AHU - Vs - AFN - Vs - 1Z

[Isolly]

just curious..

of the 1.9TDI engine...of the AHU, AFN and 1Z, which is best... gives out more power, and is open to more tuning?

[ELVIS]

Now this is a Q that will attract LOTS of differing opinions. Dont want to tell you how to suck eggs but aswell as reading any replies on here have a search on here and the Yard for build threads/how to's etc - will get bigger/balanced picture.

IMHO it would appear to be that the AFN is the superior engine BUT there does not to be a well troden install method YET. All the installs i have seen appear to have been done all differently (ish)

Ive got a 1Z (didnt do install myself) and it lends itself to least fabrication - NS engine mount. Fitted with AFN nozzles- will pull me up the A30 at Holden just past Exeter in 5th and not drop below 2200rpm and still returns 40mpg day in day out.

If you go on clubtdi you will see that they are all open to being tuned - its how much you want to throw at it and what result you want to achieve.

Nozzles, pumps,injectors,turbos,rempas/chips are applicable to all of them at a cost. My mate has a T4 that makes 250bhp on a 2.5tdi, its cost him 6 or 7k for the engine alone and smokes like a bar-steward as no-one in the UK can remap it properly and it does 1mpg (ok maybe a little more)

torque/drivablity/smiles per hour are the biggest factor for me

[ewenmaclean]

Hello,

the AHU and AFN have better pistons, and the AFN has sputter bearings. It is said that the 1z pistons can suffer under too much heat so can only be tuned up so much. If you go for really big injectors, then you'll need a bigger pump. the AFN pump has a bigger camplate and better dynamic advance, but if you go beyond about .23 then at high revs the pump'll struggle to match the map for the amount of fuel requested.

If you up the fuelling then you'll need to get more air delivered or things will get far too hot. The wastegate turbo on the 1z and AHU can be tuned to about 18 psi, but really you'd want a bigger VNT turbo and then you'll need that tuning. You can just go up a nozzle with your current turbo on an AFN or AHU, but too much and you'll smoke a lot.

How much torque are you after? Remember the more you go for the more you'll have to mod the clutch, the gearbox etc. etc....

Ewen

[busbuddy]

if you went to vw in the 90s and bought a 1Z or AHU engine they used to put the id on the block at the dealer, if you asked for a 1Z they stamped 1Z on it and AHU for an AHU, vw supplied the engines without numbers so I wouldn't bother too much about the internals of either being different


most of the mechanics in my local bentley dealers were vw trained/employed in the 80s/90s