|
|
09-11-2007, 09:35 PM | #45 | |
Major General
374
Rep 8,033
Posts |
Quote:
However, the confusing part is if we look at the BMW stated numbers (EU spec) for the M3 and the 335i, we we should see a difference of 45 kg. How come the measured numbers published on the website contradict that? Have they weighed the M3 with less than a full tank of gas? So, I'd say what is reported on that website is in question actually. Last edited by lucid; 09-11-2007 at 10:08 PM.. |
|
Appreciate
0
|
09-11-2007, 09:39 PM | #46 | |
Reincarnated
245
Rep 4,227
Posts |
Quote:
I value the current assumption but must also keep things in a relative frame of mind.
__________________
|
|
Appreciate
0
|
09-11-2007, 09:49 PM | #47 |
Lieutenant
15
Rep 471
Posts |
As per EU specs the M3 weighs 45kg more. Seems pretty straight forward to me.
In terms of actual weight. Until someone weighs two cars both with a basic equipment level with the same amount of gas, it's all guesisng (even if it's educated). Furthermore, why would BMW lie about the weight, how do they benefit? In the 335i horsepower case, the car is underrated, but only so that the numbers aren't closer to the M3. -Adam |
Appreciate
0
|
09-11-2007, 09:58 PM | #48 | |
Reincarnated
245
Rep 4,227
Posts |
Quote:
__________________
|
|
Appreciate
0
|
09-11-2007, 10:15 PM | #49 |
Major General
374
Rep 8,033
Posts |
The only thing that comes to mind is some kind of weight based custom/tax classification in a specific market they care about. Some countries have engine displacement based taxation for instance. But that wouldn't explain why they'd report the M3 to be heavier than it really is.
|
Appreciate
0
|
09-11-2007, 10:21 PM | #50 | |
Lieutenant
15
Rep 471
Posts |
Quote:
-Adam |
|
Appreciate
0
|
09-11-2007, 10:30 PM | #51 |
Major General
374
Rep 8,033
Posts |
Depends on the legal system I guess, and what kind of rationalization the company can come up with. A similar argument can be made regarding underating power: I lost control of the car because I've been told it had less power than it actualy did? Yeah, that's kind of a stretch, but...
|
Appreciate
0
|
09-13-2007, 12:17 AM | #52 |
Second Lieutenant
143
Rep 202
Posts |
So how do you explain Automobile Mag's dyno results for the 335i? Like I mentioned on a post over at 1addicts... (http://www.1addicts.com/forums/showthread.php?t=1180)
Are these guys just using the stock horsepower rating and assuming the drive train loss is whatever?
__________________
-ANDY
'05 M3 CS | Silver Grey | M Cloth OEM CSL Front - Rear - CF Roof | Dinan S2 Performance Pack | 19" RAC Monolite RG4s |
Appreciate
0
|
09-13-2007, 12:53 AM | #53 |
First Lieutenant
26
Rep 359
Posts |
Sorry if my questions sound stupid... does the rolling road test power at the wheels? How do you test power at crank then? When manufacturers quote BHP, are they refering to power at wheels or crank?
I've read reviews that a certain car tested by journalist actually produces more power on their rolling road test than the official quoted figures. Just like to clarify with the above questions. |
Appreciate
0
|
09-13-2007, 02:54 AM | #54 |
Brigadier General
478
Rep 3,044
Posts
Drives: 2011 Dakar Yellow M3, 2018 M5
Join Date: Feb 2007
Location: Orange County, California
|
consciousness?
__________________
[ESS VT2-625] [Akrapovic Evolution Exhaust] [KW Clubsports] [OSS Angel Eyes] [Revinora r-CRT Lip] [Vorsteiner Boot] [Challenge Race Diffuser] [See the Build Thread HERE] |
Appreciate
0
|
09-13-2007, 06:29 AM | #55 |
Reincarnated
245
Rep 4,227
Posts |
__________________
|
Appreciate
0
|
09-13-2007, 08:02 AM | #56 | |
Major General
374
Rep 8,033
Posts |
Quote:
|
|
Appreciate
0
|
09-13-2007, 09:32 AM | #57 | |
First Lieutenant
26
Rep 359
Posts |
Quote:
Wow... that means the mentioned car produces a shitload more power at the crank than its official quoted figures since its tested power at the wheel is already higher the figures officially quoted at crank. Kudos to the manufacturer... no wonder their cars almost always outperform their official figures . |
|
Appreciate
0
|
09-13-2007, 10:15 AM | #58 |
Reincarnated
245
Rep 4,227
Posts |
__________________
|
Appreciate
0
|
09-13-2007, 10:31 AM | #59 |
First Lieutenant
26
Rep 359
Posts |
|
Appreciate
0
|
09-13-2007, 10:37 AM | #60 |
Reincarnated
245
Rep 4,227
Posts |
Didn't know what car you were referring to.
__________________
|
Appreciate
0
|
09-13-2007, 10:55 AM | #61 | |
Colonel
99
Rep 2,000
Posts |
Quote:
If the observed, at-the-wheels figure was really 429 hp, that would mean the powerplant is generating 140 hp per liter, which stretches the bounds of credibility for a street driven, emissions legal, normally aspirated engine. Not even Honda has done that. As far as I know, they still hold the record at 120 hp per liter in the 2-liter S2000. Based on more or less standard torque per liter limits (in the low 80's), you're looking at 9000+ rpm in order to come up with that sort of power yield. Motorcycles? Yes. GT3? Nope. Absolutely terrific car, though. Wish I could afford one. Bruce |
|
Appreciate
0
|
09-13-2007, 11:32 AM | #62 |
First Lieutenant
26
Rep 359
Posts |
I'm not technically astute, so what you've said could possibly be true
|
Appreciate
0
|
09-13-2007, 11:43 AM | #63 | |
First Lieutenant
10
Rep 369
Posts |
Quote:
This methodology is wrong, because the frictional losses as a percentage of the stock numbers varies at various engine speed although the actual loss remains doesn't. Most engines above 2000 rpm will give you an approximately constant drive-train losses(approximately 10 ft.lbs variation in torque losses above 2000 rpm) |
|
Appreciate
0
|
09-13-2007, 12:22 PM | #64 | |
Major General
374
Rep 8,033
Posts |
Quote:
Regarless, even if the absolute torque loss is indeed fairly constant across the rpm range, the power loss will increase linearly with increasing rpms since hp = (torque * RPM) / 5250, which is the trend the measured power curve exhibits in relation to the stated crank power curve for the E92 M3 in the graphs referenced by the OP. Last edited by lucid; 09-13-2007 at 02:07 PM.. |
|
Appreciate
0
|
09-13-2007, 10:21 PM | #65 | ||
Second Lieutenant
143
Rep 202
Posts |
Quote:
Quote:
__________________
-ANDY
'05 M3 CS | Silver Grey | M Cloth OEM CSL Front - Rear - CF Roof | Dinan S2 Performance Pack | 19" RAC Monolite RG4s |
||
Appreciate
0
|
Post Reply |
Bookmarks |
|
|