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Engine Specific Info and Questions => IDI Engine => Topic started by: Mechdonald on March 24, 2006, 10:26:16 am
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Can a VR6 be made into a TD – seriously
I have posted this question for discussion in VWVortex and had some good response and some negative. (Thanks Malone and others for helpful info)
Please forgive me if this has already been addressed on this forum – I did a quick search with no results – (there is the guy that asked what his mileage would be if he swapped his sparkplugs with injectors…)
Just wanted to throw this question to this board as there seems to be a lot more qualified/experienced members hanging out here.
So, the question is:
What all would be involved in converting a VR6 to an IDI (n/a first, then TD) ?
Most of the work would be on the cylinder head, ie, rework to add a prechamber, cam timing, custom pistons, etc.
The head is already flat (no combustion chamber) so that helps. Is there room in a VR6 head for the prechamber?
What would be the valve timing of a diesel compared to a gasser?
Are custom pistons and camshafts outrageously expensive?
Would a injector pump from a 2.4 Volvo engine work? I would imagine the timing of the pump would have to altered (inline 6 compared to 15 degree V6)
Or alternatively, can something like this be controlled with Megasquirt? Isn’t there someone on this board attempting this?
Would an aftermarket vr6 turbo kit (fairly common these days) be modified to fit a better suited turbo?
As you can see, there are many unanswered questions.
Any helpful input is welcomed
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it'd be easier to make it an mTDI, as adding pre cups would probably be a pita. it think it would be possible, but it would rack quite a machine shop bill, and it would be kind of lame, since what i've learned in the past is that diesels are made differently from gas engines, so even after all the head work, who's to say it will hold up.
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there are also other types of injector pumps, vws have centrifugal pumps, i forget what the other kind is called but it works a little different.
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volvo offered a 6-cyl diesel that is essentially a VW 4-cyl IDI with 2 extra cylinders. i'd look into that.
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volvo offered a 6-cyl diesel that is essentially a VW 4-cyl IDI with 2 extra cylinders. i'd look into that.
could possibly fit in a mk2 :)
would be nice for a veggie conversion with lots of power
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I'd look more at the inline 5 cylinder diesel from an Audi. I think it would be more likely to fit. I see cylinder 20v RS2 engines mounted transversely using a Eurovan transmission, so why not?
Other than that, I think I'd have to agree with the others. This project is doable, but at what cost? Making it a TDI would be much easier than making it an IDI. You'd have to find some other nozzles with the correct spray angle and then I would try and use the TDI injector bodes. Add in some pistons with a swirl chamber and in theory it should work.
My concerns mirror that of the others. We have no way of knowing how durable this engine would be. I'm going to guess you'd have less than wonderful mileage. A 1.9 TDI would probably also offer you more power potential than you need as well as superior mileage, cheaper initial investment, increased reliability, and the added benefit of being able to buy parts right off the shelf. All of these things just make this project prohibitive in my opinion.
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I'd look more at the inline 5 cylinder diesel from an Audi. I think it would be more likely to fit. I see cylinder 20v RS2 engines mounted transversely using a Eurovan transmission, so why not?
Other than that, I think I'd have to agree with the others. This project is doable, but at what cost? Making it a TDI would be much easier than making it an IDI. You'd have to find some other nozzles with the correct spray angle and then I would try and use the TDI injector bodes. Add in some pistons with a swirl chamber and in theory it should work.
My concerns mirror that of the others. We have no way of knowing how durable this engine would be. I'm going to guess you'd have less than wonderful mileage. A 1.9 TDI would probably also offer you more power potential than you need as well as superior mileage, cheaper initial investment, increased reliability, and the added benefit of being able to buy parts right off the shelf. All of these things just make this project prohibitive in my opinion.
I'd say its doable. Just because GM has converted gas motors to diesel before, but it must have cost them a lot for research and development.
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i've heard really good things about the 6 cyl in volvos from the volvo guys, apparently they're monsters. on another topic of vw motors in other peoples cars, theres a guy around here that wants to put a g60 in a dodge omni, that tear some *** up, and it would bolt right in hehe.
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Even custom pistons for the VR are pretty cheap, as they are really the only internal that is needed to be changed for big power. EIP makes 600 hp turbo VR's all day, usually all that is changed internally are pistons. If a gasser VR can handle 30 psi and 600 hp, A diesel should be able to handle 25 psi or so with around 200 hp. Again, like others, the head work would be the hardest, as you would need to make a hole for glow plugs as well as injectors. I'd probably start with TDI injectors as there is no need for a pre-chamber. (but the pistons would need "chambers" to work properly.
I thought I read somewhere that VW was playing with a TDI VR6 at one point? Wonder what happened with it?
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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It's only money, with enough of it anything is possible. :wink:
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Just get a V6 TDI, much easier.
The Volvo motor you speak of is actually a VW LT motor, search for LT28, LT30, LT35, LT40, LT45, LT50 and the daddy, the LT55.
Numbers represent gross weight.
But, the Volvo motor with the intercooler produces the most power, a Nice conversion for the truck is to fit the Volvo motor, my mates LT50 recovery truck had it don, 'parently it flew!
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No idea but at a guess you,d need a custom crank, conrods, pistons and cams, possibly an uprated headgasket? do vr6,s have oil squirters?, gonna have to fit glowplugs somehow too with a hefty glowplug controller to get it up to temp? are vr,s direct injection? I really dont know that much about them.
Would be interesting as a project i suppose
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I've head some dealers doc that the VR6 was supposed to be available in diesel too.
Pretty sure that's why it has a flat head.
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why dont u jst put in a petrol vr6? (http://www.dub-marines.co.uk/boards/images/smiles/icon_confused.gif)
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why dont u jst put in a petrol vr6? (http://www.dub-marines.co.uk/boards/images/smiles/icon_confused.gif)
I'm guessing he's just trying to be different. Besides, a VR6 swap is kind of pointless unless it is turbo'd/supercharged.
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A vr6 converted to diesel, idi or tdi, is outrageous. I can't believe this is even a question... what is this, the vortex?
-Josh
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Well, a lot of people on the vortex dont understand why anyone bothers modifying a Diesel either. I say, if he's got the stones to do it, then he should do it. This forum has always been about changing the rules and pioneering new thinking. Sounds like a perfectly reasonable question to me. Do you think putting a Diesel in a Scirocco is an "outrageous" idea?
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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A vr6 converted to diesel, idi or tdi, is outrageous. I can't believe this is even a question... what is this, the vortex?
-Josh
Bwahaha! Awesome!
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I really doubt the IDI VR6 idea is feasible as a head conversion project. I don't see there being room amidst the network of intake and exhaust runners and water jacket to sink prechambers into the head. :?
It would take a lot of resources (the kind that only automotive OEMs have, or very wealthy racing team owners) to completely reengineer and manufacture from scratch a prototype cylinder head.
On the VR6 DI conversion idea - there are a few unique problems you'd need to solve that would likely make this very challenging. I'm not talking about the necessary custom pistons, rods, and reground cam, which are solveable with adequate budget. Adapting the injectors may prove challenging because I believe the TDI injectors are installed indexed and at a specific angle, and their injection pattern is designed to match that specific installation angle. Their position and installation height would also have to match the combustion chamber perfectly to get good results. If the sparkplug holes didn't happen to be in the right angle, you'd likely need different injectors. If they aren't in a central position, all at the same angle in each of the 6 cylinders, you're going to have a very difficult time achieving a "well balanced", smooth running motor.
Unique challenge number #2: the TDI intake ports are designed to impart "swirl" characteristic to the air as it enters the chamber, to bring all the air to the injector spray nozzles so you're burning more than just burning the air that happens to be in front of the injector's orifices. If you don't bring the air to the injector, you're going to get a lousy running diesel - smoking, low power, and low efficiency. You would need to add some material (maybe through aluminum welding or metallic epoxy) to the runner to give it the necessary contour to impart swirling. Perhaps you could just "eyeball" it and use a TDI's intake port shape as a guide? But you might end up with improper or uneven swirl across the cylinders. VW has means of testing the amount of swirl and to expect good results on your first try, you probably should too.
If you are still interested in these projects, you'll need to learn as much as you can about diesel engine design. At minimum you should read every VW Diesel SAE paper and technical engineering document you can find.
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I read in an SAE paper (I cannot recall which) that the VR6 motor, was indeed designed in mind for use with the diesel cycle. A major problem with the combustion chamber design, from what I've read, is the wedge shaped quench area. This could be resolved with proper/custom wedge shaped pistons, with the enhanced Japanese style cloverleaf relief in the piston surface. It is possible VW has designs somewhere for these pistons, if they got that far in the development of the engine.
If there is indeed room for a swirl chamber within the head, this project could be possible in an IDI format. A DI design would be easier in some aspects, but without strong swirl via bespoke inlet runners, would require great effort, as Jake mentioned.
As far as the IP, again from what I've read, the crankshaft has 120 degree throws, which is exactly what an inline six uses. Therefore, the injection timing should be that of just about any inline six cylinder engine. Drive for IP would be from the chain (possibly complex), or perhaps from the other end of the camshaft, like the VW inline six engine.
If you have the room, I suggest using the VW inline six that is used in VW LT vans, and Volvos, as it is a well proven, extremely strong design.
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Nah, a diesel in a Scirocco is cool. It's a bolt-in conversion, basically.
But for all the reasons listed and more, attempting to adapt a vr6 to run diesel is just plain crazy talk, I don't care how much money you've got to spend.
IT's just NUTS!! Sure, it's possible, but so is converting a rabbit into an aeroplane; although the latter is probably cheaper.
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Yeeesh - you would almost think I asked a stupid question or something :lol:
I appreciate the helpful comments from the technical side.
I'm learning quite a bit on this forum about what is possible with IDI and TDI engines. (who would have thought you could make a M-TDI? - very neat)
Sometimes, not knowing that "you can't do that" allows you to look at the problem with fresh eyes and come up with a solution. I have to do that all the time in my job.
I wasn't sure if the VR6D question had ever been asked before on here.
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I hate to put such a downer on this but where would you get a fuel injection pump to supply fuel for the correct firing order of the VR motor ? Where would you drive the pump ? (timing chain ???)
Driving it wouldnt be such a problem and tweeking it but the firing order would be the problem, and making fuel injecion lines. Machining the head for pre-chambers would be fun ! I work in the machine shop running CNC mills, this would be easy and probably not a big job getting IDI injectors into the head either but to be honest, you'd be better with a VR6 diesel with direct injection. It would take much more work to make an IDI.
I agree with the others, you would get much more power from a TDi or M-TDi in a nicer package and it would cost less also.....but then again - its all been done before hasnt it !
Best of luck. DM
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Mechdonald,
I apologize for being harsh earlier; I've no right to dump on anybody's questions. I was just in a bad mood and took it out on the board. Sorry, All! I like the open nature of the board, and hope it will remain a safe place to ask questions, regardless of their relative outrageousness.
-Josh
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As for a timng pump that has the correct firning order, you SHOULD be able to determine the firing order of the pump and match it to the engine. All yo have to do is reroute the lines to where they would need to go. Provided you have a pump for a 6 cylinder 8) .
Running the pump off a timing chain shouldn't be a real issue, but maybe you can convert to a belt system.
Bernie
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You've got to reroute the lines keeping the lengths of the tubes equal, of course.
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Josh - that's OK, I know all about being in bad moods.
Good point brought up about the pump timing. Does the VR6 fire evenly?
I was thinking of a pump off the Volvo inline 6 that naturally would have an even firing order. If the VR6 does NOT fire evenly then....there goes that idea.
I checked out a book I have in the basement last night about VW history. There is a little blurb in there about when the VR6 was introduced - VW claimed that 24V and Diesel versions were possible... the rumour is true to a point.
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Like 2383 GTD said earlier:
"As far as the IP, again from what I've read, the crankshaft has 120 degree throws, which is exactly what an inline six uses. Therefore, the injection timing should be that of just about any inline six cylinder engine. Drive for IP would be from the chain (possibly complex), or perhaps from the other end of the camshaft, like the VW inline six engine."
So there ya go. Either the volvo pump or even a cummins 6BT pump would work. Making the lines would be easy, just figure out how long you need, then buy some pre-made straight lines with fittings all in the same length and bend them to fit. Like others have said, it would be head mods and figuring out a way to drive the IP that would be the hard stuff.
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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Look at this cutaway of the VR6: About halfway down the page
http://www.me.umn.edu/~byronr/vw/gti_picts.html
Notice the position of the plug related to the combustion chamber and piston.
With the proper pistons (TDI style) and injectors in the plug holes, I think you may be able to get the swirl necessary to efficiently combust your diesel.
Bernie
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thanks for the link. that's the cutaway I've seen before - the plug is off to the side as needed.
Like many have said and somewhat verified - VW has said themselves that a diesel version is possible. I wonder how much work they did on a diesel version.
Just another question about pump timing:
If the crank is 120 degrees like a straight 6 but the V angle is 15 - wouldn't that give you DIFFERENT timing then the straight 6?
I think it would - if you make the V angle more pronounced (say 60 degrees) you can visualize it better.
Is that what gives the VR6 its neat sound? - a slightly uneven firing?
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Never mind, I got my answer about the timing
please see this article http://www.eurotuned.com/vw/VR6tech.htm
It explains the 120 degree firing order - tricky tricky.
An inline 6 pump would work then :D
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You've got to reroute the lines keeping the lengths of the tubes equal, of course.
I'm a diesel newb....why do the injector lines need to be equal length?
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i've thought about this before myself..it looks cool. i have a extra cummins pump, a couple actually .. what is the bore size of the vr6? The block could be sleeved to fit tdi pistons. The injector hold downs could be made to fit the deep well or other di injectors could be used from another kind of diesel... i have vr6 too ..mumn
time and $ ..i don't have much of either..
Thanks
Deo
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Bore of the standard 2.8 VR6: 81mm. But, you will need custom pistons as the VR pistons are sort of "wedge" shaped anyway, so....
Brendan
84 Scirocco 8v
00 Camaro L36 M49
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just found an interesting web article about reverse engineering using industrial CT scanning. http://www.materialise.com/magics-rp/copyandpaste_ENG.html
Made an inquiry locally about it but London is a medical town so not much luck in doing a cylinder head here. Very expensive to get done too.
University of Texas will do it for a pretty price - something like $85/hour and it takes a lot of hours.
Neat stuff for sure