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TDI swap questions

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out there

20+ Year Contributor
1,276
2
Nov 8, 2002
Fargo, North_Dakota
I have been driving a diesel since my DSM was smashed some years ago, and it recently occurred to me that a great combination would be a VW 1.9L diesel in a DSM. Before I get too far into this effort, I figured it would be worth asking around.

After a brief mental inventory, it seems the two _major_ difficulties will be mating the engine to the transmission, and wiring. One guy I have lunch with runs a machine shop, so I can probably get his help with that bell housing. Now, I have no experience with wiring swaps, so I need the most direction there. Because the engine I would use comes from an OBD2 vehicle, is there any realistic way to incorporate the VW ECU into a 2g DSM harness?

Am I on the right track? I am open to whatever input you guys have.
 
First of all I must say I strongly suggest you dont do this considering the major power loss you will suffer. But if you must do it your going to need to use the ecu and harness out of your vw no question. You will also need to rig up your diesel fuel pump into the dsm tank. If your friend is a good machinists he should have no problem making an adapter plate for your trans.
hope this helps and good luck!
 
I'm not looking for power gains; I'm looking for fuel economy, and awd. Since there aren't any awd diesel cars in the US (except that new BMW), I'm planning to make my own answer. Given how sturdy the stock transmissions are, a 2g seems like the perfect choice.
 
I dont want to rain on your parade but before you bolt the TDI to the AWD trans, you gotta ask...

At what RPM are you cruising on the free way in your TDI now, and how fast do you want to cruse in this high-bred?

Most diesel cars have a very low red line and max torque occurs very low in the RPM compared to gas cars, the transmission is geared accordingly. This lets you cruse on the freeway between 2000 to 2500 RPM-ish. I don't know about anyone else but in my AWD talon if I were to cruse at that RPM range I would be doing about 60-ish and get run over, I cruse between 3200 and 3500ish RPM. Diesels have come a long way I don't think they will like being pushed that high for extended periods of time. for the best MPG performance you really need to think about keeping the transmission that was bolted to the TDI engine with it, but if you want to pull a semi trailer behind your car then the TDI engine and the AWD transmission will make an excellent combination... you could probably pull your house down with it...


DSM - VW
AWD - TDI
4.929 - 3.238 Final drive
--------2.615 5/6 Final drive (Whatever that means....)
3.083 - 3.769 First
1.684 - 2.087 Second
1.115 - 1.324 Third
.883 - 0.977 fourth
.666 - 0.975 Fifth
-------0.814 Sixth
 
Great minds, eh? Earlier today, I did what you just did. I have 5 gears which are
1- 3.778
2- 2.118
3- 1.360
4- 0.971
5- 0.756
final 3.389

Cruising at 55, I'm a little below 2000. With the final drive of the GSX gearbox, I'd be a lot closer to 2500... Definitely not economic, unless I went through the difficulty of getting a new final drive gear that's closer to 3.8... and all that trouble... Back to the drawing board.

After some more seeking around, it seems Mitsubishi has a really attractive 4g56t. I guess that creates a new set of questions. How much easier would it be to transplant another Mitsubishi engine, transmission, and appropriate version OBD ECU into a GSX? Maybe a different shaft to the rear end?
 
Or just wait and buy the new AWD TDI car VW and Audi will be selling within the next year or two. That or go to a TDI swap into a Toyota truck or 4runner. That has been done many times and is well documented.
 
My brother has a MKIV TDI, so I have a little bit of experience with V-Dubs. For starters, you can't bolt that motor to our trans because you'd have to flip the orientation of the engine. In a VW the engine sits on the pass side and the trans is on the drivers. You would be best suited swapping the engine and the trans together, especially since the trans for the diesel is built strong enough to handle the torque that engine produces. Also it makes sense to keep the custom part making to a minimum, so all you need to fab is motor/trans mounts and figure out how to run the shifter. I believe they are cable style, but I haven't played around with that. As for the diesel pump, that's run off the timing belt so you don't have to worry about rigging something into the fuel tank. I fully support the idea, but there's a lot of research to do first.
 
Yes, I have considered the Toyota swap. The idea is to achieve a diesel car that is awd for a total cost that is an improvement over gasoline in the long run.

If I were interested in just throwing money at the problem, I would have bought a BMW 328d. That's more than I can justify spending, and wouldn't be as neat.

Unless something that doesn't require vast amounts of custom fabrication can be attained for my target cost (I think $6-8k is reasonable), I will either bite the bullet and buy a small truck, or awd car.
 
After some more seeking around, it seems Mitsubishi has a really attractive 4g56t. I guess that creates a new set of questions. How much easier would it be to transplant another Mitsubishi engine, transmission, and appropriate version OBD ECU into a GSX? Maybe a different shaft to the rear end?

There aren't really any other engines or transmissions Mitsubishi or otherwise that are an easy swap into a GSX so your pretty much going to be on your own with a project like this and it would take a lot of custom fabrication. As far as ECU you would probably have to use the appropriate ecu for engine that you choose and make a custom harness.
 
Someone correct me if I'm wrong, but didn't Mitsubishi offer a vehicle (in another country for sure) that had a diesel 4g63 or 4g64? I've thought about this from time to time, but nothing more.
 
Yes there is a diesel mitsubishi that fits right into place of the 4g. I believe there is also newer versions that are common rail and direct injection, but they are rarer then hens teeth. 4d65 and 4d68. As far as gears, you need final drives of a gallant gsx, they would turn your overall final into somewhere around 3.80 from 4.929. Morpius on here was playing with this idea back in about 2006.

The idi engine might be your best bet though as they will have a close rev range to a gasser, and easiest to get, but you will pay a slight efficiency penalty though.
 
Also in hindsight if you wanted to run a vw diesel you might consider running an evo4 and up transmission and transfercase. Then the you can keep the vw engine in the right direction, it will handle more torque, and easier to get tall gears (tre 3.73)

Pretty sure auto dsm rear end is same ratio as evo.
 
naw, the auto is 3.3ish rear ratio. evo 1-9 maybe even 10? all have 3.90
not sure about the galant gsx stuff
you can get an evo 5th gear it has a .617 overdrive
 
i should point out i havent personally counted the teeth on an automatic rear diff, but ive read many times thats what they are
 
If you are considering a diesal swap, the best way to do so would be to use a Mitsubishi engine and drive train, anything else and you are over complicating things. Why use anything other than Mitsubishi parts when Mitsubishi has exactly what you need. From 1991-1997 Mitsubishi Chariot had a 4d68 which is the diesel version of the 4g63, they also came with awd as an option, so you would probably have to locate this specific car and swap it's drive train.

Right now on ebay there are 4d68 pistons rods and a head for sale from UK. I theorize that the blocks of Sirius gasoline and diesel engines are the same. This could be your best bet other than locating an actual full engine obviously.

I believe these engines came mated to AWD drive trains in other vehicles as well, potentially the gallant or lancer.

I have located these engines and transmissions for sale but only in bulk order which is rather disappointing.
 
As I previously stated, the only mitsu diesel that is in the sirius family, is the 4d65/68, and they are indirect injection with is sucky. Low power and low mileage. a modern DIT engine is what is needed. VW makes several that are lightyears ahead of mitsu diesels.

also pimpy. the evo8 rear end is 3.3, just like the dsm automatics.
 
After reading all the posts, and suggestions, I did some looking around, and then kind of gave up when I saw the diesel BMW that is on the market. Anyway, I am leaning away from spending a year's wages on a car, so I'm looking more closely at a diesel awd swap again.

I like the idea of using the 4d56, because it offers more than the 4d68. Since I'm not in a hurry, this won't happen too quickly. Unless someone can offer better suggestions than an awd dsm with a diesel swap, that seems the best direction.
 
If you don't understand why someone would choose a diesel engine over a gasoline one, you'll never understand.

Why do you want to drive a turbo-charged car, and not one without forced induction? Why do you prefer awd to fwd or rwd?

Diesel has many benefits: lots of torque at low RPM, no ignition system, cooler combustion, stouter engine components. Less fell consumption is a by-product of the way it operates.
It has a significant downside: cold weather starting

This thread isn't about gasoline vs diesel; this is about putting a diesel engine into a dsm.
 
If you don't understand why someone would choose a diesel engine over a gasoline one, you'll never understand.

Why do you want to drive a turbo-charged car, and not one without forced induction? Why do you prefer awd to fwd or rwd?

Diesel has many benefits: lots of torque at low RPM, no ignition system, cooler combustion, stouter engine components. Less fell consumption is a by-product of the way it operates.
It has a significant downside: cold weather starting

This thread isn't about gasoline vs diesel; this is about putting a diesel engine into a dsm.
There are many reasons people can choose diesel or gasoline. I just wasnt able to see why you picked this platform and that motor and wanted to make it work. I understand Diesels fully and know they have a place. The amount of work required to make a VW TDI work in a dsm isnt worth it to me thats why i asked. No reason to get defensive.
 
>The amount of work required to make a VW TDI work in a dsm isnt worth it to me thats why i asked. No reason to get defensive.

There's the rub. I'm not above a lot of time, and work. Actually, even if I didn't do anything, and paid someone else to do it, I expect the cost would still be less than $40k. There are a few ideas on the chopping block. After some looking around, a 4d56t is probably the winner, if I can find one that runs with obd1 or obd2.
 
I'm interested in this engine from a performance perspective too. I thought it would be interesting in a Fox body Mustang. What does the entire engine weigh?
 
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