Torque management in action

[emarkay]

This snippet is about 700 frames, or approx. 7 seconds.

Starting from left, with about 2% to 100% throttle (floored!), you can see the transmission downshift into first, as RPM and VSS start to climb. Then as PCM calls for tranny to upshift into second, note the spark advance - it goes from the +25 range to -5 for a FRACTION of a second as the tranny shifts, as indicated by the RPM drop. Also note the (insignificant) 0.4 of KR.

Those who think TM is a major ET limiter or HP killer, can see why it's not that big of a factor, and why leaving it alone, if modifying your PCM program, is a good idea for the life of the car.

Now if you have substantially modified the drivetrain..... :)

http://www.efilive.com/upload/public/emarkay/images/tminaction.png

[joecar]

Yes this makes a good case for leaving TM enabled so it can protect the driveline :!:

Even with a modifed driveline, the trans life still can be extended with TM enabled; most people who modify the driveline also modify the engine so the same reasoning applies over again;

:wink:

[bink]

This snippet is about 700 frames, or approx. 7 seconds.

Starting from left, with about 2% to 100% throttle (floored!), you can see the transmission downshift into first, as RPM and VSS start to climb. Then as PCM calls for tranny to upshift into second, note the spark advance - it goes from the +25 range to -5 for a FRACTION of a second as the tranny shifts, as indicated by the RPM drop. Also note the (insignificant) 0.4 of KR.

Those who think TM is a major ET limiter or HP killer, can see why it's not that big of a factor, and why leaving it alone, if modifying your PCM program, is a good idea for the life of the car.

Now if you have substantially modified the drivetrain..... :)

http://www.efilive.com/upload/public/emarkay/images/tminaction.png


One pic = 1000 words! Thanks emarkay.
joel

[BowlingSS]

What about removing the TM when installing a torque converter? I have heard of a lot of people doing this after adding a TC.

BowlingSS
:shock:

[emarkay]

TM protects the transmission AND MORE IMPORTANTLY the differential..... :)

[farmtruc]

TM is EVIL!

It regulates torque output to the wheels, who wants that :?:

[Drake]

Hoo boy... it'd be nice to get a definitive answer on this.

[farmtruc]

TM will affect other vehicles differently, in this case a camaro was used as an example, but you ask any late-model truck owner and he'll disagree.
TM will have little affect on a corvette, some on an f-body and greatly reduce power and slow you down in the 1/4 mile for the trucks.
TM will slow a truck down so much, once the mods start, it will literally keep you powerless for about a second when it's doing its job.
The electronic throttle body equipped vehicles really take a beating from TM.
Just my opinion, but if you have a stock trans, remove about 60%, a shift kit 100% or if you don't care 100%.
There are a lot of drivers out there with no TM and they haven't had any problems.

later,

[Brains]

On my 1998 Formula, 6-speed, it wasn't TOO bad unless I really banged out a fast powershift. It'd then literally take a few tenths of a second to get the timing back, and that's time better spent pushing the car down the street/track. On my 2004 GTO A4, TM is (was) a MONSTER. The performance gain between with and without is incredible. As far as protecting driveline components, the rear end is much less likely to break on a shift (especially in automatic trans vehicles) than it is on the launch. Bringing the transmission into the picture, the 4L60e's weak link is maintaining enough apply for the high gear (3/4) pack. I left TM in place for the 2-3 and 3-4 shift, but eliminated it entirely for the 1-2 shift. The band is not only plenty strong, but in the (unlikely) event it ever failed its damned near the easiest component in the transmission to replace :)

[Bruce Melton]

I wonder if they migrated this TM to the MN6 C6? I hear there is something going on with them that is kicking power back under stress???

[farmtruc]

I read a little bit on the c6 auto trans controller, and if i'm not mistaken, the vette has a separate controller for the trans.
that'll be intersting.

[oztracktuning]

It made my Torque Converter equipped car change weird when i reenabled it. I had to turn it off again. It doesnt change hard anyway.

[MN C5]

TM will slow a truck down so much, once the mods start, it will literally keep you powerless for about a second when it's doing its job.
The electronic throttle body equipped vehicles really take a beating from TM.
Just my opinion, but if you have a stock trans, remove about 60%, a shift kit 100% or if you don't care 100%.
There are a lot of drivers out there with no TM and they haven't had any problems.

later,

So do you think a properly tuned PCM with TQ reduction on the up shift is going to kill your ET? I don't, but I haven't experienced being ""powerless for about a second"" either

Assuming your refering to the Throttle Position along with a reduction in timing being responsible, do you have any logs that show it happening? I'd be interested in seeing those logs. I just haven't seen this when tuning with Flashscan... When I was tuning with LS1Edit I recall this happening though..

I do agree with keeping some TQ reduction for the upshifts for a stock tranny. And IMHO for built ones too.

[joecar]

If you have an A4, the amount of TR is tunable for each gear shift.
For a daily driver, you don't want to whack the drivetrain hard on every shift.

One possibility:
tune TR so that you have some TR at non-WOT torque levels, and less at WOT torque levels
(on the street you don't use WOT often).

TR drops the spark timing for a split second (I measured about 0.2s or less);
if you're seeing power loss for much more than this then somethings else is wrong, like MN_C5 said.
Or maybe the TR curves on trucks have very large values...?

Edit: or maybe traction control is getting it's piece...?
Edit: or desired shift time is too slow and shift pressure too low...?

[joecar]

It made my Torque Converter equipped car change weird when i reenabled it. I had to turn it off again. It doesnt change hard anyway. Thinking out loud:
Stall converter slips more than stock converter, so reducing torque makes it unstall (stall 'intensity' depends on torque input);
you're right, don't really want too much (or any...?) TR with a stall converter;
but a stall converter launches harder (at higher RPM), so one would suppose your rear axle is up to taking it.

On the other hand, stock axle is weaker, so some TR is good thing in this case.

[oztracktuning]

My rear axles have been off and inspected - the splines were 'like new' and that is after about 80 races at 1.65 60 footers.

[joecar]

My work mate chewed a few teeth off the ring gear of his stock diff,
and I've seen a few others too, and a few transmissions with broken hard parts,
so I like to be a little cautious.

Over here in the US, F-body differentials have been known to be a little weak.

But, it looks like your diff and trans are doing good, so no worries mate.

Cheers
Joe
:cheers:

[Danville Performance]

On my 1998 Formula, 6-speed, it wasn't TOO bad unless I really banged out a fast powershift. It'd then literally take a few tenths of a second to get the timing back, and that's time better spent pushing the car down the street/track. On my 2004 GTO A4, TM is (was) a MONSTER. The performance gain between with and without is incredible. As far as protecting driveline components, the rear end is much less likely to break on a shift (especially in automatic trans vehicles) than it is on the launch. Bringing the transmission into the picture, the 4L60e's weak link is maintaining enough apply for the high gear (3/4) pack. I left TM in place for the 2-3 and 3-4 shift, but eliminated it entirely for the 1-2 shift. The band is not only plenty strong, but in the (unlikely) event it ever failed its damned near the easiest component in the transmission to replace :)

Well I don't know about you but I have an exploded posi and carrier and gearset because of the lack of tm on upshift. If you are making any serious amount of power than it is a really good idea. Our 02 silverado's rear posi exploded on a full throttle upshift from first two second and it wasn't pretty. We where only at about 450hp and don't have tm enabled. The diff had 60,000 miles on it when it let go. Now that we are charged we have backed the one to two shift down a bunch to make it last longer. TM will make the drivetrain last much longer. On the trany (4L60E) when you start uping the power the band is the first thing that goes because it doesn't have the surface area or servo to apply it fast enough or hard enough to stop the momentim of the drum. If you want it to handle any amount of power you need to rebuild the whole thing with quality parts that can handle the abuse.

[Brayden]

Danville Performance huh? You guys do 4x4 car conversions too?

Hehehehehehe

Gotta get DJ's truck on the dyno.. I put 452/875 down last friday..:)

[Danville Performance]

Yeah we need to get it on the dyno so we can fine tune with the wideband once we get the lock up convertor figured out. Should be interesting to see! How did you like the ride??? Pretty crazy for a stock 5.3L with stacked chips! HEHEHEHEHEHEHEHE!

[Brayden]

The only stacking going on in that trucks is with the bills... LS6 crate motor,MP112 Radix Maggy intercooled, rear end, tires, tires, tires, tires, tires, diffs, tires :)

I'm gonna have to get another turbo now.. Fockers :)

[Danville Performance]

Better get two just to be on the safe side. Hehehehehe! You should hear it with the dump plate off, sounds like a nascar!

[Brayden]

Well I've already got one.. Two will do just fine I'd say

[joecar]

Some pictures (from my friend's car)... Ouch..!!:bawl::bawl::bawl::bawl:

[agreif]

Hey, is there any way I can get a look at this graph again?

Thanks,
Andrew

[joecar]

Andrew,

The diagrams were lost when the forum went to a new engine.

The diagram showed that during a gear shift, the spark advance went to something like -5 degrees for about 0.2s and then went back to 25 degrees;

the point being that torque is reduced only for a very short time;

the amount of torque reduction is programmable, there are tables for this in the transmission calibration.

[Travis@FIR]

Does TM affect throttle plate opening between shifts on Electronic TB equipped vehicles? The timing drop explains the "pop" that I'm getting between shifts.. but I was wondering about the throttle plate opening/closing. Also.. under partial throttle/boost situations.. the ECM sometimes goes into "reduced power mode". Turning the key off, and then back on again, fixes the problem. This is a turbocharged 4.2 liter (I6) Trailblazer.. Can't wait to get some tuning options!

Travis

[GMPX]

Sounds just like what happens with the ETC LS1's. Should be fun getting these sorted.

Cheers,
Ross

[Black LS1 T/A]

When I had torque reduction enabled, on the track, each shift (an A4), I could see the nose dive down (like a granny-shift) and come back up. :nixweiss: It was a tight race, and I barely beat the guy. With TM disabled, the car shifts without this dip, and I often can't tell exactly where it shifted without checking the logs... it's that quick/seamless.

Though I had a dip, would it REALLY make much difference in ET? I can't say. I just don't run enough to get that statistic nailed down pat. But, trust me, when your car is making excess of 500 RWHP and 700 RWTQ, you can tell the difference when timing is cut like that. :Eyecrazy:

Keep in mind, I'm also the guy tht's putting his 4L60E back in this week (for the 5th tme in two years). :bawl:

[Travis@FIR]

Sounds like it's time to switch to a 4L80E... ;)