Importance on Gen4 Virtual Torque?

[smokeshow]

You, uh, you wouldn't be referring to a camshaft's effect on torque due to DCR would you?

Basically.

[SiriusC1024]

From one 'degreed engineer', who types and reads faster than normal humans, to another thanks for the clarification.

[BBA]

I think the basis of his point is using the injector scaling method.

Accurate torque would be beneficial to truncation on shifts and torque converter lockup wouldn't you say? As far as transmissions burning up maybe there was gear hunting/going in and out of lockup on these towing vehicles. Same reason it's smart to disable overdrive while in the mountains (on the pos late 90's-early 00's Ford transmissions anyway).

100% if auto trans. This setting is critical for the trans to have the proper torque signal. Doesn't really effect the motor itself though.

[ns158sl]

You would be surprised how much VT affects Gen4's. Not an easy thing to tackle and I have yet to have a decent handle on it. It is not a Gen5, but definitely similar with idle control. Trans control is a whole another animal. Are there ways to hack a toon to do what you want? Kind of. Guarantee there are underlying drivability issues if VT goes untouched, just depends on the driver/customer whether it is worth to go the extra mile(or 100,lol). I can confidently contribute is that MAP tq needs to match APC tq. Whether to pick APC or MAP for the reference is users choice, but without an engine dyno, you are pretty much inferring data with too many variables. Engine tq in the scanner is not VT data either. Until HPT catches up to EFIlive with "user defined Pids", or atleast more TQ loss tables to reference from, you wont be able to model tq very well from the ECM.

But hey, people have been tooning gen4's since they came out and obviously customers are happy with their toons. To each their own.

[cessnageek]

I agree. Starting to poke around in the VT tables. I've yet to find a method I like for "tuning" them besides guess and check. So far, I've basically just increased torque by the percent torque increase that the dyno plot shows my cam increases torque from 2400RPM and up, and I pulled 20lb-ft at idle, again due to the cam. Whether or not those are good changes, who knows. But I can say the idle torque changes have significantly helped CT downshifts. And adding torque to the VT tables will increase transmission hold pressure, so I don't see much danger in the increases I did in the higher RPM range. Just my 2 cents. Driveability is almost stock at this point, and the VT is what pushed it over the edge.

[Alex14SS]

I agree. Starting to poke around in the VT tables. I've yet to find a method I like for "tuning" them besides guess and check. So far, I've basically just increased torque by the percent torque increase that the dyno plot shows my cam increases torque from 2400RPM and up, and I pulled 20lb-ft at idle, again due to the cam. Whether or not those are good changes, who knows. But I can say the idle torque changes have significantly helped CT downshifts. And adding torque to the VT tables will increase transmission hold pressure, so I don't see much danger in the increases I did in the higher RPM range. Just my 2 cents. Driveability is almost stock at this point, and the VT is what pushed it over the edge.

I find it helpful adding 15-30% to these to help a bit in power, nothing crazy but it definitely shows

[cessnageek]

I find it helpful adding 15-30% to these to help a bit in power, nothing crazy but it definitely shows

Are you being torque limited up high then or something? Not sure how changing VT tables adds power on Gen 4. Or is it transmission related, like it is shifting faster or something?

Got an idle torque tuning idea I'm going to try. I'm going to turn all idle adaptives off, then use my RPM error at idle to adjust VT table up/down accordingly. If I understand correctly, idle air is set by a calculation based on the VT table, so this ought to tell me if I'm close or not. The idle air calc must be based on what the ECM knows the accessory and torque converter parasitics are. I still have stock converter and accessories, so I think this should work hopefully.

[ns158sl]

Are you being torque limited up high then or something? Not sure how changing VT tables adds power on Gen 4. Or is it transmission related, like it is shifting faster or something?

Got an idle torque tuning idea I'm going to try. I'm going to turn all idle adaptives off, then use my RPM error at idle to adjust VT table up/down accordingly. If I understand correctly, idle air is set by a calculation based on the VT table, so this ought to tell me if I'm close or not. The idle air calc must be based on what the ECM knows the accessory and torque converter parasitics are. I still have stock converter and accessories, so I think this should work hopefully.

Pretty much. VT gives a preliminary estimate of requested engine airflow. Other big players would be transmission shifting. There is more that it can affect, but that is the main reasons we would try to calibrate it on a Gen4. What I have found that raising/lowering blindly for a camshaft is counter intuitive and not worth it. Might help with idle a small amount, but without knowing the new spark sensitivity of the engine, then it doesnt really pay to adjust.

Quick forewarning, when you start making large adjustments, your Idle AF adapts will need extensive work depending on the engine modifications.

Again this is more of a deep dive with questionable results. Probably can get away with what everyone has been doing since the e67 came out, just rely on Spark and jack up Idle Minimum AF(for some reason people think this is BRAF like a Gen3)

[cessnageek]

Nice, thanks for the insight. Personally, I'm less concerned with high throttle. Adding the ~5% from the cam and ensuring there is no transmission slip seems good enough for me. Really excited to see what this does for idle though. Seems like idle is actually tunable to some extent, and has the potential to get the last 10% from "drives decent" to "drives like stock." Should be an interesting experiment at any rate.

[Alex14SS]

Are you being torque limited up high then or something? Not sure how changing VT tables adds power on Gen 4. Or is it transmission related, like it is shifting faster or something?

Got an idle torque tuning idea I'm going to try. I'm going to turn all idle adaptives off, then use my RPM error at idle to adjust VT table up/down accordingly. If I understand correctly, idle air is set by a calculation based on the VT table, so this ought to tell me if I'm close or not. The idle air calc must be based on what the ECM knows the accessory and torque converter parasitics are. I still have stock converter and accessories, so I think this should work hopefully.

I'd say trans putput is more present when adjusting these. pick up is wayyy faster