Auto conversion

mcrover · 5th January 2009, 08:55 PM

Originally Posted by cewilson

I've read on a couple of the english sites that the 200tDi mated to the auto is very sluggish, as opposed to the manual.

Does anyone here know anything about this? Or is it another case of people commenting on something they've never tried or owned themself?

Cheers
Chris

I doubt that anyne over here would know but all I could say is that the only 200Tdi I have driven (in a manual) was brand new and with a 20 odd' van on the back it was a low range start on hills and just slowly cruise up the hill until you found somewhere flat and then stop, put back in high and start again.

Once moving I think it pulled better than the 300Tdi we tried the following week but that was a 130 not a 110 but both were tray backs.

I'd be thinking that like the 300Tdi+ZF, it would be a pretty good combo and probably better in some ways than the manual.

**cewilson** · 5th January 2009, 09:03 PM

I'm going to have to work out ratio's for it. I am running the Disco high range gears in the transfer case at the moment, so it should hopefully be very similar to a standard 200tDi Disco ratio.

Cheers
Chris

**Scouse** · 5th January 2009, 10:11 PM

Originally Posted by cewilson

I've read on a couple of the english sites that the 200tDi mated to the auto is very sluggish, as opposed to the manual.

Does anyone here know anything about this? Or is it another case of people commenting on something they've never tried or owned themself?

Cheers
Chris

There was one 200tdi auto Disco out here in 1993/1994 for evaluation by LR. It was driven by a friend of mine who was quite surprised how well it went on his 160km daily commute.

I didn't drive the car myself so I can't say how it compares to the 300tdi autos.

**justinc** · 6th January 2009, 06:51 AM

Chris I would swap back to the 1.410:1 transfer gears as the auto goes really well in front of the standard defer TC. It hits 4th lockup earlier, and the 3rd gear lockup mod makes them perform like a manual on the highway. You'll find that the OD in lockup is higher geared than the 5spd in top, and this will mean sluggish performance when in 4th lockup with the disco high range gearing and 235/85/16 tyres. However The 3rd gear lockup mod allows for you to have similar ratios as 4th gear with your LT77, at about 70km/hr.

You'll be happy with the auto conversion

JC

**Reads90** · 6th January 2009, 07:26 AM

Originally Posted by cewilson

I've read on a couple of the english sites that the 200tDi mated to the auto is very sluggish, as opposed to the manual.

Does anyone here know anything about this? Or is it another case of people commenting on something they've never tried or owned themself?

Cheers
Chris

I know that The 200 TDi Auto box makes a 300TDi go really well. and that is the most done conversion

mcrover · 6th January 2009, 09:38 AM

Originally Posted by justinc

Chris I would swap back to the 1.410:1 transfer gears as the auto goes really well in front of the standard defer TC. It hits 4th lockup earlier, and the 3rd gear lockup mod makes them perform like a manual on the highway. You'll find that the OD in lockup is higher geared than the 5spd in top, and this will mean sluggish performance when in 4th lockup with the disco high range gearing and 235/85/16 tyres. However The 3rd gear lockup mod allows for you to have similar ratios as 4th gear with your LT77, at about 70km/hr.

You'll be happy with the auto conversion

JC

This is why I woud like to go a Deefa TC in my Disco seems I run 235 85 16s on my disco.

**Slunnie** · 6th January 2009, 09:51 AM

Originally Posted by Reads90

I know that The 200 TDi Auto box makes a 300TDi go really well. and that is the most done conversion

Did the 200tdi still run the ZF 4HP22 but with different gear ratios?

**cewilson** · 6th January 2009, 12:01 PM

Originally Posted by Slunnie

Did the 200tdi still run the ZF 4HP22 but with different gear ratios?

The gearbox, transfer case and diffs are still the same ratio. I have heard this a few times, but I really don't understand why.

The only thing that i can think of is maybe the valve body is different between a couple of years of the box?

**cewilson** · 6th January 2009, 12:15 PM

I did some calculating today with regards to ratio's.

Diff - 3.54:1
Transfer High - 1.22:1 (Disco high range)
Transfer Low - 4.34:1 (Maxi-Drive low range).

Comparing the two boxes (LT77S in black, ZF4HP22 in blue):
Note - these figures below are the total ratio in each gear, inc the transfer case, diff and tyre diameter.

High Range -
1st - 15.95 10.71
2nd - 9.21 6.39
3rd - 6.03 4.32
4th - 4.32 3.14
5th - 3.33
Reverse - 14.81 9.01

Low Range -
1st - 56.72 38.1
2nd - 32.75 22.74
3rd - 21.46 15.36
4th - 16.36 11.18
5th - 11.83
Reverse - 52.68 32.05

So the easy way of explaining all of the above - is that off-road this change would hurt me.

Now looking at the road side of things, I found the following applies when in top gear (LT77S in black, ZF4HP22 in blue):

80km/h - 1887RPM 1655RPM
100km/h - 2358RPM 2069RPM
110km/h - 2595RPM 2276RPM

So JC, yeah I agree with you that I might need to look at the Defender high range again.

To be quite honest, I think the easiest (and cheapest) way of getting an automatic in a Defender would be with a 300tDi. In my case it's going to end up being a hassle, and more importantly it looks like it'll actually hurt my off-road performance. AND I AIN"T DOING THAT!!!!!

Bugger
Chris

**Slunnie** · 6th January 2009, 12:45 PM

Originally Posted by cewilson

So the easy way of explaining all of the above - is that off-road this change would hurt me.

Chris thats not necessarily the case because the ZF 4HP22 locks up the torque converter in 4th at over 80km/h, so where the gearing appears mismatched you need to also factor in the torque multiplication. The area where you will lose somthing is engine braking - but when things are that greasy that you need it, then the auto still has enough, especially with MDE 30%'s!

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