Timing AHU injection pump on an AAZ

[otm646]

I am swapping in an AAZ into my 79 rabbit. The idea came up of using an AHU injection pump to replace the mechanically controlled AAZ pump.

I personally like the charicteristics of a IDI better for a performance application. I am looking to have all the telemetery of the electronically AHU while keeping the performance aspects of an IDI.

The conversion is simple to CE2. I already have an CE2 Golf body harness in hand and a engine harness and computer out of a 98 Jetta on its way.

I would use the IDI injector body from a Mercedes 60X with the built in needle lift sensor.

I also would transfer over the crank and the crank position sensor from one of my spare TDI blocks.



My question comes to ECU tuning. start of injection obviously occurs sooner in an IDI.

Does somone have documentation of the differences between start of injection between an AAZ and a TDI?

The build thread will start soon!

 

[vwmikel]

What do you intend to do about the AAZ not having the spot for the crank sensor, nor the wheel on the crank?

 

[compu_85]

Our research had shown the AAZ and 1Z lower ends were the same and the port for the CPS was there. Have you seen otherwise? We will be installing a TDI crank anyway to remedy the problems with the AAZ's sprocket keyway.

-Jason

 

[vwmikel]

To my knowledge, the boss for the sensor is cast into the block on the AAZ, but it has not been machined out. You may find it easiest to use the 1Z/AHU block and crank with the AAZ pistons.

I'm not really sure about the idea of the IDI engine being a better performance base. I used to have a 1.6TD with 10mm pump, GTD injectors, and 2.5" exhaust running 26 psi and it only managed 93 whp while filling the shop full of smoke. It seemed quite inefficient to me.

 

[alphaseinor]

I think it's an interesting idea to have a computer controlled IDI, but I have to agree with VWmikel... since you are having to place the computer into the harness; why not just go with a TDI? the ALH is getting to be a bargain if you look around (sub $1200 with harness). With just some sprint 520's you would be putting out about what you can get from your IDI with lots of mods.

 

[otm646]

I am replacing the AAZ crank with a 1Z crank from a dead motor sitting in the shop. while i am in there i will check to see if the boss for the sensor is machined out.

over on vwdiesel.net people see to have reasonable proof you can get over 120hp fairly inexpensively and reliably.

http://www.vwdiesel.net/phpBB/viewt...s=0&postorder=asc&highlight=aaz+dyno&start=15

Not based soley on that thread, it is just an example.

there is another thread, which i can't find now, which shows an AAZ with a k24 turbo and injectors pulling 140hp, I'll post it when i head into work.

I know dyno vs dyno is a craps shoot, i don't want to get into that. i am speaking in general terms of what is possible.


I already bought a complete 1993 AAZ Jetta (the whole car) for $450

I can get a complete TDI harness with ECU out of a 98 (the ECU to get) for $200

I have an injection pump with 300k miles sitting on my shelf ready for a rebuild for $600

I have all the parts i need to make this happen.
I have not heard of anyone attempting this either, I like the unique challenges in it.

Like i said before i like the power delivery and revviness of the IDI over the TDI in a performance application.