The V8 Owners Forum -

Presently rebuilding a 3.5 V8 for my comp safari land rover. The engine has had some tuning in the past, ie, omega pistons, 3.9 heads, balanced rods and competition cam shaft ect. At the moment it runs on standard twin SU carbs, but I would like to fit fuel injection. Can anyone reccomend the best system I can fit that can be sourced from genuine land rover parts.

Thanks

if you want something easy to fit and cheap and simple have a look on ebay for a flapper set up ...they do come up now and again ..but make sure its complete with ECU / airflow meter / manifold / plenum and wiring loom ( UNCUT ) and what sometimes forgotten the resistor pack ...the only thing you will need to add is a fuel , its very easy to fit ...
and it will make it more economical and feel a lot more responsive ..

in fact here's one : http://cgi.ebay.co.uk/ROVER-V8-KIT-CAR- ... 1e62ab5d7e

Thanks again for replies. So far we have one vote for Hot Wire as fitted to 3.9 Disco. One for Megasquirt and one for the flapper type system.As I have 4 off road L/Rovers to maintain and repair at the moment,( three V8's on carbs + one TDi) I think the megasquirt is to time consuming to get involved with right now. That leaves the two factory systems used on V8 L/Rovers, which is it to be? I guess when this engine is worn out I'll be replacing it with a 3.9 or 4.2 instead of trying to squeeze more BHP from this 3.5.

Hello Larry, The 3.5 Flapper is probably the most documented system - for the home enthusiast, that is - and likely to be the easiest to transplant.

Spares are readily available S/H and lots of folks know how the system works.

It does have its vices, but they are generally due to poor maintenance and upkeep as opposed to component failure.

If you need more than 200 horses - easily - then look elsewhere.

You might consider learning all about the system before making your decision - if so - browse my site.

The problem with the flapper system is it's old - and some parts wear out. The ECU can suffer from dry joints which are difficult to find.

I thought I'd posted that neither the flapper or hotwire are really suitable for modified engines as they can't be re-mapped properly. But both can work just fine on standard engines.

I changed the cam on an otherwise standard 3.5 with the flapper system for one said to be suitable for it - and was most disappointed with the results. So changed back to a new standard cam.

I'm happy with my Megasquirt on an otherwise standard 3.5. I'd not make any extravagant claims about maximum power for it over a flapper in good nick - but the driveability at low/medium engine speeds is vastly better. The flapper tends to run weak apart from on full throttle. My car is an auto, so tends to spend a lot of time in the highest gear, but now pulls like a train without having to floor it.

The problem with the flapper system is it's old - and some parts wear out. The ECU can suffer from dry joints which are difficult to find.

I thought I'd posted that neither the flapper or hotwire are really suitable for modified engines as they can't be re-mapped properly. But both can work just fine on standard engines.

I changed the cam on an otherwise standard 3.5 with the flapper system for one said to be suitable for it - and was most disappointed with the results. So changed back to a new standard cam.

I'm happy with my Megasquirt on an otherwise standard 3.5. I'd not make any extravagant claims about maximum power for it over a flapper in good nick - but the driveability at low/medium engine speeds is vastly better. The flapper tends to run weak apart from on full throttle. My car is an auto, so tends to spend a lot of time in the highest gear, but now pulls like a train without having to floor it.

larryowner wrote:Thanks again for replies. So far we have one vote for Hot Wire as fitted to 3.9 Disco. One for Megasquirt and one for the flapper type system.As I have 4 off road L/Rovers to maintain and repair at the moment,( three V8's on carbs + one TDi) I think the megasquirt is to time consuming to get involved with right now. That leaves the two factory systems used on V8 L/Rovers, which is it to be? I guess when this engine is worn out I'll be replacing it with a 3.9 or 4.2 instead of trying to squeeze more BHP from this 3.5.

it very much depends on what you want , if you want simplicity then FLAPPER every time , forget HOTWIRE they are getting old too but there are lots of things to go wrong and do ! , that are expensive to replace ... if you want horsepower then go aftermarket

daveEFI , just a thought if yours is running weak have you tried taking some tension off the AFM spring , it worked on mine ..

Many moons ago I bought a complete engine off fleabay and had the seller strip all the gubbins from the injection off it for me as it was going to be sent to Cape Town until I discovered to my horror that it cost close on 4 times what I bought it for to ship, so if you want a hotwire setup with plenum, manifold, dizzy, ECU etc etc drop me a pm and I will give you the guy's name that has it in his loft in the UK.
It's in the North Denes area, and I will be open to ideas on price etc from those who know better on here.

bodger wrote:

larryowner wrote:Thanks again for replies. So far we have one vote for Hot Wire as fitted to 3.9 Disco. One for Megasquirt and one for the flapper type system.As I have 4 off road L/Rovers to maintain and repair at the moment,( three V8's on carbs + one TDi) I think the megasquirt is to time consuming to get involved with right now. That leaves the two factory systems used on V8 L/Rovers, which is it to be? I guess when this engine is worn out I'll be replacing it with a 3.9 or 4.2 instead of trying to squeeze more BHP from this 3.5.

it very much depends on what you want , if you want simplicity then FLAPPER every time , forget HOTWIRE they are getting old too but there are lots of things to go wrong and do ! , that are expensive to replace ... if you want horsepower then go aftermarket

daveEFI , just a thought if yours is running weak have you tried taking some tension off the AFM spring , it worked on mine ..

Well, if the hotwire is getting old, where does than leave the flapper?

I've read about altering the spring tension on the flapper - but how does that allow for a modified engine with different compression, valve timing etc properly? The beauty of EFI is it should meter fuel correctly for all circumstances - if all you just want is peak power at any cost, use carbs.

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Well, if the hotwire is getting old, where does than leave the flapper?

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the whole sentance ... forget HOTWIRE they are getting old too but there are lots of things to go wrong and do ! , that are expensive to replace ...

they are both old but the hotwire being more electronic and a lot more expensive to fix , where as the flapper is more mechanical and therefore easir and cheaper to sort out ( personal experiance on both )

Opinion seems to be that the EFi and the flaper system want work well with a modified engine. I had hoped the EFi system would sort out what was needed with the input from various censers including the lamda censer in the exhaust. With twin S U's I can adjust the mixture at idle and try various needles, but never sure if the mixtur is about right at higher speeds.

The flapper system is 'open loop', i.e. it does not have any lambda sensors. It is mapped to the engine configuration (i.e. a standard SD1 or Range Rover), and assumes everything is factory spec. Any changes, and the fuelling map will not be accurate. It will still run OK though, but not to factory emissions standards!

The hotwire system does have optional lambda sensors, but I have no idea how much it 'learns'. Not a lot I suspect.

The very latest Thor from a P38 Range Rover will fully map itself, but it's just about impossible to make the engine run without it being installed in a P38 Range Rover with all the other ECU's for it to natter to.

Chris.

larryowner wrote:Opinion seems to be that the EFi and the flaper system want work well with a modified engine. I had hoped the EFi system would sort out what was needed with the input from various censers including the lamda censer in the exhaust. With twin S U's I can adjust the mixture at idle and try various needles, but never sure if the mixtur is about right at higher speeds.

Don't think the flapper was used with a lambda sensor in the UK - and the export versions which did weren't much good.

A normal Lambda sensor is only any good at keeping the mixture at stoichiometric - which unless you're using a cat, you won't want anyway.
Aftermarket units like the MegaSquirt can use a wideband Lambda to keep the mixture where you've decided it should be.

DaveEFI wrote:

larryowner wrote:Opinion seems to be that the EFi and the flaper system want work well with a modified engine. I had hoped the EFi system would sort out what was needed with the input from various censers including the lamda censer in the exhaust. With twin S U's I can adjust the mixture at idle and try various needles, but never sure if the mixtur is about right at higher speeds.

Don't think the flapper was used with a lambda sensor in the UK - and the export versions which did weren't much good.

A normal Lambda sensor is only any good at keeping the mixture at stoichiometric - which unless you're using a cat, you won't want anyway.
Aftermarket units like the MegaSquirt can use a wideband Lambda to keep the mixture where you've decided it should be.

Dave

Please explain

The Lambda is mounted between the engine and the CAT so in reality it has no idea if cats are fitted or not!

All the cats do is burn off any thus far unburnt hydrocarbons

Ian

A cat will have a very short life unless the mixture is kept close to stoichiometric. That is why narrow band lambda sensors are fitted. Without a cat. you can use a much wider range of AF ratios - to get maximum performance and economy. Especially on an old engine design.

A wideband lambda sensor will tell you what the actual AF ratio is - but these are much more costly than a narrowband one. And can be used in closed loop to control a suitable ECU.

Both the flapper and hotwire are pretty crude devices compared to modern EFI. They don't 'learn' in the way these often do. Which is why using them on a modified engine is not a good idea. It's bad enough trying to keep them running perfectly on a standard unit.