OK, so I'm curious about a couple things regarding OBD2 cars and engine swaps. *The recent posts by Siena and others who have put 4.2 V8s into their A4s has me thinking seriously about this swap at a point in the not-too-distant future, when my current AHA V6 finally gives out (which it shows no sign of doing at the present time), or at whatever point as I have collected the necessary parts for the conversion (provided it isn't a five-figure investment - I will be doing the work, not paying someone else to do it). *I'm not asking here about specifics (ie, what clutch setup has to be used to mate my transmission to the V8, or if there's a listing of the required repinning of the engine bay harness to incorporate it into the car), but more some general questions about the whole idea of the swap and making it legal in the eyes of the state.

What I'm wondering first is how to make all of this pass inspection. *I know the inspection laws vary state to state, and I'm not concerned with making the emissions tests pass (I'm in non-metropolitan NY, and our emissions portion consists of hooking up a scan tool to the OBD2 port, scanning for codes, and having the inspection passed or failed via live connection to Albany, but we don't have the tailpipe sniffer tests that the city has) - that part is easy, as long as the smog-related gear is working right. *My understanding is that when the ECU is scanned at inspection, the encoded VIN number is among the data that is transmitted as a check-and-balance to make sure that the shop isn't scanning one car and stickering another - can anyone confirm this? *If that's the case, how will they be able to legally sticker my car if the VIN number sent to Albany via the ECU scan does not match that on the dash plaque in my car?

I know that there are laws on the books that make it illegal in some states (and NY is probably one of them) to use a replacement engine that is older than the car (ie, you can't put a 96 engine in a 99, but you could put a 99 engine in a 96, for example), but that's not really a concern since the desirable 4.2L engines are all newer than my pre-facelift 99 A4. *I know there are guys stateside who have done or are doing this conversion, some even using the twin-turbo 4.2 from the earlier RS6 cars. *I'd be thinking more like the 360hp first-gen S8 engine, or if that wasn't available, the normal 300hp 4.2 from the A6/A8 - either would be a serious bump from the nearly-200hp AHA engine I have, so neither would break my heart to have in the car. *Even the 300hp engine would be a huge bump over what I have now.

The other question regards the dash/instrument cluster. *I've read in the past that replacing the cluster requires a dealer to "flash" the ECU to communicate with the new cluster. *Anyone know whether that can be done using an A8/S8 ECU and an A4 dash cluster, or if the donor car would also have to donate at least the electronics of its cluster to drive the gauges? *I know this isn't a common swap - it's really only been pioneered relatively recently and only by a few guys - but it's worth posting up in the event they see it and reply, or if someone else has feedback that can help, so that the information is available to everyone.

I'm just trying to get deep background at this point, because I'd hate to go through the expense and hassle of all this work only to find out I can't get it inspected and drive it publicly on the road. *Siena and others out there who've done it, any advice on how to handle these issues?

 

I'm putting together a "how to".

http://www.ozaudi.com/forums/showthread.php?t=22760

 

Great info so far. I've bookmarked it and if this ends up going through I'm really going to be using that info - thank you

I'm curious about one of your comments - you replied to one guy that your goes "alright" and I'm a little confused by that. I'd think that with such a jump in power and torque that it'd probably go quite a bit faster than that, so is it only ok because you're comparing it to something else, such as a stage 3 S4? Or is there such a luxury-like tune to the engine due to the ECU and cams that you never really get much of a sensation of speed?

 

I used the term "alright" as I haven't fitted my new injectors, and fully mapped it yet. So, I won't use WOT till I've finished.

 

I know you're right about the engine swap thing, old into new is bad, new into old is legal. I know there are several other caveats, but can't recall at the moment. Give me a few days to try and find the article. It had to do with what motors you could legally swap into modern cars. It was from an episode of Xtreme 4X4 on Spike lol. The deal was, they were swapping a 5.7L Hemi into a Jeep Wrangler, and wanted to keep the clear title. This was legal because that particular motor came from the factory in the Jeep Grand Cherokee Ltd. (what year, i can't say) As I recall, as long as the donor car and the motor are newer than the project car, and you can retain all of the emissions and safety features of the newer motor, you should be good to go.

Conversely, if you wanted to say, swap in a LS1 (:shudders, you *could* do that, but you'd have to change the car title to salvage which would change your insurance and registration and yada yada yada. At least....thats how I understand it? Lemme see if I can find some info regarding the topic.

And I gotta say I saw this one comin, everytime someone talks about V8's in B5's, Devil gets wood ROFL

 

Funny too because my whole automotive life I couldn't have cared less about V8s and I've been a boost junkie but there's something about this swap that just seems right.

But no LS engine - world-class powerplant but swaps are complicated enough without that hassle. I've been through a couple and this will be project enough without trying to integrate a GM drivetrain into an Audi.

 

i didn't see anything about the passenger side engine bracket mod. isn't that necessary? and what about exhaust?

 

Exhaust will be fabbed - Keith has a pipe bender and Bill is looking at Mig welders. As for the bracket, I'll have to look into it if Siena hasn't covered it by then, or if it's not incorporated into the mount relocation parts that he makes.

 

i remember Siena modding the bracket and so did TheRussian. it's only a slight mod though i think. i know Siena said that he does have copies for sale though

 

I do have both side brackets, as well as the front torque mount.

V6 12V down pipes / catalysts bolt directly to the V8 32V exhaust manifold.