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Re: Fans revisited/power upgrades

To: triumphs@autox.team.net, LBPB1@aol.com
Subject: Re: Fans revisited/power upgrades
From: Dave Brink <dbrink@niu.edu>
Date: Tue, 16 Mar 1999 07:01:27 -0600
References: <5dd2f9fc.36ee2629@aol.com>
LBPB1@aol.com wrote:
> 
>          Ok  guys......I know I started all this and I dont mean to stir the
> pot any more,

Why don't I believe you ;)


> but I just talked to the man who I quoted as saying that the
> switch from mech. fan to electrical was worth about 12 HP. He also is the one
> who told me that switching the alternator on and off or moving it to be
> powered from the drive shaft was worth about the same HP.

Please stop baiting the nice people on this list.  

>           Now I dont know much about calculus and my engeniering experience is
> confined to my garage or back yard. One of you guys said that the only way to
> tell if this was true was to put the motor on a dyno and that "seat of the
> pants" testing was a poor test. Well he did dyno the motor......so his numbers
> were not just off the top of his head.
>           Of course the motor tested was a competition motor and most of the
> gains were in the higher rpm range I think, but I still imagine that there
> could be something to gain from the fan change.

You shouldn't still be imagining it after the response you have
received.  You SHOULD have a very clear concept on what exactly the
gains are.  If you didn't listen to the answers then I don't know what
more to say.

>            Building the brackets and a pully to power the alternator off the
> drive shaft is a bit much for street applications I think.

Ok, so you are interested in horsepower gains only while the car is 
stopped I guess.  That'll work great with your new electric fan.

> And  I dont know of
> many cars that you need to put on jack stands to change the alternator or
> tighten the belt! He said that by moving the alternator aft of the
> transmission you salvage HP that would be lost anyway instead of pulling HP
> from the motor directly.

Well, he is correct there.  It's worth 8 HP regardless of the
application.

> It also helps the front to rear power distribution.

This is also true, by reducing eddy currents in the chassis you can
realize a 1/2 second reduction in ETs AND better mileage.  It's like
having built in fuel line magnets.

> Still only minor points when it comes to street cars.
>            All this discussion has been very very interesting and I wish that
> my friend was on line because I know he would enjoy it, but he only uses his
> computer for CADing the suspensions and chassis he builds and other race car
> stuff.
>            Thanks to all those who resopnded. Ill be careful of the topics I
> raise in the future! :-)

What about the present?

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