RS4 B7 Stated Power claim of 420ps MKII

[Sims]

... well said fella maybe, we are the voice of the silent majority and needs others to stop this repetitive thread nonsense

Arthur is on this thread, and happy to post as others are. Would it not be easy for you to just ignore this thread?

[ArthurPE]

Porsche are DI now

Audi was not really pushing the envelope
larger displacement (4.2 vs 4 or 3. and compression ratio (12.5 vs 12, iirc) so actually Audi engines are less stressed than the others...

My point is that in practice, for what ever reason, the results are very different. There is something that you are missing in your calculation. If it was that easy to get 100hp per litre out of a NA car, why arn't all manufactures doing it.

Posted by 2ManyToys on another thread.

Audi was competing with other German manufacturers in the quest for 100ps per litre (996 GT3), the 1st time they had achieved this in a NA engine.

BMW had achieved 107 with the E46 M3 & 112.5 with the CSL but the M5/M6 were at 100ps per litre. So a good benchmark.

So Audi pushed the envelope as far as they could - that's normal. As they have done with the RS5 at 450ps = 107 ps per litre.

But am I right in thinking the Porsche, the BMW & the Audi engines are different technology? The last one being DFI?

[scaghead]

There are three live carbon threads on the go at the moment, with postings today. They run to 38 pages or 537 posts. Why resurrect something that's been untouched for 6 weeks?

[ArthurPE]

there is 'nothing missing'
they choose not to, that's all
they sacrifice specific output for economy (in operation and manufacture)
all it takes is revs (P = T x w) and compression (T ~ Cr)

2manytoys: My point is that in practice, for what ever reason, the results are very different. There is something that you are missing in your calculation. If it was that easy to get 100hp per litre out of a NA car, why arn't all manufactures doing it.

[Sims]

Porsche are DI now

Audi was not really pushing the envelope
larger displacement (4.2 vs 4 or 3. and compression ratio (12.5 vs 12, iirc) so actually Audi engines are less stressed than the others...

But they were not then....

The E46 is 3.2, the M5/M6 5 litres and the GT3 was 3.6. You have 3 decade history with BMW engines, and you know how good they are, and why they were the benchmark for Audi with this NA engine.

Also we are not taking about the stress, more the effect of the type of engine.

[Sims]

There are three live carbon threads on the go at the moment, with postings today. They run to 38 pages or 537 posts. Why resurrect something that's been untouched for 6 weeks?

I refer you to page 6, and the explanation given. I am at a loss why you want to stop this discussion.

[ArthurPE]

But they were not then....

The E46 is 3.2, the M5/M6 5 litres and the GT3 was 3.6. You have 3 decade history with BMW engines, and you know how good they are, and why they were the benchmark for Audi with this NA engine.

Also we are not taking about the stress, more the effect of the type of engine.

what are the compression ratios? the most important factor for specific output...

who said they were the benchmark? 100 HP/liter was the target..it's a common benchmark or metric, Honda did it with the S2000

it's all about stress, or more accurately 'pressure', as in mean effective ~ compression ratio...

the new M3 is 4 liter, the RS4 4.2, same HP, so the stress is less due to a larger displacment...but the RS4 has a higher Cr, that's how it makes up the difference...but really it's a factor of revs, the M3 revs higher so more P, the RS4 has more torque 295 vs 317...

[mark758]

sims your games are very childish.. i am getting bored with comming on here now... i am up for a bit of banter as well as learning/sharing things rs4.. but you take groundhog day to a different level... we never hear about you enjoying your car/ past cars just same old drivel... and before you say it i have not been brain washed by p-g, arthur, petroldave and whoever else .... do us a favour and go on holiday for a couple of weeks and let this forum re-fresh itself.. cheers

I have had my car for three years now and although im not a big poster have found this forum a great source of information, however recently it has become nothing more than a place where 'some' people have nothing better to do that slag off the rs4 and fellow owners.
Although I dont understand alot of the science in Arthurs post's he puts in alot of effort to put logic and reason into it where 'others' just seem to come back with comments I would expect from a cocky 12 year old.

I believe in the old saying 'if its not worth saying then shut the f**k up. ( maybe not so old but still!)

Happy rs4ing to all the Happy rs4ers out there and thankyou to all of those with positive input on this forum.

I think you both make excellent points that the over twelves on here would fully support.

I'd just prefer certain person's to use an avatar...
... that way posts from that 'contributor' can be more easily identified and act as convenient breaks as we happily digest Arthur's material

[Sims]

But they were not then....

The E46 is 3.2, the M5/M6 5 litres and the GT3 was 3.6. You have 3 decade history with BMW engines, and you know how good they are, and why they were the benchmark for Audi with this NA engine.

Also we are not taking about the stress, more the effect of the type of engine.

what are the compression ratios? the most important factor for specific output...

who said they were the benchmark? 100 HP/liter was the target..it's a common benchmark or metric, Honda did it with the S2000

it's all about stress, or more accurately 'pressure', as in mean effective ~ compression ratio...

the new M3 is 4 liter, the RS4 4.2, same HP, so the stress is less due to a larger displacment...but the RS4 has a higher Cr, that's how it makes up the difference...but really it's a factor of revs, the M3 revs higher so more P, the RS4 has more torque 295 vs 317...

Once again, it's the headline number that mattered to the manufacturers, how it was achieved was not of consequence provided you had acceptable reliability,durability & economy. The RS4, or the M3 brochure do not mention compression ratios in the main body of the text but dooes mention power/torque/cubic capacity

The S2000 is an absolute gem, but it's more like the E30 M3 driving characteristic.

The Germans wanted torque and power. 100ps per litre was the goal.

[Sims]

I'd just prefer certain person's to use an avatar...
... that way posts from that 'contributor' can be more easily identified and act as convenient breaks as we happily digest Arthur's material

Sure, if that pleases you.

And you do realise that most of Arthur's posts are on carbon denial, whereas mine are across wider topics.

If 246.com does not want Carbon discussed, the solution is obvious - both Art & I take time off.

[ArthurPE]

I don't think it's the 'headline' numbers that sell these cars
the buyers are far more sophisticated

and the numbers were a consequence, a by-product of the design, not the reason for it...

all the brochures I have mention the Cr and all the press releases do also...

actually the e30 M3 had great low end T (for it's time) compared to the S2000, which has to be wrung out to make power...

the Germans goal was >90% torque over the widest band possible, the specific output was a consequence of that design goal, not the reason for it...they have ALWAYS designed for flexibilty/elasticity...
ref. page 4 in the hardbound RS4 book, I quote: "more than 90% of this power (sic torque) is available between 2250 and 7600 rpm"
no where do I find a reference to 100 HP/liter...

torque and power are 2 different things, as the S2000 proves, high specific power, low torque...

Once again, it's the headline number that mattered to the manufacturers, how it was achieved was not of consequence provided you had acceptable reliability,durability & economy. The RS4, or the M3 brochure do not mention compression ratios in the main body of the text but dooes mention power/torque/cubic capacity

The S2000 is an absolute gem, but it's more like the E30 M3 driving characteristic.

The Germans wanted torque and power. 100ps per litre was the goal.

[ArthurPE]

the reason for the 90% torque over a wide band?

a = F/m, in this case force F = torque
so the wider and more liear the band the higher and more linear the acceleration...
HP at a fixed rpm is only good for steady state high speed driving
with a wide T band you get both

[NIKKIrsSIXX]

I like my RS4. It goes really fast, and I reckon thats one thing we all agree on here. Dont really care for all this banter about carbon so instead of being stuck next to my computer reading about it we might as well cut down on that to spend more time depositing on our valves!

Some of these chaps have spent hours and hours constructing clever replies with sums in them and everything but that time could have been spent driving the bloody things!!

The RS4 is now another car getting old now, its an Audi and they will last and go well for a very big mileage so lets just use em while we can before we have to all use biofuel cars or whatever.

[ArthurPE]

you call it carbon denial, I call it objective reasoning...

and since you've been here, yes, many have been in rebuttal of BS you post, as in 'the RS5 is derived from the V10, so it's different', when in REALITY the V10 was derived directly from the V8, sharing all key dimensions and all major components modified for 2 more cylinders...

why don't we leave it up to the readers to decide the merits or range of our posts...most have been around longer than you, so they have a pretty good feel for my 'pre sims' posting content, lol

I'd just prefer certain person's to use an avatar...
... that way posts from that 'contributor' can be more easily identified and act as convenient breaks as we happily digest Arthur's material

Sure, if that pleases you.

And you do realise that most of Arthur's posts are on carbon denial, whereas mine are across wider topics.

If 246.com does not want Carbon discussed, the solution is obvious - both Art & I take time off.

[ArthurPE]

best post yet

I want a jetpack next

I like my RS4. It goes really fast, and I reckon thats one thing we all agree on here. Dont really care for all this banter about carbon so instead of being stuck next to my computer reading about it we might as well cut down on that to spend more time depositing on our valves!

Some of these chaps have spent hours and hours constructing clever replies with sums in them and everything but that time could have been spent driving the bloody things!!

The RS4 is now another car getting old now, its an Audi and they will last and go well for a very big mileage so lets just use em while we can before we have to all use biofuel cars or whatever.