2FST4U

Hi all, not many of you really know me because I mostly read on this forum, but I am planning out my future urq project. I would like to hear from those of you who have converted to 20V... AAN or 3B
What are the major differences between the two engines? aside from the fact that the AAN can be tuned with RS2 parts much more easily in a bolt-on procedure.. what are the other differences? Performance? Sound? Cost?
Where did you get the conversions done? Did you do them yourself or did you take them to a shop?
As you all know... projects are all up in the air at the beginning and I am just trying to get as much of this figured out much earlier, although I know that 85% of the things will end up changing along the way somewhere.
Thanx for your help in advance

losdos

I haven't done a conversion, but as far as I know the differences between the 3B and the AAN are fairly small and include:

The 3B has distributor ignition, the AAN direct fire
A different intake manifold
The AAN makes ~10hp more (direct fire)
The alternator is on the other side of the block

AFAIK, the block and head are virtually the same. So if you're talking about manifolds, injectors and such, you can use RS2 parts on either. If you've talking about stuff like the RS2 MAF or something, that's a question that I have no answer for. I'm not sure if it works with both of the OEM ECUs.

Check out the link below and check out the 'Featured Users' section. There are a couple of 20v cars in there.<ul><li><a href="http://034EFI">http://www.034efi.com</a></li></ul>

urq20vt

There is a LOT of information.

Rich L.

The early RS2 was a distributor engine just like the 3B. There really isn't any difference in bolting RS2 parts to a 3B or an AAN. Software is where they differ.

Rich
85 urq 20v (3B w/ RS2 Goodies)

Rich L.

MAF is identical 3B to AAN.

urq20vt

The early S2 used the 3B with a distributor, but RS2 _never_ did. In fact, a distributor will not fit on a car with an RS2 intake manifold. BTTriedT. As for tuning, with the same components (turbos, injectors, etc.) the AAN have more power than the
3B because of the more advanced fuel injection and ignition system. I'm not saying that you can't get good horseopower out of a 3B, just that you will get a little more out of the AAN.

Other than the distributor, there are other factors that make an AAN stronger than a 3B. One little known fact is that the AAN block itself has more reinforcement than the 3B. The AAN also has better rod bearings and different rods. I have never heard of rod failure on an AAN, but I have seen four 3Bs with bent or broken rods. One local ur q 20V went through two 3B bottom ends and then switched to an AAN bottom and hasn't seen another failure.

From a conversion standpoint, the 3B (especially if you can find one from an S2) is a MUCH simpler installation in an ur q. It is as close to "plug and play" as you are going to find. The S4/S6s that we got in the US are very different in the layout in the engine bay and electrically, which means you need lots of late S2/RS2 engine parts to make it all work. From an electrical point of view, the AAN harness is also very different, meaning lots of work to get it configured properly.

Steve

ralleyquattro

Oil Pan,
Intake Mnifold etcetc. etc.
Water Manifold.
Ancilary brackets.
Harmonic balancer.
Flywheel (AAN had dual mass..
The list goes on and on...
It's much easier and less expensive to do a 3B swap... best to find an S2 engine.. however 200q 20v will do just as nicely.

If you do want AAN style i.e. coil/cylinder find an ABY or just spend the exra bit up front and find an RS2 motor in Europe... not that difficult.

HTH
Martin
www.quattro.ca

Rich L.

Sorry for the mis-information. I just dug around a little bit and Steve's correct. The S2 got the 3B initially (changed somewhat from the 200's 3B)and then the ABY. The ABY eliminated the distrubutor in favor of individual coil packs. The RS2 then got the ADU, which was an ABY with different manifolds, turbo, injectors, MAF, etc.

Another difference to note between the 3B and AAN is the head gasket. Paper-ish on the 3B and metal on the AAN. I didn't know about the block difference.

My coupe has a 3B that I rebuilt with aftermarket rods, main bearing studs and head studs, AAN bearings and head gasket and RS2 turbo and exhaust manifold. I thought I was set but now I'm worried about the block.

Thanks Steve,
Rich

fusilier

cpayne bent a rod on his AAN.

urq20vt

<center><img src="http://pictureposter.audiworld.com/22057/picture048_11jun04.jpg"></center><p>Here is a picture of his original rods and bearings that I took today.

Seeing that the bearings and crank were destroyed, he decided to upgrade the rods while he was at it. The little piece of bearing on the bottom was all that was left of one of the #5 bearings. His Pauter rods just came in, so it looks like his engine will be going back together soon.