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Offline Powdermonkey

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1.9tdi vs 2.5tdi
« on: June 15, 2016, 10:42:02 pm »
Hey guys, new to the forum (it's great!) and new to T4s, but not to TDIs. I coaxed my a4 Jetta tdi to 350k miles before it decides to die. I'm fairly facile with the ALH TDI motors, so they definitely interest me as a power plant for a syncro TDI swap in a t4 camper van for my wife and our dogs. I know they are definitely low on power at baseline, and I'd want to get at least injectors and a chip to tune the ECU, probably a FMIC as well. That's what I had on the Jetta and it moved. Well.

My concern or query however, is how much better is the AXG 150hp 2.5TDI? I would love to get my hands on one of these guys, I just have some slight reservations. Mainly on being able to find parts as well as the über short timing belt change interval (times 2 belts). I'm not worried about changing the belts, I did a few of the timing belts myself on the ALH, and I still have those tools. The other concern is that getting parts will be difficult at best. Unless a lot of the ALH parts potentially can be made to fit?

For those that have driven both flavor of this swap and that have made similar decisions already about this here in the U.S., what drove your decisions? Any tips or hints? I know that Justin (?) aka greaseworks (?) is on here and I've seen more from him here than the other forums, so I'm hoping he and cavevan both will chime in.

I look forward to putting more technical topics up here and growing this forum and community!

-Ryan

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Offline andrew

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Re: 1.9tdi vs 2.5tdi
« Reply #1 on: June 15, 2016, 10:56:16 pm »
I have not had the pleasure of driving a 5-cylinder TDI. While there is an extra cylinder for power, I'm not sure if it's needed or not. These are big vans and beyond a towing application, you're not going to find a transmission that can take advantage of the power off the line; it'll all be later on in second and third gears at least. Also the timing belt with the four-cylinder is so so easy compared to a Jetta or Passat-- so much room. Don't have to jack up or remove the passenger side wheel. Not missing the extra cylinder taking up space in that regard.

That said, I suspect that the major advantage to the five-cylinder is the overall engine balance. The original gasser (which is, I know, obviously not a diesel) vibrated the cabin a lot less. Fewer degrees between ignition events can only be a plus in this regard. I can make it up mountains just fine with my 1.9, VNT17, 11mm and .205 nozzles, but I find most of the time I'm just driving. Mostly I just want my two year old to go to sleep or to be able to hear the radio.

As far as parts go, I have ordered several things from European suppliers. Waiting weeks for them to arrive sucks sometimes. While I wouldn't anticipate needing a ton of hard engine parts, if you want to rely on the vehicle consistently maybe a two-week downtime (+£20 international post) is unacceptable.

If they run significantly smoother it is pretty tempting for my next one (down the line). Doing it for the weirdness factor is another perk (people around here already can't quite figure out what I'm driving). I only know of one 2.5l swap, so it'll be interesting to hear what others say.

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Offline Mike

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Re: 1.9tdi vs 2.5tdi
« Reply #2 on: July 15, 2016, 06:56:20 pm »
Bump.  Count me interested as well.  I would need the 2.5 for occasional race car towing..

Re: 1.9tdi vs 2.5tdi
« Reply #3 on: September 19, 2016, 06:56:55 am »
I've done one 2.5l TDI T4 conversion and it has pros and cons. It is a strong and smooth motor and runs out quite nicely. However, IMO the cons win out and it is not my first choice for eng options. 

Few things to consider:
This eng is not legal to use in the US. It has not met the epa specs and therefore will be limiting for registration in DEQ/CARB jurisdictions.

The 4-cyl TDI eng properly built/tuned will reliably put out all the power you could want, all the while having all service parts and consumables available in the N. American market.

As mentioned previously the 4-cyl eng also affords the added benefit of a wealth of extra space on the belt side of the eng where 90% of service over the life of the eng will take place. 

Hope this helps,
Justin


2000 EVW 5-spd TDI
Justin
2000 EVW 1.9l TDI 5spd Syncro