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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 205

United Kingdom 
LT77 Gearbox ratio's & 200 tdi power/performance
My 200 Tdi 90 has the LT77 gearbox and when driving there seems quite a difference in gear ratio's between 4th & 5th.

I find that you have to drive to 50mph in 4th before trying to get into 5th and if you slow in 5th to below 50mph you have to change down as it seems too high in gearing & labours.

My friend drove it and suggested tweaking the the fuel pump to give it abit more power but I was not sure if that was the answer, he thought it could do with tweaking compared to several he had owned & tuned before.

I also wondered if there was different versions of the LT77 gearbox available over the years?

Power wise it seems to pull but I think the top end power might be slightly lacking though the turbo sounds strong.

Should I consider some tuning?? It does have a large intercooler and straight exhaust but I'm unsure of whether the pump has ever been adjusted before.

I have checked timing & it starts cold without using the glowplug heaters. Thumbs Up
Post #615640 9th Apr 2017 9:52pm
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Kit



Member Since: 12 Feb 2016
Location: Shropshire
Posts: 1110

United Kingdom 1993 Defender 90 200 Tdi SW Scotia Grey
The gearbox might have been rebuilt at some point with a longer 5th, have you checked the old paperwork?
Post #615646 9th Apr 2017 9:56pm
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ickle



Member Since: 22 Jul 2010
Location: South Vendee
Posts: 1728

France 2008 Defender 110 Puma 2.4 CSW Alpine White
I upped the boost pressure and tweaked the fuel on my 200 bitsa and it was superb!
Post #615648 9th Apr 2017 9:58pm
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ickle



Member Since: 22 Jul 2010
Location: South Vendee
Posts: 1728

France 2008 Defender 110 Puma 2.4 CSW Alpine White
- mine was also running 265's and a 1.2 transfer box
Post #615650 9th Apr 2017 9:59pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 205

United Kingdom 
Shamefully the engine & gearbox was swapped prior to my purchase. They did'nt record anything for the swap. I took it as a unfinished project. The only paperwork I have was for prior to that Crying or Very sad Crying or Very sad
Post #615651 9th Apr 2017 10:02pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 205

United Kingdom 
ickle wrote:
I upped the boost pressure and tweaked the fuel on my 200 bitsa and it was superb!


Did you run a EGT or Boost Gauge?

My friend mentioned quite high BHP numbers being achieved years ago from 200/300 tdi's.

I was reluctant to tune it when I bought it but having been using it for driving to work recently I realise that a little tune might be sensible.

He suggested removing the the diaphram and adjusting the Diaphram spring pre-load to give it a bit more top end performance.

He tunes his to get about 70mph in 4th gear......I don't drive that hard though Embarassed Embarassed
Post #615655 9th Apr 2017 10:10pm
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Kit



Member Since: 12 Feb 2016
Location: Shropshire
Posts: 1110

United Kingdom 1993 Defender 90 200 Tdi SW Scotia Grey
I am going to run an EGT and boost gauge before I start to fiddle with mine, although it goes quite well at the moment to be honest!
Post #615661 9th Apr 2017 10:18pm
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ickle



Member Since: 22 Jul 2010
Location: South Vendee
Posts: 1728

France 2008 Defender 110 Puma 2.4 CSW Alpine White
I set it with a gauge at about 18psi boost, didn't leave it connected when done though, adjusted fuel until it only smoked on very hard acceleration, 70 in 4th no problem, 85 on the motorway again no issues, MT tyre noise seemed to be the limiting factor.
Post #615663 9th Apr 2017 10:19pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 205

United Kingdom 
Kit wrote:
I am going to run an EGT and boost gauge before I start to fiddle with mine, although it goes quite well at the moment to be honest!


I think mine is a bit lacking though I drive fairly gentle.

I'm running Insa Specials, lift & external roll cage...and two winches...so I'm carrying a bit of extra weight but nothing major.

Sounds like I better have a play and see what I can gain. Thumbs Up
Post #615666 9th Apr 2017 10:25pm
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Kit



Member Since: 12 Feb 2016
Location: Shropshire
Posts: 1110

United Kingdom 1993 Defender 90 200 Tdi SW Scotia Grey
I was running 33x12.5 but no extra weight 1993 200 Tdi 90 CSW
1956 Series 1 Hard-top
1958 Series 1 Soft-top
Post #615668 9th Apr 2017 10:26pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 205

United Kingdom 
ickle wrote:
I set it with a gauge at about 18psi boost, didn't leave it connected when done though, adjusted fuel until it only smoked on very hard acceleration, 70 in 4th no problem, 85 on the motorway again no issues, MT tyre noise seemed to be the limiting factor.


Ahh...mine must need setting up as I get about 50mph is where it stops pulling in 4th and in 5th about 65ish...though I have not really tried max speed!

My friend said it seemed like the throttle was not opening enough!

Did you T into the wastegate pipe to measure boost? I gather 18psi is the sensible max. I run a massive intercooler. Would you suggest that I check EGT after tuning?

Did you adjust the diaphragm & diaphragm pre-load for fuelling?

Thanks for your help. Thumbs Up Thumbs Up
Post #615676 9th Apr 2017 10:38pm
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LANDROVER



Member Since: 13 Feb 2016
Location: EAST OF ENGLAND
Posts: 205

United Kingdom 
Kit wrote:
I was running 33x12.5 but no extra weight


I was running 33x13.50x15 Maxxis Mudzilla's but swapped to 265/75/16 now...improved the handling.. Laughing

Thanks for your advice and help. Thumbs Up Thumbs Up
Post #615682 9th Apr 2017 10:47pm
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ickle



Member Since: 22 Jul 2010
Location: South Vendee
Posts: 1728

France 2008 Defender 110 Puma 2.4 CSW Alpine White
It was several years ago now, but I took the pressure at the manifold, sorry can't remember if I drilled and tapped it or t'eed into it somewhere, I also ran a huge intercooler and straight through 3" exhaust.

As I wasn't doing anything out of the ordinary, I never bothered with the exhaust gas temp, there were no issues in the 7 years I used it or in the 3 years after I sold it, the next owner I think ran it with the radiator & intercooler full of mud and cooked it.

There is a very good write up on line on how to tune the 200tdi, I can remember shortening the rod on the turbo and altering the screws on the pump, but its too long ago now for details - it must be my age!

good luck

Keith
Post #615828 10th Apr 2017 6:24pm
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benniferj



Member Since: 20 Oct 2016
Location: Basingstoke
Posts: 361

United Kingdom 2003 Defender 110 Td5 XS CSW Oslo Blue
I'm on a 200tdi/Lt77 with a 1.6 transfer box, 285/75/16s. For me I think this gives me a slightly poor gearing with some of the ratios being in between where they want to be. I think a 1.4 transfer box would probably shift everything back into place with the bigger wheels nicely.

I'm in the process of sorting out tweaking the pump, I'm running about 15psi boost 'says the gauge' and I have tapped my exhaust manifold with a 1/8npt probe - sadly faulty out of the box so waiting for the new probe to arrive! Then I will tune the pump and maybe I can get away without changing the ratios if it gives me a bit more low rev fuelling bite.
Post #615972 11th Apr 2017 9:14am
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