Engine Specific Info and Questions > TDI Engine -General Info

Audi 5cyl 2.5 tdi 1995 116hp turbo choice and mods


Hi everyone, a european dude here, just got my first TDi and gonna start to modify it, info is kind of hard with an old car like this though...
Hope i am in the right section with audi since it is tdi but not vw ( it is VAG though)

The car is a 1995 audi a6 avant 2.5 tdi

1. From what little info i can gather the engine is supposed to be AAT with 116hp, pistons in the aat engine are supposedly cast instead of forged (in AEL and volvo d5252t) and weaker but almost nobody seems to know the limit, but i did read 230hp limit online, does anyone know the limit here?

2. Stock flywheel might be double mass or single mass(some sources online say aat has single mass) and stock clutch pressure plate is supposed to be good for 200hp? uprated sachs that can handle 500nm is avaliable but how much a double mass flywheel can handle is unknown... does anyone know what i got and the limit before they break?

My plans with current information is a nice daily driver with uprated mechanical injection pump, injectors and matching turbo to hit 200hp (maybe 220?) i wish to keep stock intercooler, uprated pressureplate might be ok if it doesnt make clutch too hard pressed(wife drives this car too)

3. Turbo! Stock is supposed to be kkk k14 good for 160-170hp, people online recomend holset he221w as a good replacement, but this turbo has 5.5cm 6cm and 7cm exhaust housings and nobody seems know how this affects a 5 cylinder 2.5 tdi, smaller giver better spool but restricts top end power, some say 5.5cm is perfect and the big 7cm will make for very slow spool and sluggish engine, while others say 7cm is great for my big engine and that the smaller is gonna be restrictive even at 200hp. Does anyone know more about spool rpm and exhaust sizing?

shorter version

1. How weak are AAT engine pistons?

2. How weak is AAT flywheel(is it double or singlemass?) and clutch pressureplate and how heavy is the uprated sachs pressureplate?

3. Is holset he221w correct for me and what difference does exhaust sizing do for spool and power at around 200hp+?

Any help is much apriciated


1. I dont think they are that weak. There is chanell on YouTube named karrosschip someting Like that they had att with gt2260v big nozzles and revd 5500+ Rpm for some time until block cracked not pistons.

2.flywheel i think is single masa idk how much power Will hold.

3. There are some Mercedes om605 2.5 litter runing 5.5 cm housing on he221wg i think id chose a bigger housing cause member Here runed 1.6 TD engine with 5.5 cm, full boost at 2500 rpm.


[0] Message Index

Go to full version