AFR and boost issue
 

Hi all,

I had my car on a rolling road today and it's down on power and the AFR is all over the place.

I was wondering if anyone could give some advice on that the issue could be?

2005 Impreza WRX Prodrive - no other performance modifications other than the PPP.

Was expecting way more than 130BHP at the wheels, since I should be around 260BHP at the flywheel -

http://i.imgur.com/6NhZuYT.jpg

and the AFR is all over the place -

http://i.imgur.com/nupmqte.jpg

Apparently I didn't hit more than 9psi of boost.

Any help would be much appreciated.

Thanks,
Foz

Whose RR was that as the graphs are very different to the DynoDynamics ones?

There's definately an issue there and an AFR of 10.2 is pretty rich - check/clean the boost solenoid and check all the vacuum lines.

Worth getting to a mapper to have the map tweaked, the PPP maps are not all they are cracked up to be!

It was at JF Automotive in Maidstone.

I don't really know what I'm looking at haha - what should the AFR be?

I'll clean the boost solenoid tomorrow.

It seems to drive alright, but if it's been like this since I've owned it then I wouldn't know any different - it's still quick.

Yeah, might be worth upgrading some parts and getting another map.

Thanks for the reply :)

Pop over and see Charlie at www.surreyrollingroad.co.uk for a power run . I'm sure he'll clear things up and if you book it for a Friday duncan racedynamix will be there . Tell him CJ sent you

I have seen 2 different maps from Prodrive for the WRX from this era.

One has fuelling pretty well pegged at 11.2AFR on boost which is a good target, although the map is quite crudely set to 11.2AFR which is unlike any other (a lot of copy/paste going on).

The other Prodrive map can be anywhere between 10.2, 10.45 and 9.65 at full boost depending what cells in the map you are hitting.

That AFR trace you have posted would seem to indicate you are on the latter Prodrive map.

The power output provided can be adjusted by the operator. If the load is not calibrated correctly for the car (i.e they are not used to running Subaru's) then the figures can be well off.

I once went to a non-Subaru wise tuner and the first run was 355BHP for a car that was rated at 320BHP. A tweak of the rollers and it was at 326BHP.....simple as that.

P.S that's a pretty crude/crap plot and scaling on the RR plot. Looks more like an etcher-sketch

The torque setting, although quoted as being in Nm is plotted to look more like lb/ft as the torque and power traces cross at 5250rpm.
This only happens if BHP and lb/ft are plotted on the same scale. Therefore your torque in lb/ft is 130 which matches the power, so sounds correct. Just a bot low.......

Hence why I said take it to Charlie ;)

Hi,

Ok great - thanks for the replies.

I'll look at going to Surrey Rolling Road.

Cheers guys.

I've heard Charlie does £35 runs most weekends. Can't remember where I heard it though.

Do you know what it's boosting either from an installed gauge or the dyno.

Dyno was 9psi, my gauge says 20psi which i know has always been way off.

Cheers.

9psi (0.62 bar) sounds like it's in limp mode or the boost controller is knackered. Therefore the figure recorded sounds bang on.

It should be 17.5psi (1.2bar), so your gauge, taking into accounting for reading error (most gauges over read a touch) sounds about right.

Perhaps the dyno pulled the wrong pipe off to connect their gauge, preventing your boost control solenoid working.

Go see Charlie.........

+1 for Charlie (and C.J) - had my car power run last year when SES went down, and am booked in to see Duncan on 22nd May for a remap and run at SRR - great guys and very helpful ! :ok:

Are these guys any good for RR and mapping? http://www.monzasport.com/

There a main stealer, don't have a rolling road and if they mapp it'll be prodive mapp or PPP standing for Piss Poor Performance !

Monza are a relatively new Subaru dealer - from my limited experience of them, I wouldn't go there for any work on a scoob. They've been an Alfa dealer for decades (hence the Monza part of their name) so that's more their specialism.

Speak to Surrey Rolling Road.....

I wasted. Y time going to Monsay for parts, they just weren't interested. I now go to bell and Coalville for parts, which is a ball ache. Tuning and diagnosis, stay away from main dealers and got to specialists.