# TT Engine Info (A dummies guide)



## STUT (May 14, 2012)

Just come across this so thought some of you might benefit from reading it.

There are four different 1.8T motors that were used in the TT, by engine code they are:
In the 180 - ATC, AWP (UK codes to come)
In the 225 - APX, BAM

Here's some facts pertaining to high performance applications of these engines:

All 1.8T TTs have a forged crank and pistons.

Yes, all TTs, right down to the FWD have forged internals (minus the rods). The stock crank has yet to break from a high HP applicatoin, same with the pistons; they are made by Mahle and have withstood over 700 bhp. The part prone to failure is the rods, which is discussed below.

Rods in 1.8T TTs vary in size, but some 180 and 225 models have the same rods.

The ATC engine, used in model year 2000 TTs, uses 20mm wrist pin rods, which makes its internals identical (strength wise) to those used in both 225 motors. However, in 2001, Audi started using the BAM motor which does in fact have weaker 19mm rods. The rods shouldn't be trusted for applications above roughly 300 ft-lbs of torque.

The 225 has a "webbed" block...but nobody has broken a 180 block yet anyway.

Audi included some "webbing" around the 225 block to increase its strength. However, at least in the short term, someone has yet to cause the 180 block to fail.

Some TTs have wideband oxygen sensors, some have narrow band.

Early 180 TTs did not use a wideband oxygen sensor and later models did. Not all 225s have wideband; the APX 225 motor, used until somewhere in 2003, still uses narrowband. The AWP 180 motor, used in TTs since 2001, incorporates wideband. In a nutshell, ATC(early) 180s and APX 225s don't have wideband, AWP(later) 180s and BAM 225s do have wideband.

Wideband is a highly desirable option for tuning, since it allows the engine to precisely control air fuel ratios to the point where the engine can run without a MAF sensor, given the proper ECU software.

The 180 and 225 have different compression ratios.

The 180hp TT has 9.5:1 compression whereas the 225hp TT has 9.0:1.

225s have bigger injectors

225s have 380cc injectors whereas 180s have 318cc. For almost any big turbo setup, however, injectors will have to be swapped out.

Some TTs have variable valve timing, but it's not for performance.

VVT is used on startup for emissions and makes for ridiculously expensive cam chain tensioners.

There are other differences between the 180 and 225, primarily related to the turbo hardware.

[smiley=book2.gif]


----------



## nilrem (Sep 9, 2011)

Errr...didn't get that of a U.S. site did you by any chance ?

What about the APX & BAM engine ?


----------



## STUT (May 14, 2012)

nilrem said:


> Errr...didn't get that of a U.S. site did you by any chance ?
> 
> What about the APX & BAM engine ?


Google my dear friend, I've edited it so just need to swap the US for the UK 180 codes. Bobs your uncle, fannys your aunt!


----------



## james 91 (Jul 12, 2011)

Good post. I was under the impression the BAM and APX rods are forged despite the fact they use 19mm wrist pins


----------



## Andi.k (Jan 5, 2013)

I found this very interesting pal, thanks a lot!

[smiley=thumbsup.gif]


----------



## STUT (May 14, 2012)

james 91 said:


> Good post. I was under the impression the BAM and APX rods are forged despite the fact they use 19mm wrist pins


I think alot of people did. I only heard different when i was getting shown a local lads modified TT when he told me that engines before had stronger components. [smiley=gossip.gif]


----------



## Bago47 (Nov 27, 2011)

Thanks, this is really usefull!

But what can you say about APX engine with AUQ head (as in my case)? Are they the same or is one weaker/stronger?


----------



## R222CEC (Jun 22, 2012)

There's a 150 model too which is missing

Sent from my iPhone using Tapatalk


----------



## james 91 (Jul 12, 2011)

STUT said:


> james 91 said:
> 
> 
> > Good post. I was under the impression the BAM and APX rods are forged despite the fact they use 19mm wrist pins
> ...


'Weaker' in terms of wrist pin diameter perhaps. I'm positive K03 engines dont use forged rods though mate.


----------



## Paulj100 (Mar 24, 2009)

So the early APX is a stronger engine than the BAM?


----------



## JAMason (Dec 13, 2011)

alij100 said:


> So the early APX is a stronger engine than the BAM?


Only when it comes down the the rods! The BAM has a safer engine in the sense that if something starts to go wrong the ECU will pick it up sooner, throw a fault code up earlier and go into limp mode to save you a dead engine. The APX will keep on chugging until it kills its self and then you will get your code!


----------



## Paulj100 (Mar 24, 2009)

Lol! So it's stronger but not safer :roll:


----------



## JAMason (Dec 13, 2011)

alij100 said:


> Lol! So it's stronger but not safer :roll:


Pretty much. BUT there should be no need to worry about it if you service it regularly and look after it  with warming up properly and cooling down periods. :wink:

Jack


----------



## Paulj100 (Mar 24, 2009)

Cheers Jack. Iv always serviced it properly being a performance engine letting it warm up properly etc but I have just one question when I get to my destination should I let it tick over for a while to let the turbo cool down? As I have heard of people fitting turbo timers to there turbo cars to help cool them down :?

Paul


----------



## Jazzle (Aug 3, 2012)

And what about the one with 190bhp?


----------



## Jazzle (Aug 3, 2012)

alij100 said:


> Cheers Jack. Iv always serviced it properly being a performance engine letting it warm up properly etc but I have just one question when I get to my destination should I let it tick over for a while to let the turbo cool down? As I have heard of people fitting turbo timers to there turbo cars to help cool them down :?
> 
> Paul


Depends how hard you push it, if you have just driven t how it should be driven i do. If i am just sitting in traffic and pootling about at a casual 30 and stuff i dont bother as its not boosting much.


----------



## STUT (May 14, 2012)

Jazzle said:


> And what about the one with 190bhp?


TT with 190 BHP?


----------



## Bago47 (Nov 27, 2011)

STUT said:


> Jazzle said:
> 
> 
> > And what about the one with 190bhp?
> ...


There is also one with 163bhp... 180 (I believe) is the same as 180, with different map.

And about cooling the turbo down; do we really need to? Isn't there a pump, which is running for a few minutes after turning the engine off? And if we really have to: for how long should I let engine at idle after driving for a few mins above 4000-4500 rpm?


----------



## Paulj100 (Mar 24, 2009)

Yes I'm sure our cars are fitted with an after run pump to cool the turbo down but I'm not defiantly sure. Hopefully someone with a bit more knowledge can confirm this.


----------



## JAMason (Dec 13, 2011)

Yes, there is a cooling pump for The turbo, if you switch the ignition off after a spirited drive it should kick in if it reads the turbo is too hot. It's happened to me a few times, I seriously thought I had broken the ignition first time as it sounds like the car is still running with the key out! Haha. It's not essential to sit and let the turbo cool after every drive, but I try to as its not exactly hard to sit and listen to the radio for 3 minuets after parking!

Jack


----------



## nilrem (Sep 9, 2011)

The electric water pump will run even if you don't start the engine.

Just turn the key to the position before the engine starts and off again and it will run for around 5 mins or so.


----------



## JAMason (Dec 13, 2011)

nilrem said:


> The electric water pump will run even if you don't start the engine.
> 
> Just turn the key to the position before the engine starts and off again and it will run for around 5 mins or so.


Learning something new then! That's what that water pump does then!

Jack


----------



## james 91 (Jul 12, 2011)

Here's a list of engine codes I compiled from ElasaWin with the years they were introduced, for UK engines.

Key (V: VVT, S: Secondary Air Injection)

_1999_
*AJQ* (180bhp --)
*APP* (180bhp -S)
*APX* (225bhp VS)

_2000_
*ARY* (180bhp VS)
*AUQ* (180bhp VS)

_2001_
*BAM* (225 bhp V-)

_2003_
*AUM* (150bhp VS)
*BHE* (250bhp VR6)

_2004_
*BPF* (250bhp VR6)

_2005_
*BFV* (240bhp V- Quattro Sport)

_2006_
*BVP* (160bhp VS)
*BVR* (190bhp VS)


----------



## STUT (May 14, 2012)

Good effort matey


----------



## rodhotter (Dec 30, 2011)

my 2001 225Q engine code is AMU in the USA what about ME? i always like to learn about cars especially mine, thanks for taking the time


----------



## STUT (May 14, 2012)

rodhotter said:


> my 2001 225Q engine code is AMU in the USA what about ME? i always like to learn about cars especially mine, thanks for taking the time


I replaced the US with the UK, but when I find time I will fully update the post for you all


----------



## dizzle (Mar 22, 2009)

The ATC engine, used in model year 2000 TTs, uses 20mm wrist pin rods, which makes its internals identical (strength wise) to those used in both 225 motors. However, in 2001, Audi started using the BAM motor which does in fact have weaker 19mm rods. The rods shouldn't be trusted for applications above roughly 300 ft-lbs of torque.

So in other words the 225 BAM engine is not a good as the other 225 engines? i am slightly confused as i originaly was informed the BAM engines are the ones to go for on the TT?
I am wondering this as i Have a 225 BAM 2002 TT


----------



## Bago47 (Nov 27, 2011)

dizzle said:


> The ATC engine, used in model year 2000 TTs, uses 20mm wrist pin rods, which makes its internals identical (strength wise) to those used in both 225 motors. However, in 2001, Audi started using the BAM motor which does in fact have weaker 19mm rods. The rods shouldn't be trusted for applications above roughly 300 ft-lbs of torque.
> 
> So in other words the 225 BAM engine is not a good as the other 225 engines? i am slightly confused as i originaly was informed the BAM engines are the ones to go for on the TT?
> I am wondering this as i Have a 225 BAM 2002 TT


BAM engines are safer, unless you're planning a hybrid turbo on stock rods (or remapped to 280bhp+, which is unlikely).


----------



## Paulj100 (Mar 24, 2009)

I don't know how true this is but was told that the APX engine is a stronger and more reliable engine compared to the BAM engine which is a safer engine due to having more sensors. 
What about these coil pack failures wasn't it just on the BAM engines :?

Paul


----------



## Bago47 (Nov 27, 2011)

Sorry for offtopic, but if 19mm rods are good only for up to 300 lb/ft, how much is it safe to run on a 20mm rods?


----------



## The Godbarber (Jul 12, 2015)

JAMason said:


> The APX will keep on chugging until it kills its self and then you will get your code!


Pmsl at this, sorry but it's sooooooo funny!!!


----------

