Re-educate me on how to shop for a used RS4

[dparm]

Howdy all. Previous two-time Audi owner (B6 S4, B8 S4) and multi-time German car owner. Currently have a C63 daily driver but have been thinking about finding an RS4 as a fun second car -- I always wanted one but ended up with an E90 M3 years ago instead. I don't regret that decision as both cars were pretty amazing!

I'm admittedly a bit out of the loop on the B7 RS4s these days. Even when they were relatively new, the carbon buildup was a thing and I remember the adjustable suspension was known to flake out early. Now that these cars are approaching 15 years old and many of them are over 100k miles, what are the other things to be aware of and look for? Planning to give JHM a call and get their thoughts but there is likely to be a little bit of bias there.

Additionally, can anyone recommend some good independent Audi shops in the Dallas-Ft. Worth area? I'd like to have one I can rely on for any sort of "rehab" a used one might need and to just do some simple mods, if the mood strikes me. Also, which dealers in the metroplex are the best?

[ginch]

I'm on my second RS4 that I have now owned for almost 5 years. I would start off finding a car that has a lot of maintenance records. Both cars I bought were well maintained and low mileage. I always like a starting point with every pre-owned car I buy so I immediately did a carbon clean, plugs, injectors, coil packs and replaced all fluids. My car needed brakes as well (which have come down a lot in price). I also did suspension but not because of a DRC failure but more so to lower the car a bit. Also, check the door blades for warping. These are now next to impossible to find in NA. Overall, try to find a clean, well maintained vehicle. I wouldn't worry too much about the mileage as these cars are very stout and reliable once gone over. Good luck with your search! They are truly special cars!!

[dparm]

Thanks for the tips. Talked to JHM and they said to check a lot of the rubber components such as hoses and bushings as those will likely be getting brittle after 15 years; apparently the hoses can be hard to come by. They also suggested replacing the factory crankshaft pulley which is known to separate, in addition to the obvious carbon clean and coilover swap.

[philbegas]

JHM has a bit of a vested interest in selling you parts though to be fair lol

[dparm]

JHM has a bit of a vested interest in selling you parts though to be fair lol

Of course, but their perspective was important because they invest in R&D for parts that will be in demand and sell. They're not going to sink $50k into developing a part that no one needs. They developed the crankshaft pulley because the OEM one is lousy.

This is why I also posted here to hear from the community.

[philbegas]

I've just heard mixed reviews about certain things from JHM. For example, their tunes are colloquially known as "JHbooM" for being too aggressive

On another note, the two things really known for blowing these motors are:

1. Old injectors

2. Intake manifold flap screws backing out and falling into the engine

If you're looking at a 100,000 mile RS4 I would probably budget for injectors, CC, and then deleting the intake manifold flaps altogether.

[dparm]

2. Intake manifold flap screws backing out and falling into the engine

LOL wow. There's been no aftermarket solution to this? I would think that removing the flaps hurts drivability and robs power, but it probably beats a blown engine.

[philbegas]

I did it and drove without a tune for like 8 months. It was a bit jerky until the car warmed up. Especially when you crossed the 3k RPM point where the flaps open or close (idk which direction the movement goes). I finally opted to get a jackal tune and the jerkiness is gone and the car pulls clean to redline.

I think some people will replace the flap arms with stronger billet ones from JHM or 034, and then loctite the screws probably, but given that replacement engines are rare and expensive, most would rather not risk it when given the option.

[87vr6]

LOL wow. There's been no aftermarket solution to this?

There is.

It's called loctite. lol.

Or removal

[dparm]

Sounds like I need to research that a bit more. Long runners are better for low RPM power, so my guess is that they close at 3K RPM to force the air through the shortest runners possible to maximize high RPM power. Lots of cars have had two-stage manifolds.

[philbegas]

JHM sells the flap delete kit so you can call em again lol

[S3NICK]

The feedback I received is to leave the factory crank pulley. I was going to get a JHM pulley but was told it's unnecessary. YMMV.

[dparm]

The feedback I received is to leave the factory crank pulley. I was going to get a JHM pulley but was told it's unnecessary. YMMV.

Interesting. JHM told me that the factory one is known to separate and eventually fail...hence why I'm asking here to see if that is indeed a common issue or not.

[Fourplay]

Sounds like I need to research that a bit more. Long runners are better for low RPM power, so my guess is that they close at 3K RPM to force the air through the shortest runners possible to maximize high RPM power. Lots of cars have had two-stage manifolds.

The flaps artificially create a "longer runner" by closing off half of the intake runner (flush with the intake divider) below ~4.5K rpm. You're just forcing the air through a smaller hole so it increases intake velocity.

Then the flap "opens" to be flush with the intake runner above 4.5k RPM, allowing air to flow through the entire runner. That's why cars with bad flap actuators or leaks in the actuation system fall flat on their face above 4.5k RPM - they have extremely restricted intake runners. Check vacuum function by pressing S button to open/close exhaust flaps.

If you're buying one, look for frequent oil changes because the DI dilutes the oil. You want injectors done at most every 100k miles, carbon cleaning done, PCV replaced, etc. Check the oil cooler because the connectors corrode and the part is extremely expensive. Door blade warping happens on almost every car because the design is crap and causing water to get behind and rust//warp the blades. The part is NLA from Audi (or at least extremely tough to find). DRC will eventually leak (have never had it leak on any of my cars, but it definitely happens).

Then it's just the standard stuff. CV joints tend to leak, brake rotors are very expensive to replace so try to find a car with fresh rotors. Glovebox and armrest break.

[USAFS4]

LOL wow. There's been no aftermarket solution to this? I would think that removing the flaps hurts drivability and robs power, but it probably beats a blown engine.

dparm, removing flaps greatly improves drivability. I wish I had done it sooo much sooner. The engine is way happier with out those darn flaps. I remember reading one persons response when I was looking into removing mine saying, Audi engineers put them in for a reason so why second guess them. IMHO, and I'm no mechanic, but I think the flaps were an after thought for emissions and fuel economy. Nothing more. Some have reported a rough idle at start up but I never noticed that. All I ever noticed was the engine revved much more freely, the car left from a dead stop in daily driving much much better. The car is so much better to drive now I can't believe Audi engineers really would have wanted to put those flaps in if they didn't have to.

[dparm]

Thanks for the explanation. I assumed it was a dual runner design, sounds like they are just bisecting the existing runner a bit. Interesting choice.

Also, thanks for the tip on the oil cooler. I'd have that checked as part of a PPI.

[z28plus]

If you de flap, is it required to tune?


Sent from my iPhone using Tapatalk

[dparm]

If you de flap, is it required to tune?


Sent from my iPhone using Tapatalk

Seems like the answer is no, as long as you don't mind some reduced drivability/NVH.

[blubusdrvr]

Funny, I’ve NEVER heard of anyone having an issue with the OEM crank pulley. I just assumed they sold their lightweight version to help spin the motor faster. Plenty of other sh*t to check/replace on this car/engine as has already been mentioned, the crank pulley wouldn’t be on my list. Obviously higher mileage examples will probably need the clutch addressed in addition to everything else. X2 on frequent oil changes.

[S3NICK]

Interesting. JHM told me that the factory one is known to separate and eventually fail...hence why I'm asking here to see if that is indeed a common issue or not.

They may be trying to sell you their crank pulley : )

On an S4, I do agree it makes a difference. For the moment, I'll stick with the factory pulley on my RS4. If you're looking for a performance gain, I think there are other areas that'll net more value off the bat.

[Old_skool]

Also, check the door blades for warping. These are now next to impossible to find in NA. !

The door blades (all 4) are the exact same part (and OEM part # 's) as the flat, regular a4 door-blades. This includes all b6 flat door blades. The only different blades are the s-line, which flare out slightly, and s4, which flare out substantially (approx twice as much as the s-line blades).

Just to re-iterate, the b7 rs4 door blades are identical to b6 & b7 a4 door blades.

[outsider6661]

The door blades (all 4) are the exact same part (and OEM part # 's) as the flat, regular a4 door-blades. This includes all b6 flat door blades. The only different blades are the s-line, which flare out slightly, and s4, which flare out substantially (approx twice as much as the s-line blades).

Just to re-iterate, the b7 rs4 door blades are identical to b6 & b7 a4 door blades.

They not the same as the RS4. The ones from the B6/7 A4s are different. I replaced the passenger side front. If you look closely you can see that the b6/7 door blade isn't identical to the rs4 door blade

Sent from my SM-N975W using Tapatalk

[Old_skool]

They not the same as the RS4. The ones from the B6/7 A4s are different. I replaced the passenger side front. If you look closely you can see that the b6/7 door blade isn't identical to the rs4 door blade

Sent from my SM-N975W using Tapatalk

Interesting, I could have sworn they were the same part number when I looked at etka.

Just re-checked, and in the european market at least, the b7 rs4 door-blade part number is identical to the b6 a4 part number, but indeed is actually different to the b7 a4 part number, which potentially correlates to your differing door blade... did you fit a b7 a4 door-blade? I never previously bothered to check if the b7 a4 part# were different to the b6 a4 part# and just assumed they were the same.

So it seems that at least in etka, the b7 rs4 and b6 a4 flat blades are the same part, with the b7 a4 being slightly different (as in your photo).
I will physically visually check the part numbers on both cars (b7 rs4 & b6 a4) blades to confirm this 100%.

Either way this is good info, thanks

[Toronto5.5]

Interesting, I could have sworn they were the same part number when I looked at etka.

Just re-checked, and in the european market at least, the b7 rs4 door-blade part number is identical to the b6 a4 part number, but indeed is actually different to the b7 a4 part number, which potentially correlates to your differing door blade... did you fit a b7 a4 door-blade? I never previously bothered to check if the b7 a4 part# were different to the b6 a4 part# and just assumed they were the same.

So it seems that at least in etka, the b7 rs4 and b6 a4 flat blades are the same part, with the b7 a4 being slightly different (as in your photo).
I will physically visually check the part numbers on both cars (b7 rs4 & b6 a4) blades to confirm this 100%.

Either way this is good info, thanks

You're right. B7 RS4 door blades are B6 A4 door blades. B7 A4 door blades are a slightly different shape (they still fit and work just fine, but there is a slight difference in the blade design).

[Rilla]

The flaps artificially create a "longer runner" by closing off half of the intake runner (flush with the intake divider) below ~4.5K rpm. You're just forcing the air through a smaller hole so it increases intake velocity.

Then the flap "opens" to be flush with the intake runner above 4.5k RPM, allowing air to flow through the entire runner. That's why cars with bad flap actuators or leaks in the actuation system fall flat on their face above 4.5k RPM - they have extremely restricted intake runners. Check vacuum function by pressing S button to open/close exhaust flaps.

If you're buying one, look for frequent oil changes because the DI dilutes the oil. You want injectors done at most every 100k miles, carbon cleaning done, PCV replaced, etc. Check the oil cooler because the connectors corrode and the part is extremely expensive. Door blade warping happens on almost every car because the design is crap and causing water to get behind and rust//warp the blades. The part is NLA from Audi (or at least extremely tough to find). DRC will eventually leak (have never had it leak on any of my cars, but it definitely happens).

Then it's just the standard stuff. CV joints tend to leak, brake rotors are very expensive to replace so try to find a car with fresh rotors. Glovebox and armrest break.

It is not artificially creating a longer runner, it is more what you said about velocity. From Audi:
“the air mass would flow through the upper section of the intake port and induce a tumbling, charging motion inside the cylinder”
In contrast, runner length is about pressure pulses.


Sent from my iPhone using Tapatalk

[Rilla]

There is.

It's called loctite. lol.

Or removal

The flaps are know to crack off even if the screws stay put. Probably fatigue in the material from working against the carbon buildup


Sent from my iPhone using Tapatalk

[ebaer49]

Howdy all. Previous two-time Audi owner (B6 S4, B8 S4) and multi-time German car owner. Currently have a C63 daily driver but have been thinking about finding an RS4 as a fun second car -- I always wanted one but ended up with an E90 M3 years ago instead. I don't regret that decision as both cars were pretty amazing!

I'm admittedly a bit out of the loop on the B7 RS4s these days. Even when they were relatively new, the carbon buildup was a thing and I remember the adjustable suspension was known to flake out early. Now that these cars are approaching 15 years old and many of them are over 100k miles, what are the other things to be aware of and look for? Planning to give JHM a call and get their thoughts but there is likely to be a little bit of bias there.

Additionally, can anyone recommend some good independent Audi shops in the Dallas-Ft. Worth area? I'd like to have one I can rely on for any sort of "rehab" a used one might need and to just do some simple mods, if the mood strikes me. Also, which dealers in the metroplex are the best?

Subscribed. Interesting since I am somewhat in the same situation. Multi-time German car owner, but now a Tesla as DD and am looking for a second fun vehicle with a V8 since it is all going away. Was looking at C63 but M157 has various points of issues and is an automatic. C55 is stout but also automatic.
Sorry, coming back on-topic.
B7 S4 4.2 40v - manual; has no carbon issues; potential cylinder scoring and chain/guide replacement; still some with lower mileage
B8 S5 4.2 FSI - manual; carbon issue but can be managed, no known cylinder scoring and no chain/guide issue; still some with lower mileage
B7 RS4 4.2 FSI - manual; carbon issue but can be managed, no known cylinder scoring and no chain/guide issue; only high-mileage examples on the market

Am bouncing between the three at the moment with having the most recent reading done on the RS4 but thank you all just learned something additional about the intake flaps.

[philbegas]

The flaps are know to crack off even if the screws stay put. Probably fatigue in the material from working against the carbon buildup


Sent from my iPhone using Tapatalk

The previous owner of my car installed the 034 billet arms with this in mind

[jonan]

There is.

It's called loctite. lol.

Or removal

you can loctite the screws, but the flaps themselves have broke and fallen into the combustion chamber borking the motor...many such cases...

also @dparm, as far as i'm aware, none of the coolant hoses are NLA, i've actually refreshed the entire coolant system on two RS4s and the hoses were readily available...door blades, that's a different story though...

- - - Updated - - -

The door blades (all 4) are the exact same part (and OEM part # 's) as the flat, regular a4 door-blades. This includes all b6 flat door blades. The only different blades are the s-line, which flare out slightly, and s4, which flare out substantially (approx twice as much as the s-line blades).

Just to re-iterate, the b7 rs4 door blades are identical to b6 & b7 a4 door blades.

false...

- - - Updated - - -

Funny, I’ve NEVER heard of anyone having an issue with the OEM crank pulley. I just assumed they sold their lightweight version to help spin the motor faster. Plenty of other sh*t to check/replace on this car/engine as has already been mentioned, the crank pulley wouldn’t be on my list. Obviously higher mileage examples will probably need the clutch addressed in addition to everything else. X2 on frequent oil changes.

i wouldn't get their pulley because then you couldn't use a single mass LWFW unless you want tons of NVH...

[Old_skool]

- - - Updated - - -



false...

- - - Updated - - -

Yes, you are correct... that statement was false... I made an assumption that b7 a4 blades were the same as b6 a4 blades BEFORE doing any checking of part numbers and comparisons etc.

i have now (with the help of a few other forum members a and ETKA/dealership parts department... as i began to divulge in post #23 in this thread + others) confirmed that the b7 a4 blades are definitely NOT the same as b7 rs4 blades,

and in doing so, I have also confirmed 100% (through physical testing/comparing/fitting etc)
that b6 a4 door blades are 100% the exact same identical part as the b7 rs4 door blades.

[ginch]

Does it really matter though because you cannot get those either!

[Old_skool]

Does it really matter though because you cannot get those either!

Sure, maybe not available brand new...

but it sure does open up the pool of cars getting dismantled/parted out that they can be salvaged from as used replacement parts, plus much cheaper too... so I feel it matters in a positive respect for the community from the following viewpoints...

MUCH higher volume of the exact same used (not new) parts in existence therefore much more choice, leading to higher probability of finding better condition components, and higher probability of colour matching, most definitely cheaper (as a used/not-new part) due to high availability and co-existing on a lower tier model, plus higher probability of finding at a local dismantlers without the need for additional shipping + can inspect condition with own eyes before purchase etc.

so does it matter... i believe it does in those respects... which was the whole point of the journey to verify what is what in the first place.

[RS4forfrank]

Hey OP,

I currently have two RS4s. 2007 with 190K miles and a just purchased 2008 with 125K miles, both black. 07 is stock-ish, I upgraded stereo. APR Tune, de flapped, 034 rear sway bar, LWFW, 034 motor mounts, and replaced DRC with Bilsteins. 07 has been mine since 2013. The 08 description is here https://bringatrailer.com/listing/2008-audi-rs4-100/ I am getting it ceramic-ed this weekend. I took out the wireless CarPlay module mentioned the sound quality sucks compared to wired and I don't mind the wired.

I feel like they/ AUDI broke the mold on these cars. Super car performance in a sedan you can take to the snow, ability to carry you and 2 buddies with golf bags in the trunk...what else do you want?

If you're interested in buying one send a PM.