tdi engines and engine numbers

A

Audiobull

A2OC Donor
I have noticed there is a fair few tdi engines out there.
ive not got a tdi yet but i am looking to build a tdi for the track.
They seem to be different ps and bhp models. the vw starts at 70-75ps and go to around 80ps then there seems to be a jump from 80ps to 90ps for the a2 diesels.

what are the engine numbers/codes for the best tdi engines so i can make sure i get the right engine or can i have confirmation that amf and bhc are 74bhp and atl is 89bhp.
what is the difference between them? could i get an amf and put atl internals in it? is the atl the same engine on the outside? as in are the bolt holes the same and the shape the same.

Does the amf have a lower compression ratio then the atl? I will be putting a rather large turbo on so will it be wise if i go for the lower compression ratio then the higher?

not sure where i should have put this post.
 
Hi Audiobull,

You're right; The AMF and BHC engines are from the TDI75 and the ATL is from the TDI90.

All engines use the same block (and head, I think), but from there differences start to appear. The ATL engine has different injectors, uses a lower compression ratio, has a variable geometry turbine turbo, a dual mass flywheel, a different EGR valve and anti-shudder valve, 5V glow plugs and a different management unit. I'm sure there are other subtle differences too, such as pipework routing, etc.
The differences between the AMF and BHC engines are not well documented on these forums, and I'm yet to meet anyone who can categorically say what the differences are. Even Vince at Stealth Racing, who's worked on both engine types many times, isn't quite sure where the differences lie. It's been suggested that the exhaust manifold on the later BHC engine has been reworked for better flow, though a side-by-side comparison has never been published in these pages. I've driven both types many times, and can say with some confidence that the later BHC engine picks up better from standstill and has its output peak sooner, but it then starts to die as you take it into the higher rev range. The AMF engine is comparatively slow to pick up but output continues to build later into the rev range. Vince's dyno plots also suggest this is the case.

The ATL (TDI90) engine is less reliable than the two flavours of 75PS engine due to its DMF in particular. Although its VTG turbo is less reliable than the 75's fixed-vane turbo, you may consider the VTG a real advantage considering your application.

Cheers,

Tom
 
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Just adding to Tom's comments, I think all BHC and ATL engines have the different exhaust manifold with the turbo housing integrated into the casting. As you will be using a new EX manifold and Golf turbo I think the AMF engine would be the most sensible (and cheaper) starting point.


If you sift through this on line parts catalogue it may help you work out the differences between engine models in more detail - http://www.partscats.info/

Cheers Spike
 
I thought the ATL in the TDI 90 had a lower compression ratio, so it could run higher boost?
http://www.audiworld.com/news/03/111003/content.shtml
So presumably different crank

Yes I think the big difference is the exhaust manifold with integrated turbo. When the turbo went on my TDI 90 it took them a while to find a replacement, quite rare.

The TDI 90 pulls like a train from about 1700 rpm, peaks at maybe 3000 and power is flattish from there to about 4000. Makes a hell of a noise by then though.

Will miss the oomph, I am starting to look at new cars and don't find many small cars with that kind of get up and go.
 
ok thanks to all, the comments are extremely detailed which is much appreciated.

This will be solely for track so should i be looking at the atl? given that i dont need to worry about turbo reliability as i will be putting a great big one on it, will i still need to worry about the dmf too? I will just swap out for a smf and change the gearbox anyway.

the thing is i need to get the right donor car to start with so if any atl wiring etc is different i am best to get the tdi90 over the tdi75 now rather then later which is what i need to clarify really.

as for spare engines it seems i am safe to buy a 75 block and transfer the inners to the 90 if i blow something. I am one of these people that thinks you can never have enough of something important. A spare engine is always handy so i am never left off the track too long.
 
from what i have been reading the tdi90 runs pistons from the asz while others run pistons from pd100 and the tdi90 has bolt on bits from the higher pd series such as the injectors and has a lower compression ratio of 18:1 compared with 19.5:1.
I am not going to jinx anything but i am going big with this project so need as many of those small horses from this mini 3 pot tdi as i can. If it blows up i will learn and change something on the next one but it will not be my daily driver so alot of the normal worrys go out the window.

Smoke on the other hand is something on my mind. it can keep it clear till 3000-3500 but over that it will start to smoke i reckon and from reading even adjusting the injectors does not help much. is there a limit to the smoke out on track, cant say ive ever need to worry about that.
 
Has anyone converted an A2 to a 4cyl Tdi engine like a 1.9Tdi or 2.0 Tdi from a Golf or Leon? The front end is the same as the 3cyl so the engne mounts would be simple at that end. The engine bay should fit a 4cyl as the 1.6FSI fits.
Gearbox is standard VW parts bin, the only change would be the driveshafts - maybe the petrol ones would help?

could make an interesting project....
 
id be interested in that BUT and a major BUT is weight. The a2 is soo light that putting a great big heavy 1.9tdi would defeat the idea for track use. Road use it would probably be loads of fun though. think of most of the 1.9tdi parts on a 1.4tdi and then you will have much more fun ;-)
 
How would one go about working out the differences between a 75bhp and a 90bhp tdi model? If the advert doesnt mention it i wouldnt know would i? any help much appreciated
 
Audiobull said:
How would one go about working out the differences between a 75bhp and a 90bhp tdi model? If the advert doesnt mention it i wouldnt know would i? any help much appreciated
Click to expand...

Do you mean adverts for complete A2s, or loose engines?
 
complete car. engine wise i will just look out for a atl code but as an advert you cant really ask the old boy or young lady that owns it (for examples) to look for the engine code. most wont even reply to that question.
 
You can tell a TDI90 by its rear disc brakes and by the I in the TDI badge being red. A TDI75 has rear drums rather than discs and the TDI badge is silver throughout. :)

Cheers,

Tom
 
Tough question

I am pretty sure the 90s had disc brakes on the rear, the 75s had drums, so if you ask the advertiser it should be fairly easy.
 
thats perfect. thank you for that everyone. thats a pretty easy thing to spot. happy days now to find a dead one. he he
 
RickyG512

The simplest way is to look on the sticker on the inside of your service log that shows all of the vehicle options. I think it is about line 4 that says 'engine' and will have AMF of BHC etc.
If you do not have the service book it is also on a sticker on the car. There is one under the boot floor in the plastic storage area where the Bose would go.
 
Thanks Sootywg,

I have the BHC engine, just out of interest, what's the differences between the two 1.4 TDI's ( both 75 horsepower), is one better than the other, is there like a list of differences or summin?

Thanks again
 
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