathing mods, with 14.6 PSI at the top.

Power Junkie

iTrader: (1)

Does Andy F map Unichip's?? Would it be worth waiting to get an Apexi AVC-R?
Unichip really not my choice of ecu but cant afford to change at the moment

john banks

No he doesn't. Can't you find someone to tweak the Unichip and set it up for a variety of boost levels? Then you can use the Dawes or AVC-R?

Power Junkie

iTrader: (1)

Unichip do a boost controller module. The map is very good at the moment so dont want it changed much. what would need to be done to the map for raised boost?

john banks

The boost controller module used to be an open loop device, there was talk of a closed loop 3d boost controller a few years back, but I never heard any more about it.

To be mapped for higher boost would need the mapper to run the car at higher boost and map it to suit.

The boost controller doesn't really matter terribly much, you just need to come away with a map that is setup for all the boost profiles you could run, and has been tested fully at your highest boost level, and a bit beyond to allow for overboost.

Whether some mappers would want to map an STi 5 to higher boost is another matter, some are reluctant because of the reputation of STis blowing up, especially if they mainly do non-Subarus. Some experienced Subaru tuners wouldn't do STis either.

You could try contacting Dastek in Dalgety Bay, Fife. Gerry would be able to either sort you out or tell you who could since he is the Unichip distributor in the UK.