'91 Vanagon Automatic 15° mTDI ALH Conversion

[syncroserge]

the funny thing about that video is watching the coolant temp needle

must have been a really hot day the way it's climbing so fast..

you should see mine here in january when it's -20 to -30 F .. darn ALH ..

[?Waldo?]

Yup, I didn't start the video until after I had finished running a couple errands. Then a fairly high speed uphill run and a jaunt on the freeway finally got the needle off of COLD...

Here's some more info for anyone interested in the tach install. Due to this being an mTDI there is no ECU and so no engine speed signal generated. Some folks use the alt W-signal (unrectified A/C signal) but pulley size differences can cause calibration issues and also mess with the dynamic oil pressure warning system function. To that end I decided to stay with a gasser tach and to generate the necessary 2 pulses per rev to drive it.

Here are the fabbed components I came up with:

They fasten to the engine like this:

I replaced two of the four crank bolts with studs and coupling nuts and then installed a short bolt into the open end of the coupling nuts in order to read off the flat face of the bolts. The bracket was designed so that I could still access the main crank bolt for rotating the engine by hand:

I had a little concern about crank thrust changing the air gap, but it doesn't seem to be an issue. Tach operation is solid. On another install I might be tempted to rotate the sensor so that it is perpendicular to the crank axis and then install two longer bolts into the coupling nuts in order to read off the shanks of the bolts but this works fine for this install. The sensor that I used is part number XR3Z-7H103AB and retails for approx $25. It generates approx 1.9v A/C. I found that it would not drive the stock '91 vanagon gasser tach (arghhh....) but that it works well with an early mk2 gasser tach. Oddly enough I have two early mk2 gasser tachs and only one would work with the system. I'm not sure if the one that didn't work was because of a fault with the tach or a difference in design. Although I had to disassemble the instrument cluster to install the mk2 tach, I did not make any changes to the wiring. The probe has two interchangeable connections and one goes to ground and the other goes to the green wire that was previously connected to the WBX ignition coil. I have considered installing magnets instead of the two bolts in order to bump up the signal output in order for it to work with the stock vanagon tach. I'm curious if anyone has any other suggestions.

[human compass]

Hey Andrew, sweet project! I'll have to look for you around town to check it out. Surprised we havent run into each other. Here is a pic of mine, honk and I'll likely pull over and chat!

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84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp

[?Waldo?]

I thought I'd give a quick update. The van has run flawlessly. I just filled it up and the total miles since last fillup were 390. All the miles were in-city driving. It took a total of 15.28 gallons. That works out to just over 25.5 miles per gallon.

Since my last update to this thread I really haven't done anything to this van except install '93 Eurovan seats in the front and I did a fairly thorugh cleaning of the front carpets. Other than that I've just driven it.

[denwood]

That's excellent fuel mileage Andrew, particularly given all city. What would you project for highway? My a3 TDI averages 37 mpg (UK) city, and jumps to about 56mpg (UK) highway...obviously a much smaller/aerodynamic vehicle. The thought of going diesel with my i4 Westy auto has crossed my mind many times.

The dipstick and tach projects show some great creativity
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Cheers,
Dennis Wood
The Grape

[?Waldo?]

My gallons are all US, not imperial (UK). 25.5 miles per US gallon = 30.6 miles per imperial gallon.

I have found that vanagons do not have as dramatic a difference in-city vs. freeway as other vehicles. Probably it is due to such large frontal area and high drag that wind resistance is a bigger factor. I think I'd probably see 27ish mpg (US) for freeway driving. I'll report back after I take it on a trip.

[denwood]

Understood..that's why I quoted my numbers as UK. I'm in a weird place as officially I should be quoting l/100km, however most would find those numbers relatively useless over the border

One wonders what a proper lock up torque converter would yield in improvements.
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Cheers,
Dennis Wood
The Grape

[?Waldo?]

I'd love to have a lock-up TC option. My current TC is the stock vanagon version with a stall speed @ 2800 rpms or so. The ALH has peak torque below 2,000 rpms so I believe I would get both better fuel economy and better performance with a lower stall speed. During acceleration my engine spends most of its time between 3,000 and 4,000 rpms.

[OddN]

Great info on the mTDI combined With the Automatic.

I have a European spec Caravelle Coach With the 112i DJ engine and an NJ Automatic (the one With 3,73 final drive) The van is lowered and having 16 inch tires, 245/45R-16 rear, similar rolling radius to the Stock 205/70R-14.

Im considering a diesel swap, either for an AAZ or a TDI, but Im a bit concerned about the gearing. I do not want taller tires, and the cost of a New set of ring/pinion (eg 3,27:1) is a bit steep. The diesel engines are easily obtainable here, but I dont want to end up With something that isnt driveable in 60+mph.

What is Your experience With Stock tires om Your combo?
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1991 VW Multivan syncro 1,9 TD

[?Waldo?]

I do not have any experience running stock tires on this particular van. I first drove this van with 27" diameter tires. More importantly, they are the only tires I have had installed since installing the tach. That said, I've run stock tires and this same tire on other manual trans vanagons I have owned and have found that the tires drop approx 200 rpms off of stock tires. My prediction is that with stock sized tires you would fluctuate between 3700 and 4000 rpms @ 60ish miles. That won't hurt the AAZ or TDI engines, but your fuel economy will suffer. To get a better idea, watch the video I posted and add 200 rpms to the tach for any given speed. Even with high cruising rpms you'll still get much better fuel economy than a DJ. When looking at the fuel economy thread I am astounded by the poor fuel economy numbers of the WBX engines. It would be impossible for me to stomach low to mid-teens in MPG coupled to the gutlessness of the 2.1 or even worse, the 1.9WBX.

I would make a note regarding that video. I remember hearing the sound of the engine change a few days prior to making that video with a slight drop in power. A few days after shooting that video, the hiss sound got worse and power dropped off more significantly along with black smoke in high pedal situations. On close inspection I found that the boost hose between the turbo and intake (still un-intercooled) had burst. My point is that the video was taken with a bit of a boost leak. After replacing that hose the power was back to normal.

Personally I feel the 3.73 is still too short even with 27" tires. I have been considering various options. I may spring for the 3.3 R+P. I also may shave the trailing arms and run even larger rear tires. I also plan on running a lower stall torque converter in order to move my rpms to the 2,000-3,000 range rather than the 3,000-4,000 range.

[OddN]

Thanks. 4000rpm at 60 mph seems a bit high for comfortable cruising With the TDI, I agree With that. And you wont have much left in terms of accelleration above 60.

When it comes to fuel economy, I believe the DJ With its higher compression is a bit better than the other wbx engines. I have never been below 15mpg With mine even in low speed winter city driving. And cruising in 50mph gets an average of 25. It requires 98 octane though, which is a bit more expensive.

My syncro With AAZ Conversion is usually between 25 and 30 mpg.

So I guess i will have to include a new R/P in my calculations then. Maybe a Subaru engine isnt so bad after all
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1991 VW Multivan syncro 1,9 TD

[mtsipe]

Hello,
I need your help. I swapped my 2.1L WBX for a 1.9L ALH TDI motor. I would like to get my temperature gauge working. What was the process that you used to do so? I figured besides the automatic transmission versus my manual, the swaps seem identical. The temperature gauge light works, which I believe is a coolant level sensor but I'm not completely sure (the light goes off when I top off of the coolant).

Also, before my mechanic performed the swap. I had an oil pressure gauge installed but is no longer functional with the newer motor. Is there a sensor on the TDI that I can connect to the gauge that I have?

I appreciate any help you can provide me with,
Thanks
Matt

[Zeitgeist 13]

Can you post up pics of the left and right sides of the engine, especially the sections near the firewall? We need to see how your mechanic set up the coolant flange on the rear of the cylinder head (where the coolant temp sender resides), and the oil filter tower. These should be easy issues to resolve
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[MarkWard]

I believe the wire color was maintained. The wire for the coolant temp gauge is Blue with a Yellow tracer in the Vanagon. Not sure what you are using for a temp sender or if you have stayed electronic or converted to mechanical pump, but the engine should have a 4 wire temp sensor near the back of the cylinder head which on the vanagon is "forward".

You should have the original molded plug that connects to the sensor and it would have a blue wire with a yellow tracer. For the 4 prong sensor to work, it will also need a ground. Brown wires are usually grounds. Splice the 2 blue with yellow tracers together and you should be good to go.

If you don't have the original pig tail harness for the coolant temp sensor, you would need to figure out the pin out of the 4 prong sensor.
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☮️

[Zeitgeist 13]

The stock 2WD WBX temp sending unit fits right into the coolant flange on the rear of the cyl. head. I also used the same oil pressure sending unit and mounting kit on my ALH as was installed on my WBX.
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Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[?Waldo?]

In another thread it was mentioned that the 4-prong coolant sensor from the AAZ fits the ALH coolant flange (plastic or metal). The sensor is part # 357919501 (green ring) and has the correct operational range for the vanagon temp gauge and the glow plugs. The 4 prongs have 2 grounds and two separate temp reading circuits so the one sensor will do it all.

I have not yet used that on my van. When I did my install I used a mk2 metal coolant flange that had accommodation for two separate senders and I made a little adapter plate for mounting it. When I get around to installing the 4hp22hl I have sitting on the floor of my garage I will update that flange with the metal ALH one, add the coolant glow plugs, and use the AAZ gauge. I figure I'll wait until then as I will need to update the hose routing at that time to eliminate the coolant/ATF heat exchanger as I will use oil to air one with the Porsche unit.