Google| Subject | Re: Ideological differences between big 3 german, americans and jap trash |
| From | Alan Baker |
| Date | 02/23/2014 22:24 (02/23/2014 13:24) |
| Message-ID | <ledoub$6o6$1@news.datemas.de> |
| Client | |
| Newsgroups | comp.sys.mac.advocacy |
| Follows | -hh |
| Followups | -hh (52m) |
On 2014-02-23 20:54:27 +0000, -hh said:
-hhFrom a pure, "platonic" view of "ideal", perhaps not, but no car is designed in isolation.
On Sunday, February 23, 2014 2:55:02 PM UTC-5, Alan Baker wrote:Alan Baker-hh
On 2014-02-23 12:16:04 +0000, -hh said:Power application can certainly induce Under/Over, but since its>> observable even when the throttle is neutral, weight distribution plays>>a large part as well. The Q7's is front-biased 52%-48%, which will>>induce more understeer plowing.Actually, HH, I've got to disagree with you here. There's nothing in a> weight bias that close to even that means you can't design the> suspension without understeer.
The magnitude/significance, or the potential to minimize the factor wasn't my concern. All I was pointing out is that by being a nose-heavy configuration, it isn't pedantically considered to be optimal.Alan Baker-hh
Yes: as a car's weight bias departs more from 50-50, then the tradeoffs to create neutral handling get larger...
So then you are agreeing with me that it isn't ideal.
I guess I'm only really objecting to the word "will", as in "will induce more understeer plowing", and phrased that way, I'd have to grade it at best as "incomplete". "will induce more undeersteer plowing unless the designers appropriately design for that weight distribution" would be better. :-)Alan Baker-hh
... but when you're relatively close>to 50-50, it's just not a big deal.
That's a "significance" judgement on if a suitably-small difference is noteworthy or not: it doesn't abolish the fact that a difference nevertheless exists.
-)
All you're saying is that you're agreeing with me that a departure from ideal results in deoptimization and trade-offs...but you also believe that from a pragmatic standpoint they may not necessarily be of great enough magnitude to be of general concern.Correct.
If we were only talking about advice for Nicolas and his fellow drivers of the "Soccer Mom" skill set, I'd be inclined to agree with you on that point. But Nicolas will invariably claim superiority, even though he's IIRC never taken any performance driving training in his life, nor tracked, nor AutoX'ed and so forth. FWIW, there are some vehicles which do things like relocate heavy components such as the battery to the opposite end of the vehicle so as to improve vehicle weight distribution...a contemporary example is the Audi SQ5, which is front-engined but has its battery in its trunk. The Q7 on the other hand...Sure. But these tradeoffs aren't really big enough at the magnitude under discussion to concern even a car that is raced. When you can, you avoid making the trade-off--as you say, by doing such things as moving the battery to the rear (as the Miata's designers did as well, BTW), but if other considerations leave you with a small front or rear bias, it's really no problem at all to tune the suspension to compensate; even after its initial design for a different weight bias. Technically, the result will be a tiny fraction less ultimate lateral grip, but it won't really be noticeable even at extremely high levels. From the truly high-performance driver's perspective, proper handling balance is paramount.
From a performance driving standpoint, if you really want to optimize the whole package, you need to trade-off the best weight distribution for steady-state lateral grip for a rear weight bias that makes braking more effective (by getting the car closer to a 50-50 LOAD distribution when at maximum deceleration).
But I ramble... ...this really has been a passion of mine for a long time. :-)
02/07/2014-
-
-
-
