John,
Many thanks for the notes. The list is a really powerful resource, and
each subsequent reply adds a little more to the mix (your's definitely
included!) and I feel I already know enough about this mod to make it work!
On the pressure front - your right: everyone has made the same
observation - these are not electrically triggered but pressure triggered
so they have to have high pressure. On the tank front - I think I might be
lucky. From my reading of Piggott, it looks like all tanks were baffled
(as part of standarization as much as fuel surge) in very late 1971 for
1972 model year. I haven't had any surge probs with the ZSs (I know that
the float chamber acts as a short term reserve, so it wouldn't be as
obvious but we do use the car in autocross and haven't seen a problem there
- then again, maybe we're just too slow!!).
I am very interested to learn more about the Bosch route - have you got a
spec for the pump (and hopefully an idea of what it lives in so I might be
able to recycle one!). On the priming pump front - universal advice is get
one! What do you use as your low pressure primer pump?
I also was asked if I was purchasing the distributor for the car (one post
mentioned that the PI doesn't have the dual vaccuum unit - nor does the
1972 carb TR6 anyway), but I am sure that the centifugal bob weights and
springs are different. Did you have to do much to your '71 system on that
front?
Although I would be limited by the SCCA rules for mods to autocross cars
(or would have to compete against Formula Fords!), I can't do too much to
the internals, but I am interested in what you did to get the power up to
190bhp!
I will be keeping a log on this task and will post it, hopefully, to the
FAQs. Before I do, I'd appreciate it if you would be willing to check my
interpretation of how this might be done!
Cheers,
Tony
> Been following your thread on the Digest. You WILL need a high
> pressure pump (about 120lb) to operate the injectors. they have a
> 'crack' pressure of about 40 lbs. ie. they won't open until at least
> 40lbs. The system will not work with only 18 to 20 lbs. If you're
> worried about the Lucas pump over heating, install a Bosch unit. These
> are readily available and mine operates at a little over 120 lbs. The
> advantage of these is that the fuel passes through the pump (unlike
> the Lucas unit) keeping it cool.
>
> You will also need to install either a surge tank or baffle your fuel
> tank. The US spec fuel tanks are not baffled and you'll suffer from
> fuel starvation when cornering unless you modify the system. (ask me
> why I know this!). I have installed a surge tank, a pre-pump (about
> 3lbs pressure) and the Bosch main pump on my '71 ex US TR6 and have
> never had a problem since. BTW, my much modified '6 puts out about
> 190 bhp with the injection system - much better than the standard 120!
>
> John Mc
> '71 TR 6 PI
> 'Fast is First'
>
>
>
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