mplspilot

iTrader: (7)

Stock 9.8 VIII turbo with 1000cc and one Walbro 255

Log 1:
7000 rpm
21.3 psi
10.9 AFR (gas configured wideband)
87% IDC

Log2:
7125 rpm
20.1 psi
11.2 AFR (gas configured wideband)
82% IDC


I don't see how the max PSI matters when it comes to IDC's, but since you asked it was 27psi in log 1 and 26psi in log 2. Logged with JDM MAP.

mrfred

iTrader: (50)

First tank of E85. Probably more like E75. No tuning except to dial in the injector scaling. Running FIC 1050s scaled at 696 cc/min. I'm finding that FIC 1050s are pretty much exactly 2x the flow capacity of stock injectors.

7000 rpm
20.0 psi
11.0 afr (gas configured)
70% IDC

With more tuning, I suppose I'll hit about 80% IDC.

Pump gas values are:

7000 rpm
20.0 psi
11.0 afr
47% IDC

fre

iTrader: (4)

I think another big factor is fuel rail, fuel lines and fuel pumps being used. By simply switching from a inline walbro 392 to a bosch 044 my A/F ratio went from 12.5:1 to 11.5:1 and my duty cycles dropped from 98% to 94%. So it runs richer and runs less duty cycle. Now that I have it dialed in at 11.7-11.8ish I am down to 92% duty cycle.

mrfred

iTrader: (50)

The more powerful pump is pushing up the fuel pressure.

fre

iTrader: (4)

The base fuel pressure stayed the exact same at 50psi. I checked it and didn't touch the regulator.

On the top I believe it is simply keeping up now, where the walbro was not keeping the 1:1 ratio as boost got really high. The 392 is nowhere near as good as the bosch in the 80-90psi range.

mrfred

iTrader: (50)

ok, I checked, and you're not on the stock turbo, so not surprising that a more fuel pumping power made a difference. Stock turbo setups should be fine with a Walbro. Max boost I figure I'll see at 7000 rpm is 22 psi which gives a fuel pressure of 65 psi (or maybe less since the Evo base pressure is closer to 40 psi). A Walbro can flow 4 liters/min at 65 psi. If my FIC 1050s are at 85% IDC, that's 3.4 liters/min. More realistic is probably about 80% IDC since which gives 3.2 liters/min. So there's still a reasonable (but not fantastic) amount of additional fuel flow available with stock turbo setups. My concern with a stock turbo is not for the Walbro but the fuel rail.

eitan

iTrader: (1)

Stock VIII turbo, FIC 950s, 25 falling to 22-23, 62% max IDC.