Hi All,

Can anybody tell me at how much boost a MY99 Euro spec Impreza runs? 0.93 bar, is that right?
I'm having a friend who turned up the boost (without using an Elec. Boost controller) to 1.5 bar. When I was talking about my Subaru dealer about raising the boost, he told me that it's impossible to do that without one of these HKS, Apex controllers. And that anyway the standard pistons would not cope long with this boost level. Althoughn my friend runs like this for 10000km's now without any problems.

Any advice on that is welcome.

Thanks,

Al

 

1.5 Bar does seem a bit high.

Rich

 

surely the ECU overboosts at 1.25 bar?

 

Oops, that should mean 1.05 not 1.5!!
Sorry for that.

Al

 

On my scoob-99 with EMS-chip (dutch product), peak-boost goes 1.25 - 1.3 bar; normal max boost: 1.2 bar.
Did already 43.000 km (car-total: 83.000km) with the chip; the car is really used: 5 times Nürburgring this year and many Autobahn-km's with 200+, and much full-acceleration & topspeed.

Till now, no problem at all!

Geert

 

Manually increasing the boost, with an electronic black box is straight forward enough!

Have a look here:

 

Ok,

So I can just turn the boost up to 1.05 or even 1.1 without blowing the engine apart?
Strangely, there are lots of threads about this but nobody ever gave a clear answer if :
YES do it or
NO don't even think about it

Al

 

I get around 15.5 PSI peak, 14 held in my MY00 UK spec.

That's 1.06 bar peak, 0.96 bar held

This data is from an Autometer boost gauge mounted by my own fair hand, so may be horribly wrong.

 

Alberick,

A qualified 'yes'....

The amount of boost the engine will tolerate is also very dependent on the fuelling and iginiton timing that the engine is set up for (with a programmable ECU).

The standard ECU program is designed for the stock boost levels, and it may not be suitable for sustained running at higher boost levels. The stock ECU cuts the ignition at 1.15 bar, but this isn't the same as saying that the stock ECU map is safe to run at this level.

Having said that, 1.05 bar is a pretty mild re-boost, and should be safe. The JECS ECU map seems to get good power increases with a small boost increase - presumably it runs a fair bit of advance on the ignition .

I run a possumlink on my MY98 UK which was mapped to run a maximum of 1.15bar (held rather than peak).

Rgds,

Alex