Another Saturn TDI Conversion

specialed1995

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Feb 1, 2015
Location
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TDI
1Z 1.9 TDI from 1996 B4 Passat
Hello Everyone

I am following in user CFM's footsteps and working on building my own Saturn TDI conversion like the one found here: http://forums.tdiclub.com/showthread.php?t=193909 and will require the help of some more experienced people that are on this site. I have been carefully studying CFM's conversion, making plans and trying to get as much as possible figured out for over a year now, and also I've been purchasing all the parts I will need slowly along the way. I've already good a good bit of the parts I will need, minus the major parts like the engine, transmission and the car that it will eventually go in, but I've tried my best to get all the little parts that make this conversion possible.

I plan on emulating CFM's design in most ways, but I've made little changes here and there that I would like to run by you guys on here and see what your thoughts are.
For instance, I plan on using the MK4 pedal assembly because it would be much easier to fabricate a bracket that would bolt to the Saturn firewall, and from doing some googling I've found conversion guides that say its possible. I also plan on using an MK4 shifter assembly and was wondering if that will work with the AHU transmission. I will be posting more on this thread in the coming days of all the plans I have written out so far, such as the wiring diagram, a list of all the parts I've got so far, and other things I've calculated since I became interested in doing this conversion.

The reason I'm doing this is twofold: I want to replicate the fuel economy results obtained by CFM because I'm cheap, and I love the Saturn S-Series and plan on driving them for as long as I can. Also, just the engineering challenge of putting this type of thing together and making it all work is exciting for me, especially since this has only been done one other time. Thanks for all the help in advance.
 
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specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
Here's a list of all the parts I've got so far:

1. Saturn CV Axles
2. 2 Passenger side VW CV Axles
3. Machined axle adapters
4. MK4 gas pedal assembly with connector
5. MK3 gas pedal connector
6. MK4 shifter assembly with cables
7. MK3 fuel filter with check valve
8. Saturn Fuel Pump/Sending Unit converted to lift pump
9. Saturn Clutch Master and Slave Cylinder
10. Braided Steel flex hose for clutch
11. Saturn engine cradle
12. Stant 13519 In Hose Thermostat

I still have to find a lot of the major parts like the AHU drivetrain (any ideas?), wiring harness, and a Saturn to put it all in, but I planned on waiting until I have all the little parts before I get the bigger parts, that way once I do, everything will be ready to starting putting together.

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algirdas

Veteran Member
Joined
Jan 23, 2009
Location
Cincinnati,OH (Dubwerx)
TDI
98 jetta AHU
Yes, the MK4 shifter box and cables will work with the AHU transmission BUT YOU MUST also change to a MK4 shift tower assembly and weight, the vertical shaft that rotates and moves the shift forks. May also need the aluminum shift tower guide from bottom of trans.
 

specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
Yes, the MK4 shifter box and cables will work with the AHU transmission BUT YOU MUST also change to a MK4 shift tower assembly and weight, the vertical shaft that rotates and moves the shift forks. May also need the aluminum shift tower guide from bottom of trans.
Thank you for that information. I'll see if I can find one somewhere online.
 

specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
I also have another question about interchangeability. The MK4 pedal assembly looks like this:

And the MK3 style pedal looks like this:


(I know this pedal is not from an MK3, just showing it for an example)

I have both of these pedal assemblies and took the side cover off and everything but the circuit board looked exactly the same, so I switched the diesel one for the gas one so I could have the regular looking gas pedal instead of a plastic one. Just wondering if this will not work or create any problems or if it will be fine?
 

specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
I have been taking measurements off my Saturn engine cradle and comparing them to the pictures off CFM's thread and have come to some conclusions, as he did not give dimensions of anything on his thread.


From what I can tell the added crossmember in this picture is approximately 30 inches long and made from 2.5 square steel tubing 3/16 inch thick. I'm sure the bolt holes won't have to be exactly the same so I'll have to wait until I get the engine in the vehicle and mark where everything needs to be before I weld everything up but I can at least purchase the metal need to do this.

I can also tell from this picture that some supporting sheet metal was welded underneath the crossmember for reinforcement. The factory thickness of the metal was 0.070 inches so I'll purchase some 0.120 inch thick steel sheet and cut to the size and shape of the saturn engine cradle and weld it on underneath before I put the crossmember and sway bar brackets back on.

I am still trying to figure out the dimensions of the custom engine mounts show below:




I have a couple other pictures that I will link as soon as I figure out how to post them.
 

archemitis

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Joined
Nov 16, 2012
Location
minnesota
TDI
200 Golf, 1974 Westfalia TDI
My engine came with a MK3 pedal assembly and I used a MK4 pedal because it worked with my swap.
I know the newer pedal will work, I just dont remember if I had to change the wiring or if it just plugged in.
 

specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
I made another major step in this conversion today by purchasing the engine that will ultimately go in the car. I found an AHU engine complete with wiring harness, ECU, manifolds, alternator and starter. I've been looking for quite a while and finally found one that was reasonable.
 
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Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
That engine looks like an AVF a longitudinally mounted design - not typically found in North America - where did you find it?

The engine code will be stamped in the block just above the oil filter housing.
 

specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
That engine looks like an AVF a longitudinally mounted design - not typically found in North America - where did you find it?

The engine code will be stamped in the block just above the oil filter housing.

I found it on an ebay listing. Are there any major differences between an AVF and an AHU?
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
The block and head are very similar, but the mounting is going to be wrong - that engine is designed in a lengthwise installation, and has mount brackets spaced evenly on either side.

A regular AHU would have a mount bracket on the passenger side rear of the engine, and the center of the front. The remaining mount attaches on the rear drivers side on the transmission, giving you three triangulated mounts.

If you have the engine, harness and ECU for that engine, I would sell it and get a real AHU that would be much better suited to an SL2's engine bay.

Alternately get an ALH - the pendulum mounting system is more similar to the pendulum mounts of all but a 1991 Saturn.

<- Source, Saturn Saab Isuzu technician from 1992 to 2002
 

specialed1995

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Feb 1, 2015
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United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
I will take pictures of the engine when it arrives and post it on here to show everyone what I have to work with so far.
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
I found an Auction with those exact same pictures for $1500. Please tell me you did not buy that for your Saturn (the auction I found has not ended).

You can get an AHU and harness and transmission for far less than $1500.
 

Hasenwerk

Vendor , w/Business number
Joined
Nov 28, 2003
Location
Quesnel, BC
TDI
1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
I agree with others here - not an AHU, but something from a Audi or Passat from Europe. The issue is going to be the AC compressor is going to be on the wrong side. If you are getting the electronics with it, it will also have an immobilizer because it is a non-north american engine. It would be a decent engine for someone installing into a Ranger or pickup that has the steering rack in the way though.
 

specialed1995

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Feb 1, 2015
Location
United States
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1Z 1.9 TDI from 1996 B4 Passat
Well I didn't actually buy it from the auction, I called the number listed in the ebay auction and made the deal on the phone. I'm going to take those pictures down because they are inaccurate and reflect my very limited knowledge of VW still, but I am trying to learn.

I did verify 100% that the engine I purchased was an AHU, but I'm going to wait until it gets here and post my own pictures, just so I can't screw anything else up lol.

As far as it being too expensive I've been trying to find one for probably 4 months now and this was the first one I've found. If you know where to get them, please let me know.
I already have made the deal so the engine, wiring harness and various other parts are already taken care of. So the only two major parts I need now are a transmission (I've done some research and found that a code EGR transmission will work best in my application since I'm using an MK4 shifter, PLEASE correct me if I'm wrong)

I'm still looking for a Saturn to do it with, but that will be my last purchase as I don't really have a lot of room to store all this stuff.

I will keep you guys posted.
 
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Windex

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Cambridge
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05 B5V 01E FRF

Hasenwerk

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Joined
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Location
Quesnel, BC
TDI
1982 Cabriolet (BEW|VNT17|Stage4), 1989 VW TriStar Syncro soon-to-be CR TDI (CBEA), 2001 Ford Ranger Edge 4x4 (ALH|VNT17|R520|Stage4)
Why are you "stuck" on an AHU? These motors are getting quite old and most have mega miles on them now.

You can get complete ALH (2000 to 2003) cars around here for a $2000 Canadian if you do your shopping - this way you have the whole car to play with in case you need parts. The turbo is more modern, the ECU can be flashed over the OBD port, CAN bus for cool things like my CAN2DASH gateway and usually less mileage. I think there is more collective knowledge on the ALH than there is on the older 1Z/AHU engines.

Just my two cents anyhow!
 

specialed1995

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United States
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1Z 1.9 TDI from 1996 B4 Passat
Well I guess you were right yet again lol, but I've already accumulated lots of the parts I'll need and am very limited on room so a whole car wouldn't be practical for me, but I greatly appreciate you for sending me those links.

Now my biggest concern is getting this swap all sorted out and obtaining a transmission. I've heard that an EGR code transmission will work with the AHU and be compatible with my MK4 shifter, can anyone verify this? Other than a new clutch and timing belt what are some other things I should check/do while I have everything apart?
 

specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
Why are you "stuck" on an AHU? These motors are getting quite old and most have mega miles on them now.

You can get complete ALH (2000 to 2003) cars around here for a $2000 Canadian if you do your shopping - this way you have the whole car to play with in case you need parts. The turbo is more modern, the ECU can be flashed over the OBD port, CAN bus for cool things like my CAN2DASH gateway and usually less mileage. I think there is more collective knowledge on the ALH than there is on the older 1Z/AHU engines.

Just my two cents anyhow!
I decided on the AHU because from what I've read the wiring is much simpler, the ECU doesn't have an immobilizer, and it just seemed more basic, which is suited to my style. I'm not saying I'll never try to do it with an ALH, but for right now my choice is the AHU.
 

specialed1995

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Feb 1, 2015
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United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
I have already contacted a machine shop and have the axle adapters being machined as we speak, and they should arrive with a couple weeks. I'm still trying to figure out how to properly measure the axle length, but of course I can't do that until I have the engine and trans mounted up in the car where it's going to go.

For the engine mounts I plan on following in CFM's footsteps and fabricating the front engine mount and rear trans mount and adding a new crossmember to the engine cradle in order to use the stock VW trans mount bolted to the front by the starter.

This is just another idea but if the engine I get comes with AC I would like to find a way to use the VW AC compressor with the Saturn AC system. I know I would most likely have to get new lines with different fittings and reroute them to make them fit, but if it's possible I'd like to keep the AC, even if I have to rig it up to a toggle switch.

As far as power steering goes I am doing a pump delete and plan on cutting the lines on the power steering rack, running a rubber hose with a "T" fitting to both ends, and run the other end up to a little reservoir (like one for a clutch master cylinder, new of course to avoid contamination) just to keep the rack lubricated. These cars are very light and are not hard to drive with no power steering, so I don't mind losing that.

I am open to any and all suggestions, this is a fun learning experience for me and I'm enjoying every minute of it. Thanks everyone
 

Windex

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Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
For the manual steering, you should seek out a rack from a Saturn "SL". It was an entry level model with manual steering. It would simplify your manual steering solution.

For the AC, you will need to fabricate lines, and route them differently, as the AC compressors are in different places in these cars, but the SL's had a variable compressor TXV system, just like the jetta/Passats that the AHU came in, so you should be able to make it work. You would need to marry the Saturn HVAC with the VW ecu, but it should be doable.
 

specialed1995

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Feb 1, 2015
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United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
I've seen manual steering racks for sale online, but if I can save money and use the rack that's already in the car by just modifying it I'll do that because to be honest I'm pretty cheap lol.

I remember there being a couple wires coming out of the ECU for the AC, but I can't recall right now which ones they were (I have a whole list of all the wiring I've sorted through so far and several wiring diagrams I've found online tho) but I agree there's got to be a way and it shouldn't be too difficult.

I'm still trying to figure out what size square tubing I'll need for the engine cradle crossmember, but I'm sure it doesn't have to be exactly the same as what CFM used in his conversion, as long as its thick enough to hold up to what the engine puts it through it will work.

I'm going to also weld a thicker piece of sheet metal on where the crossmember and sway bar bolt on to reinforce that too. I would guess that 1/8 inch sheet metal would do, probably two 1 foot square pieces which I could cut into the shape they need to be and drill new holes for the crossmember and sway bar. I plan on welding nuts inside them to make bolting everything back together a breeze.

I've also ordered the Energy Suspension Doughnut Bushings that CFM used for motor mounts and will use them as a template to draw up plans and get better measurements for the mount and get everything finalized. Once my engine gets here I'm going to measure the distance between the two bottom bolt holes on the front of the block (to the left of the crank pulley when looking at the engine from the front) and see where the holes in the mounts are going to go, same with the holes in the transmission where the axle drive hub comes out to make that mount. From CFM's pictures they both are designed very similar so the sizes for one should be pretty similar to the other, aside from factoring in clearance issues, which I'm sure I'll figure out once I get the drivetrain sitting in the vehicle.
 

Windex

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Apr 1, 2006
Location
Cambridge
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05 B5V 01E FRF
Good that you're making progress.

Other than the elimination of the hydraulics, the manual rack also has more turns lock-to-lock compared to the power rack, so parking lot effort is less strenuous.

However the power rack should work just fine, just be harder to turn when the car is at low speed.

EDIT - $69 including shipping... http://www.ebay.com/itm/96-97-98-99-SATURN-S-SERIES-SEDAN-STEERING-GEAR-RACK-MANUAL-RACK-PINION-8027425-/112117718495?fits=Make%3ASaturn%7CModel%3ASL&hash=item1a1abc9ddf:g:K48AAOSwi0RXyITp&vxp=mtr
 
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specialed1995

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Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
Something I haven't quite figured out yet is the wiring for the cooling fan. I plan on using the Saturn fuse box and just adding fuses and relays in as I need them, and I plan on keeping my manual fan switch, which grounds the relay and turns the fan on, but I'm not clear on how the ECU tells the fan to come on. I don't remember reading anything about the cooling fan in the ECU wiring diagram so I hope you guys can help me.

I looked into my wiring diagram and found that ECU Pin 28 is the AC output to the relay and ECU Pin 37 is the AC input from the switch inside, but that's all I could find as far as the ECU goes, I haven't investigated any further than that yet, tho.

Thanks for all the support and encouragement!
 
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1.9ZOOK

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Dec 13, 2015
Location
Downstream of a Volcano
TDI
ALH Samurai
With the suggestions of others on here I went with a thermostatic switch.I
wanted to use the OEM controller but it didn't work and I almost overheated
badly.With this switch you can dial the fan to come on within 5 or so degrees
of what you want.

 

specialed1995

Well-known member
Joined
Feb 1, 2015
Location
United States
TDI
1Z 1.9 TDI from 1996 B4 Passat
With the suggestions of others on here I went with a thermostatic switch.I
wanted to use the OEM controller but it didn't work and I almost overheated
badly.With this switch you can dial the fan to come on within 5 or so degrees
of what you want.

Thank you so much!!!
That would a simple solution, which I love!
Do you have a link or a part number for that?

Also does anyone know the temperature at which the fans should kick on?
 
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