Ok here's the update I've been waiting for and hopefully you too!
So lets recap, we got to the stage that we were at last time, (268bhp), with everything standard on the car except for some Aga 7 rated plugs and running on V power only since the bottom end was forged.
Our ideal target for this car was to get to an initial stage of 300bhp and similar torque. So the next stage plan was launched.
A VF35 went on for starters, but due to the original injectors reaching 98% on the previous map I had to do something with them in order to be able to keep up with the VF turbo.
Some of my modified blue injectors were called for. I modded a set and sent them away for flow matching and cleaning, returned with excellent results, 750cc and all within 1.8% of each other.
So off to the dyno I went, with a Cosworth filter stashed in the boot ready for an air filter test also.
I must thank and commend the guys from Silverstone Autosport for letting me commandeer their dyno for 3 hours. Absolutely cracking bunch of guys and only down the road from me!
At Silverstone:
Anyway on with the power graphs....so after some playing around I managed, (albeit right on the limit), to extract:
As I wrote on the dyno chart, this is just VF35, my own 750cc injectors and PFR7Bs. You'll remember that I had some cheap Ebay 7 grade spark plugs in. I mapped the car first on these and managed 294.6bhp, thinking that they may be the limitation to achieving 300bhp swapped them out for NGK PFR7Bs instead and am surprised to add that they made no noticeable difference to the cheap nasty plugs!!
It was evident that having all the cats still in place was not only making the turbo a little laggy, but also limiting the amount of boost available to play with, only being able to boost 1.3bar mid-range tailing off to 1.2bar top end. With decats in place I expect to be able to hit 1.4-1.5bar mid-range easily to hit the same torque as bhp. Torque currently is slightly less than the TD04 at 277lb/ft.
So next up was the air filter test. Being that I was at Silverstone, (an appointed Subaru service centre), they had a Pro-R air filter on the shelf to try and I'd brought along a Cosworth filter that Andy has stashed in the car. Both brand new of course.
The Cosworth was first, no increase in peak power, but a noticeable improvement in breathing at the top end:
The Pro-R air filter went on immediately after with almost identical results. In-fact it was about 2bhp more than the Cosworth at it's biggest improvement. So to be fair, the Pro-R filter lives up to bigger named filters and of course is warranty endorsed by Subaru!
I'm pleased with the results from today, though a little disappointed we didn't see over 300bhp. The Cossie filter has stayed in the air-box along with the NGK 7s, VF35 and EngineMapper 750cc injectors still on the car ready for some more miles. Next up will most likely be exhaust related, cat back, decats, headers hopefully to see us past 320-340bhp.
After that, well I saw a shiny 20G sat in Andy's workshop last time I was there with the Test Mule's name on it!
Feedback and debate welcomed!
Graham