Mr Whippy
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| posted on 8/1/09 at 07:56 AM |
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Converting Carb to Injection & LPG
Ok this kind of thing is a bit out my league being still in the carb dark ages 
Many of you will know by now I have a bluebird 1.8 auto, its been converted to LPG which works great but that system still uses the carb down stream
so all the nasty restrictions due to the small butterfly valves and naff inlet manifold is I feel unnecessarily restricting my poor little engine. The
LPG set up is closed loop and required a Lambda sensor to be fitted so I thought why not just ditch the carb and either fit separate throttle body’s
or instead (what I actually prefer) get new inlet manifolds made, fab in steel a Plenum chamber and fit a large single point fuel injection throttle
valve, say off a 2ltr engine with the LPG fogger just in front of that.
All this seems quite straight forward but what about all the electronics, would a ‘Mega Squirt’ system work here? Do I need to get an injector
specifically rated for that size of engine or will the system automatically match it? Am I also going to have to fit an airmass sensor too?
Seems a shame all that good injection stuff lying unloved around the scrappys and me still stuck with 90’s low tec…
[Edited on 8/1/09 by Mr Whippy]
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ashg
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| posted on 8/1/09 at 09:10 AM |
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get a set of throttle bodies and multi point inject the lpg.
Anything With Tits or Wheels Will cost you MONEY!!
Haynes Roadster (Finished)
Exocet (Finished & Sold)
New Project (Started)
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Mr Whippy
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| posted on 8/1/09 at 09:17 AM |
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quote:
Originally posted by ashg
get a set of throttle bodies and multi point inject the lpg.
I already have the LPG fogger which is single point. What's the advantage of using four throttle bodys rather than one big one? Its no race car
just a daily driver and I'm just trying to make it breath better. Also like to keep it very simple
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Mr Whippy
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| posted on 8/1/09 at 09:35 AM |
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ah ha found someone doing what I want to an old BMW, except the lucky sod has a manifold
linky
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sebastiaan
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| posted on 8/1/09 at 06:21 PM |
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don't do it.
A fogger or venturi system on a large volume (EFI) manifold is asking for trouble. Expect large backfires that possibly end in your car going up in
flames. If you want to convert it, fit multipoint injection as suggested here earlier. You'll need to get a new vaporizer then too, since your
current system works at ~ atmospheric pressure, whereas the injected systems work at approximately 15psi overpressure.
Regards,
Sebastiaan
ps. I make a living designing LPG conversions, so shoudl know what i'm on about 
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britishtrident
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| posted on 9/1/09 at 08:03 AM |
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If it works don't fix it buy something else.
Apart from the above pitfalls if you actually did it the first thing that would happen is the JATCO autotransmision would be toast. JATCO (formerly
Nissan) autoboxes are not exactly renown for reliability.
[I] “ What use our work, Bennet, if we cannot care for those we love? .”
― From BBC TV/Amazon's Ripper Street.
[/I]
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Mr Whippy
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| posted on 9/1/09 at 08:20 AM |
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No problems with the transmission yet though I have fitted a remote oil cooler, its not used for towing either, so touch wood. Had quite a few autos
over the years, most problems are due to infrequent oil changes and overloading. I might look at the multi-point idea if I can find a manifold for the
injection setup, or might make one like the F1 car have with the injectors spraying down the inlet from above. Cheers.
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zilspeed
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| posted on 10/1/09 at 07:18 PM |
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quote:
Originally posted by Mr Whippy
No problems with the transmission yet though I have fitted a remote oil cooler, its not used for towing either, so touch wood. Had quite a few autos
over the years, most problems are due to infrequent oil changes and overloading. I might look at the multi-point idea if I can find a manifold for the
injection setup, or might make one like the F1 car have with the injectors spraying down the inlet from above. Cheers.
If you read the installations instructions for Multipoint LPG, one of the criteria os that the injectors shoudl be as close as is possible to the
petrol injectors. Tha'ts because they are taking their parameters from them, so should really be in the same position.
That's how my setup works anyway :-)
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