Mk3 Interceptor: This is my 440 EFI conversion log.

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Steve Payne
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Steve Payne »

Philip Lochner wrote:In my mind it is hardly worth going EFI and then not do away with the dissy. The reason they are limited in ignition control is because they retain the dissy (which limits the amount of advance* one can have).

But one could still buy the Throttle body and then use any other ECU to control it which would then also offer distributorless and fully mapped ignition.

* My E-type cruises for miles on end with 50degs advance running at 17.5:1 AFR.
I use a crank trigger and retain the distributor purely to distribute the spark, the limiting factor is not the distributor but the engine. If you use high teens of advance for idle and the max you will put in is high 40's it only the phasing that needs to be changed.

I have found the leanest I can go on cruise is 16.3 with about 45 degrees of advance. Any less fuel or more advance and you can feel it.

I have found fuel injection will give you about 15% inprovement in fuel consumption but with the Overdrive as well keeping the revs at about 2000 for cruising it can be as much as 50% driven crefully.

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Julian
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Julian »

I'd say my edelbrock efi made about a 2-3 mpg improvement. Doesn't sound as good as a % does it? The higher comp, alloy heads, headers etc should help also. In my case they were fitted before the EFI.

Of course since all this engine work makes it goes better one tends to use it which doesn't help minimize consumption. That said I doubt anyone with an interceptor has improving economy as their priority. If it is leave it parked and polish it!
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Philip Lochner »

Steve Payne wrote:
Philip Lochner wrote: but with the Overdrive as well keeping the revs at about 2000 for cruising it can be as much as 50% driven crefully.
More info on this overdrive please?

Since my tacho is not working yet, what rpms does the Mk3 do when going 120km/h (75mph)?
Best regards
Philip
Mk3 7.2 #128/8120 Jan 73 http://tinyurl.com/hsjucm5
Mk3 7.2 #2240.9677 May '74 modified:
Fuel injected: http://tinyurl.com/qyrx93f
GM 4L60e 4-sp transmission: http://tinyurl.com/qxlwk95
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Philip Lochner »

DPP wrote: as I will be staying with a carb
From what I have read and learnt about the Carter Thermoquad, I am very impressed with the fuelling adjust-ability and the ease thereof that it offers! (Not that I have actually done this yet) On the primary barrels its just a case of twiddling the metering rod screw from the top and on the secondary barrels its a case of bending the baffle's ear and the pre-load on the baffle's torsion spring. It promises therefore to be able to offer the ability to achieve favourable AFRs both on steady cruise as well as mid and full throttle - if tuned correctly. In fact, I will endeavor to see what I can achieve with the carb by using my Innovate MTX-L wideband oxygen sensor - just to satisfy my curiosity (and serve as a benchmark once EFI conversion is complete).

It has been a trend on the factory setup of the Land Rover's I've played with that the factory setup tends to run excessively rich at full throttle. Huge fuel savings could be brought about (with increased performance) just by bringing the AFRs back from the 10-11's to around the low 13's AFR. It would not surprise me if the 440 would show similar trends.

Someone on this forum said (cant remember who) that a well tuned 440 can benefit a lot with mapped timing alone (possibly more than EFI) - my gut feel agrees with that statement wholeheartedly. EDIT (15 Aug 2013): I have now been running the car quite a bit exactly like this with MS controlling ignition only and all I can say is WOW, what a huge improvement!
Last edited by Philip Lochner on Thu Aug 15, 2013 4:25 pm, edited 1 time in total.
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Philip
Mk3 7.2 #128/8120 Jan 73 http://tinyurl.com/hsjucm5
Mk3 7.2 #2240.9677 May '74 modified:
Fuel injected: http://tinyurl.com/qyrx93f
GM 4L60e 4-sp transmission: http://tinyurl.com/qxlwk95
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by glenn999 »

Thanks for the heads up Glenn. Yes, I'm aware that there might be issues. I have a friend who is highly competent with GRP and Carbon Fiber. My plan is to give him the current bonnet as template so he can make me another from which I will simply cut a hole for the air filter to clear and then he will make a scoop to cover that once we know how much clearance is needed. (I would very much like to fit the supercharger later on as well....)

I'm also eyeing those side gills. Would be very nice if I could find a way to route cool air from those to an air filter on either side of the engine and then route that through a Y feed into the throttle body using a low profile inverted bowl on top of the throttle body.... The wiper motor on the LHS appears to be in the way though. If I could get this to work, I might be able to retain the original bonnet (preferred).
The Victor and a rootes type supercharger on top will be challenging the radio antenna for height..

I would really look into the pro flo xt intake and draw air from in front of the radiator like late model corvettes (over the radiator). If choosing this route you will have to swap to a wire linkage to the transmission (you have to modify this with the victor as well). Hood clearance should be a non issue.

Rootes superchargers typically mount on intakes made for the application.
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Steve Payne »

Philip Lochner wrote:More info on this overdrive please?

Since my tacho is not working yet, what rpms does the Mk3 do when going 120km/h (75mph)?
The overdrive is part of the replacment gearbox, I have used a Dodge A518 with lock up torque convertor. This is a later development of the 727 but was only designed to be used on small blocks so an adaptor plate is needed.

The selector and kickdown cables and linkages are exactly the same but the speedo cable needs to be longer. A shorter propshaft, a fabricated crossmember and some electrical connections and I have overdrive in top gear with a lock up torque convertor. 1850rpm at 70mph instead of 2700. A much quiter drive and off course a fuel saving if driven carefully.

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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Steve Payne »

Julian wrote: That said I doubt anyone with an interceptor has improving economy as their priority. If it is leave it parked and polish it!
I agree Julian but having an Interceptor that does 20mpg makes it more usuable and more affordable. The best bit is the increased range when using the car for long trips, on a trip to Germany a few years ago I did 330 miles before the low fuel warning light came on.

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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Chris_R »

Philip Lochner wrote:BUT, mpg depends more on gearing than it does on fuelling/timing in my unqualified opinion. My '80 XJS is a good example. This car has a so-called pre-HE engine, notorious for bad mpg. I have fitted my MS + distributorless system to this car but I have also fitted a 5sp manual conversion to the car which brought the cruising RPMs down from just under 3000rpm to 2000rpm. I believe (unproven) that the change in gearing has done much more for the car's consumption than the EFI upgrade.
I would agree with you on that.
The amount of fuel needed by the engine (any engine) does not really change just because you change from carburetor to injection. The volume of the engine does not change and the stoichiometric mixture will not change either. You still need the same fuel/air mix no mater how that mixture is delivered. Therefore the optimal consumption of fuel by the engine does not change.
The main difference between carburetor and fuel injection will be the precision and reliability by which the amount of fuel needed is delivered. You might gain a small improvement from the better precision of delivery at all speeds but a correctly set carburetor should deliver the same amount of fuel when cruising as a correctly set injection system so little if any difference.
if you have lower gearing then if the engine RPMs come down, then the volume of fuel/air mixture consumed in a given period of time will also come down, therefore you are using less fuel. There are other factors to do with loading, optimal engine speed etc. and how much of the energy consumed is delivered as mechanical energy so it will not be a straight equation, but generally, lower RPMs at cruising speed will translate to lower fuel consumption.
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Steve Payne »

Chris_R wrote:The main difference between carburetor and fuel injection will be the precision and reliability by which the amount of fuel needed is delivered. You might gain a small improvement from the better precision of delivery at all speeds but a correctly set carburetor should deliver the same amount of fuel when cruising as a correctly set injection system so little if any difference.
By being able to adjust the fuel so accuratly while driving is the way you get the fuel savings and the better drivabilaty. You can tune the engine ( or your passenger can ) while cruising, this way you can keep adjusting to get it 100% accurate. Yes I am sure with enough patience you can get good results with a carb but at best it will only be 90% as good as properly set up injection.

Also you can have the best of both worlds with injection, rich for maximum power when its needed and lean for the best economy. A lot of the modern systems when fitted with a wide band lambda sensor will also self adjust to keep the optimum settings correct under all conditions. All you need to do is tell the ECU what size of engine and its spec and it will do the rest itself.

Also other benefits are easy starting hot or cold, better drivabilaty, a steady idle under all conditions even with A/C on and idling in ''D''.

The downside is the cost, using a kit you are looking at about £2000 plus fitting.

The pay back is about 35,000 miles if you get a 10% fuel saving but personally the way the car drives and starts is worth the money.

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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by azenis »

Pity those edelbrock kits are only for the 440 and there is no version of the manifold available for the 383.
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Steve Payne »

The Edelbrock kit is probably the one to avoid, the hardware is great but the ECU and software are rubbish.

There is nothing wrong with buying an inlet manifold drilling it and installing your own injector bungs and rails.

There is so much hardware available for aftermarket fuel injection now.

Unless you are after the ultimate in power throttle body fuel injection is very good and works well on these engine, I have installed a couple on 383's with good results.

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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Philip Lochner »

Steve Payne wrote: I have installed a couple on 383's with good results.
Just out of interest, what ECU do you use Steve?
Best regards
Philip
Mk3 7.2 #128/8120 Jan 73 http://tinyurl.com/hsjucm5
Mk3 7.2 #2240.9677 May '74 modified:
Fuel injected: http://tinyurl.com/qyrx93f
GM 4L60e 4-sp transmission: http://tinyurl.com/qxlwk95
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Philip Lochner »

Steve Payne wrote:Also other benefits are easy starting hot or cold
Just for interest.

Mine starts instantly hot or cold. When cold I just have to tap and release the throttle for the choke to engage but when hot, no accelerator action is required.

Friend of mine has a Holley on his Mk3. What a mission to get that thing to start...
Best regards
Philip
Mk3 7.2 #128/8120 Jan 73 http://tinyurl.com/hsjucm5
Mk3 7.2 #2240.9677 May '74 modified:
Fuel injected: http://tinyurl.com/qyrx93f
GM 4L60e 4-sp transmission: http://tinyurl.com/qxlwk95
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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Steve Payne »

Philip Lochner wrote:
Steve Payne wrote: I have installed a couple on 383's with good results.
Just out of interest, what ECU do you use Steve?
I use the Holley ECU, I have been using that system for 8 years and though not the most impressive of systems seems to work well on these engines.

It can use a wide band sensor, has idle stabilization if you have ignition control and is well priced.

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Re: Mk3 Interceptor: This is my EFI conversion log.

Post by Philip Lochner »

Another part of doing such an EFI conversion is planning.

There are a few aspects to such a conversion that requires careful planning such as:
  • Trigger wheel and sensor
    fuel supply - EFI does not like fuel starvation
    clean air supply (combined with cool air supply: cool air is more dense, thus more power)
    coil pack mounting
Well, I am glad to announce that a solution for the trigger wheel has presented itself! I found this web site:
http://www.bobclevenger.com/Crank-fired%20ignition.html

Whereas Bob did a 36-1 trigger wheel because he was using the EDIS-8 unit, I will be doing a 60-2 (or 60-1) implementation just because I can ( and perhaps it offers slightly more accuracy)!
Best regards
Philip
Mk3 7.2 #128/8120 Jan 73 http://tinyurl.com/hsjucm5
Mk3 7.2 #2240.9677 May '74 modified:
Fuel injected: http://tinyurl.com/qyrx93f
GM 4L60e 4-sp transmission: http://tinyurl.com/qxlwk95
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