retrofitting efi?

[lil nicky]

Hi,

I'm thinking about making my 3500s more fuel efficient so as to employ it as a daily driver. Swapping the gearbox for a five speed from an SD1 seems reasonabley straight forward, but what about efi? From what I understand I'll need the injection manifold from something like a late 80's Range Rover, an ECU (whether from the same car or a after market unit) and a set of sensors for temp, crank etc? Is that it? Anything else? Seems the tricky bit is fitting the sensors and setting up the ECU, but have I missed anything? And when all this is down, will it actually provide much of an increase in fuel economy? Any advice / constructive critcism welcome. :wink:

 

[chrisyork]

The 5 spd LT77 gearbox will make a noticeable difference to economy. Or, if you have an auto and want to stick with auto, a ZF HP22 has the same overdrive top ratio as the LT77 with lock-up on 3rd and top so is a dramatic improvement economy wise over a Borg Warner.

If the objective is to make the car sufficiently economical for use as a daily driver I wouldn't go the injection route. A lot of work for only a marginal improvement. Why not fit an LPG installation? If you have the dosh to source new, fine. But there are getting to be lots of old Range Rovers going for scrap now that have been converted. The trick is to be in the right place at the right time!

Chris

 

[ghce]

SD1 heads I would suggest may save on fuel also, other thanb the box change I think driving style has the greatest effect.

Graeme

 

[rockdemon]

An electric fan instead of the engine driven one will help a little, and didnt somebody say that for motorway work the police spoilers have an effect?

Rich

 

[1396midget]

free flow filters

free flow exhaust

bigger valve heads

Electric fan

Remove all the things that cause the engine to have to work at just being on, then compliment it with a light right foot. I did these mods on the Midget (without the light foot thing) and mpg went form about 36 to 45. And it made it go better as well.

Thinner 'eco' branded tyres make a bit of difference on other cars, not much options to play with here though. Make sure starter is in good nick so you can stop start yourself.

 

[ghce]

Dont know about the thinner thing...yes better MPG but less safety, the same size tyres but in silicone will reduce rolling resistance plus give you better stopping power ie better MPG and better safety

 

[lil nicky]

Hi,

Exhaust and filters sound good. Fan too as they're all simple stuff. With regards the gearbox, I'm guessing it needs to be the LT77 from the SD1 for the ratios. My assumption is anything from a land rover or sherpa van would not work well in a car?

 

[arthuy]

I wouldnt waste time or money on the efi set up. if you were going to do it then perhaps fitting a 3.9 set up is better than the early system.

My 87 EFI Range rover 16mpg everywhere, My 85 Vitesse auto 18mpg 90% of the time and 24 on a long run.

Colin

 

[darth sidious]

Hi,

Exhaust and filters sound good. Fan too as they're all simple stuff. With regards the gearbox, I'm guessing it needs to be the LT77 from the SD1 for the ratios. My assumption is anything from a land rover or sherpa van would not work well in a car?

Unless I'm mistaken (which is not that uncommon! ), I'm sure the ratios for Landrovers and sherpa's are on the "too low" side for a car (unless you want to make a car capable of moving heavy load weights!)

 

[ewokracing]

If you were keen, I'd get a 4 barrel aftermarket injection throttle body, an edelbrock inlet manifold, then something like a microtech or haltech computer and hand controller. You'd need to do something about the fuel system though, maybe an intank fuel pump like a Bosch unit.

No idea if Microtech or Haltech is supported in the UK though. Problem is, by the time you start doing all of this, that's quite a few tankfuls anyway!

 

[LeeEFi]

Hi,

I'm thinking about making my 3500s more fuel efficient so as to employ it as a daily driver. Swapping the gearbox for a five speed from an SD1 seems reasonabley straight forward, but what about efi? From what I understand I'll need the injection manifold from something like a late 80's Range Rover, an ECU (whether from the same car or a after market unit) and a set of sensors for temp, crank etc? Is that it? Anything else? Seems the tricky bit is fitting the sensors and setting up the ECU, but have I missed anything? And when all this is down, will it actually provide much of an increase in fuel economy? Any advice / constructive critcism welcome. :wink:

Hello,
I've recently gone back to Efi on my SD1 as it didn't really seem right without it as it was originally so equipped. If you're very keen on the Efi option, I would go for a Land Rover/Range Rover 'hotwire' system, as it is more reliable and efficient than the earlier SD1/Range Rover 'flapper' system. I've gone done the hotwire route for my SD1:

In addition to the hotwire Efi, I have fitted the slightly larger 3.9 V8 which works superbly with the hotwire system. Of course, when fitting Efi to the P6 you'll have to fit an inertia switch to the eleccy supply to fuel pump, plus a suitable swirl pot of some sort for a constant fuel supply to the high pressure pump.

But basically just three wires will get the hotwire Efi up and running. I'm currently getting 26mpg from my SD1 at the moment which has an autobox, and to be honest, it's exactly the same mpg as when I was running SU's. So a lot of messing for not a lot of gain, if extra economy is what you're after.

As for gearbox options, the LT77(if you prefer a manual box)will be a real boon on the open road with its very tall gearing, but not any better than the standard 4-speeder around town for obvious reasons. I don't know anything about the ZF 4-speed autos other than they're a nice high geared autobox, but a bit more involved to install I would imagine?