Help planning new project... AAZ with 2.0L block, does it worth it? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Help planning new project... AAZ with 2.0L block, does it worth it? by 2west on 06 Apr, 2014 08:19
• Hi guys,
  
             after considering MANY options, I'm back to one of my first idea to swap a diesel VW into a Toyota truck. The fuel efficiency vs money investment being the prime considerations.
  
  As you understand I'm a little bit on the heavy side as it will be a 01-04 Tacoma quad cab with 33" tires used for daily driver.
  
  I want to use an all mecanic injection . Everything on the truck will be converted to the more mecanical possible. I'm located in Canada so because the AAZ engines are available, I think it would be a good starting point.
  
  Alongside of proper axle gear selection, in order to have a little bit more power off-boost power for highway cruising, I'm thinking about the following options:
  
  Oversise bore of the AAZ block to fit bigger pistons
  I also heard I could use BHW block to increase the displacement to 2.0L that could be a good idea, but still don't know the power gain vs investment ratio.
  
  The other solution is just to clean the cylinders and install new rings with stock pistons if everything still spec.
  
  
  I plan to run a bigger turbo (advise for money wire/power/avaibility would be greatly welcome) and a front mount intercooler with pump modifications. I don't know yet which kind of nozzle I would need. I heard the engine can be still reliable with 20 psi of boost? I'll install a EGT for sure to follow all that.
  
  I'm not looking for HP numbers pissing contest with no offence to anyone, I just want a reliable motor with enough power for decent hill climp speed do matter if I have to downshift to keep the pace and off boost fuel efficiency.
  
  Thanks in advance for all the inputs! 
• #1 by theman53 on 06 Apr, 2014 10:19
• For the lower Rpm power the TDI Ahu style would probably fit your bill better. You could use an aaz block like I am in my Jeep build thread and put TDI pistons in it. A rover pump from the UK guy and you are all mechanical. As far as reliability and fuel efficiency I would go TDI.
• #2 by bbob203 on 06 Apr, 2014 10:26
• unless you want to burn WVO go tdi.
• #3 by 745 turbogreasel on 06 Apr, 2014 14:02
• Why not just use a 2LT?
• #4 by 2west on 06 Apr, 2014 14:54
• I remember like 7 years ago I had considered a tdi converted to mecanical pump... mtdi. Today I don't understand the point because most of the gain comes from the comparison between stock output numbers that are mostly better for the tdi because of the electronic injection. Do the tdi have mecanical advantage I don't know about?
  
  @Theman53, you talked about using tdi pistons, what is the advantage or where could I read about it?
  
  Maybe I'm wrong but at this point, what is important would be to compare the off boost dyno curves between an AAZ and any other AHU or ALH. When I will need more power it will come from the increase in boost anyways.
  
  I've calculate that I need 42 hp to keep my highway speed of 70mph with that truck so I only need an engine that produce at least that off boost power amount of power at a given rpm, pick my gear ratio accordingly and I'm good with it.
  
  
  For what I read by your replies converting the block to a 2.0L is not that important?
  
  
  @745 turbogreasel. I explored the possibility fot a 2L-T. It's pretty rare here and it doesn't tolerate the higher boost levels very well. Big tendancy to overheat. I already own one and it's true the head craking issue is a real issue. Parts are not very much available also. The 2LT-IIE are more available but need to be imported at least from the US. If you add the cost of the rebuild to it and the mecanical pump to convert them, they don't worth it.
  
   I've also explored the 1KZ-TE and 1KZ-T possibilities, both very good engine. Therefore they are both very very rare and expensive. Therefore they have plenty of power but maybe too much as they have a mpg close of what I have right now with my 3RZ that is not good enough. It won't pay by itself ever whatever the distance I could make with it considering also diesel cost like 12% more than 87 gas.
  
  On the other hand, 1.9VW are available and for cheap, I can have parts for good prices and they tolerate well higher boost level. they also have the reputation to be very strong for their size. I do lots of city mileage so it should pay back the investment quite fast even if it's more for the fun than the ecenomy that I make it.
  
  Thanks for all your replies
  
• #5 by TimpanogosSlim on 06 Apr, 2014 15:12
• you might try to get DJTC's attention. he doesn't participate much on this forum (more tdiclub) but he just pulled an AAZ out of his 1990 toyota pickup in favor of some sort of tdi project.
• #6 by theman53 on 06 Apr, 2014 15:41
• Quote from: 2west on 06 Apr, 2014 14:54

  I remember like 7 years ago I had considered a tdi converted to mecanical pump... mtdi. Today I don't understand the point because most of the gain comes from the comparison between stock output numbers that are mostly better for the tdi because of the electronic injection. Do the tdi have mecanical advantage I don't know about?
  
  @Theman53, you talked about using tdi pistons, what is the advantage or where could I read about it?
  
  Maybe I'm wrong but at this point, what is important would be to compare the off boost dyno curves between an AAZ and any other AHU or ALH. When I will need more power it will come from the increase in boost anyways.
  
  I've calculate that I need 42 hp to keep my highway speed of 70mph with that truck so I only need an engine that produce at least that off boost power amount of power at a given rpm, pick my gear ratio accordingly and I'm good with it.
  
  
  For what I read by your replies converting the block to a 2.0L is not that important?
  
  
  @745 turbogreasel. I explored the possibility fot a 2L-T. It's pretty rare here and it doesn't tolerate the higher boost levels very well. Big tendancy to overheat. I already own one and it's true the head craking issue is a real issue. Parts are not very much available also. The 2LT-IIE are more available but need to be imported at least from the US. If you add the cost of the rebuild to it and the mecanical pump to convert them, they don't worth it.
  
   I've also explored the 1KZ-TE and 1KZ-T possibilities, both very good engine. Therefore they are both very very rare and expensive. Therefore they have plenty of power but maybe too much as they have a mpg close of what I have right now with my 3RZ that is not good enough. It won't pay by itself ever whatever the distance I could make with it considering also diesel cost like 12% more than 87 gas.
  
  On the other hand, 1.9VW are available and for cheap, I can have parts for good prices and they tolerate well higher boost level. they also have the reputation to be very strong for their size. I do lots of city mileage so it should pay back the investment quite fast even if it's more for the fun than the ecenomy that I make it.
  
  Thanks for all your replies
  
  

  The TDI is more efficient that the IDI design. Several members on here have went the M TDI option. It is still a mechanical pump, even if it is an E TDI. The more efficient design should yield you better fuel economy and no prechamber in the tdi head will get you reliability. I think you should read up more.
• #7 by 2west on 06 Apr, 2014 17:47
• 
  [/quote]
  I think you should read up more.
  [/quote]
  
  
  I definitely will and I think I'm in the right forum for it.
  
  Thanks!
• #8 by vanbcguy on 06 Apr, 2014 21:16
• Quote from: 2west on 06 Apr, 2014 14:54

  I remember like 7 years ago I had considered a tdi converted to mecanical pump... mtdi. Today I don't understand the point because most of the gain comes from the comparison between stock output numbers that are mostly better for the tdi because of the electronic injection. Do the tdi have mecanical advantage I don't know about?
  

  
  The VE TDIs don't get anything "extra" power wise from their electronics.  The pump is still a VE-style mechanical pump pushing fuel in to mechanical injectors that pop at a certain pressure.  A properly tuned M-TDI can make the same power as an electronic TDI just fine.
  
  The electronics do allow the TDI to meet modern emissions regulations however.  The electronic system is reasonably easy to adjust in a scientific manner too without needing other measuring tools.  Want to tweak the timing curve? Change some numbers.  On a mechanical pump it's springs and shims, plus it is extremely difficult to measure without a pump testing machine.
  
  VNT turbos are the other big thing an electronic TDI gets you without much trouble.  You can definitely make one work on a mechanical engine, but not as easily as an electronic one.  That's Mk4+ territory though.
  
  All of that said, a mechanical AHU would be my choice over an AAZ (and in fact that's what I'm building right now).  The AAZ is pretty darn close to an AHU already - the major difference is the shape and location of the combustion chamber.  Mechanical pump + AHU = AAZ reliability with better power, torque and parts availability.
• #9 by 2west on 07 Apr, 2014 14:30
• Yes, I think I will look for an AHU. ALH are great also, but with the AHU, because they don't have the vacuum pump on the end of the camshaft, it  will allow me to have less problem with firewall clearance. It seems I had forgotten about the IDI vs TDI is not a matter of electronics but a matter of the injection process itself. Direct injection mecanical will be nice.
  
  I will read more about all that and read all these stickies and it should help me.
  
  Thanks