A 3.4 DOHC Build then... F40 Turbo (Page 34/57)
fieroguru DEC 28, 09:20 AM
So roughly 10-100 mph in about 9 seconds... that would be fun!
Fierobsessed DEC 28, 04:04 PM
Sort of. My speedometer needs calibration badly. It's way off. Second gear to 80 on a F40? More like 60-65 probably. But I was taking my sweet time shifting...

I am having one strange issue with tuning. Any time I'm coming off the throttle fairly quick, I'm getting a heafty burst of knock. But under 10 PSI of boost, there is no knock and the timing is ramping back in. So when I shift, I'm starting back in to boost with a large amount of retard that tapers off over time. If I'm in second gear for a while and I just whack the throttle, I'll have no retard issues and it pulls so hard!

Maybe I still have boost in the intake between the throttle blade and the valves when decel enleanment kicks in creating an instant lean condition for a couple of engine rotations? It's really strange! Not sure just yet what's causing that.
fieroguru DEC 29, 09:45 AM

quote
Originally posted by Fierobsessed:

Sort of. My speedometer needs calibration badly. It's way off. Second gear to 80 on a F40? More like 60-65 probably. But I was taking my sweet time shifting...

I am having one strange issue with tuning. Any time I'm coming off the throttle fairly quick, I'm getting a heafty burst of knock. But under 10 PSI of boost, there is no knock and the timing is ramping back in. So when I shift, I'm starting back in to boost with a large amount of retard that tapers off over time. If I'm in second gear for a while and I just whack the throttle, I'll have no retard issues and it pulls so hard!

Maybe I still have boost in the intake between the throttle blade and the valves when decel enleanment kicks in creating an instant lean condition for a couple of engine rotations? It's really strange! Not sure just yet what's causing that.



I can hit 70 mph in 2nd gear at 7K with my F40, so it didn't seem too far fetched... all comes down to tire diameter at that point.

You might try turning off decel enleanment to see what happens. Also its quite possible you just have too much timing in the high to moderate vacuum and high RPM areas of the timing table. I know I had to tweak mine some on the LS4 since they never expected shifts to happen at 7K and see those areas of the timing map at with the throttle closing.
brian89gp JAN 13, 11:39 AM
I have a $DF mask I modified for boost kicking around here somehwere if you want it. Lifted the spark/fuel control off of $8F but never got around to the wastegate. Was a daily driver for 2 years running 36# injectors from a 3800SC and if I remember right there were very little tuning changes below 100kPa that I had to make.

[This message has been edited by brian89gp (edited 01-13-2014).]

Fierobsessed JAN 20, 03:05 AM
I'd love to look at your $DF code. Curious though, why go through the troubles of adapting DF? I know it's an improvement over the existing 8F, but is it worth the effort? 8F is ok, I haven't really had much trouble trying to get it to do what I want. DF does have the advantage of being manual, and is compatible with my EGR...
brian89gp JAN 22, 09:16 AM

quote
Originally posted by Fierobsessed:

I'd love to look at your $DF code. Curious though, why go through the troubles of adapting DF? I know it's an improvement over the existing 8F, but is it worth the effort? 8F is ok, I haven't really had much trouble trying to get it to do what I want. DF does have the advantage of being manual, and is compatible with my EGR...



I'll dig it up this week. One other thing that I just remembered, I ran two MAP sensors, one 1 BAR as a dedicated barometer that was open to the atmosphere and one 2 BAR for manifold pressure. The barometer calculation in 8F I considered inadequate.

Which is more difficult, retuning all of 8F for a different engine? Or modifying DF but leaving the tuning for stock 0-100kPa untouched?

1. It is already tuned for the DOHC, and a turbo doesn't change most of the tuning. You get an instantly drivable car that you only have to tune for boost and tweak in a few other spots
2. The DOHC with a manual trans can be interesting to tune to be hospitible when done from scratch
3. Stock the RPM range on the tables is higher

[This message has been edited by brian89gp (edited 01-22-2014).]

Fierobsessed JAN 23, 12:09 AM
Sounds good! I'd definitely give it a shot, just so long as the code doesn't require the extra SRAM of the 9396. I'll take a peak at BCFA and look at it's memory map.

Thanks!
Fierobsessed JAN 24, 07:29 PM
Looking into using $DF, BCFA based...
I found one possible issue in the memory map. L0200. I don't believe the 7730 has access to that address, it is written to but disabled from reading by calibration (manual transmissions only). It's towards the end of the code not sure what it does, all I know is that it appears to only be able to write $00 to it. Since it is always zero, not having any storage hardware at that address may not be an issue at all.

In the meantime I managed to calibrate my Speedometer.

My old Getrag was a 30 tooth reluctor, so I worked around that number:
225/45/17 tires are 25" diameter, so 78.5" circumference.
That's 807.13 rotations per mile, times 30 reluctor teeth is
24214 pulses per mile. So 24K PPM. Got it.

So, the first thing I did was set my IP Pulse divisor to 128 ($80)

My notes on pulse divisors...
A B C
0 = 0 = 0 0 0 Divide by 1 (4000 ppm VSS)
4 = 128 = 1 0 0 Divide by 6 (24000 ppm VSS)
2 = 64 = 0 1 0 Divide by 7 (28000 ppm VSS)
6 = 192 = 1 1 0 Divide by 8 (32000 ppm VSS)
1 = 32 = 0 0 1 Divide by 9 (36000 ppm VSS)
5 = 160 = 1 0 1 Divide by 10 (40000 ppm VSS)
3 = 96 = 0 1 1 Divide by 11 (44000 ppm VSS)
8 = 224 = 1 1 1 Divisor disabled, no output

Wiring and configuration of the Dakota Digital SGI-5C module

Power and Ground are straight forward.
Sensor ground: I wired to the Purple wire from the VSS
Input: I wired to the yellow wire from the VSS
Out 1: goes straight to Pin B10 on the ECM
I deliberately left pin B9 on the ECM OPEN. It is already grounded inside the ECM.
ECM pin B11 goes to the pull-up circuit, here:


The calibration switches are all turned OFF.

First I started with the calibration I first thought would be accurate. 6 Coarse, 9 Fine. Which is a calibration factor of .383.
By dividing the 30 teeth of the getrag's reluctor, by the 78 teeth of the F40's ring gear/reluctor. I got .384; .383 was the closest setting.

I verified accuracy on a police speed display, which seemingly to be perfectly accurate according to our other vehicles.

So now my speedometer is accurate. Worked like a charm. Now I just need to fix my road speed constant so that the ECM MPH matches the speedometer. That should be pretty straight forward.

I'm still tweaking values here and there in the code. Fueling is pretty much bang on. I'm curbing the issue I'm having with knock while shifting by pulling my timing in the 4800+ RPM column so that it is 17 at boost, and 23 at full vacuum. There was a 35 degree peak in between, but now its just a straight line. I think that 35 degree peak while coming off throttle was causing a knock burst. We'll see!
Steven Snyder FEB 11, 01:09 AM
Looking good. It sounds tame in that video, but it sure hauls ass! I've got to come out that way and check out your car sometime.
brian89gp FEB 19, 10:47 PM
Thought that $df requires '9396 but can't say I ever researched it in depth.

Can't figure out how to attach files to this forum. If you PM me your email I'll get them sent over. What I have:
1. HTML files with the assembly changes commented and documented
2. the BIN files I used (125 of them in total) with an Excel spreadsheet documenting the tuning change (and/or assembly change) for each one

[This message has been edited by brian89gp (edited 02-19-2014).]