RS4 Power (BHP)

[honest]

okay, will post when i can scan them - thanks!

[Acquiesce]

I have only had my RS4 a couple of weeks now and it is easy to get sucked into this whole RR/BHP talk floating around and start loosing sleep about it. Bottom line is I haven't got a clue what BHP my car is running but I do know that it blows the doors off the Porsche Cayman S it replaced and puts a huge grin on my face everytime I floor it. Many years ago I had experience using RR's with my MINI Cooper S. Got involved in some banter on a Renault Clio Sport forum and it all turned into a bit of a "my cocks bigger than yours" when it came to comparing cars over a forum. It turned out there were a few decent chaps on there and we regularly went out for runs and I attended a RR day with them. From memory not one Clio put out nearly the 172 BHP as quoted by the manufacturer (Clio 172). Most came in around the 140's. Meanwhile my standard Cooper S (163bhp) came in at a stonking 185bhp !!! The reason explained for this was that the Clio engine was N/A (Like the RS4) and the Cooper S engine Super charged. The air feed from the RR was fed directly into the Super Charger whereas on a N/A engine there is no where for it to go which had an effect on the figures. I am not the most technical person when it comes to stuff like this but maybe someone could explain what I am trying to say more thoroughly!!!

[scaghead]

real world performance is as others have already said the only way to know for sure.... not mickey mouse rr figures. like p-g said i have had 3 rr since last december all different one 310, and two around the 400 mark.. but i have done jack diddley to the motor over this period other than oil change.

[honest]

Results attached, do I have a problem?

Analysis appreciated.

[Les]

Well said scaghead, I think owners are getting caught up in this situation and it is a shame as, probably, most cars are running fairly well and are not down much on power.

I think those who are having performance issues are however right to pursue a fair solution, after all we have all bought these cars because of their stonking performance although I'm sure some will say otherwise

For me there is no way that a machine can measure the power of these cars accurately, it has to be done using mathmatics and physics. Multiple runs on the 1/4 mile will give a good idea and remember if you are using properly calibrated equipment in dry, windless conditions then your fastest time is all you really need The RS4 can't do a quick run unless it has the appropriate power...... simples! If you use an average that will tell you what you can easily achieve but your fastest time will tell you how powerful your car is when you don't balls up a gear change or have a poor reaction time.

[Andyuk911]

Results attached, do I have a problem?

Analysis appreciated.

Yes looks like vacuum fault .. check all lines .. including the exhaust valve ..

Lots to check ...

http://www.jlosee.com/images/RS4/PDF/TS ... fold-2.pdf

[W8PMC]

My motor, now through 40K miles feels quicker than ever & having owned from new i feel i'd know if i was up/down. I've no idea what RR power figures it puts out as the car has never ventured onto a RR & likely never will.

Had a 540BHP M5 & 560BHP RS6 beforehand & my DMS RS4 feels no slower than both of those cars, so i'm happy it's punching at it's correct weight.

[PetrolDave]

Results attached, do I have a problem?

Analysis appreciated.

Yes looks like vacuum fault .. check all lines .. including the exhaust valve ..

Lots to check ...

http://www.jlosee.com/images/RS4/PDF/TS ... fold-2.pdf

Second that - there's no "kick" at 5500rpm which suggests that the vacuum is leaking away so the "power flap" isn't operating.

[ArthurPE]

Results attached, do I have a problem?

Analysis appreciated.

Yes looks like vacuum fault .. check all lines .. including the exhaust valve ..

Lots to check ...

http://www.jlosee.com/images/RS4/PDF/TS ... fold-2.pdf

my thoughts exactly....that car is making 200 whp...300 Hp at the FW with 100 in losses

what's consistent is all cars have ~100 HP in losses when measured...
a cf of ~35% so 1.35 x whp ~ crank for this car...
so if you make 305 whp x 1.35 ~ 412..
losses ~25% or 100/414

so any car making 300+ at the wheels is making rated HP...
THAT's why wheel numbers are the only ones to consider...
and using a dyno that MEASURES losses

[toomuch]

My motor, now through 40K miles feels quicker than ever & having owned from new i feel i'd know if i was up/down. I've no idea what RR power figures it puts out as the car has never ventured onto a RR & likely never will.

Had a 540BHP M5 & 560BHP RS6 beforehand & my DMS RS4 feels no slower than both of those cars, so i'm happy it's punching at it's correct weight.

Ive taken both my cars for a blast today and the RS4 is not that much slower than the M6 that has been dynoed at 518bhp.

So IMO the RS4 has to be giving 400+ BHP

The car drives excellent and it plenty fast compared to other fast cars end of.

I would say thats all that matters.

[PetrolDave]

The car drives excellent and it's plenty fast compared to other fast cars - end of.

I would say that's all that matters.

Well said

[RI_RS4]

if far off, check for vaccum leaks, some folks had them, once fixed the car was as good as new...

you imply you've done dyno runs...post them so I can pick them apart...lol

Several comments. Some engines have had vacuum leaks. Some have had significant intake valve deposits. Both causing peak torque reductions. In a recent (1 week ago) US example, oil returned through the PVC system had mucked up the valves, and the intake manifold ram flap, causing engine check codes. The problem was severe enough to keep the flaps from opening completely.

Personally, I like to use a chassis dyno for comparing uncorrected wheel torque. If done using the same procedures on the same dyno each time the results are very repeatable. Any significant relative differences noted are due to real issues.

[RI_RS4]

Another comment. Just because your RS4 is running well and producing full power now, does not mean that all RS4s are, or that yours will continue to. Clearly some are not producing full power. Some have vacuum leaks. Some have intake valve deposits. Some have manifold flap problems ... etc.

I know specifically of RS4s with diagnosed IVD problems in Iowa, Delaware, Mass., and Mississauga, Ontario, along with those in the UK. Given the small RS4 production run, and the fact that only a small percentage of owners frequent forums like these, I'd be concerned that these are leading indicators of something that has a larger scope. I wouldn't spend much time worrying about it, however I would keep my eyes wide open and be aware for the future, since Audi repair facilities are not always forthcoming with information.

Here's the most recent thread on the topic of intake valve deposits that I am aware of. The owner contacted me last week. As you can see, quite a few owners have chimed in with the word about the issue from their own dealer service departments in Kansas City, Ontario, Utah ... etc.

http://www.audizine.com/forum/showthread.php?t=297492

[aidanjaye]

Remember though that in the US your petrol is sh*t, cheap sh*t granted but still sh*t quality.

[RI_RS4]

Aidan,

So? Audi is required to design their engines for the fuel quality world wide. If their engines can't handle it, then they have a design defect. They know going in what the quality of fuel is in every country they sell to.