Possible? Ignition cut while shifting automatic gearbox like 8hp

[loskani]

Hello,

is it possible make ignition cut / ignition retard while shifting like in 8hp (dodge, audi, bmw) for FORD 10 speed auto?

thx

[engineermike]

Yes, I’ve done it.

[loskani]

Min Spark Tq Ratio ?

[engineermike]

You basically have to force the SAI system to skip S and A and go straight to I. To do this, you'd have to set Shift Modulation to 1.0 in table 33458 (spark only torque ratio) and confirm Shift Modulation is set to 1.0 in table 44775 (fuel cut torque ratio). Then start lowering trans torque modulation for the particular gear change, rpm, and torque level where you want it to occur. Keep lowering it until you get the effect you want. It sounds better when the shifts are quicker so you might play with the character assignments as well. One other thing, I've been told that 33456 can also be used to do this, but I haven't done it so I don't know how to set it up and what the effects are.

[veeefour]

You basically have to force the SAI system to skip S and A and go straight to I. To do this, you'd have to set Trans Tq Trunc to 1.0 in table 33458 (spark only torque ratio) and confirm Trans Tq Trunc is set to 1.0 in table 44775 (fuel cut torque ratio). Then start lowering trans torque modulation for the particular gear change, rpm, and torque level where you want it to occur. Keep lowering it until you get the effect you want. It sounds better when the shifts are quicker so you might play with the character assignments as well. One other thing, I've been told that 33456 can also be used to do this, but I haven't done it so I don't know how to set it up and what the effects are.

you mean shift modulation? Truncation is never used.

[engineermike]

you mean shift modulation? Truncation is never used.

Yep, my mistake....fixed it.

[RobCat030]

I'm pretty sure these methods are ignition retard only. Ive only been able to do ignition cut via assembly code patch

[engineermike]

Rob, the method I posted above prevents it from using S (spark retard) and A (air/fuel) to modulate torque. It has to resort to I (ignition cut) to reduce shift torque. I’ve tested it and it works after a few iterations using different torque modulation values. However, like most “novelty tuning”, I wind up putting it back normal after driving for a bit.

[RobCat030]

Interesting. I wasn't certain if it actually cuts power to the coil entirely, or just modulates the dwell angle/time in some way. My efforts weren't producing an actual cut without actually forcing the ignition driver to zero

[veeefour]

Interesting. I wasn't certain if it actually cuts power to the coil entirely, or just modulates the dwell angle/time in some way. My efforts weren't producing an actual cut without actually forcing the ignition driver to zero

You can get close to zero but somehow it will never go completely to zero to produce a hefty burp - no matter what ford made sure it wont happen.

There are multiple ingredients to cook this soup: torque delta, min spark, modulated torque, arbitration, ramp rate...instead using simple spark cut like others.
Pls share more about that patch of yours, you can email me directly if you dont wont to go public. Ill share my findings in returr.

[RobCat030]

Thanks for confirming that for me. No problem discussing patches here. Ford OS has few or no instances of cutting the ignition driver entirely, but Bosch hardware does allow it. By inserting a custom function in assembly code, you can trigger an ignition cut via something like CC Cancel button and build endless boost on turbo cars. It's extremely violent and on a few test cars we snapped the turbo mounting studs right off the turbo manifold. A mass-produced solution would have to be much more polite in order to not break components

[veeefour]

Thanks for confirming that for me. No problem discussing patches here. Ford OS has few or no instances of cutting the ignition driver entirely, but Bosch hardware does allow it. By inserting a custom function in assembly code, you can trigger an ignition cut via something like CC Cancel button and build endless boost on turbo cars. It's extremely violent and on a few test cars we snapped the turbo mounting studs right off the turbo manifold. A mass-produced solution would have to be much more polite in order to not break components

Same as PCM tech doing in their custom OS. Somehow GT500 shifts nicely and its not just DCT - tried to implement changes but to no avail.

Willing to share that code?

[RobCat030]

Probably not at the current moment until I can devise a way to ensure it doesn't get wh*red out on MHH

[veeefour]

Probably not at the current moment until I can devise a way to ensure it doesn't get wh*red out on MHH

What if I tell there is a way to do that with what you have in HPT currently?