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commonrail? can I swap one to work for diesel purposes?
by
NintendoKD
on 07 Sep, 2009 06:13
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Have an 80' rabbit diesel, the newer engines have commonrail systems on them. Rather than try to hunt down a salvaged one and possibly pay a small fortune for it is there anyway that it would work from a gasser? lots of gasoline engines have this system, is there a way to convert/install/mod this to work in my older car? Higher pressure fuel=better fuel economy=better performance right? I understand that the injectors are pezoelectric? what electronics would I have to take as well? Dimensions???
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#1
by
Rabbit on Roids
on 07 Sep, 2009 08:03
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gasoline injection takes place an under 100 psi. diesel injection takes place at over 2000 psi. diesels also dont breathe in the fuel with the air. they just suck in clean fresh air. the fuel is injected at the very top of the stroke, and the compressed air ignites it.
so, in other words, gas fuel injectors will not work on a diesel. EVER.
but if you took a common rail injection system like whats in the new TDI's or the duramax/cummins that use the CP3 pumps, you could adapt one of those to work probably. but this is definitely not for the light walleted person. its gonna cost a ton of money to make something like this work. to get a common rail system to work, you basically have to take the electronics system off one engine, and graft it to another engine.
how much money you looking to spend here? might be cheaper to just drop the whole duramax in your rabbit.
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#2
by
the caveman
on 07 Sep, 2009 08:08
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uhh, the short answer is -no
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#3
by
Rabbit on Roids
on 07 Sep, 2009 08:15
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oh, its possible, ive seen a diesel V6 chevrolet engine. it started out life as a gasoline engine. some dude made some super high pressure piezo infectors for conversions, and he had some sort of home brew (but beautifully done) electronics system/ecu for the engine. and the worst part, it was HELLA EXPENSIVE!
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#4
by
lord_verminaard
on 08 Sep, 2009 09:20
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He's pulling your leg. GM had a 4.3 V-6 diesel as well, from the factory.
Brendan
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#5
by
Rabbit on Roids
on 08 Sep, 2009 09:26
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He's pulling your leg. GM had a 4.3 V-6 diesel as well, from the factory.
Brendan
im pulling someones leg? no, im really not. it was a GM 3.4 litre or something V6. a new one. i just read about it a few months back in the Diesel Power magazine. he takes gas engines, and puts these special injectors in them and retrofits them to diesels. and i didnt even know that they made 4.3 diesels. what did they come in? i dont care how ***ty they are, i want one.
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#6
by
NintendoKD
on 08 Sep, 2009 21:17
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NAH! the beautiful thing about older diesels is no fancy schmancy electronics, Don't want to deal with em. I was just wondering if there was a way to retrofit a system from another vehicle to my car, I can manage some modification/fabrication so it wouldn't cost much except for the pick-and-pull parts to make it. Can a gasoline commonrail handle the pressures of a diesel commonrail? I guess that was my question, use a much cheaper much more common system from a gasser and add the correct diesel components, and voila everyone can use commonrail on their older car to achieve more power and efficiency.
I think it can be done, without staeling one from a new tdi "too new, too hard to find, too exspensive" no thanks. I must apologise, I am new to this forum but not to automotive tuning, I sometimes have ideas out of scope but not out of reach, I find the more radical the better.
Thanks,
Kevin
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#7
by
NintendoKD
on 08 Sep, 2009 21:36
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#8
by
maxfax
on 08 Sep, 2009 21:45
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Gasoline injectors & fuel rails will not handle the pressures needed for diesel.. I think about the highest pressures I;ve seen a gas engine injection operate is about 120 psi versus the close to 1900psi that our diesels operate.. Seals would never hold, injectors would blow apart, or at best just leak..
The reason for the high pressure on a diesel is that diesel fuel does not atomize as easily as gasoline.. Heck gasoline turns to vapor just sitting in a bucket at room temp..
I'm not going to say that fabricating such a setup is imposible, but you're gonna need injectors and plumbing designed to handle alot more pressure...
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#9
by
NintendoKD
on 08 Sep, 2009 21:52
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so the question remains, can you use the rail from a gasser and swap the injectors as opposed to the confuzing mazelike piping that is currently there?
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#10
by
arb
on 09 Sep, 2009 08:48
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Guys, you have the right idea about CRD, but you are off by an order of magnitude. The current crop uses 1600 - 2000 BAR, not psi. That equates to 23,200 psi - 29,000 psi. The higher being the new bread for the latest electric piezo injectors. They use this high pressure because they do up to 5 injection events per combustion cycle per cylinder. I have first had experience with the CRD they put in the Liberty when I worked at their head quarters
http://www.vmmotori.it/en/01/00/01/dettaglio.jsp?id=56 (the RA 428 DOHC )
Attaching a CP3 pump, common rail, and adapting the injectors is the easy part. I bet many of us could do this. The problem comes in the controls. There needs to be a precision crank angle sensor. (The source of many PowerStrokes dying along the freeway) And the computer needs to have a profile to the specific engine - valve timing, compression ratio, displacement, barometric pressure in the intake, temp, etc, etc. The difference can be dramatic if the profile does not match the engine.
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#11
by
NintendoKD
on 09 Sep, 2009 09:35
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So then I guess my next question is How does the VE pump work? I am sure there is already a thread on this? thanks guys and sorry about all of the annoying questions, I have to start somewhere.
Thanks for all of the great input and knowledge,
Kevin
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#12
by
Rabbit on Roids
on 09 Sep, 2009 09:42
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the way i learned about VW pumps was, get a junk one, take it apart. CLEAR APART! well, i have still never taken out the vane pump, but i can guess as to what it looks like. i took a junk 1.6 pump and just sat down one day and started tearing into it. they are pretty friggen simple if you can look at something and determine how it works. but use a junk pump or one you dont care about, cause then if you break something its not a big deal.
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#13
by
diesel smoke
on 09 Sep, 2009 20:40
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He's pulling your leg. GM had a 4.3 V-6 diesel as well, from the factory.
Brendan
im pulling someones leg? no, im really not. it was a GM 3.4 litre or something V6. a new one. i just read about it a few months back in the Diesel Power magazine. he takes gas engines, and puts these special injectors in them and retrofits them to diesels. and i didnt even know that they made 4.3 diesels. what did they come in? i dont care how ***ty they are, i want one.
Wonder if he upgrades the bottom end. Because if it isn't...well...
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#14
by
arb
on 10 Sep, 2009 05:31
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He's pulling your leg. GM had a 4.3 V-6 diesel as well, from the factory.
Brendan
im pulling someones leg? no, im really not. it was a GM 3.4 litre or something V6. a new one. i just read about it a few months back in the Diesel Power magazine. he takes gas engines, and puts these special injectors in them and retrofits them to diesels. and i didnt even know that they made 4.3 diesels. what did they come in? i dont care how ***ty they are, i want one.
Wonder if he upgrades the bottom end. Because if it isn't...well...
Probably would not matter as long as he is not trying to make huge amounts of power with the diesel conversion - reason, today's engines are designed to have around 2x the power of 25 years ago. So, the lower ends today are much stronger than in the past.