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Who can tell me a little more about the operation of the torque converter? I recently did a trip over to Coffin Bay from Melbourne with our light weight CT in tow. The trailer was probably around 1.0 - 1.1T and the rear of the car was lightly loaded.
I had plenty of time / kms to take note of a few things, one of the things I noticed was that the torque converter appeared to always be locked when 'cruising' at speeds above 118km/h in 5th. If you put the boot into it then it would change back to 4th, if you accelerated harder but smoothly it would stay locked up and gradually accelerate.
At lower speeds I found that I had to be below about 104 to keep it locked up most of the time in 5th, it would still unlock of course when accelerating mid up hills and change to 4th if hard accel.
So, speeds from 104-110 saw the converter hard to lock up but possible down a slight hill and then if you eased back onto the gas on the next flat it might stay locked up.
From 110-118 it wouldn't lock up on a flat.
So - is there an RPM limit in X gear that forces the converter to lock regardless of other parameters? It seemed like this was the case at 118km/h in 5th. If so, is this an economy decision or to protect the converter from excessive work (heat)?
The result was that the RPM was lower at 118 in 5th than it was at say 106 in 5th.
I also found on a few legs that the economy was no worse when at 118+ than if I sat in the 105-108 range. I assume due to the RPM.
An important factor here - I use 265/75 tyres and I am trying to decide with my setup (light weight CT) whether my economy will improve much if I drop back to the 265/70 tyres next time around. When I bought the tyres the 75 series was cheaper and they fill the guards much sweeter and any benefit with foot print is always nice.
My best ever economy for the vehicle was the 1st time I drove the car back from NSW with 265/70 tyres, down the Hume with cruise set on 120km/h, which was 7.8L / 100 - no passengers, no trailer.
My worst on the highway was on this trip at just over 16L / 100 which was both at the 118+ and on a separate tank @ 108.
Best on the trip was the last tank back into Melb on Easter weekend from Horsham at 103 (100 zone) and 113 (110 zone) although I also had the down hill runs from Ballarat in my favour. I haven't actually filled it yet but am guessing by the kms it's somewhere in the 13L / 100 range.
I do a lot of driving with the trailer at around the 110 mark. An idea I had was to put in a torque converter lock up switch. Based on the economy results at 118 it would seem worth it for typical speeds of 110 - anyone ever done that before? I contacted Wholesale Automatics and asked, they haven't done it before, I offered my car as a bunny car but they barely shifted on a high price.
Who can tell me a little more about the operation of the torque converter? I recently did a trip over to Coffin Bay from Melbourne with our light weight CT in tow. The trailer was probably around 1.0 - 1.1T and the rear of the car was lightly loaded.
I had plenty of time / kms to take note of a few things, one of the things I noticed was that the torque converter appeared to always be locked when 'cruising' at speeds above 118km/h in 5th. If you put the boot into it then it would change back to 4th, if you accelerated harder but smoothly it would stay locked up and gradually accelerate.
At lower speeds I found that I had to be below about 104 to keep it locked up most of the time in 5th, it would still unlock of course when accelerating mid up hills and change to 4th if hard accel.
So, speeds from 104-110 saw the converter hard to lock up but possible down a slight hill and then if you eased back onto the gas on the next flat it might stay locked up.
From 110-118 it wouldn't lock up on a flat.
So - is there an RPM limit in X gear that forces the converter to lock regardless of other parameters? It seemed like this was the case at 118km/h in 5th. If so, is this an economy decision or to protect the converter from excessive work (heat)?
The result was that the RPM was lower at 118 in 5th than it was at say 106 in 5th.
I also found on a few legs that the economy was no worse when at 118+ than if I sat in the 105-108 range. I assume due to the RPM.
An important factor here - I use 265/75 tyres and I am trying to decide with my setup (light weight CT) whether my economy will improve much if I drop back to the 265/70 tyres next time around. When I bought the tyres the 75 series was cheaper and they fill the guards much sweeter and any benefit with foot print is always nice.
My best ever economy for the vehicle was the 1st time I drove the car back from NSW with 265/70 tyres, down the Hume with cruise set on 120km/h, which was 7.8L / 100 - no passengers, no trailer.
My worst on the highway was on this trip at just over 16L / 100 which was both at the 118+ and on a separate tank @ 108.
Best on the trip was the last tank back into Melb on Easter weekend from Horsham at 103 (100 zone) and 113 (110 zone) although I also had the down hill runs from Ballarat in my favour. I haven't actually filled it yet but am guessing by the kms it's somewhere in the 13L / 100 range.
I do a lot of driving with the trailer at around the 110 mark. An idea I had was to put in a torque converter lock up switch. Based on the economy results at 118 it would seem worth it for typical speeds of 110 - anyone ever done that before? I contacted Wholesale Automatics and asked, they haven't done it before, I offered my car as a bunny car but they barely shifted on a high price.