RWD Conversion

[thorrinn123]

I am looking at a 2003 A4 Avant 3.0 that the owner converted into a rwd and welded the diff can it be converted back to awd and what all needs to be done if it can?


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[thorrinn123]

Anyone?


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[AvantNoir]

Diff will need to be replaced for sure. Probably needs axles. 3.0 v6 is a POS engine. Would be better to 2.7t swap while you’re restoring the drivetrain.


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[grayjay]

Anyone?


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They likely did this by opening the transmission and welding up the center front/rear split differential and possibly removing front driveshafts. It would likely be very expensive to remove and go through the welded transmission, replacing the differential parts that they welded up and anything else damaged. Almost certainly cheaper to source a used replacement transmission, and swap it out and replace any absent front driveshafts. Better yet, just pass on buying this project unless it it nearly free. I would highly suspect that the rest of the car/engine is severely abused since they likely performed the RWD downgrade in order to drift.

[Kevin C]

Is it a stick or an auto?

[thorrinn123]

6 sp manual


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[Gin+]

I'd have a little fun before converting it back...

[86turbodsl]

Diff will need to be replaced for sure. Probably needs axles. 3.0 v6 is a POS engine. Would be better to 2.7t swap while you’re restoring the drivetrain.


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While you can swap a 2.7 in very easy, i think the above statement is an overstatement. I've put 317K on my 3.0 with no real issues.

[walky_talky20]

The usual process to create a RWD A4 is to remove the torsen center diff, weld it on the bench, and pop it back in. There is really no damage to anything other than the torsen diff itself. So you just need another torsen unit that matches that transmission. Unfortunately for you, these aren't commonly floating around outside of Audi transmissions, so you basically just need find another matching transmission. Then you can pop the donor center diff out and put in your car. So this does not avoid buying a transmission, but DOES avoid the labor of dropping the entire transmission out of your car. Get the pair of front axles with the donor transmission if you can, unless you got those with your car or something.

This is not irreversible. You just need to find the stuffs.

[Mike Tries]

Well... Devil's advocate here... why bother converting it back to AWD?

aaaaaaand.... I'm reading your location as a place that still has winter. Maybe that's why.

[JoshDub]

The center diff is located at the back of the transmission. Pop off the cover plate, swap out the welded diff for a new diff, and get back to awd. You'll need to refill some transmission fluid and you may or may not need front axles. It's pretty straight forward.

[Turbo510]

While you can swap a 2.7 in very easy, i think the above statement is an overstatement. I've put 317K on my 3.0 with no real issues.

As a fellow 3.0 driver, I agree, although mine's only done 280,000 miles. I've never owned a 2.7, but they appear to be a complex setup with two hard-to-access turbos, oil and coolant plumbing, and lots on induction/intercooler hardware.

[EuroxS4]

As a fellow 3.0 driver, I agree, although mine's only done 280,000 miles. I've never owned a 2.7, but they appear to be a complex setup with two hard-to-access turbos, oil and coolant plumbing, and lots on induction/intercooler hardware.

I disagree,worst engine ever made by audi right next to the 2.0TFSI and the new EA839 all are piles of garbage. Great candidate for a 2.7T swap. Just make sure to go STK that way you don't have to pull the engine to change the turbo out.

[canonball]

I'd have a little fun before converting it back...

+1

[SideMirror]

The way I feel about the 3.0L engine is it is a good daily driver but can never be more than that because power modifications are very limited.

I modified mine 6 years ago a JHM tune with downpipes gains about 20 hp for $1800. I like the linear power feel of the throttle from second gear onwards. I drove the 3.0L for 3 year's before selling.

Consider a 2.7 swap and collected the parts including the harness and engine (all for sale if wanted).

I also own the 1.8, and 2.7 all 6MT. If more power is what you're after the 1.8 or the 2.7 engines can be modified as far as your money can take you.

But it's all about what you want in your car to be happy. Have fun!


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[86turbodsl]

I disagree,worst engine ever made by audi right next to the 2.0TFSI and the new EA839 all are piles of garbage. Great candidate for a 2.7T swap. Just make sure to go STK that way you don't have to pull the engine to change the turbo out.

Ok, as an engineer, i need to see data. Please give me some concrete reasons why the engine is a POS. I agree with the assessment that it's not really made for significant modifications or big power. So leave that out. In a daily driver setting, WHY do you feel the engine is the "WORST" engine ever made by Audi? And secondly, have you left out the B6/B7 S4 4.2L?

[negativegain]

And secondly, have you left out the B6/B7 S4 4.2L?

HOT TAKE INCOMING!

I totally get it tho

[CJM_RVA]

And secondly, have you left out the B6/B7 S4 4.2L?

Isn't that more of a packaging problem than an issue with the engine itself? (Yes, I see you specified B6/B7 S4). I don't see a lot of hate for the 4.2 in A6 or A8 applications.

[86turbodsl]

Isn't that more of a packaging problem than an issue with the engine itself? (Yes, I see you specified B6/B7 S4). I don't see a lot of hate for the 4.2 in A6 or A8 applications.

Packaging driven decisions, i agree with that. The chain drive system is a nightmare. Took them quite a while to get it ironed out. I assure you that engine went through a lot of validation, and it still made production before it was all right. Don't get me wrong, i WANT to love the B6S4 engine and want to own one, until i think about it for a minute. I always back away. The belt drive 4.2, i'd own one in a minute. Good engine. Low warranty.

[EuroxS4]

Ok, as an engineer, i need to see data. Please give me some concrete reasons why the engine is a POS. I agree with the assessment that it's not really made for significant modifications or big power. So leave that out. In a daily driver setting, WHY do you feel the engine is the "WORST" engine ever made by Audi? And secondly, have you left out the B6/B7 S4 4.2L?

Ok let me make the correction 3.0 and a 4.2 engines are the biggest piles of shit they ever put into the b6 chassis.

Engineers have their place is every setting. This isn't one of them. My data shows that 3.0 engines are giant piles of shit based on the fact that every single one i've seen needed cats, a torque converter, cam adjuster failures, among other issue like insufficient cam hardening that the "Engineers" couldn't get right on the early engines from 2002-2003.

Engineer Noun [En-Ju-Neer] Someone Who Does Precision Guesswork Based On Unreliable Data Provided By Those Of Questionable Knowledge. See also wizard,magician.

[86turbodsl]

Ok let me make the correction 3.0 and a 4.2 engines are the biggest piles of shit they ever put into the b6 chassis.

Engineers have their place is every setting. This isn't one of them. My data shows that 3.0 engines are giant piles of shit based on the fact that every single one i've seen needed cats, a torque converter, cam adjuster failures, among other issue like insufficient cam hardening that the "Engineers" couldn't get right on the early engines from 2002-2003.

Engineer Noun [En-Ju-Neer] Someone Who Does Precision Guesswork Based On Unreliable Data Provided By Those Of Questionable Knowledge. See also wizard,magician.

I am an engine design engineer. Guess i should have said that. You are welcome to your opinion, even if it sounds like you have no direct knowledge of what engineers actually do.

[EuroxS4]

I am an engine design engineer.

I'm not gonna say anything. That's just about says it all.

[86turbodsl]

I'm not gonna say anything. That's just about says it all.

You have no direct knowledge of me, so you can't say anything of substance. I'm published and have patents. And don't need your validation. Later.

[Cvelbar]

- - - Updated - - -

I'd have a little fun before converting it back...

+2

[Cvelbar]

The way I feel about the 3.0L engine is it is a good daily driver but can never be more than that because power modifications are very limited.

I modified mine 6 years ago a JHM tune with downpipes gains about 20 hp for $1800. I like the linear power feel of the throttle from second gear onwards. I drove the 3.0L for 3 year's before selling.

Consider a 2.7 swap and collected the parts including the harness and engine (all for sale if wanted).

I also own the 1.8, and 2.7 all 6MT. If more power is what you're after the 1.8 or the 2.7 engines can be modified as far as your money can take you.

But it's all about what you want in your car to be happy. Have fun!


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you said you had the necessary supplies for a 2.7 swap, what would that entail and what would you let it go for?

[ImRobBailey]

And secondly, have you left out the B6/B7 S4 4.2L?

Having just purchased a B6S4 I feel a little called out...but I love the car so far. Granted, I haven't done any engine work (yet) and I'll need to do chains and a new sump...hmmmm maybe I'll sell it to another sucker before I need to do all of that.

Just kidding. This may be a dumb question - any way to convert a chain driven 4.2L to belt driven?

[walky_talky20]

Yes. The Belt-Drive 4.2 engine will bolt up in it's place. Lots of other stuff needs changed along with it (basically the same stuff people would do for a 2.7T swap), but it does bolt up.

[86turbodsl]

Having just purchased a B6S4 I feel a little called out...but I love the car so far. Granted, I haven't done any engine work (yet) and I'll need to do chains and a new sump...hmmmm maybe I'll sell it to another sucker before I need to do all of that.

Just kidding. This may be a dumb question - any way to convert a chain driven 4.2L to belt driven?

That was not my intent. Sorry if you feel that way. I *WANT* a B6 S4, every time, until i realize what i'd be in for, since i maintain my own vehicles completely. I'm unwilling to write a check for maintenance as big as the purchase price of a car. I've almost pulled the trigger several times until i gain back my sanity and realize it's an engine pull for almost anything.

[86turbodsl]

Yes. The Belt-Drive 4.2 engine will bolt up in it's place. Lots of other stuff needs changed along with it (basically the same stuff people would do for a 2.7T swap), but it does bolt up.

It bolts up, but it's a very very tight fit, and there's modifications of parts that the factory wouldn't do. They did the rear chain drive 4.2 so they didn't have to cut so many corners to fit in a belt drive. That said, i'm willing to engineer and fabricate my way around those issues to have a belt drive 4.2 in a B6. VERY VERY few of those have been completed to this point. Clint was supposed to make me a harness, but he's disappeared so i guess i will have to make my own.

[EuroxS4]

Having just purchased a B6S4 I feel a little called out...but I love the car so far. Granted, I haven't done any engine work (yet) and I'll need to do chains and a new sump...hmmmm maybe I'll sell it to another sucker before I need to do all of that.

Just kidding. This may be a dumb question - any way to convert a chain driven 4.2L to belt driven?

Timing chains and phasers and guides every 100k if your lucky. Boat anchor to avoid at all costs. The best thing anyone can do to a b6 s4 is swap in a VRT, or a belt driven v8.

[Michael O]

I am a mechanical engineer ( BSME cum laude, 1972 w/ math minor) with 50 years of ft experience in aerospace, automotive and industrial/ process and power gen ..Latest as Sr Staff Engineer on the F 35 with lead responsibility for Pratt & Whitney and Hamilton Sundstrand ( both now Divs of Raytheon) 25000 rpm engine driven fuel pumps and fuel systems integration. Twenty years in automotive R&D Six patents, payload specialist Space Shuttle candidate chosen by NASA. Have had 6 MBs and one Audi. Audi has had many serious "issues" ...2.0 engines, timing chains at rear of 4.2 , water pumps behing timing belts , plastic coolant flanges, coil pack screw ups.HP fuel pump cam follower nightmares...MB had their 380 single timing chain recalls , a few cam and rocker arm metal mismatches ( like on my M103 engine ) but MB was quick to replace it all no charge at 135000 miles and 8 yrs old. ) Audi gets an F in my book. Truth in Engineering It Is Not !! Had only one audi, but really two... "the first one and the last one"

[Kevin C]

I am a mechanical engineer ( BSME cum laude, 1972 w/ math minor) with 50 years of ft experience in aerospace, automotive and industrial/ process and power gen ..Latest as Sr Staff Engineer on the F 35 with lead responsibility for Pratt & Whitney and Hamilton Sundstrand ( both now Divs of Raytheon) 25000 rpm engine driven fuel pumps and fuel systems integration. Twenty years in automotive R&D Six patents, payload specialist Space Shuttle candidate chosen by NASA. Have had 6 MBs and one Audi. Audi has had many serious "issues" ...2.0 engines, timing chains at rear of 4.2 , water pumps behing timing belts , plastic coolant flanges, coil pack screw ups.HP fuel pump cam follower nightmares...MB had their 380 single timing chain recalls , a few cam and rocker arm metal mismatches ( like on my M103 engine ) but MB was quick to replace it all no charge at 135000 miles and 8 yrs old. ) Audi gets an F in my book. Truth in Engineering It Is Not !! Had only one audi, but really two... "the first one and the last one"

This is why no one likes engineers on forums!!!!

[BumblebVR6]

This is why no one likes engineers on forums!!!!

Had one ask me the other day if it was worth buying a donor car (Lexus IS) with less miles to swap the engine since his had 200K miles and had a few issues :-). I almost fell over. Transmission was low on fluid so it was causing some sputtering/shuddering. Once that was resolved the car ran like a champ as most Lexus' do. Engineers are funny.