questions on the VAG engine

[lsvag]

im looking to buy either an audi S3 (225), a3 1.8t (150) or an a3 1.8t (180) VAG engine.

1) what is the difference between the (150) and (180) versions of the a3 (apart from the obvious power difference, DUH)

2) which of these engines is "large port"/"small port" and what is the difference ? (not literally, but mechanically, what effect does it have on performance/potential performance)

3) which of these engines has the most power potential and which can handle 300-350+ bhp the most comfortably and for the least money?

cheers

 

[obi_waynne]

The engine codes are what matters. AGU is a stronger block and has large ports. (Forged Pistons IIRC).

The turbo is different - the 225 uses the KO4, the 180 is a KO3s and the 150 is a KO3. The KO4 cannot be swapped on to a KO3 as they are different sizes and need plumbing in. Newer cars with 150 still have the KO3s and are just mapped to the lower power level.

I'd say to go with an AGU block and get a KO4 turbo fitted, this should be good for your power gain.

 

[lsvag]

According to wikipedia, the engine codes vary. The 150's codes vary between AGU/ARZ/ARX/AUM. Are they all similar ?

Which engine codes should i look out for, and which should i avoid ?

 

[obi_waynne]

Pgarner is the man when it comes to engine codes. Some are transversely mounted and some are longitudinal but in the A3/S3 they will be transverse.

Bear in mind that the S3 has the haldex quattro and would be better at putting the power down than a standard one.

I'd say stick with an AGU and you'll be happy. This is the engine I have in my A3 (which is actually for sale btw!)

 

[lsvag]

just found a site that has answered all.

just realised my dad had a 1999 golf gti 1.8t (150) .. which im guessing is an AGU. If only i had known 8 years back.

 

[obi_waynne]

Isn't that always the way, I bet you wish he'd hung on to it! What are you looking out for then?

 

[lsvag]

I still need to make my mind up. Just done a bit more research and have come to a conclusion.

like you said, S3 has 4wd to put the power down better and S3's 225 is can get high 200's maybe 300+ from a ecu remap and better externals bits and bobs

Whereas the AGU is more of a hardcore tuner engine. A few people claim 350, with a better turbo and external bits and bobs, on standard internals and 600 + :O on stronger internals.

but then again, im not looking to go full out. 300's is good enough. but then again, an AGU is pretty exciting to have, knowing what its capable of

 

[obi_waynne]

I've been pleased with mine, it's not missed a beat and as you say, you know you can get that little bit more out of it if you need to.

I still get 35mpg as the average which is pretty good for a car of that performance.

 

[pgarner]

it fepends on what your looking for

the old AGUs were 150 bhp
the later AUMs were 150 bhp

AGUs remapped to around 190 whereas the AUMs 210.

waynne mentioned turbos before the post 2002 have the k03s turbo even the 150 models, AUM is the most common one, you cant get the k03 turbo that was originally on the AGUs as its been replaced by the k03s one (if you actualy were to go into a dealership and ask for a k03s youd be told that they dont exist there is only k03 and k04 as its just partnumbers )

the difference between the post 2001 150 and 180 - the map in short, there are a few small changes but nothing major.


small and large port. early engine had the large port
later engines have the small port. can be a bit of a pain finding injectors for the large port without using adaptors.

AGUs are classed as safe till around 350bhp on standard
AUM and AUQs are safe till 300.
this doesnt mean that at 301 they will go bang

AMK and BAM engines from the 225 go for a premuim

but generally they are all the same block in short. a tuning company in the uk did have an octavia vrs sitting at 601 at the wheels - it uses the AUQ engine.

if your after a cheapish 300 then go down the s3 route. itll get you close without masses thrown at it. but even the larger k04 turbo that is fitted still doesnt like being over 300

 

[obi_waynne]

You have some pretty useful information in your head PG!

 

[pgarner]

i have even more usless information in my head to balance it out though lol

 

[obi_waynne]

 

[lsvag]

Its all making alot of sense now... but i've got 3 more questions on the AGU and the A3... 1) the reason why (correct me if im wrong) the AGU shouldn't be boosted above 350bhp is because of stock rods... what would be the bhp limit if JUST the rods were replaced with H-beam rods ?? (which, according to research, are stronger) what is the next engine component that holds it back ??...2) 9.5:1 compression ratio is pretty high for a turbo car, meaning, you have to use slightly lower boost levels, what is the highest amount of boost you can use before things start blowing up, WITH a good aftermarket intercooler..... 3) The AGU engine may be able to handle 350bhp+, but what about the A3 transmission, driveshaft and other bits and bobs.

The s3 seems like my ideal choice, BUT the AGU is an interesting prospect.. i need to know more

cheers for the extremely helpful info waynne and pgarner

 

[pgarner]

the rods in the AGU are apparently forged anyway but if your changing the rods you might as well change the pistons as well seeing the engine will be in bits.

boost levels will depends more on what turbo is fitted . a huge gt45 would be on alot lower boost than something like a 25
the high compression of the engine is actually what makes it more drivable at lower speeds. the s3 engines use 9.3:1 .

biggest issue in all the 1.8t engines is the turbos but im assuming you dont mean these

the transmission - if your flooring it all the time then theres no chance of it standing up for long, if your sensible with the power then a better clutch and single mass flywheel - note this will increase vibrations - will be sufficiant.