Miata Mailing List: December 1997, Message #118
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From: 	"Wiseman, Curtis J" <curtis.j.wiseman@lmco.com>

Subject: RE: More HP or More torque (nerdish)

Date: 	Mon, 1 Dec 1997 19:41:40 +0000



First, thanks to Mike for the explanation, however nerdy it may be.

(Some of my best friends are nerds.)



Second, I have some questions:



After examining two scenarios (torquey and peaky), Mike concluded:



>So, it seems that the solution is to have a motor that is some balance
>of torque and horsepower.  The relative "size" of the figure is just an
>artifact of the measuring system (as discussed earlier), what is really
>important is the shape of the torque curve.  If the curve is huge but
>falls off too quickly, you can't do the work fast enough to capitalize
>on the power.  If the curve peaks very late, but is not high enough
>early on, then the power is too low at low rpms to motivate the vehicle
>effectively.  So much so that you may never actually get the car moving
>fast enough to reach the power band.

Okay, then, back to the "controversy" thread.  There is often talk of 

which is better, a turbo or supercharger.  We also often hear that 

torque makes acceleration.  Now Mike brings up the shape of the 

torque curve.  Well then....



So let's put some limitation$ on the equation: if one does not 

change from the stock ECU but is allowed an ignition retard (say 

a J&S), larger injectors, an auxiliary fuel pump, and a variable 

fuel pressure regulator, which is "better," a turbo or supercharger?  

Let's also confine the discussion to street driving (to eliminate 

optimization for track conditions and keep it "real-world").



I have had the pleasure of riding as a co-pilot, er, passenger in 

Shiv's F'stein and, sure enough, there is no lag and lots of boost, 

torque, and power.  Unfortunately, I am not currently allowed to 

write checks to be drawn on Shiv's account.  I have also driven 

a 1.8 Autorotor and a 1.6 BEGI System III (kudos down San 

Antonio way).  To me, the instant boost/torque of the Autorotor 

made it more driveable than the higher ultimate hp of the 

System III (although either one beats the pants off a normally

aspirated Miata.  Blindfolded.  With one hand tied behind its

bumper.  Uphill.  Both ways.).  Autorotor boost jumped up as 

soon as you asked instead of building up.  



I also realize there are drawbacks to belts and pulleys as 

opposed to good old energy-laden exhaust but, for now, 

I'm just asking about driveability to keep the discussion

bite-sized.



Any opinions?      :-)



Curtis Wiseman & Zonker

Yellow 92A, #733 of 1,519

Fort Worth TX