DIY PRINS

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bushboy
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Joined: Mon Aug 25, 2008 8:59 am
Location: Grays Essex

DIY PRINS

#1 Post by bushboy » Mon Apr 23, 2012 6:49 pm

G'day all,
I'm new to the world of LPG but not new to fooling around with engines & cars. I have aquired a PRINS VSI system from a VW V6 Bora & will fit it to a Mazda MX6 engine, currently residing in my kit car.

On the Bora the installation of the injector jets into the manifold were lengths of plastic pipe, approx 5mm dia, locked inplace by brass fittings. As the inlet runners were long the platic tubes were also long so as to reach as close to the head as possible. A good idea?? My question revolves around the gas delivery tube after the injector. Does the tube need to be jetted? I was thinkiing of using a similar set up on the Mazda engine to deliver the gas as close to the head port as possible. However I am thinking of using copper tubing, not having the brass fitting but locking the copper tube inplace with a suitabel LOCKTITE product. Space is tight on the manifold & not having a relatively large fitting to get the manifold bolts & socket around is the goal.

When I have home internet access available again, I will post some pictures of the install.

Thanks

Bushboy
(AKA Martin)

rossko
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Location: Wiltshire

Re: DIY PRINS

#2 Post by rossko » Tue Apr 24, 2012 10:49 am

The Keihin gas injectors are the parts that are sized. You can't alter them, only choose the correct ones to begin with.

I'd ask on MX6 forums about the approach to injection points (you might need to be diplomatic about the 'host' car). It's not essential to get right up to the valves, and potentially "too close" could give mixing problems. You do need to get downstream of any variable port or idle air complications.

Can't quite picture your copper tube arrangment, just gluing tube into the manifold? Could be a disaster if it loosens and falls in.

Valve situation is unknown to me, so I think I'd go with Flashlube for safety.

Gilbertd
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Location: Peterborough

Re: DIY PRINS

#3 Post by Gilbertd » Tue Apr 24, 2012 4:11 pm

The tubes you are talking about are usually referred to as 'straws' and are used where it isn't possible to get the injector nozzles close to the inlet valves (or you can't be bothered to take it off and drill close to the inlets and just drill somewhere convenient). If you can get the nozzles close to the petrol injectors on your Mazda engine, you don't need straws.

Mazda 6 from 2002 onwards (Ford engine) needs Flashlube, earlier ones shouldn't so it depends on what year your engine is.
'96 Saab 900XS, AEB Leo, sold
'93 Range Rover 4.2 LSE, Lovato LovEco, sold
'98 Ex-Police Range Rover 4.0, Singlepoint AEB Leo, my daily motor
'97 Range Rover 4.0SE, eGas multipoint, a project.....

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bushboy
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Posts: 2
Joined: Mon Aug 25, 2008 8:59 am
Location: Grays Essex

Re: DIY PRINS

#4 Post by bushboy » Tue Apr 24, 2012 5:49 pm

Thanks Gentlemen,

The injectors are red dots and the vaporiser is good to 135kw (I think around the 180hp mark) I'm afraid I understand horse power better than kw's.

If the injectors are "sized" then all I need do is deliver the gas as close to the port as practical and pipe size, to a degree, is not important. If the "glue" fails then the hoseclamp gripping the gas pipe to the copper pipe will prevent it "falling" into the engine. It will just give an air leak, fast idle & headache trying to locate it. My issue will be fitting the connectors with out interfering with the manifold bolts. Fortunately I have a spare manifold which I intend to modify & when the time is right I'll just swap them over. When I get the internet fixed at home I'll post some pictures that will clarify a few issues. If you can imagine, the petrol injectors sit right in the middle of the V & one side of the manifold then folds back over the top of them. On one side there is a clear easy to get to place for the fittings, but the otherside there is not.

The Mazda V6 does have a VRIS but the proposed position of the gas fittings is well after the extra plumbing & butterflys.

The engine is actually from a Ford Probe. The MX6 & the Probe were a joint effort between Mazda & Ford. It is from 1995 and from what I have been reading about LPG, I'll need to "freshen" it up with some new valve seals, plugs & leads.

Thanks for the advice, no doubt I'll be back for more.

Bushboy

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