Thoughts on 8 speed auto
Discussion
Two years ago I had a 8 speed Merc on Hire for a road trip round Norway, had a gear indicator and I never saw it in 3, 5 or 7th unless i used the manual mode, it acted as a 5 speed Auto.
My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
Berw said:
Two years ago I had a 8 speed Merc on Hire for a road trip round Norway, had a gear indicator and I never saw it in 3, 5 or 7th unless i used the manual mode, it acted as a 5 speed Auto.
My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
My conclusion - your comparison is pretty much worthless. The only valid comparison would be to test the same vehicle with a 6-speed or 8-speed transmission. My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
My 340i has an 8-speed transmission and, left to it's own devices, will always head for 8th when it can. Currently it's returning an average of 33.6mpg. Compare that to the pair of 335ds I had before fitted with 6-speed autos - 37.2/37.4mpg. Now to me, getting nearly 34mpg from a 3-litre turbo petrol is pretty good, so I'd say the 8-speed transmission is pretty good at its job.
Berw said:
Both cars live on duel carriage ways, neither has ever been in 4WD.
There's your answer right there. They're both in top gear most of the time anyway. There will be little difference in those conditions Unless of course you actually mean duel instead of dual and you're settling scores with deadly weapons
Berw said:
Two years ago I had a 8 speed Merc on Hire for a road trip round Norway, had a gear indicator and I never saw it in 3, 5 or 7th unless i used the manual mode, it acted as a 5 speed Auto.
My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
Interesting observation, I think unless your 3.0 Hilux has been mapped the new 2.2 ranger has marginally more torque 265 vs 275 ftlb less power though. My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
Had a 9 speed 2.2 Evoque for a year or so and it was great, towed couple of tons very well always in right gear, old 4 speed auto V8 discovery i have now makes more of a fuss with similar load, but very different tech in the gearboxes, (would have preferred a 5 speed manual disco V8 but they are rare!)
My 8-speed auto uses all of its gears in normal UK driving, and
My 7-speed auto uses all of its gears in normal UK driving
However, it's quite normal to skip gears in my 6-speed manual....
IMO with a properly built auto there's rarely any point trying to use manual selection. The only place I find it useful is to click down a couple of gears ready for an overtake.
My 7-speed auto uses all of its gears in normal UK driving
However, it's quite normal to skip gears in my 6-speed manual....
IMO with a properly built auto there's rarely any point trying to use manual selection. The only place I find it useful is to click down a couple of gears ready for an overtake.
I have a 5 speed auto merc, it's okay, it hasn't gone wrong yet in 140k. You have to drive to it's rhythem rather than trying to make it do what you want. 1-2 change is a bit slow which could be better if the gears were closer I guess. You don't notice the other shifts. Could do with a longer motorway gear too 2000rpm = 60 ish mph. I could imagine the 7 speed is an improvement. The 9 speed sounds a bit much.
Mercedes have never done an 8-speed...
What you had was a 9-speed that you had in Sport mode; i find the low-power C-classes I rent never go into 9th in Sport mode
I must say, in my experience it will go through all 9 gears in all auto modes in normal driving. Were you flooring it to get up to speed then rapidly lifting off? That may do it.
The old 7g takes off in 2nd unless you put it in Sport or floor it - thing is it has 2 gears in reverse too so sometimes it really takes off when you're backing up
What you had was a 9-speed that you had in Sport mode; i find the low-power C-classes I rent never go into 9th in Sport mode
I must say, in my experience it will go through all 9 gears in all auto modes in normal driving. Were you flooring it to get up to speed then rapidly lifting off? That may do it.
The old 7g takes off in 2nd unless you put it in Sport or floor it - thing is it has 2 gears in reverse too so sometimes it really takes off when you're backing up
It's useful where the top gear is taller.
On the Jaguar XF 3.0 Diesel, the 6 speed auto behaves like this:
6th gear at 70mph is around 2200RPM maybe a bit more
on 8 speed auto, it's 1700-1800RPM at 70MPH.
The 8-speed auto is faster shifting etc. But it will always make use of all the gears.
On the Jaguar XF 3.0 Diesel, the 6 speed auto behaves like this:
6th gear at 70mph is around 2200RPM maybe a bit more
on 8 speed auto, it's 1700-1800RPM at 70MPH.
The 8-speed auto is faster shifting etc. But it will always make use of all the gears.
buggalugs said:
I have a 5 speed auto merc, it's okay, it hasn't gone wrong yet in 140k. You have to drive to it's rhythem rather than trying to make it do what you want. 1-2 change is a bit slow which could be better if the gears were closer I guess. You don't notice the other shifts. Could do with a longer motorway gear too 2000rpm = 60 ish mph. I could imagine the 7 speed is an improvement. The 9 speed sounds a bit much.
I’ve got the 9 speed in my CLS. It won’t use 9th much below 75mph which is a little below 1,500rpm, even then it doesn’t use 9th straightaway.Very useful for wafting but kick down usually takes it to 6th or 7th. If I just want to speed up slightly, I tend to manually drop to 8th and let it change up again when it’s ready.
The 8sod I drove in a 330d was lovely and did good of fuel
I’ve got a 6spd dsg in my golf gti which averages around 38-40 on a run
I recently drove a gti with the 7spd dsg and that got 46mpg on the same run
Not a lot of difference on the face of it but on a full tank it’s an extra 60 miles
I’ve got a 6spd dsg in my golf gti which averages around 38-40 on a run
I recently drove a gti with the 7spd dsg and that got 46mpg on the same run
Not a lot of difference on the face of it but on a full tank it’s an extra 60 miles
I had an 8-speed ZF gearbox in a BMW F22 coupe, mated to a 1.5l twin turbo. One thing that bugged me is in automatic mode it never told me what gear it was in, which I thought would be an interesting piece of information. It had good kickdown when needed and gave me reasonable fuel economy though so I was happy.
I've now got a 6-speed auto in a Lexus GS300. It doesn't tell me what gear it's in either, but whenever I switch to manual mode it always seems to be in 5th or 6th gear, even when pootling around town.
I've now got a 6-speed auto in a Lexus GS300. It doesn't tell me what gear it's in either, but whenever I switch to manual mode it always seems to be in 5th or 6th gear, even when pootling around town.
Berw said:
Two years ago I had a 8 speed Merc on Hire for a road trip round Norway, had a gear indicator and I never saw it in 3, 5 or 7th unless i used the manual mode, it acted as a 5 speed Auto.
My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
Traditional torque convertor autos do not work like manual or DCT/DSG types in that there isn't a separate gearset for each ratio. The ZF8 has four planetary gearsets which are used in various combinations to achieve the eight forward and one reverse ratios. There is certainly more complexity to achieve eight rather than three gears, but the designs are very clever.My 'daily' is a 3 Liter Toyota Hilux, had from new 6 years old and done 9,000 Miles, its great for what I need it for and does 1 liter to 10 Km, 28 Mpg, Recently I have access in work to a 2.2 liter 6 speed Ranger. almost identical size to the Hilux but no where near the torques, it does 9.8 liter to 10KM, 2% more, or 1/2 MPG better.
Both cars live on duel carriage ways, neither has ever been in 4WD.
My conclusion is that there is no benefit from the added complexity of the gears, just more to go wrong.
What are other peoples experience.
This video shows how the ZF8 works https://www.youtube.com/watch?v=FqyPizRyphQ
You might want to start with the basic first though https://www.youtube.com/watch?v=5piYEX-jRt4
I am sure the high number of ratios is yet another statistic used to persuade owners to swap to a newer model. Like the way the size/power/top speed of each model slowly ratchets up.
For a vehicle to actually need 9 gears, it would either have to have an extraordinary speed range- ie 0-300 mph, or an engine with a very small useable power band. Most modern engines are pretty flexible with flat torque curves once the turbo spools up, so I am sure 4 or at most five evenly spaced ratios would cover the expected speed range, and then add an overdrive ratio for fuel economy while cruising and you've got every circumstance covered apart from the fact your rival has just brought out a 10 speed.............
For a vehicle to actually need 9 gears, it would either have to have an extraordinary speed range- ie 0-300 mph, or an engine with a very small useable power band. Most modern engines are pretty flexible with flat torque curves once the turbo spools up, so I am sure 4 or at most five evenly spaced ratios would cover the expected speed range, and then add an overdrive ratio for fuel economy while cruising and you've got every circumstance covered apart from the fact your rival has just brought out a 10 speed.............
so called said:
Monty Python said:
getting nearly 34mpg from a 3-litre turbo petrol is pretty good, so I'd say the 8-speed transmission is pretty good at its job.
Used to get over 37mpg in my old Senator back in the 90's.So much for advancing technologies.
(from memory they only just made half that power, and if you were averaging 37mpg, it can't have been the 24v. The police ran them and ditched them largely as they were struggling to get 20mpg)
....plus getting 34mpg is not that high for a 340i. My old 640d was averaging 42-44mpg. People with 640i would claim they were getting high 30s.
Back on topic, I'm on my 3rd car with an 8sp box. They're awesome, and have all used all gears (expect the current car when in Dynamic or Race which has never used 8th gear, at least not at the top speeds I've been at).
It climbs through all gears though, and the closeness of the ratios and lightening quick shift means acceleration is relentless and never drops off.
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