06/07 WRX turbo comparison.

[Verocious]

We had a nice 07 WRX in this morning for a tune. It had a VF39, upgraded top mount, turbo back exhaust, stock injectors, and a Delta for tuning. Boost was set to 18psi. Since his tuning solution was a Delta, there was no AVCS option. This graph is comparing a Stage 2 tune with EcuTek and the stock turbo, against the VF39 tuned with the Delta from Turbo XS.



As you can see, the stock turbo spools quicker which is expected. If there was some AVCS tuning with the VF39, we could get back about 3-400 rpm of spool that was lost without it. You can see how much more air the VF39 moves up top, it just starts to walk away from the stock turbo above 4,000 rpm.


Below we have the VF39 tune with a Delta put against a Big 16g with a stock topmount EcuTek, stock injectors, and a turbo back exhaust. The VF39 spools much quicker even without any AVCS tuning, but we can see how the 16g pulls better up top. The VF39 is tuned at 18psi. The 16g is tuned at 16psi. The limiting factor for the 16g was the stock injectors.





For comparison sake here is a stock 06 WRX.




The Deltas are great, but do fall short in a couple of areas. One is AVCS tuning, and the other is with throttle control. With the DBW cars, part of the stock ECUs rev limiting comes by way of shutting the throttle plate. I am going to start to offer an open ecu flash on top of the Utec/Delta tunes. This will get better control over the throttle and then AVCS will be able to be tuned.

[RyanG]

I was wondering if you were gonna offer that. Good to know~! its crazy how big of a dip in power the stock map has.. is the delay that bad in those??

[Verocious]

The "Shark Fin Effect" on the stock cars is form them staying in closed loop for too long.

[RyanG]

yeah thats why I asked. I never realized it was that bad. Out of curiousity, can you post the A/F for that run as well? Be interesting to see.

[Verocious]

Here ya go.

[RyanG]

holy ish!! I cant believe it goes from that lean to that rich! Is it seriously off the scale???

[Verocious]

Yeah, if you think that is bad, you should see what a new Legacy Spec B does. The ECU holds the car in closed loop even longer. To the point where I would not make any more runs on the dyno.

[TROLL]

looks like the 07 STi... which is why i'm not having any fun with my car until it gets tuned properly. (got the tgv delete and aps turbo inlet install done last night... getting closer)

[Buster]

Originally Posted by Verocious

We had a nice 07 WRX in this morning for a tune. It had a VF39, upgraded top mount, turbo back exhaust, stock injectors, and a Delta for tuning. Boost was set to 18psi. Since his tuning solution was a Delta, there was no AVCS option. This graph is comparing a Stage 2 tune with EcuTek and the stock turbo, against the VF39 tuned with the Delta from Turbo XS.

As you can see, the stock turbo spools quicker which is expected. If there was some AVCS tuning with the VF39, we could get back about 3-400 rpm of spool that was lost without it. You can see how much more air the VF39 moves up top, it just starts to walk away from the stock turbo above 4,000 rpm.


Below we have the VF39 tune with a Delta put against a [b]Big 16g with a stock topmount[\b] EcuTek, stock injectors, and a turbo back exhaust. The VF39 spools much quicker even without any AVCS tuning, but we can see how the 16g pulls better up top. The VF39 is tuned at 18psi. [b]The 16g is tuned at 16psi. The limiting factor for the 16g was the stock injectors.[\b]

Im confused. Why did the VF39 make less TQ than the stock TDO4?

Also why was a WRX getting tuned on a stock TMIC but with a big 16g? And why was the only limiting factor the injectors. Also why only 16psi?

I have a regular 16g on my car right now with 565s STi TMIC and a open ecu tune running 18 psi. Im also being retuned for 22 psi but may back it down depending on what we see. But will have a TXS FMIC and a Prodrive boost solenoid. what would you expect to see from that?

[Verocious]

The VF39 made less torque because I had no way to tune the AVCS map without doing an open source flash also. AVCS tuning is worth about 20 ftlbs of torque


The tune was on the stock intercooler because thats what the client brought me to tune. Wasnt my choice by a long shot. Injector dutys were getting higher than I would have liked to have seen up top on a long pull. At 6700 rpm boost was 15.8psi and duty cycles were 95%. He did not have a fuel pump upgrade either.

At 18psi you are already close to running your injectors static. I would not run much more boost than that. The WRX ECUs can only make calculations up to 4.68v from the air flow meter. At 16psi on the car I was mentioning above, I was seeing 4.58 volts. That only left .1 of a volt before the ECU lost the ability to calculate fuel and timing needs. Some people dont have a problem overrunning sensors. But it is something I just wont do.

[Buster]

Thats a good point. So an injector upgrade would be worth it?

[Verocious]

An injector upgrade would be nice.

I didnt notice before, but if your car is a 2.0. then you wont have as much of a Maf voltage issue. But if your votages do start to get high, a big maf would be recommended. You can normaly run about 320-330whp without any problems with Maf voltage.

[Buster]

Oh okay cool! thanks.

[CHAOS]

<3 andy lolz

i cant wait to see how johns 4eat does with the 16g

[Buster]

I know right now, my my injector duty cycle is at less than 70% at 18psi I think that should leave a little room.

[CHAOS]

keith ur car should make good power with the right tweaks.

[Buster]

Well you know what its waiting on, I have the FMIC, Prodrive BCS, Meth, APS Dual Vent and EWG. I think I could get close to 320 now.

Thanks though Jon.