RS4 is the least of the M3's worries

[bruce.augenstein@comcast.]

Originally Posted by swamp2

I have heard it will not be in the US as well but certainly have not heard that officially. I hope we get it, a very nice feature - good for some definite hp to the wheels. So even though I have heard the rumor I am either assuming it is not true or just taking a best case scenario based on the features of the EU car (even if it is not the one I will get).

-Charcoal filter ~10 hp at the crank
-Regenerative braking ~5-10 hp at the wheels

We could be looking at about 20-25 less hp at the wheels for the US car, UGH! I suppose this is worst case scenario but since the rwhp is "hidden" and all BMW has to quote is crank hp it is just another way the US gets screwed and gets a slower car, double ugh.

I thought we had already discussed some of this? Oh well.

Assuming regenerative braking is shorthand/marketing talk for disabling the alternator during hard acceleration so no power is lost to charging at that point, what are we really talking about here?

Assuming 125 amps at 14 volts max charge rate, and also assuming around 80% efficiency (alternator will be well over that, but some power is lost to resistance in the wiring), we're talking, what, three HP?

Now assume well under a third of that number unless you're running A/C along with the rear window defroster, seat heat on extra crispy and that aftermarket boom box in the trunk during your drag race or top speed run.

Now multipy that by 85% to get the rear wheel number...

...and you discover that two healthy hamsters can generate that amount of power.

OK. Three hamsters.

OK, now figure (and here's the real point we discussed before) that the SAE is already on board with this for the ratings run.

Either way, we're talking a dimple on a pimple on a flea's left nut. It just doesn't matter.

Charcoal filter? I must've missed that. How will that be worth 10 HP and why won't the SAE be informed?

Bruce

[footie]

Originally Posted by southlight

Here was hope that another one would take that "statement" on so I don't have to, but nevertheless.

What the hell are you talking about? I'm trying not to comment your verbal lapses, so here are the facts:
You're telling the M3 being 7 seconds faster on Nürburgring than the S4. Right, but that's the B6 S4, so we're not talking about 265bhp on the S4, we're talking about 344bhp (in germany - that's one hp more than the M3 had in Germany). So no power advantage at all for the M3, same power which resulted in 7 seconds difference. The S4 you're talking about (B5) does the Ring in 8.42 (so we're at 20 seconds!).
Referring the RS4 you're providing the same kind of misinformation: The 375bhp achieved a 8.25 (3 seconds slower than M3).
So who's the fanboy now? Stop bashing with wrong information! :mad:
To cool down you could read some S5/335i comparisons to get an idea who the duel between M3 and RS5 will end...

Best regards, south

I know this was going back quite a bit but it amazes me just how misinformed some people are to what other brands are producing.

South is correct that the duel between the new M3 and RS5 will be something similar to that of the S5 and 335i, but only if you agree that the S5 is slightly better than the 335i because this should be the case when the RS5 arrives, it should be slightly better than the M3. But like all RS models it will also command a slightly higher price as well.

[southlight]

Originally Posted by footie

I know this was going back quite a bit but it amazes me just how misinformed some people are to what other brands are producing.

South is correct that the duel between the new M3 and RS5 will be something similar to that of the S5 and 335i, but only if you agree that the S5 is slightly better than the 335i because this should be the case when the RS5 arrives, it should be slightly better than the M3. But like all RS models it will also command a slightly higher price as well.

Quite an old post. Let me say this:
Although I'd personally prefer the 335i, the overal performance of the S5 is quite good. I think it's a matter of taste which car one prefers.
Referring to RS5: There's no doubt that it should be better than the M3 due to its later debut. But will it reach the expectations? Will Audi allow it to have higher output than the R8? IMO too many unanswered questions. My prediction is a tie.. What do you think?


Best regards, south

[footie]

Originally Posted by southlight

Quite an old post. Let me say this:
Although I'd personally prefer the 335i, the overal performance of the S5 is quite good. I think it's a matter of taste which car one prefers.
Referring to RS5: There's no doubt that it should be better than the M3 due to its later debut. But will it reach the expectations? Will Audi allow it to have higher output than the R8? IMO too many unanswered questions. My prediction is a tie.. What do you think?


Best regards, south

I'm not sure if it will be a tie though I do expect it to be quite close. On performance I reckon the RS5 will win easily just like the C63 does in comparison tests but unlike it where the extra power becomes a problem to use the RS5 shouldn't be bothered with this. I believe in every discipline of their performance be it acceleration, braking, cornering, lap times the RS5 will be better, but whether it will capture the pure driving pleasure that the M3 has is a different question.

That is the all standing argument between AWD vs RWD and to date very few awd cars have the same driving pleasure and feel that a good rwd car has. Like you say it will all depend on what you are after in the end.

[southlight]

Originally Posted by footie

I'm not sure if it will be a tie though I do expect it to be quite close. On performance I reckon the RS5 will win easily just like the C63 does in comparison tests but unlike it where the extra power becomes a problem to use the RS5 shouldn't be bothered with this. I believe in every discipline of their performance be it acceleration, braking, cornering, lap times the RS5 will be better, but whether it will capture the pure driving pleasure that the M3 has is a different question.

That is the all standing argument between AWD vs RWD and to date very few awd cars have the same driving pleasure and feel that a good rwd car has. Like you say it will all depend on what you are after in the end.

Do we have information on RS5's engine yet? Can't imagine the RS5 besting the M3 on track with an slightly improved RS4 engine...


Best regards, south

[footie]

Originally Posted by southlight

Do we have information on RS5's engine yet? Can't imagine the RS5 besting the M3 on track with an slightly improved RS4 engine...


Best regards, south

You are right, there is no true info on the engine only speculation which includes not only the current RS4 engine 420ps (not likely), RS4 with twin turbos 480ps (possible) right through to the S6 engine in a higher state of tune 480ps (possible).

I personally like the idea of the big V10 as it would allow the RS5 to bridge the gap between either the M3 or M6, but what would such a heavy engine not do to the handling and that includes the RS4 engine with turbos, it to would weigh quite a bit.

I have tried to read up as much on all the M3's rivals and future rivals and I read about something called Valvelift, have you heard of it and if so is it similar to BMW's Vanos system? If it something different is it possible that the RS5 could have the current RS4 engine only with this technology and what potential power gains could be had.

Sorry to put you on the shot like that.

[southlight]

Originally Posted by footie

You are right, there is no true info on the engine only speculation which includes not only the current RS4 engine 420ps (not likely), RS4 with twin turbos 480ps (possible) right through to the S6 engine in a higher state of tune 480ps (possible).

I personally like the idea of the big V10 as it would allow the RS5 to bridge the gap between either the M3 or M6, but what would such a heavy engine not do to the handling and that includes the RS4 engine with turbos, it to would weigh quite a bit.

I have tried to read up as much on all the M3's rivals and future rivals and I read about something called Valvelift, have you heard of it and if so is it similar to BMW's Vanos system? If it something different is it possible that the RS5 could have the current RS4 engine only with this technology and what potential power gains could be had.

Sorry to put you on the shot like that.

If I understand it correctly Valvelift is a combination of BMW's VANOS (valve control) and Valvetronic (valve lift). What seems to be different is that Audi's Valvelift only controls the intake valve, whereas VANOS in its current stage also has a outlet control. The valve lift of both Audi's and BMW's systems however work on the intake valves only.
How much power gain that new Valvelift system would be good for? Don't know. Both Audi and BMW mention the lower fuel consumption: BMW claimed up to 10% for Valvetronic, Audi 14% for Valvelift.

Agree that it wouldn't be a good idea to feature the V10 in the RS5, the weight increase might be too big.


Best regards, south

[swamp2]

Originally Posted by bruce.augenstein@comcast.

I thought we had already discussed some of this? Oh well.

Assuming regenerative braking is shorthand/marketing talk for disabling the alternator during hard acceleration so no power is lost to charging at that point, what are we really talking about here?

Assuming 125 amps at 14 volts max charge rate, and also assuming around 80% efficiency (alternator will be well over that, but some power is lost to resistance in the wiring), we're talking, what, three HP?

Now assume well under a third of that number unless you're running A/C along with the rear window defroster, seat heat on extra crispy and that aftermarket boom box in the trunk during your drag race or top speed run.

Now multipy that by 85% to get the rear wheel number...

...and you discover that two healthy hamsters can generate that amount of power.

OK. Three hamsters.

OK, now figure (and here's the real point we discussed before) that the SAE is already on board with this for the ratings run.

Either way, we're talking a dimple on a pimple on a flea's left nut. It just doesn't matter.

Charcoal filter? I must've missed that. How will that be worth 10 HP and why won't the SAE be informed?

Bruce

Bruce, just FYI - a really old, almost dead thread, but your points are valid/worth responding to.

The engine specs should include with alternator so actually what it really means is that in an apples to apples comparison the M3 engine is actually making less power than any other engine without R.B. since it must have those losses included and still rate at the net output.

What R.B. offers though is IMO a good performance and green enhancement. As much as I am not fan of much BMW marketing I do think "efficient dynamics" is real and present in the car. I suspect the E9X M3 to have an alternator similar to the E60 M3, which is a full 2.4 kW this means 3.2 hp. My initial estimates were indeed quite liberal. I don't know enough about how the cars electrical system works to say how much of that peak 3.2 hp would typically be consumed and if it varies strongly with the current use of accessories such as stereo and AC.

The charcoal filter is an secondary filter in the intake tract of the E60 M5 present for (I think) insuring no loss of fuel vapors from the intake system to the atmosphere. From reading up on this over at m5boad.com and some tentative dynos, I think the estimate was that removing this filter was good for about 10 crank hp. I have not heard definitively if the M3 has this filter. Can some owners chime in?

[V8convert]

Originally Posted by southlight

If I understand it correctly Valvelift is a combination of BMW's VANOS (valve control) and Valvetronic (valve lift). What seems to be different is that Audi's Valvelift only controls the intake valve, whereas VANOS in its current stage also has a outlet control. The valve lift of both Audi's and BMW's systems however work on the intake valves only.
How much power gain that new Valvelift system would be good for? Don't know. Both Audi and BMW mention the lower fuel consumption: BMW claimed up to 10% for Valvetronic, Audi 14% for Valvelift.

Agree that it wouldn't be a good idea to feature the V10 in the RS5, the weight increase might be too big.


Best regards, south

How much more of a weight increase would it be?

[footie]

Originally Posted by V8convert

How much more of a weight increase would it be?

I believe if the engine isn't changed from the one in the S6 the extra weight between the 5.2v10 and the 4.2v8 is 30kgs. More than you would want but extra alloy or CF panels at the front of the car could counter this.

Though I hope they chose to go the v8TT route as to me a RS model isn't compete without turbos.