Low power output, B7 RS4

[kiwi_rs4]

Just for reference, a year ago on the same rollers kiwi_mtm's stock B5 RS4 did 229kw at the wheels and mine did 224 (same day). 2 days ago kiwi_mtm's stock B7 RS4 did 213kw and my B5 RS4 did 266kw with cat-back exhaust and remap (Viper Tuning). The B7 obviously is down on power, but the question is why? Or is this normal and accepted for a B7 these days - carbon build up and all that? By the way the torque figures on that dyno are raw figures so don't mean much (apart from the curve of course).

[2manytoys]

Pal, there is nothing wrong with the B7 in the previous run. If there is carbon I'd say there is such a small amount it's not having an effect. If anything, it's the hot air and retarded timing on the Dyno that is going to cause more impact (in the Dyno example on the other page).

If you are hoping the B7 is going to make as much power as your almost 22PSI boosted B5 it's just not going to happen. At Wheel Power (B7 stock v B5 stock) is hard to compare too, as you've found out, again, probably due to the hotter intake temps the B7 will make while stationary/on the Dyno.

Mal.

[mark758]

The best check is to time a warm B7 RS4 car from 3000->8000 rpm in 3rd gear.
Around 8 seconds is correct for a healthy stock car.

More and more convinced Dynos primary function is as a revenue generation tool for tuners ....

Wonder whether Vettel was fretting over dyno printouts or just focused on his lap times ? lol

[2manytoys]

The RS4 has a signature shape in the graph. As long as that shape is there everything should be fine.

I'm not a fan of the 3000-8000 run as that's also not accurate (I've experienced "good" times but been 30kW at the wheels down on power). I'd say the 3000-8000 run is good only if you are logging intake temp and timing. With intake temps less than 20C you should see timing around 30 degrees (you should not really see any retardation, assuming you are running 98RON fuel)

[neckarsulm]

To the OP, the flap sounds like it's stuck as mine was.
You need to strip it down, file a bit off so it doesn't bind on the body and lube it up.
Or just replace the airbox base.
Will this make a difference?
Well if it's an intake air temp issue you have then it can only help.

[kiwi_mtm]

Maybe a complete random event, but the car failed to start this arvo. Audi tech arrived, and diagnosed as a faulty speed sensor. Onto the transporter.
Beginning to wonder if its a lemon!

Will have them look at those misfires. Are misfires logged common (see codes earlier on this post) ?

[sonny]

Maybe a complete random event, but the car failed to start this arvo. Audi tech arrived, and diagnosed as a faulty speed sensor. Onto the transporter.
Beginning to wonder if its a lemon!

Will have them look at those misfires. Are misfires logged common (see codes earlier on this post) ?

Was it ticking when you pushed the start button (but not turning over)?

[kiwi_mtm]

Maybe a complete random event, but the car failed to start this arvo. Audi tech arrived, and diagnosed as a faulty speed sensor. Onto the transporter.
Beginning to wonder if its a lemon!

Will have them look at those misfires. Are misfires logged common (see codes earlier on this post) ?

Was it ticking when you pushed the start button (but not turning over)?

It turned over easy, but just would not fire. ie not a battery problem.
Audi techs VAG computer stated failed speed sensor.

[sonny]

That sucks, only reason I say is that my starter motor failed soon after I purchased my car, Thank god for warranty.

Your alloys look good in that pic.

[mark758]

Hope your car problems are resolved - great looking car.
I've invested in some basic racelogic toys for testing how the old girl is doing.

[ArthurPE]

Maybe a complete random event, but the car failed to start this arvo. Audi tech arrived, and diagnosed as a faulty speed sensor. Onto the transporter.
Beginning to wonder if its a lemon!

Will have them look at those misfires. Are misfires logged common (see codes earlier on this post) ?

I wouldn't worry about those
misfires happen normally
did they set the light?

you had 4 codes, all related, 3 misfires and one set by those (multiple misfires)
all happened at the same time 35394 km, 817 rpm, 2 km/hr, 23% load...while starting out...
fault fequency for each is '1', each only happened once...
all on the same bank...

[Stoffle32]

the air flap is worth about 30wkw...
here in SA we had a few Rs4's run only 174wkw at the wheels (Also at altitude so add around 17%) And the problems on the dyno we have found out are a few things...
1. Those cars intake flap was not working...
2. Traction control was not fully off only half (did one car back to back with traction control half on and fully off gained 9wkw...)
3. insufficient cooling from the dyno fan...
4. Runs were done in 3rd gear, cars that run in 4th gear have higher Power outage on the dyno (Some dyno operaters wont allow you to run in 4th though has its approaching 200km/h on the dyno!
Oh and all these cars were done on 95ron not 98

[kiwi_mtm]

the air flap is worth about 30wkw...
here in SA we had a few Rs4's run only 174wkw at the wheels (Also at altitude so add around 17%) And the problems on the dyno we have found out are a few things...
1. Those cars intake flap was not working...
2. Traction control was not fully off only half (did one car back to back with traction control half on and fully off gained 9wkw...)
3. insufficient cooling from the dyno fan...
4. Runs were done in 3rd gear, cars that run in 4th gear have higher Power outage on the dyno (Some dyno operaters wont allow you to run in 4th though has its approaching 200km/h on the dyno!
Oh and all these cars were done on 95ron not 98

I would be hanging by the rafters if my RS4 did 174wkw!
> Do you really think a 'closed' air flap accounts for that much? 30wkw is allot!
> Traction. I'm 'think' they ran it with it ON. Is it normal to turn it off for a dyno run?
> Cooling, not really sure.
> 3rd gear was used, and appreciate the 4th gear comments.
> Mine runs 98 RON

[2manytoys]

The Dyno operator did the run in 4th gear (speed confirms this). It's actually written as 4th Gear on the graph too.

I'd also be almost 100% sure they would have turned traction control off.

If you have VAGCOM see if you can log timing and timing retardation, including logging Intake Air Temp.

Here are two logs from my car (once the engine was replaced). The first is early in the morning on the highway, the second is from the Dyno run I posted earlier. Sorry about the quality, but you can sort of read what is happening. You'll notice the Dyno run log has an Intake Temps of 41 Degrees C! At this temp there is some timing correction.

Highway Run (3rd Gear) - Very little correction


Dyno run - Some timing correction

[Stoffle32]

Just remember 174wkw is at altitude... So around 203wkw, if it was done at the sea level like you, and its on 95, so figures are probably just bellow yours...