Just as the title says, I wanted to know what the RPMs of your 4-Speed Magna while you are doing 100 Kmp/h....
I was interested to know if if increased torque lowered the RPM through the clever O/Drive.
I've heard some earlier 4 speeds did about 2200 RPM...
And there no harm in getting that info either, its just the TL/TW I'm really interested in...

My TL 4 speed does 2100 rpm @ 100kph with standard tyres and rims.

Thanks, Oh forgot mine, Just under 2000 rpm at 100, just slightly less again with newer, fuel efficient tyres.
235/40/18's.

Same four speed behind the 3.5 since the 3.5 came out. There was a 3 litre 4 speed out that had different ratios and lower overall gearing.

Nothing you can really do to alter the overall gearing on these cars. Not easily that I know off. Maybe swap the diff' ratios out, but even then I'd say you'd very limited. And it wouldn't be cheap.

The "clever overdrive" is just the torque converter locking up. Takes out the slip in the fluid coupling. Meaning, more torque wont change anything. Its load controlled, so maybe it would lock up a few hundred RPM earlier?

The overall gearing of the 4 speed auto is just fine for the 3.5

Your rpm...
The rest we know, but thanks....
I'm looking for differences.....

Hey Skapper, question for you, if the load sets the torque converter, would the load be met by the work effort of a motor, the work effort (torque) would be met by a torqueir motor at a lower rpm, would that be right...???
I'm just trying to figure out the variances here.
Otherwise, we'd all be doing the same rpm's.
I'm a,bit out of my depth here, but I thought the two were related.

Work effort, increased torque - still the same transmission. Its fixed ratios that we're working with, there would be some variances in torque converter slip ad transmission efficiency but the point is with those ratios you will always get a certain RPM @ 100kmph (not allowing for tyre diameter differences).

Increases engine performance are unrelated to the mechanics of a transmission.

I don't have a TL/TW four speed. I have a TJ (with a TE transmission apparently) that does the usual 2100rpm @ 100kmph.

I think I need to run a few experiments.
Where are the RPM in O/D when accelerating from 90 to 100 -
Simulate loads long uphills
RPM @ 100
RPM from 90 to 100.

I'm guessing the ECU calculates loads from the TPS (throttle position sensor) and road speed.
But I wouldn't mind a bit more TW 4 speed info.

The only other thing, would be minor tweaks in the ECU or the trans in a TW.

Just to let you know my train of thought here, if the load is calculated by the ECU, using the TPS ( maybe manifold vaccuum as well), gear, and road speed, a torquey motor require less pedal to maintain certain speeds. (Hence the work effort).

I am looking for the reason why my TW does 2000 RPM @ 100.

There was some info at where the trans locks up in O/D but I can't find it.

Thanks, Oh forgot mine, Just under 2000 rpm at 100, just slightly less again with newer, fuel efficient tyres.
235/40/18's.

My TW wagon is the same on factory 16's.

Thanks, that helps....

Still trying to sort out out a thing or two...
I wonder if the KW and TW VRX differ from KL and TL VRX - RPM @ 100....

Is that a gearbox or the ECU for the difference in the TW's....

Torque makes SFA difference at 100, just hold the gears a bit better uphill before kicking down....
Its weird to hold the tippy in fourth, @ 80 kmph, punch accel the build RPM to 2000, and watch the speedo wind from 80 to 100 while the tacho stay at 2k.
Wont do that very often, (never again actually) apperently builds a up a lot of heat through the TC... Only took a few seconds tho....

Anyone shed some light on the real difference tween the TL and KL......

Don't forget tyre circumference - my TL has 205/65R15 tyres....KL I think has 16" tyres so maybe their rolling circumference is 5% different which would account for 100rpm difference @ 100Kph.
Also I'd figure that speedos and tachometers in mass produced cars are not exact instruments....so allow a tolerance there as well.

Valid points.
Rolling difference, 15" to 18" is 0.4%, mine was smaller Also GPS says 96 actual to 100 indicated.....Pretty much what everyone else gets on properly sized tyres...
I've had the the luxury of 2 clusters, both the same, and I reckon the speedo's on 90% magna's would within 1 % of each other...
Plus the other TW was 2000 RPM@100....
More info, More TW's

I've gained the impression that there's some variability in the stall speed of torque converters which might be part of what you're seeing. I can't recall the source but the figures for the TJ AWD I've seen were 1800-2200rpm (stock). The stall speed seems also dependent, at least to some degree, on engine torque.

I've not been able to pin down exactly how the torque converter lock-up is activated, but based on the behaviour of my mildy modded setup it definitely is torque sensitive. Before the mods I was never aware of the lock-up operating, now its quite irritating. I do know that the lock-up will not operate until the ECU determines that the ATF is at a sufficient temperature (took about 6 minutes at 110kmh on the Stuart Hwy from an overnight stop at Coober Pedy in winter for it to activate, though I do have a cooler fitted).

The lock-up operation also appears to be different between tippy mode and full-auto mode, reflecting the driving intent in the different modes.

Thats right Shoot, when i checked my stock 4spd wagon it was on 2200rpm till it warmed & locked up.

Never notice it in my "improved" AWD, but apart from the rare times the Mrs drives it, it only gets driven in tippy mode....(the last 30k)

Its weird to hold the tippy in fourth, @ 80 kmph, punch accel the build RPM to 2000, and watch the speedo wind from 80 to 100 while the tacho stay at 2k.
Wont do that very often, (never again actually) apperently builds a up a lot of heat through the TC... Only took a few seconds tho....



That's normal behaviour and doesn't upset the torque converter.
In the TS V6, I can get it on 2,000 rpm from takeoff, and sit on 2,000 rpm all the way up through the gear changes to 80 KPH before the revs start to go up. Like I said, normal behaviour.

Torque converter stall speed - easy way to find out what it is for your car, is to be stationary, left foot on brake (hard), select drive, punch the accelerator. Where ever the tacho needle points to, is the stall speed. Do it quick and no harm is done.

I've not been able to pin down exactly how the torque converter lock-up is activated, but based on the behaviour of my mildy modded setup it definitely is torque sensitive. Before the mods I was never aware of the lock-up operating, now its quite irritating. I do know that the lock-up will not operate until the ECU determines that the ATF is at a sufficient temperature (took about 6 minutes at 110kmh on the Stuart Hwy from an overnight stop at Coober Pedy in winter for it to activate, though I do have a cooler fitted).

.

Just out interest, here is a snip from Marks 4WD who fit Commodore engine to 4WD's and would be similar to Magnas. :
The Commodore automatic transmission has an in-built torque converter clutch, which reduces the efficiency loss of the automatic transmission by manually coupling the input shaft to the engine, under certain load conditions. These conditions are met when the engine coolant temperature is above 42°C, the vehicle speed is above 72 Kph, and the throttle is open. Without a vehicle speed reference this function is not possible.