Looking to build

[MrCypherr]

Im looking at building a TDI engine in a mk3. Now, Im familiar with the PD engines that when built with proper internals and whatnot, can put out alot of power. Im looking to build a somewhat high tq engine and put it in a mk3. I was looking around and I noticed alot of the cars have the AHU in them. Is that one of the better engines to use or is there another engine that I can use to build a high tq engine with?

Thanks!

 

[oilhammer]

I assume you mean an A3 car, like a 1998 Jetta? Do you already have the car or is there some specific reason for choosing that particular car?

The ALH engine found in the early A4 cars and even the BEW engine in the later A4 cars is a better starting point for power mods. And they *can* be put in the older platforms with a little work.

You will have to define "high torque", as they already have quite a bit for their size. But the BHW is the Torque King as far as 4 cyl TDIs sold new in North America, with a peak of 247 (almost 100 more than the AHU engine). But it is in a bigger, heavier car with a longitudinal mounting.

 

[vanbcguy]

There's nothing stopping you putting decent power out of an AHU - tuning is more of a challenge since it's chips rather than flashing the ECU. The ALH block is stronger but the block is rarely an issue.

Sent from my XT1097 using Tapatalk

 

[MrCypherr]

The car has a AHU already in it, so I was going to use that and build it. But, if the ALH or BEW can fit inside, then I wouldnt mind swapping that in.

I would like to make atleast 300tq out of the AHU but if we are moving to a ALH/BEW, then I would like to aim for atleast 400. Thus why im asking if I should bother with the AHU.

Thanks!

 

[oilhammer]

I think you should spend a lot of time reading first. And define what specific need you have for this engine. Because while you can increase the output of these engines quite a bit, you bump up against a problem with poor driveability, reliability, durability, as well as all the other items the engine needs to get the power to the ground suffering.

The AHU is an engine that was dated when it came out, based on a design from 1974. The ALH is a fresh start, and is a superior arrangement overall. They do not suffer from the weak crank snout since it is beefier, the flexing of the lower block is less concern since the cast oil sump is also used to make the bellhouse a true full circle. They run a single poly belt for the accessories, closer to the front of the engine. The timing belt is thicker and more durable. The injection pump is better, and has easier choices for more power options. The lubrication system is totally different and improved, no leftover bits to drive a mechanical gasoline fuel pump and ignition distributor for carburetted gas versions like the AHU still carries with it. The ALH's head also flows a wee bit better, and has better valves, valve guides, and even the ALH's pistons are improved. Yes, you *can* upgrade a lot of the items on the AHU to bring it to that level, but the ALH is already there.

However, if you already have an AHU, I understand why you'd want to use it. But, with your lofty (unrealistic, most likely) goals, the costs involved should be of no consequence, and doing the work involved to put a newer engine in your car should not concern you.

The A3's chassis isn't well suited for that kind of power either, and will need a lot of tweaking and improvements just to be able to handle it, and it'll still end up being a white knuckle ride that will try every chance it gets to place you in a ditch.