Torque Truncation Table?

[gt90stang]

Hi all,

Has anyone successfully used the Torque Truncation Table FN1119 to remove timing at high RPM in 1st gear with A9L or A9P?

I’ve been fighting getting my timing tables, functions and scalars set and have them so I don’t get any detonation in 2nd or 3rd gear, but I do get light detonation at the 1-2 shift at WOT. I’ve tried pulling more timing without affecting overall power in 2nd and 3rd , but I have to pull way too much for overall performance. I’m hoping with FN1119 I can fix this because:

At Wide Open throttle, SAF is determined from the following equation.
SAF = FN131 + FN133 + FN134 + KWS1 + FN135 - 'C'

N > TTNOV * VSBAR --------------------------| Torque Truncation Spark
| 'C' = FN1119
|
| --- ELSE ---
|
| 'C' = 0

With my AOD in first (2.40) with 275/40R17s and 3.73 gears my RPM/MPH or N/V = 117.7 @ 4K RPM and 34 MPH. From what I’ve read here from fireguy50, 86GT, Cougar5.0 and others it seems that the numbers in the FN1119 table at the appropriate RPM/Load points should be positive because they are subtracted (- ‘C’) from the timing equation. Right? The address for TTNOV for my A9P is 0x7430h according to 86GT. Anyone know what the default TTNOV is for A9P? (I think it is zero) What type of number format is it? If TTNOV = 0 then it seems the PCM is always using FN1119 (with zeroes in all the cells), so it just won’t work putting numbers in cells as they would always be used at the appropriate RPM/Load of FN1119 without changing TTNOV.

The other bummer is I don’t have a way to edit TTNOV in my tune, so is there another way to just pull timing in 1st at high RPM?

Thanks, Don

[Cougar5.0]

I am using the TTNOV to remove timing in first gear to make 1st usable. I'm also hoping to dial in the timing removal vs RPM & load to get a perfect launch using a KB at the track - will find out soon as I already have the tunes on different switch positions on my Tweecer (I hate April showers). I'm using the TunerPro editor to create a program with the proper TTNOV multiplier. The default TTNOV in A9L is 255 - but even that is deceptive as I have learned (through trial and error) that the multiplier for this function is 4. So the A9L default is actually 1020 making the function irrelevant. My current TTNOV is 160 (40) with tremec & 3.73's - it works like a charm though it still takes some getting used to as I'm pulling a full 10 degrees of timing at torque peak! It's like two different motors when shifting from 1st to second. If I can just get the torque to apply properly to keep the tires on the edge of traction I should be able to achieve some stunning launches. I feel like I devulging a big secret here - maybe I'll self destruct this post in 2 days :D

[gt90stang]

Cougar5.0,

Thanks for the info. I toyed with this for a while on paper and found that you should calculate TTNOV for 1st and 2nd gear then use the average of those two numbers. Now I'm working on figuring out how to edit my Tweecer file :baby: for TTNOV.

Thanks, Don

[Dale McPeters]

Now I'm working on figuring out how to edit my Tweecer file :baby: for TTNOV.

Thanks, Don

:lol:

Edit a true binary file and then load it in the TwEEcer.

[gt90stang]

Dale,

No problem, was wishing I could just edit the .ccf file as it has many many changes from stock :drool:

Anyways I did figure the easiest way to calculate TTNOV. Use this equation:

TTNOV = TRM * TGR *RGR / 60

TRM = Tire Revolutions per Mile
TGR = Transmission Gear Ratio
RGR = Rear Gear Ratio

You'll notice that TTNOV doesn't change with RPM.

So calculate for 1st and 2nd gear ratios and average the two to get TTNOV. Then divide that by 4 (thanks Cougar5.0) and choose the closest integer, then convert to base 16. Hopefully this is a single byte variable. Is this right? :popcorn:

Don

UPDATE: check out this spreadsheet for TTNOV calculations:

http://www.geocities.com/dbennettya/Mustang_PCM/TTNOV2.xls

[gt90stang]

Got Her Done! :banana:
Used TunerPro binary editor to edit a stock A9P bin file. For my AOD, 3.73s and 275/40R17s TTNOV = 96. So 96/4=24 and 24d = 0x18h which I put into 0x7430h then saved the new bin file. Then I used Caledit to pull in all the functions and tables that I modified and lastly had to manually edit all the scalars to my mods. I also had to edit FN1119 to put the timing to be removed from 1st gear in my case 8* at load=1 and 4* at load=0.75 both at 4K RPM and above. Works like a champ pulling 8* at WOT in 1st and not 2nd or above. :chug: It really feels weird because it is full on until 4K RPM and then softens a bit until the shift then it is full on again.

YMMV, Don

[Dale McPeters]

Got Her Done! :banana:
Used TunerPro binary editor to edit a stock A9P bin file. For my AOD, 3.73s and 275/40R17s TTNOV = 96. So 96/4=24 and 24d = 0x18h which I put into 0x7430h then saved the new bin file. Then I used Caledit to pull in all the functions and tables that I modified and lastly had to manually edit all the scalars to my mods. I also had to edit FN1119 to put the timing to be removed from 1st gear in my case 8* at load=1 and 4* at load=0.75 both at 4K RPM and above. Works like a champ pulling 8* at WOT in 1st and not 2nd or above. :chug: It really feels weird because it is full on until 4K RPM and then softens a bit until the shift then it is full on again.

YMMV, Don

TunerPro works great for things like this that Mike has not made available
in Caledit for the more advanced users. Paul B. also has a new version of
his EEC-Editor out too, that you can build you own definition file. I have just went back to using Moates chips and using TunerPro & EEC-Editor for the son & daughters cars as it saves a lot of time and effort.

Glad you got it done.....;)

-Dale

[Cougar5.0]

Got Her Done! :banana:
Used TunerPro binary editor to edit a stock A9P bin file. For my AOD, 3.73s and 275/40R17s TTNOV = 96. So 96/4=24 and 24d = 0x18h which I put into 0x7430h then saved the new bin file. Then I used Caledit to pull in all the functions and tables that I modified and lastly had to manually edit all the scalars to my mods. I also had to edit FN1119 to put the timing to be removed from 1st gear in my case 8* at load=1 and 4* at load=0.75 both at 4K RPM and above. Works like a champ pulling 8* at WOT in 1st and not 2nd or above. :chug: It really feels weird because it is full on until 4K RPM and then softens a bit until the shift then it is full on again.

YMMV, Don

Alright! It's pretty bizarre huh? I have mine pulling up to 10 degrees at a peak torque because I'm trying to eliminate tire spin. It totally kills the motor's power in 1st!

Oh, and thanks for the link to the spreadsheet - it's more convienient than calculating based on my datalogs. I like how you check the points at multiple RPM's even though you know it's a constant :D I was the same way - I manually verified several RPM's by hand - hmmm, it comes out the same no matter what RPM! :lol:

[gt90stang]

Cougar5.0

How's the torque reduction working? I might try it if it works good.

Don

[gt90stang]

Bump

Cougar5.0

How's the torque reduction working? I might try it if it works good for reducing tire spin. :popcorn:

Don

[QWKSNKE]

Is it safe for me to assume that is only an item modified in auto cars?

[sailorbob]

Because it's the ratio of vehicle speed to revs the eec can apply it to manual cars too.