Hi Dave,
I'm certainly no expert, but find this topic very intriguing and some good suggestions have already been given. I agree your first step will be to do lots of research, even on a local level to see if there are specialists in your area that might offer help, parts that might be available, others who have made similar conversions and might provide some guidance, etc.
I know very little about the "universal" application EFI systems mentioned, but am always a little skeptical of these. Still, they are certainly well worth exploring and considering.
In Roger William's book you will find several other EFI options discussed.
First, a section is devoted to converting to an original Lucas PI system and includes some ideas how to improve upon that system. There are advantages to this, such as that it is a proven system. I'm not talking about reliability, just that all the myriad system details were worked out for you, many years ago by the factory engineers. The years since have shown up the weaknesses of that system and ways to correct them. Disadvantages would be that some parts might be very hard to find and/or expensive. Also, later forms of EFI might be more advanced and could offer better tuning potential and higher general reliability.
Roger also suggests how you might cobble together an EFI system from used parts, and lists some of those parts and the specific cars they can be found on. In this case, I think anyone doing it would need some level of knowledge and expertise, or be willing to research and learn it, before attempting! Alternatively, a good local shop with a lot of EFI skills and knowledge might help.
The third method Roger covers is to install a kit that's already been sorted out for you, specific to the car.
www.revingtontr.com in England is probably the premier source today, selling Luminition and Webcon (weber carbs manufacturer) EFI system kits carefully tuned for the different TR models. Both are pretty expensive. The Luminition is just a little cheaper but a little less sophisticated, too.
These complex kits are the top end of the price scale, of course. But going the other routes might prove to be false economy, if you end up doing a lot of expensive testing and sorting before getting it "right" (or worse, never really getting results that satisfy you!). What appeared cheaper initially could end up actually costing more.
You will need to do other prep work on the engine to bring it up to EFI standards, if you expect EFI to perform well. A different cam is definitely called for and, I think, different compression ratio is used (which might need to be modified from the original specs to accomodate changes in today's fuels and/or regional fuel differences).
Also, the EFI (PI) cars used a different cylinder head than the USA cars. I bet the US head could be used in some instances, perhaps with some modifications. But, for example, I don't think the Lucas PI system can bolt up directly to it. A replacement PI head might make more sense. Depends upon availability and cost. Carefully research other factors, such as if there is a different head gasket and/or valves, etc. used with PI. Even the exhaust might be different. I'm certain the fuel tank arrangement is different from the carbureted models.
All in all, I think it's great you are considering this and I'm not trying to dissuade you in any way. In fact, I'd like to try a similar conversion too, some day!
In general, William's take on EFI is that anyone considering performance upgrades to their TR should try to get a ride in an EFI converted car before commmiting time and money to other routes of improvement (such as dual Weber carbs). He feels strongly that EFI is a super way to bring the cars up-to-date in terms of performance and "fun", and highly recommends EFI for serious consideration.
Please keep us posted!
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