E85Forum.com

seanmathes · Joined: 29 Apr 2009 Posts: 20

I am trying to tune my twin turbo GT with 160 # injectors. I am also running this on E85. Running a SCT BA2800 MAF. Tuning with an xcal 3 and advantage 3 software.

My tuner says we have to get the values for the low slope and high slope as well as the breakpoint.

Can someone please help me get started with this? I didn't get any help from the tuning SCT manual and SCT will not provide tech support on these injectors?

Is there a formula to get started? Also what else am I going to need to change?

Here are the injectors I am using.

http://www.lightningforceperformance...oducts_id=1095

Thanks for any advice.

Sean

TimZ · Joined: 02 Feb 2008 Posts: 48 Location: Dearborn, Michigan

seanmathes · Joined: 29 Apr 2009 Posts: 20

Yes SCT uses a chip or flashes the factory ECU. They do have settings for different fuels but nothing for E85.

I should have mentioned this before but I installed a versalfueler so that I can run low impedance injectors.

Also we already tried to scale down the injector size and it didn't work well. I am pretty sure I need an injector breakpoint calculation as well as the slopes.

I haven't found the breakpoint yet but a friend of mine found the slope info and min pulsewidth on a german site here.

http://www.bjprace.se/spridare/b1600.htm

Statiskt flöde vid 2.7bar (39.15psi) = 1680 cc/min / 160.0 lb/hr OBS vid 2.7Bar
Statiskt flöde vid 3bar (43.5psi) = 1770 cc/min / 95.0 lb/hr / 12.0 gm/sec
Statiskt flöde vid 3bar (43.5psi) = 998 cc/min / 95.0 lb/hr / 12.0 gm/sec
Dynamiskt flöde vid 3bar (43.5psi) 2.5ms pulse width and 10ms repetition rate = 2.2 gm/pulse
Resistans: 5 Ohm .Många motorstyrning klarar köra dessa som både hög eller lågohm.
Kontakt: Standard Bosch EV1
Low injector slope: 0,044912 lb/s
High injector slope: 0,035086 lb/s
Minsta repiterbara pulsvidd vid 2.7bar: 1.642ms
Injector voltage offset as function of batt voltage:
6V=2.26ms 8V=1.32ms 10V=0.82ms 12V=0.5ms 13V=0.38ms 14V=0.46ms 15V=0.16ms

seanmathes · Joined: 29 Apr 2009 Posts: 20

I found the injector slope straight from Ford so I used those which I have also attached for you to look at. The slopes and injector minimum pulse width were larger than the maximum values in Advantage III so I scaled by 50%. I scaled high slope, low slope, injector minimum pulse width, breakpoint, manifold volume, maf transfer function and engine displacement. The car would run but barely, it was extremely rich around 11.5 at idle. Short term fuel trims were between 5-15 and voltage at 980 through a snap on solus scanner. After the initial scaling we started pulling fuel out of the MAF transfer curve, we also tried to adjust the low and high slopes. Nothing worked we couldn’t get it to lean out.

Also, we were told to put all of the multiplier values to 1 as it’s a return fuel system.

Fuel injector values before scaling:
Low slope 0.044912
High slope 0.035086
Breakpoint 0.0002751948
Min. pulse width .00642

Fuel injector values after scaling by 50%:
Low slope 0.022456
High slope 0.017543
Breakpoint 0.0001375974
Min. pulse width 0.00321

After numerous attempts at pulling fuel through the MAF transfer we added 10% to the slope values (multiplying values by 1.1) again nothing worked.

sean

SWR · Joined: 05 Sep 2009 Posts: 20 Location: Norway

seanmathes · Joined: 29 Apr 2009 Posts: 20

Can anyone please walk me through the scaling process just to make sure I'm doing it correctly?

I cut the slopes, breakpoints, and engine displacement in half. This is all that it should take to get it right isn't it?

I was so ridiculously fat I tried everything, pulled tons of fuel out of the MAF transfer, I tried to increase the slopes again to the max values even after the scaling and nothing would get it to lean out. It was below 10 on AFR.

Any thoughts? I was thinking that maybe the min. pulsewidth is too large or maybe the injector offset table needs to be scaled down as well because it's still adding the same amount of fuel to the scaled slopes from the offset table?

SD Speed Parts · Joined: 14 Jul 2009 Posts: 3 Location: Collinsville, Ok

Scale the hi and low slopes, displacement, the airflow portion of the MAF transer function, air manifold volume, and the injector breakpoint.

For more info check the sidebar on page 110 of Greg Banish's book Engine Management Advanced Tuning. It is a well written and easy to follow book on tuning.
_________________
E85 in
Owasso, Ok $1.99 as of 6-25-10

www.sdspeedparts.com

seanmathes · Joined: 29 Apr 2009 Posts: 20

I am waiting for greg's book to arrive. Can you please explain what the airflow portion of the MAF transfer is?

SD Speed Parts · Joined: 14 Jul 2009 Posts: 3 Location: Collinsville, Ok

The MAF transfer function has two components. One is voltage. The other for the airflow at the corresponding voltage. For example 5V = 1644 kg/hr. So when when you scale to stay within the PCMs limits, you scale the airflow and leave the voltage unchanged.
_________________
E85 in
Owasso, Ok $1.99 as of 6-25-10

www.sdspeedparts.com