Rolling Road on 24/11/2007

[mixja]

I'm surprised at the AFRs - 11.5:1 - I would have expected 12-12.5:1 for a NA high performance car...there is definitely more power to be had from a remap running leaner AFRs...

[t_urbo]

Here you go t_urbo, some light reading.....

http://www.fireblades.org/forums/genera ... m-air.html

http://www.sportrider.com/tech/146_9912_ram/index.html

Your a funny guy.

Who is comparing the RS4 engine with a 20,000 rpm F1 engine?

Wheres the comparison with the motorbike engine? I think your Sat-Nav is broken and it has sent you down a dirt track!

Im not saying the B7 does not like to be forced fed, im saying it is not due to the design of the air box.

RR's will never replicate road conditions exactly but with the B7 engine it wont be far off.

Its nice to hear that K & N still have a few loyal followers after all the MAF claims they had recently.

You're the funny guy chief. Who is comparing an RS4 engine to an F1 car - Em me stupid..... I tried to calm you down a bit before by saying I didn't want an argument but you've clearly not taken your medication(s) this year. Read this to about 2/3rds the way down (if you can). I'm not making this stuff up..... I was actually trying to stop people being so disappointed by figures from the dyno when their car may in fact be a perfectly healthy 414bhp during real motoring conditions (which is what I suspect).

http://www.evo.co.uk/carreviews/cargrou ... i_rs4.html

In case your A.D.D. is preventing you reading this I'll summarise - the RS4 engine at 8200rpm generates a piston speed of 25.5 metres per second which is a match for an f1 car, regardless of its higher rev range.

The comparison with a bike engine is that both are high performance high revving engines with very small opening times for the valves when compared to regular run of the mill engines. In order to deliver enough air to the combustion it helps if the inlet is slightly pressurised. This is what the bike magazine ram air test example is trying to demonstrate to you if you'd actually take the time to read the fecker. This whether you like it or not is partly the reason why the plastic reaches forward to the front of the car for this 'ram air effect'. The other reason is for cold air rather than directly from the hot engine bay.

I've been fortunate to never had any bother with K&N's / MAF and I firmly believe them to be a good product compared to the standard OEM.

Maybe your sat nav is broken it seems to have guided your head up your own arse.....

Your links and comparisons inform me you are clutching at straws.

You have gone from the B7 having forced induction (which is simply does not) to any old <beep> you can paste up.

Oh and the B7 is 414HP/ 420 BHP theres a difference.
,

[rs4v8]

http://www.sportrider.com/tech/146_9912_ram/index.html

Your a funny guy.

Who is comparing the RS4 engine with a 20,000 rpm F1 engine?

Wheres the comparison with the motorbike engine? I think your Sat-Nav is broken and it has sent you down a dirt track!

Im not saying the B7 does not like to be forced fed, im saying it is not due to the design of the air box.

RR's will never replicate road conditions exactly but with the B7 engine it wont be far off.

Its nice to hear that K & N still have a few loyal followers after all the MAF claims they had recently.

You're the funny guy chief. Who is comparing an RS4 engine to an F1 car - Em me stupid..... I tried to calm you down a bit before by saying I didn't want an argument but you've clearly not taken your medication(s) this year. Read this to about 2/3rds the way down (if you can). I'm not making this stuff up..... I was actually trying to stop people being so disappointed by figures from the dyno when their car may in fact be a perfectly healthy 414bhp during real motoring conditions (which is what I suspect).

http://www.evo.co.uk/carreviews/cargrou ... i_rs4.html

In case your A.D.D. is preventing you reading this I'll summarise - the RS4 engine at 8200rpm generates a piston speed of 25.5 metres per second which is a match for an f1 car, regardless of its higher rev range.

The comparison with a bike engine is that both are high performance high revving engines with very small opening times for the valves when compared to regular run of the mill engines. In order to deliver enough air to the combustion it helps if the inlet is slightly pressurised. This is what the bike magazine ram air test example is trying to demonstrate to you if you'd actually take the time to read the fecker. This whether you like it or not is partly the reason why the plastic reaches forward to the front of the car for this 'ram air effect'. The other reason is for cold air rather than directly from the hot engine bay.

I've been fortunate to never had any bother with K&N's / MAF and I firmly believe them to be a good product compared to the standard OEM.

Maybe your sat nav is broken it seems to have guided your head up your own arse.....

Your links and comparisons inform me you are clutching at straws.

You have gone from the B7 having forced induction (which is simply does not) to any old <beep> you can paste up.

Oh and the B7 is 414HP/ 420 BHP theres a difference.
,

Dude seriously, you need to take your medication. Rather than having a go when you don't agree, try having a normal level headed discussion.

Not clutching at anything you d*ck. If you actually read the links you'd see some facts. Not the shi*te you've dreamed up in your tiny mind or have no evidence for. Convieniently you've gone quiet about the F1 comparison you so hastily scoffed at, eh?

Where exactly did I say 'forced' induction? There's a world of difference between 'forced' i.e. turbo or s/c and a handful of millibar overpressure I'm describing. If you want to try it disconnect the plastic duct from the front of the car to the airbox and go for a drive.

WTF are you on about 414 / 420? That is what I'm trying to say that the car is on the road, but you might not see it on a RR for the reasons stated IMHO.

you

I hear these'll help with your A.D.D.

[simple1]

This type of personal insulting is not acceptable Mr RS4V8, by all means discuss your views about the cars, your views about the posters we can do without.

[t_urbo]

In case your A.D.D. is preventing you reading this I'll summarise - the RS4 engine at 8200rpm generates a piston speed of 25.5 metres per second which is a match for an f1 car, regardless of its higher rev range.

What do you want me to say? How about what a load of crap!

1. In std form the B7 revs to 8150 not 8200.

2.You say they both have a piston speed of 25.5 metres per second, so did one of my ex's, so does that mean i can liken her to an F1 engine.

3. Where can i get that medication, im going to need it after reading your dribble.

[rs4v8]

This type of personal insulting is not acceptable Mr RS4V8, by all means discuss your views about the cars, your views about the posters we can do without.

Point taken, takes two to tango mind you, and I did say that I was not wanting an argument with the guy earlier in the same thread which didn't seem to keep him happy. Discussing my views (about cars!) was what I was trying to do, by showing some info from outside the site which I found to be interesting (and which I thought might be applicable to the discussion (for which I got a slagging for)......

[alex_123_fra]

http://www.sportrider.com/tech/146_9912_ram/index.html

Your a funny guy.

Who is comparing the RS4 engine with a 20,000 rpm F1 engine?

Wheres the comparison with the motorbike engine? I think your Sat-Nav is broken and it has sent you down a dirt track!

Im not saying the B7 does not like to be forced fed, im saying it is not due to the design of the air box.

RR's will never replicate road conditions exactly but with the B7 engine it wont be far off.

Its nice to hear that K & N still have a few loyal followers after all the MAF claims they had recently.

You're the funny guy chief. Who is comparing an RS4 engine to an F1 car - Em me stupid..... I tried to calm you down a bit before by saying I didn't want an argument but you've clearly not taken your medication(s) this year. Read this to about 2/3rds the way down (if you can). I'm not making this stuff up..... I was actually trying to stop people being so disappointed by figures from the dyno when their car may in fact be a perfectly healthy 414bhp during real motoring conditions (which is what I suspect).

http://www.evo.co.uk/carreviews/cargrou ... i_rs4.html

In case your A.D.D. is preventing you reading this I'll summarise - the RS4 engine at 8200rpm generates a piston speed of 25.5 metres per second which is a match for an f1 car, regardless of its higher rev range.

The comparison with a bike engine is that both are high performance high revving engines with very small opening times for the valves when compared to regular run of the mill engines. In order to deliver enough air to the combustion it helps if the inlet is slightly pressurised. This is what the bike magazine ram air test example is trying to demonstrate to you if you'd actually take the time to read the fecker. This whether you like it or not is partly the reason why the plastic reaches forward to the front of the car for this 'ram air effect'. The other reason is for cold air rather than directly from the hot engine bay.

I've been fortunate to never had any bother with K&N's / MAF and I firmly believe them to be a good product compared to the standard OEM.

Maybe your sat nav is broken it seems to have guided your head up your own arse.....

Your links and comparisons inform me you are clutching at straws.

You have gone from the B7 having forced induction (which is simply does not) to any old <beep> you can paste up.

Oh and the B7 is 414HP/ 420 BHP theres a difference.
,

Hmm, the B7 is actually 420 HP and 414 bhp. It also redlines to 8,250 rpm according to the manufacturer's brochure and specifications. My rev counter seems to agree with this anyway...whether it never quite gets there in reality is another matter. Peak power is at 7,800 anyway so it isn't overly critical.

[simple1]

[quote="alex_123_fraHmm, the B7 is actually 420 HP and 414 bhp. It also redlines to 8,250 rpm according to the manufacturer's brochure and specifications. My rev counter seems to agree with this anyway...whether it never quite gets there in reality is another matter. Peak power is at 7,800 anyway so it isn't overly critical.[/quote]

Which leads to another question, what is the difference in numbers between Horse Power and Break Horsepower. As the Germans quote and measure figures in PS. does the quoted output become a translation from PS to Bhp and lose or gain some in that process..

[t_urbo]

Alex, you have the BHP/HP conversion the wrong way around. It is 420 BHP and 414 HP.

Yes indeed you car does show 8250 on the dash and in tha Audi brochure but it is only hitting around the 8150 mark.

[simmo]

A RR is fine for measuring comparative changes to engines output (i.e. when doing tuning work) as the drive train losses (which ought to remain relatively the same anyway) can be ignored.

IMHO not sure how you could 'infer' the ABSOLUTE power/torque produced by an engine using a RR. How do you measure the drive train loss? If a % estimate for drive train loss is used then surely the 'result' is nothing more than a fancy guess.

If its absolute power you need to measure - hire a specialist, tear the engine from the car, put it on a bench dyno and go for it.

If you seriously want to try and match the manufacturers figures, run the engine for an equivalent of 10,000 miles, rip off the air-con and all ancillaries, strip the engine and clean all the components, reassemble, replace with fresh light-weight oil, new filters and plugs, ditch the cat use the highest octane fuel available and re-program the ECU with a 'pre-production' optimised map. You might get close

That may all be correct - the point is that Audi quote the figures of 414 in the brochure - as air con etc is standard then as a consumer, we should expect the cars that we bought (largely based on that brochure info) to produce the power stated.

Be very interesting to get a group of us to run RS4's on this dyno (it's truely an excellent peice of kit) - perhaps if others are interested we could have an RS4 day one weekend and try to put the power matter to bed once and for all - it would be good to see different age / mileage cars on the same (and high tec) dyno. Anyone interested?

If we get a few of us, the price will be £40.

Regards Mark

Hi. The point I was trying to make is that a RR type dyno is NOT the correct piece of equipment to determine the actual crank output of an engine. It simply cannot - no matter how sophisticated, shiny and new or smart it may be. The only instrument that will give you ACTUAL power at the crank is a bench mounted engine dynanometer. Every other type of RR type instrument is just a frig (to put it politely ) in terms of giving you the true crank HP/BHP/KW/NM/lb-ft. You can bet its a bench dyno that Audi and every engine/car/bike manufacturer have used when calculating and stating their output figures. I understand that a RR is far more accessible but its really comparing apples and bananas.

The second point I was trying to make is that all production engine manufacturers will quote their power figures in a 'setup' that is optimised (within he realms of the SAE/DIN/ISO or whatever measurement standard) for the standard they are measuring to. Often there will be quite a staggering difference between this setup and the vagaries of an engine in a production environment i.e. your car. We all know the RS4 engine is pushing the envelope in terms of output; expecting each and every 'street' RS4 engine to produce exactly 420ps/414bhp (and measure this on a RR) is cloud cuckoo land - unless the engine is matched/blueprinted and individually measured/certified and has a plaque to state to produce exactly this output.

So if your intent on using a RR just be aware of these facts when drawing a conclusion as to the 'output' the RR is predicting. It is only that, a prediction. Have fun.

[alex_123_fra]

Alex, you have the BHP/HP conversion the wrong way around. It is 420 BHP and 414 HP.

Yes indeed you car does show 8250 on the dash and in tha Audi brochure but it is only hitting around the 8150 mark.

I'm pretty sure I'm right. 420 HP (or PS, in other words metric or "continental" horsepower) is the same as 414 imperial horse power or bhp. Hence the conversion from HP to bhp being a division of the HP number by 1.01387:

i.e. 420 HP / 1.01387 = 414.25 bhp

[t_urbo]

You've just confirmed what I was saying. 3rd gear would be what? 60-90mph as a rough guestimate, 5th will be well above that. Try sticking tour hand out the window at over a ton. Your hand will be blown backwards. This is the pressure which should be in your intake (or very close to it, a wee bit less due to frictional loses across the filter and round the bends). Without this your engine is being starved of air as rather than being force fed it is having to suck air though the pipes. Not enough air means not enough fuel and a power output less than expected.

Where's this Clive Atthows audijohn?

Where exactly did I say 'forced' induction? There's a world of difference between 'forced' i.e. turbo or s/c and a handful of millibar overpressure I'm describing. If you want to try it disconnect the plastic duct from the front of the car to the airbox and go for a drive.

What was that about the plastic duct?

[simple1]

I think Alex is correct as PS and HP figures are higher than Bhp figures, didnt know the conversion formula though, thanks for that.

[rs4v8]

You've just confirmed what I was saying. 3rd gear would be what? 60-90mph as a rough guestimate, 5th will be well above that. Try sticking tour hand out the window at over a ton. Your hand will be blown backwards. This is the pressure which should be in your intake (or very close to it, a wee bit less due to frictional loses across the filter and round the bends). Without this your engine is being starved of air as rather than being force fed it is having to suck air though the pipes. Not enough air means not enough fuel and a power output less than expected.

Where's this Clive Atthows audijohn?

Where exactly did I say 'forced' induction? There's a world of difference between 'forced' i.e. turbo or s/c and a handful of millibar overpressure I'm describing. If you want to try it disconnect the plastic duct from the front of the car to the airbox and go for a drive.

What was that about the plastic duct?

I'm not able or willing to have a discussion with you anymore as it doesn't seem possible or worthwhile. I tried to avoid an argument. You've got your opinion and I've got mine (plus some data which i believe supports it).

[t_urbo]

Alex, you have the BHP/HP conversion the wrong way around. It is 420 BHP and 414 HP.

Yes indeed you car does show 8250 on the dash and in tha Audi brochure but it is only hitting around the 8150 mark.

I'm pretty sure I'm right. 420 HP (or PS, in other words metric or "continental" horsepower) is the same as 414 imperial horse power or bhp. Hence the conversion from HP to bhp being a division of the HP number by 1.01387:

i.e. 420 HP / 1.01387 = 414.25 bhp

Oh err, i think your right.
Nice BTW.