Upgrading 90 for more speed?

[Fattylewis]

I have a 1987 90 with original gear box and a 200tdi lump, fitted this year. I would like to upgrade it so I can do at least 55mph without it sounding like it needs another 4 gear changes if you know what I mean. I was told that I could put a diso transfer box in? It that right? How much work? Or is there another way when on a budget ?

 

[Discokids]

Disco transfer box is easiest way, a common swap for people who regularly drive on fast roads.

 

[danny6801]

Half a days work but will be easier if there is 2 of you as they are really heavy.

 

[flat]

What transfer box have you got at the moment?

What was your vehicle before the engine transplant? Is it ex-mil?

Reason I ask is I have a 200tdi 90 and can hit over 80 (on private roads officer). It's a bit lairy at that speed and it's much nicer at 65-70 and better on fuel to. I have the 1:1.4 ratio box (standard defender) the disco is 1:1.2 and the low range box which you could potentially have is the 1:1.6

Worth ruling out problems with the engine first, is the turbo making boost, is the boost diaphragm and pin working.

A 200tdi in good fettle with a standard 1:14 x-fer box should do more than 55mph easily

 

[Chalky.]

I've taken to pootling along at 45 mph most of the time for the very same reasons, the gearing is just so bloody low on defenders, any more and the rpm's creep up and then cabin noise and relative economy are gone! Mines a td5 but the same low ratio trany box, I'm saving up for a roverdrive!

 

[300bhp/ton]

I have a 1987 90 with original gear box and a 200tdi lump, fitted this year. I would like to upgrade it so I can do at least 55mph without it sounding like it needs another 4 gear changes if you know what I mean. I was told that I could put a diso transfer box in? It that right? How much work? Or is there another way when on a budget ?

Standard Defender should be fine tbh. Should happily sit at 65mph+

What transfer box and tyres size are you running? Also some LT-77's have a shorter 5th gear.

Swapping in a Disco transfer box is an option. But to be honest it'll probably kill the performance. Sure it'll lower cruising rpms. But acceleration will suffer. And if you haven't got enough power to pull the gearing, you'll end up using 4th where you used to use 5th.

For the record, a Disco running stock 28-29" tyres pulls about the same mph/1000rpm, as a Defender with 32" tyres.

 

[fanatic]

stick an ls1 in it

 

[Woldsguy]

My 1988 90 with 200tdi and standard x-fee box will hit 75 (on private roads). Not sure I'd fancy doing a long distance at that, but it will happily sit at 60 with a bit to spare underfoot.

Perhaps check turbo first, my turbo intake came loose and fell off the other week and I was getting about the same speeds the OP is talking about.

 

[Marmaduke]

What size tyres are fitted on it, it might just be a case of putting 235/85's or 265/75's on if you've got small ones on

 

[Chalky.]

Standard Defender should be fine tbh. Should happily sit at 65mph+.

I think your idea of happily and mine differ somewhat drastically

 

[lightning]

My standard TD5 110 CSW at 60mph is at 2500rpm and at that speed it is very happy.
70mph is about 3000rpm well within the rev range.
Flat out she will do 90mph, not sure of the RPM, but at that speed the wind noise becomes excessive as the door seals seem to give up.
But who wants to drive at 90mph in a Defender?
Best to remember you are driving a truck, sit at 60 and let the streams of cars blather past in the outside lane.
You will still get where you are going.

 

[Chalky.]

Then the CSW' must have much better soundproofing than a standard 90 van, I suppose obviously it would! There's no way in hell id take mine to 90, and whilst 3000 rpm maybe considered safe, engine wise, it certainly isnt comfortable volume wise, plus 3000 rpm at 70 is very low geared so I can totally understand why you'd want to decrease the revs in some way

 

[Chalky.]

I have a 1987 90 with original gear box and a 200tdi lump, fitted this year. I would like to upgrade it so I can do at least 55mph without it sounding like it needs another 4 gear changes if you know what I mean. I was told that I could put a diso transfer box in? It that right? How much work? Or is there another way when on a budget ?

So essentially if your on a budget the best bet is a disco trany box, or Ashcroft do a transfer gear kit, or the best, but most expensive bet is the roamer or roverdrive, (both same) giving you a 6th gear which increases top gear by 28%, cruising around at normal driving speeds rpms would be around the 1500 mark, apparently a great bit of kit but hideously expensive

 

[Turboman]

I have a 1987 90 with original gear box and a 200tdi lump, fitted this year. I would like to upgrade it so I can do at least 55mph without it sounding like it needs another 4 gear changes if you know what I mean. I was told that I could put a diso transfer box in? It that right? How much work? Or is there another way when on a budget ?

Going through it and finding what is limiting the performance might be the best idea. Filters, tappets, timing check etc.
200Tdi should be comfortable at 65, and top out 75 mph. Even my standard engine Ninety will cruise at 60, and get over 70 for a short time. Tdi produces 25 horse more than mine.

 

[lightning]

Yes a sixth gear would help, although you'd need a remap too.
I just sit at 60-65mph which seems fine.

 

[300bhp/ton]

Then the CSW' must have much better soundproofing than a standard 90 van, I suppose obviously it would! There's no way in hell id take mine to 90, and whilst 3000 rpm maybe considered safe, engine wise, it certainly isnt comfortable volume wise, plus 3000 rpm at 70 is very low geared so I can totally understand why you'd want to decrease the revs in some way

I think you maybe need to look at what an average hatchback spins over at to sit at 70mph.

But if your complaint is noise. Then frankly you have the wrong vehcile and you'd be much better off with a Discovery. You'll never stop the noise. This is because the body mounts metal on metal to the chassis. A Discovery body is not only more rigid, but it sits on larger rubber donuts that isolate it from the chassis.

Over gearing a Defender will just make it sluggish to drive. And on a motorway you'll not be able to pull 5th up hills. Which means dropping to 4th. So more revs and noise than if you'd left it alone.

Another option for the op is to up size tyres. A 255/85R16 will no problem, isn't too wide, but is about 33" tall. With the stock gearing and transfer box this should be more than sufficient. If it's still too noise and you really do need to do a lot of high speed motorway, then sell it and by a Disco.

 

[wammers]

I think you maybe need to look at what an average hatchback spins over at to sit at 70mph.

But if your complaint is noise. Then frankly you have the wrong vehcile and you'd be much better off with a Discovery. You'll never stop the noise. This is because the body mounts metal on metal to the chassis. A Discovery body is not only more rigid, but it sits on larger rubber donuts that isolate it from the chassis.

Over gearing a Defender will just make it sluggish to drive. And on a motorway you'll not be able to pull 5th up hills. Which means dropping to 4th. So more revs and noise than if you'd left it alone.

Another option for the op is to up size tyres. A 255/85R16 will no problem, isn't too wide, but is about 33" tall. With the stock gearing and transfer box this should be more than sufficient. If it's still too noise and you really do need to do a lot of high speed motorway, then sell it and by a Disco.

But then he would have an illegal speedo wouldn't he?

 

[300bhp/ton]

But then he would have an illegal speedo wouldn't he?

Only if it if was correct to begin with

 

[Chalky.]

Yes but we're not talking about an average, petrol hatchback are we? We're talking about a load lugging landrover engine,the 2 simply are not comparable! And anyway, we own our various landy's because we require certain things from them, or because they have a particular place in our hearts. So I Love defenders, ill do anything in my capability to make it more efficient, quieter etc etc, and ill put up with it not being as quiet as a disco because I simply don't Love discos! And selling it will never be an option for me!
How I drive, an overdrive will be the best bet, I tow big trailers regularly with chippers etc, so enjoy the low gearing, but when we want to trundle down to France to visit the g/parents etc, it becomes more noticeable, hench a nice 6th gear for those lovely long flat stretches'! And you don't need a remap to pull a 6th gear in an unloaded 90 on a motorway

 

[Chalky.]

I take onboard about your point with tyre size, I have 265/75 r16's which are roughly the same rolling diameter as a 7.50 standard (tall) tyre