[DML] Continued: Horsepower vs Torque

["content22207" <brobertson@xxxxxxxxxxxx>]

185 was General Motors' published net HP rating for a 4 barrel 350
circa 1981. Look it up. Make sure you're not confusing gross HP with
net HP -- American manufacturers changed to a net calculation around 1972.

The only way you're going to get a normally aspirated large bore
gasoline engine to continue to produce usable power up to 5,000 RPM is
with serious modification to the valve train (short duration, high
lift, overlapping time, etc). In the process you'll render it totally
useless for street driving. Won't even idle less than 2-3,000 RPM.
Higher compression is also necessary -- another point you and I
disagree on.

I didn't invent algebra BTW. If you don't like the way numbers come
out of a HP calculation, don't point fingers at me. You are using the
same formula as James Watt, aren't you?

Consider this: if turbocharged high rev'ing small displacement engines
were as powerful as you insist, wouldn't they be installed in every
pickup and delivery truck in the country? I have never seen a tow
truck with with any of the engines you eMailed me under the hood. I
have seen them with diesels (let's talk about low rev'ing torque!)

The concept is very simple: an engine that produces all its power in
the upper RPM ranges is basically useless until you rev it up there.
Subjected to a significant load from a standstill you'll either stall
it or burn up the clutch disc(s) trying to move. 

Bill Robertson
#5939

>--- In dmcnews@xxxxxxxxxxxxxxx, Jim Strickland <ihaveanaccount@xxxx>
wrote:
> 
> On Sun, 02 May 2004 18:55:55 -0000 "content22207"
> <brobertson@xxxx> writes:
> > My
> > contention, then and now, is a high rev'ing turbocharged small
> > displacement engine does not produce very much torque. 
> 
> what's "very much"?
> A turbocharged 1.5L BMW F1 engine generates 500ft-lb of torque.
> A production 2.0L rotary twin turbo generated more torque than the 4.6L
> northstar v8 (297 ft-lb vs 295 ft-lb).
> 
> In fact, smaller engines generate more torque for their size than larger
> engines.  A turbocharged Lotus 2.2L makes more than TWICE the torque for
> it's size than the chevy 350.  
> 
> Your assessment of the chevy 350 is also not entirely accurate.  You say
> that the "185 Net HP" translates to 330ft-lbs of torque, but the peak
> horsepower for the vette's 350 is attained at 4000 to 5000RPM.  There is
> much less HP at 3000RPM.  Also, I don't know of any 350s that have HP as
> low as 185 and torque as high as 330ft-lb.  
> 
> 
> It's normally expensive and a pain to replace the transmission as
well as
> the engine in a conversion, but I'd consider an engine swap to be
> incomplete if you can't count on the transmission to take the beating
> that an engine can dish out.  
> 
> If you're replacing the engine in the Delorean, you've probably already
> passed the point where the 'collector status' of the car has any value. 
> Personally, it seems unlikely to me to swap a PRV back into a car that's
> gotten an engine swap to another engine.  I think the car would have to
> have significant colllector appeal for such a "unswap" to be reasonable
> or desirable.
> 
> 
> Jim 
> 1537
> 
> ...
> > 
> > That's what killed Darryl Tinnerstet's input shaft (a stock 350 is
> > "only" rated 185 Net HP, but at 3,000 RPM that translates into 330 
> > Ft
> > Lbs of Torque).
> > 
> > I do have a spare high compression Ford 460 you might be able to
> > shoehorn back there...
> > 
> > Bill Robertson
> > #5939
> > 
> 
> 
> ________________________________________________________________
> The best thing to hit the Internet in years - Juno SpeedBand!
> Surf the Web up to FIVE TIMES FASTER!
> Only $14.95/ month - visit www.juno.com to sign up today!




To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
     http://groups.yahoo.com/group/dmcnews/

<*> To unsubscribe from this group, send an email to:
     dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
     http://docs.yahoo.com/info/terms/