Will a B7 RS4 fit in a B6 S4?

[njpena]

So my b6 is probably on its last legs at the moment. I have some money saved up. I was just doing some thinking and would a B7 RS4 engine fit into the B6? If not I might just buy a new S4 engine and swap it in. Or do I say the hell with it and sell it. I would do the timing replacement but I got an oil leak somewhere and we all know thats like looking for a needle in the haystack with these engines.

[fR3ZNO]

They're the same platform...

[njpena]

I mean yeah I know that but I just wasn't sure if they had any little difference that I should be aware of.

[james12lucy]

Little differences? They are completely different engines! You are going to need a new transmission, new driveshaft, new centre differential, new rear differential, engine, all associated plumbing, all radiators, both ECUs, a new wiring harness, and more.

It’s going to cost you more to build that car then it would be to buy one. I’m not saying it can’t be done, but it’s not going to be even close to easy.


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[fR3ZNO]

He just asked if it'd fit! Didn't say anything about making it run, hehe.

[james12lucy]

He just asked if it'd fit! Didn't say anything about making it run, hehe.

Good point. So technically it won’t, because it would also need a new rad cradle to fit.


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[87vr6]

Good point. So technically it won’t, because it would also need a new rad cradle to fit.


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Stop. Just stop


OP, yes, the B7/8 RS4 motor will easily fit into your B6, provided you have all the proper accessories.

[VinnysS4]

Lol. Yes it will fit. Anything will fit if you make it

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[fR3ZNO]

Anything will fit if you make it

[james12lucy]

Stop. Just stop


OP, yes, the B7/8 RS4 motor will easily fit into your B6, provided you have all the proper accessories.

Pardon me?

You’re 100% incorrect. It will not easily fit. If you’re asking literally can you bolt it in, yes, you can bolt the B7 RS4 engine into the B6 S4 engine mounts and that’s about it.

Quite literally, everything else in the engine bay is different. Sure, they’re both 4.2L V8 engines, but they’re about as different as any two engines can be. Further to this, there was never a B8 RS4.

So, before you tell me to stop, just stop, do some homework. And before you ask if I know what I’m talking about, refer to the photos below, and my history on this forum.






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[VinnysS4]

Technically there is a b8 rs4. Just saying



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[chrislane31]

LMK if you are serious, I am parting out an RS4 right now. The motor is pending, but still have a bunch of other stuff. Going to part it down to a shell and then sell the shell for everyone that needs the rear quarters, doors, sideskirts, trunk, bumper, etc.

[james12lucy]

Technically there is a b8 rs4. Just saying



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The technicality is that it’s a B8.5. So technically correct.


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[S4Bennett]

I want to say the only mounting difference for the long block is the front mount or what everybody calls the snub mount. The BNS mounts to a bracket off the pass-side frame rail and the BHF/BBK use a snub mount on the radiator core support.

The B7 RS4 might spline directly with the B6 S4 transmission since you can use B7 RS4 clutch discs as a bolt-on (JHM LWFW with Stage 3/4 disc uses a B7 RS4-compatible disc).

Electronics are less obvious.

[Mr. Corey]

Look up Dsgrays build thread. S4 trans has slightly different gearing but it bolts up no problem. Most of the B6/7 S4 peeps are running the RS4 flywheel etc ...... The RS4 has two ECU's so you need to relocate your battery to the trunk. Fueling is different but if you had a parts car it would be the way to go since that engine is much more robust. Front snub mount like mentioned... not sure what else. Its possible and has been done by several AZ members, if your willing to put some extra energy into swapping, and love the B6.... I say go for it!

[jhoward]

Totally doable, but you'll really want a whole donor car to do the swap. An rs4 that's been rear ended would be perfect. I looked into doing it to mine, but gave up when I looked at the cost


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[Jdsb6s4]

Technically there is a b8 rs4. Just saying



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OH SNAP!

[VinnysS4]

OH SNAP!

Lol

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[Jdsb6s4]

I would go with another BHF engine and install all the fun upgrades while engine is out. Headers, LWCP, LWFW, clutch, SAI deletes and timing components. All that will end up costing less than a RS4 swap.

[Mr.Wrong]

Pardon me?

You’re 100% incorrect. It will not easily fit. If you’re asking literally can you bolt it in, yes, you can bolt the B7 RS4 engine into the B6 S4 engine mounts and that’s about it.

Quite literally, everything else in the engine bay is different. Sure, they’re both 4.2L V8 engines, but they’re about as different as any two engines can be. Further to this, there was never a B8 RS4.

So, before you tell me to stop, just stop, do some homework. And before you ask if I know what I’m talking about, refer to the photos below, and my history on this forum.






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You don’t need new transmission, B6/7 S4 transmission will work just fine. Also I’m pretty sure he meant BNS block from B7 RS4 & B8 RS5....

The only way it’ll cost you more than to buy an actual RS4 is if you take it to the fancy Indy shop and just throw cash their way to make it happen. If you’re a DIYer & tech savy, it could be done and it’s not rocket science. There’s a few members who have done it here. I think most recent one or al least from top of my head would be tjbradney. Although his starting point was not a B6 S4, but rather B7 S4 DTM which makes little difference anyways. OP I suggest you PM him and ask for details of what issues he ran into and what all he needed to make it happen.

[Nollywood]

The B7 RS4 motor may be different to the B6/7 S4 version, but as far as a swap goes, it’s not a non-starter.

It will bolt up to the S4 transmission just fine. It doesn’t have to use the RS4 running gear. Besides the RS4 transmission being geared lower to take advantage of the RS4 engine’s higher-reviving nature, the transmissions are identical.

It all depends on how far the thread starter’s willing to go, but from his post, I’d say he’s just asking about the engine, not building a B7 RS4 clone.

[87vr6]

Pardon me?

You’re 100% incorrect. It will not easily fit. If you’re asking literally can you bolt it in, yes, you can bolt the B7 RS4 engine into the B6 S4 engine mounts and that’s about it.

Quite literally, everything else in the engine bay is different. Sure, they’re both 4.2L V8 engines, but they’re about as different as any two engines can be. Further to this, there was never a B8 RS4.

So, before you tell me to stop, just stop, do some homework. And before you ask if I know what I’m talking about, refer to the photos below, and my history on this forum.

So, basically, what you're saying is.. It DOES fit. There's no way around it. The B6/7 cars are basically the same under the skin. What you're stating is just simply a ridiculous argument. Would you tell the owner of a 1.8 MK4 jetta that, no the MK4 R32 motor does not fit his car, because it's a different motor, uses a different trans, etc? Because, news flash, they fit fine. Just like putting a BNS into a B6. It fits fine.

Also, sweet burn on the B8 RS4s... You must really know what's up, especially with the homework comment and all