I’m considering fitting EFI to my Daimler V8. It won’t be until I get the motor rebuilt, which will be part of a full restoration I’m planning for this time next year. So I’ve plenty of time to think about it. I’m into modern upgrades to make the car more usable. I already have electronic ignition & electric power steering, so there’s no issue with keeping the car original. I was just wondering if anyone’s done it & what they think about it, as well as any issues encountered with the fitment. I’ve been looking at this outfit here. It’s expensive, but looks to be the complete package. Thoughts?
https://www.classicfuelinjection.co....v8-premium-kit

 

The prices and difficulty can range considerably for EFI depending on how much you either can or want to do yourself. I did EFI to my 3.8 S Type using Megasquirt and similar carb adapters from Patton Machine. They replace the piston and suction chamber of the SU carb with an adapter that carries a fuel injector.

I found that once you get the tuning done, there is a noticeable difference in the running quality. However, it took me a long time to get it close to an OEM running quality and it's not there yet. I think my problem is twofold, and I am hypothesizing on both of these. The first is that since I am using the throttle body injection system, the fuel pressure is low, nominally 13 psi. I used TBI style fuel pumps that are supposed to be able to lift fuel, and I put the pumps in the place of the SU pumps on top of the tank. I think I experience occasional low pressure either though knockoff pumps ( I don't know if they are genuine Walbro pumps) or cavitation/vapourization of the fuel caused by suction lowering the vapour pressure. Occasionally it will go lean, yet I can shut the car off and restart and it is ok.

The other problem I think I am getting is fuel puddling behind the bridge of the SU's at idle, as the carb adapter doesn't hold the injector at an ideal angle. It's worse at idle where I get inconsistent air-fuel ratios, yet is fine at higher loads on the road.

It's not a this year project, but I need to position the pumps so they are gravity fed ( this is usually very important for high pressure EFI pumps) to avoid any possible fuel starvation problems, and I have already made a different manifold to use a Chevrolet TBI assembly from an early 90's truck. From experience, I know those work very well and seem to run forever.

I did the EFI partly because I really disliked the original starting carb arrangement and it being either on or off. For me it went from starting the then gradually became black smoke rich as the engine warmed up, then the carb shut off and the car went so lean it stalled and wouldn't reastart. Not good when I had just pulled out into traffic and the car stalls. After nearing being broadsided when the car stalled, I went looking for a better alternative. I also did EFI simply for the technical challenge, and I enjoyed the learning process. It was a long and involved process to program the Megasquirt system, as there are so many parameters that you need to know and understand, but I found the process rewarding.

I probably could have fixed some of the problems with a manual choke conversion, but I also drive the car through large elevation differences and a carb can't compensate for that and EFI can.

I have also fitted a 5 speed manual transmission, but with the EFI and distributorless ignition my 3.8 can achieve around 9.4 L/100km on a long highway run across the Canadian Rockies. I have a 3.77 rear axle and a 0.73 OD ratio, I'm not sure how that would compare to the ratio in an original manual with OD setup.

 

Thanks for the detailed reply. You’ve given me much to think about. I think a lot more research is required

 

https://forums.jag-lovers.com/t/seri...upgrade/416690

The link above has a description of work upgrading the EFI of the series 3 XJ6. Although the XJ already has injection and it's a different engine from yours, it covers a lot of what's involved in a very practical way. And much of it is using components available in Australia

 

Good luck, and feel free to ask any more questions.

One important thing to consider is injector size, going too big is a problem because they can't be turned down enough to give a good idle. It seems that about 1.3 milisecond opening time is the absolute minimum you can practically achieve for an injector, if the injector is too big it will flow too much fuel at idle at that opening time. It seems that many of the EFI systems are designed for the larger American V8's and they would flow too much fuel for the Daimler V8.

Megasquirts biggest advantage and biggest drawback at the same time is its flexibility and adaptability. As it can be used with nearly any gasoline engine; you could put it on a lawnmower if you wanted, but you also need to determine the correct parameters for your particular engine. That can take a lot of time and experimentation. The "self learning" systems are not bad, but you also lose the ability to fine tune to your engine. A friend of mine has a pair of 1967 Chryslers, both with the 440 engine. One he did with Megasquirt, the other with a Holley Sniper system. The Megasquirt car does start and run better, but it took a lot more time and effort to get it to that point. Not everyone has the time, desire or skill to do that amount of fabrication, programming and tuning.

 

I'd agree with JB on MegaSquirt. I read a lot on it a few years ago. Undoubtedly, it is s very good system and good value, but there are a huge number of not quite finished MS projects. My inclination is to go with something that has a good reputation, comes from a helpful supplier, doesn't do a load of things you don't require, and the local rolling road tuners are familiar with. In Australia that would probably be Haltech.

For converting the existing SUs, the advantage is that it keeps an original look and avoids the problem of fabrication of a new inlet manifold. On the other hand, one of the attractions of injection are the torque and power increases that can be obtained with decently long, unobstructed inlet runners.

Incidentally, much of the performance gain from an ECU is from the ignition mapping and elimination of the vacuum and centrifugal advance in the distributor.

JB - the Laycock overdrive ratio is approximately 0.79, slightly lower than your 5th gear. It nominally gives 80mph at 3030rpm. With the Jaguar transmissions, it's quite attractive to swap a 3.54 (non overdrive) axle for the 3.77.

 

I would agree with that. I did ignition first, then EFI and the ignition did make a noticeable difference to the amount of torque.

When I was making the decision to do EFI there were not nearly as many choices as there are now. The DIY part of MS also appealed to me. Like everything, you either pay in cash upfront for a commercial system or pay with time later to build and program a DIY system.

 

JB - what did you for the return lines to the tanks? Did you follow something like the system on the series XJ? At least, the MK2 has only one tank. Unfortunately, it's not the best shape for injection as it's not easy to arrange a sump. I'd thought of using a 'swirl pot' with the swirl pot in the boot away from the heat of the engine, but it's extra complication with an extra pump to fail

 

My feed line is nylon and used an XJ selector valve to determine which tank the pumps draw from. Unlike an XJ, I have 2 pumps, one for each tank. The pump and selector valve are wired together. For the return, I used the original steel feed line, with XJ non-return valves before each tank so there is a positive shutoff to each tank. I put an elbow into the drain bung on the bottom of the tank and the fuel returns there. That way I didn't need to make any alterations to the original tanks that couldn't be reversed.

I'm tempted to use one pump and mount it on the rear suspension cross member, just like the early XJ40's did. The reason I didn't do that was the fuel line would have to cross the exhaust somehow and I wasn't comfortable with that.

I would have thought with a single tank the Mark 2 would be much easier. You could do an in-tank pump arrangement, similar to 3.8 E Types, but use a modern pump. Many of the later cars (like X300's) simply have a metal shroud around the pump to make a well that it sits in. That prevents fuel starvation in cornering. The shroud is simply a baffle welded to the tank floor with scallops on the bottom edge to allow fuel to flow past, but at a controlled rate.