Date: Thu, 1 Apr 1999 09:40:11 -0800 From: "I'm Batman" <batmannopsamam.city.com [email withheld because of spam bots and crazies]> Subject: Re: 9-3 v 328i (subthread:4 v 6+ cyl)
The *real* reason why F1 cars don't use 4 or 6cyl motors *anymore* is because of F1 regulations....not internal mass or friction. In *naturally aspirated* form, at a given displacement, more cylinders of a smaller size yield less internal mass therby allowing higher rpm. Higher rpm means more power. Recal F1 *used* to run turbo charger 4 and 6 cyl motors. But, now that they can't use forced induction they're forced to play the displacement game. And since displacement is fixed at a certain limit, it makes more sense to use V12 and V10 motors. V10 being the sweet spot it would seem. If you were to use a V6 or I4 of the same displacement, it's cylinders would be larger and heavier than their V10 or V12 counterparts. Thus producing fewer rpm and less power. Philip Hult <hultnopsamdu> wrote in message news:7dvm0h$e05$1nopsam.mr.net... > > Tim Baker wrote in message <370369d9.231326710nopsam.sgi.net>... > >On Thu, 01 Apr 1999 08:17:57 GMT, Riff <turbospgnopsamsouth.net> wrote: > > > >>"Who care if its the fastest 4 cylinder?" > >> > >> > >>I do! a 4 cyl is better than an 8cyl because it has > >>1 less internal friction > > > >Are you suggesting that the cyliners in a 4 cylinder engine glide > >easier than those in a V8? Granted a V8 has more moving parts which > >would translate to more overall friction. But, with this rationale, > >we should all have Briggs & Stratton air cooled engines in our cars. > >If this is truely the case, than why do all Formula 1 cars use V10 and > >V12 engines? Especially given the fact that they turn 15-18000rpms as > >a matter of normal use. I would think the fabricators of these spare > >no expense machines would want to take full advantage of that low > >internal friction of a 4 cylinder engine. > > > Recall if you will that F1 cars aren't notorious for real great 0-30 times. > Low internal friction helps with those quick starts, as the engine needs to > accelerate as well. Put your car in nuetral slam on the gas, it take .5-.75 > seconds for the engine to redline, low internal friction reduces this, and > aids in low gear acceleration. An F1 car by contrast doesn't have much need > to accelerate from 0-30 very quickly, so it is less of an issue. It is true > that all else being the same lower engine friction = more output, I don' > think that this is, however, the commercial ratrionale for making low > friction engines. Friction = heat, heat = death to all things automotive. > By reducing friction in an engine, one reduces wear on all the moving parts > of an engine. Less wear = longer life. In summary, I don't think that the > formula 1 car engines are going to give me 200k+ miles with out a rebuild. > In contrast Briggs & Stratton engines, especially 2 stroke (even fewer > moving parts!), are commonly used in applications where long, relatively > maintenance free life is expected; lawn movers, snowblowers, pumps, > generators...etc. > > > > >>2 higher power to weight ratio > > > >That depends entirely on the size, materials used and the type of > >construction. The Mercedes V8 powerplant in a CART Champ car is > >smaller and lighter than a Saab 4 cylinder and produces in excess of > >1000 hp. Have you ever seen the V8 engine in a Lotus Esprit? Its > >slightly larger, slightly lighter and much more powerful than the > >turbo 4 it replaced a few years back. > > > Once again I suspect there aren't alot of those merc v8's with 200k+ miles > on them. > > >>3 can be put in smaller compartment to have a better handling car. > > > >What was I thinking? Gee, I guess thats why Ferrari, Lotus, > >Lamborghini, Porsche 911, Corvette, Viper, NSX, Bugatti, Camaro, > >Firebird, Mustang, BMW 540i, Mercedes Benz C430, Lexus, Infinity, F1, > >CART, IRL, INDY Lites, and just about every other high performance, > >good handling car out there uses a 4 cylinder powerplant. Oh wait, > >none of these use a 4 cylinder powerplant. Duh. > > > >Good handling cars are not the result of smaller engine compartments > >and 4 cylinder engines. Good handling comes from proper engineering > >and good design. The Chevy Corvette comes to mind. Huge engine and > >engine compartment and incredible handling. And, lets not forget the > >Dodge Viper with its mammoth V10. > > > >>4 is easier to work on > > > >Oh really? In what way? > > Less moving parts, less cramped. Wanna change all the spark plugs on your > 8cyl? I bet I could change all of the ones in my 4 banger in roughly half > the time! Generally more available room and larger spacing between parts > too. > > > > >>I have seen 500 hp 4cyl 8v 944 turbo's > > > >And, I have seen 900 HP cast iron push rod V8s in Chevrolet Corvettes. > >So what? > > > >>if SAAB could have a 3.0L 4, that would be cool > > > >Personally, I'd rather see an all aluminum narrow angle 3.0 liter DOHC > >32 valve V8 easily and comfortably producing, lets say 270 HP, in a > >Saab. This would be much more efficient and reliable than an > >overbored and strung out stroked 4 cylinder engine any day. > > > Yeah, but it wouldn't have that racy highRPM-highHP feel to it, it would be > more like an... um Cadilac. Lot's of power, no doubt, but a substatially > diffenent feel. > > >>Mark > >> > >Tim, agreeing to disagree > > > >> > >>Tim Baker wrote: > >>> > >>> >The Saab Turbo is one of it's kind, you don't find a 4 cylinder in that > >>> >region with that performance. > >>> > >>> This is the same thing they said about the Lotus Esprit. But, what > >>> kind of engine does that speedy little devil now sport? Can you say > >>> small displacement V8? I dont think your arguement for the for the 4 > >>> cyliner has much merit. Who care if its the fastest 4 cylinder? > >>> > >>> > > > > My additional thoughts, > > I think that one of the more substantial differences in 4 vs 6+ cyl engines, > is that in general higher cylinder engines are designed with shorter > strokes. The shorter and higher firing rate (each cylinder fires once per > revolution, right?) produces a substantially smoother power in the low rpm > range, and in general lowers the redline, and flattens out the top of the HP > curve. (I know there are exceptions in $100k racing cars, but were talking > comercial right?). I would suspect, (I haven't designed a lot of IC engines > myself, yet <smirk>) that a larger displacement per cylinder and larger > stroke length is more responsive to turbo charging. Turbocharging > incidently is what gives SAAB 4cyl engines that racy feel we loyalist love. > I for one have heard complaints from the non-turbo charged 6cyl SAAB crowd > that they have a lot of power, but they don't feel the same. (I would be > very interested in trying SAABs new asymTurbo V6, but until they mate it > with stick (currently only available with an auto tranny), I will let it be. > > telling what I know, and making up the rest, > -Phil > > 84 900 Turbo Sedan 200k mi and still purring > 89 900 Turbo Conv 80k > 90 9000 CD Turbo, 100k > > >
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