B8 RS4 and engine carbon issues

Post by **kiwi_mtm** » Fri Dec 28, 2012 6:35 pm

firstly, apologies if this has been brought up before.

Does anyone know if there has been any changes to the B8 RS4 (and RS5) motor to reduce the carbon build-up intake issues?

Post by **sonny** » Fri Dec 28, 2012 7:03 pm

MRC had a B8 on there rollers a few weeks ago, think it made 430ish standard. Doug confirm?

So you could say there not making the 450 number due to CB?

Who knows, suppose we will find out soon.

Post by **Nickyboy** » Fri Dec 28, 2012 8:42 pm

Do engines produce more power as they age?

Post by **adsgreen** » Fri Dec 28, 2012 9:04 pm

Nickyboy wrote:Do engines produce more power as they age?

Yes and no...
You generally find that engines loosen up after a while. Same with transmissions and it can take a fair amount of time - some cases of 10-20k miles. Then they will peak and start to wane as things wear like piston rings.

Post by **HYFR** » Fri Dec 28, 2012 9:05 pm

Think it was 434PS
That's close enough!
My V10 pulled 516PS vs. 525PS

Dyno is rarely 100% spot on rated power! Way too many variables

Given a healthy B7 is c.390, that's an extra 45PS plus a double clutch gearbox....gonna be quicker!

Post by **adsgreen** » Fri Dec 28, 2012 9:11 pm

D_K wrote:Think it was 434PS
That's close enough!
My V10 pulled 516PS vs. 525PS

Dyno is rarely 100% spot on rated power! Way too many variables

Given a healthy B7 is c.390, that's an extra 45PS plus a double clutch gearbox....gonna be quicker!

Supposed to be 450 iirc (same as the rs5)

Totally agree that rollers have a margin of error - tbh trying to read absolute numbers is always going to be hit and miss.
20ps out is only 4% error - I've seen rollers with way more error than that.
Remember the 450 rating is under ideal bench conditions - manufacturers are allowed to use the best fuel, humidity, etc.
The best way to use rollers is a before and after and when doing a shootout with other cars.
Wouldn't surprise me if the dct transmission has more rolling resistance.

Post by **Nickyboy** » Fri Dec 28, 2012 9:49 pm

It's interesting that the RS4 on a dyno produce slightly less and the S4 and S5 produce slightly more on a dyno than quoted. Hence my question above as I wondered if the RS4 didn't have enough miles under its belt.

Post by **HYFR** » Fri Dec 28, 2012 9:57 pm

The 3.0TFSI has so much more to give than the 333PS Audi state. Where as the 450PS from 4.2litres NA is pretty close to the limit

Post by **adsgreen** » Fri Dec 28, 2012 10:02 pm

Nickyboy wrote:It's interesting that the RS4 on a dyno produce slightly less and the S4 and S5 produce slightly more on a dyno than quoted. Hence my question above as I wondered if the RS4 didn't have enough miles under its belt.

Not really - forced induction is like that (iirc the s4 and s5 are supercharged?)

Post by **Nickyboy** » Fri Dec 28, 2012 10:08 pm

adsgreen wrote:
Nickyboy wrote:It's interesting that the RS4 on a dyno produce slightly less and the S4 and S5 produce slightly more on a dyno than quoted. Hence my question above as I wondered if the RS4 didn't have enough miles under its belt.
Not really - forced induction is like that (iirc the s4 and s5 are supercharged?)

Yes they are. Still, Audi could have quoted them at 350-360 which is where they dyno normally. I'm sure they know where they really dyno.

Post by **RS6chris!** » Fri Dec 28, 2012 10:47 pm

Surely Audi must now be aware of the carbon issues dating back to the B7?

If so they must have tried to mitigate against them in this engine?

I believe the V8 R8 doesn't suffer half as bad as the B7 due to the better intake manifold etc??... I may be wrong??
Hopefully the B8 engine bay allows more space for improved breathing?

Chris

Post by **535dboy** » Fri Dec 28, 2012 10:50 pm

So what is the verdict?

Post by **adsgreen** » Fri Dec 28, 2012 11:08 pm

RS6chris! wrote:Surely Audi must now be aware of the carbon issues dating back to the B7?

If so they must have tried to mitigate against them in this engine?

I believe the V8 R8 doesn't suffer half as bad as the B7 due to the better intake manifold etc??... I may be wrong??
Hopefully the B8 engine bay allows more space for improved breathing?

Chris

The r8 has a manifold that features straight intake trumpets where as the rs4 bonnet makes this impossible so they are bent back on themselves. It might make the problem less apparent but I'm sure I've seen reports of BNS engine r8's having carbon too.

However if the problem is internal egr or valve stem seal related then it would be possible to adapt and tweak things without redesigning the engine.

Post by **adsgreen** » Fri Dec 28, 2012 11:11 pm

Nickyboy wrote:
adsgreen wrote:
Nickyboy wrote:It's interesting that the RS4 on a dyno produce slightly less and the S4 and S5 produce slightly more on a dyno than quoted. Hence my question above as I wondered if the RS4 didn't have enough miles under its belt.
Not really - forced induction is like that (iirc the s4 and s5 are supercharged?)
Yes they are. Still, Audi could have quoted them at 350-360 which is where they dyno normally. I'm sure they know where they really dyno.

Possibly but I think with forced induction and the DIN requirements for rating an engine mean that it tends to underread.
There are also a few more variables with FI so it wouldn't surprise me if they err a little bit low

Post by **S4Player** » Sat Dec 29, 2012 9:04 am

I've seen r8'a make anywhere from 360 onwards, Dave on here made 384 at an RR day at Mrc so the r8 certainly suffers it as well. Doug could comment more as they've recently just purchased an r8

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