mTDI swap into 87 Toyota...planning stage

HaNd_SoLo

Member
Joined
Apr 9, 2014
Location
Gold Country, CA
TDI
None...yet
Hi! I've been lurking around here, on and off, for the last couple of years contemplating doing this swap. The other options were running the stock 22R on propane or a 3RZ from a Tacoma. I have finally settled on an AHU TDI. :rolleyes:
Unless I score a deal on another pump, I will more than likely end up using a Land Rover 300TDI pump. I'm not looking for huge power, mostly fuel efficiency, simplicity, reliability and torque. This will definitely be mTDI with a wastegated turbo, please don't sidetrack this thread with eTDI or VNT chatter.
After reading through every mTDI and toyota swap I could find, as well as various normal swaps, there are still a few things I have not been able to find answers to.
What size fuel lines should I be running? The stock toyota lines IIRC are 5/16 supply and 1/4 return. What size are the stock VW lines? With the LR pump being 11mm, I imagine they will need to be a little larger that the VW lines.
I plan on running an inline lift pump. What volume should it be able to flow to keep up with the pump at 5000rpm? I don't plan on running 5000rpm, but if the power bug ends up biting me, I would rather not have to deal with fueling issues. :D
Which stock (not necessarily TDI) exhaust manifold places the turbo highest up and farthest toward the front (timing cover end) of the engine? I can fabricate an adapter for the turbo, if necessary.
There's more, but that's all I can remember at the moment.
 
Last edited:

vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
The fuel lines will be fine the way they are currently.

The vast majority of the fuel drawn in by the VE pumps us ejected out the return again - fuel circulation through the pump is what cools the pump. So an 11mm pump doesn't really need anything different fuel line wise, the actual low pressure feed pump is identical.
Choose a lift pump that can flow 30 gph and you will be fine. Keep the pressure below 10 PSI or you may damage the front seal of your injection pump. Ideally choose a pump like the Facet Posi Flow ones that don't shut off the flow of fuel should the electric pump fail.

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HaNd_SoLo

Member
Joined
Apr 9, 2014
Location
Gold Country, CA
TDI
None...yet
The fuel lines will be fine the way they are currently.

The vast majority of the fuel drawn in by the VE pumps us ejected out the return again - fuel circulation through the pump is what cools the pump. So an 11mm pump doesn't really need anything different fuel line wise, the actual low pressure feed pump is identical.
Duh... :eek: I knew the size determines injected fuel, it just didn't click that it wouldn't affect circulation...

Choose a lift pump that can flow 30 gph and you will be fine. Keep the pressure below 10 PSI or you may damage the front seal of your injection pump. Ideally choose a pump like the Facet Posi Flow ones that don't shut off the flow of fuel should the electric pump fail.

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A couple of threads on here led me to believe it was significantly more than that. IIRC, they were down to 1psi or less at around 3500rpm with a 30-something gph pump.

you can use a trapezoid td manifold or an AFN/BHW manifold although the trap td mani definitely holds the turbo up higher
Is this the manifold you're talking about?
 

vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
The mechanical pumps have a tiny little 1mm orifice that all fuel must exit on the return side. I don't believe the electronic pumps have the same orifice. It is related to the timing advance on the mechanical pumps - they use the pressure internally in the pump casing to control advance. Anyhow you would be hard pressed to get 40+ GPH through a sub-1mm hole, so really that is as large as your lift pump needs to be with a mechanical pump.

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HaNd_SoLo

Member
Joined
Apr 9, 2014
Location
Gold Country, CA
TDI
None...yet
The mechanical pumps have a tiny little 1mm orifice that all fuel must exit on the return side. I don't believe the electronic pumps have the same orifice. It is related to the timing advance on the mechanical pumps - they use the pressure internally in the pump casing to control advance. Anyhow you would be hard pressed to get 40+ GPH through a sub-1mm hole, so really that is as large as your lift pump needs to be with a mechanical pump.
Very good info, thank you!
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
I have a k14 wastegated turbo with a top mount manifold for sale!
 

HaNd_SoLo

Member
Joined
Apr 9, 2014
Location
Gold Country, CA
TDI
None...yet
I have a k14 wastegated turbo with a top mount manifold for sale!
Surely, a PM would have been more appropriate? :p However...

From my reading, the k14 has a bit higher boost threshold and a little better efficiency at 15+psi than stock (k03 or gt15), correct? I'm currently planning on running the stock turbo and the better efficiency would be welcome. I do not want to sacrifice any bottom end boost, though.

This is the exhaust manifold discussed above? The k14 came as two different turbo flanges, the trapezoidal and a triangular pattern, I believe.
 

HaNd_SoLo

Member
Joined
Apr 9, 2014
Location
Gold Country, CA
TDI
None...yet
I've got an idea I would like to test out. Does anyone nearby-ish have a junk ALH block they want to get rid of cheap? As long as the transmission and injection pump sides of the engine are undamaged, it'll work. I'm in Sonora.
 

vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
The K14 is a pretty good option honestly. It doesn't have the efficiency or pressure ratio capability of a newer turbo but it will definitely do better than the stock AHU turbo. Won't spool QUITE as early but will still kick in plenty soon.

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