DIY_EFI Digest V1 #241

[einarp]

>The biggest problem with almost any dyno is getting rid of the heat 
>generated. For a 200HP engine, that's more than 500,000 BTU/hr.
>That's enough to boil off 523lbs of water per hour, or 65 gallons.

Hook it up to your hot water tank, spa or swimming pool. No, I'm not
joking. They are ranging from large to huge in heat storage capacity,
and you can enjoy the heat before it dissipates.

>Someone on the hotrod list a long time ago suggested putting a hall effect 
>type sensor at the both ends of the driveshaft and measuring how much it 
>twists.

It would be easier to find the exact weight and gearing of the car, and a
rev sensor on a wheel. But still doesnt take care of 2 problems: The wear
and tear on your drivers license as you're testing high end power, and how
to hook up measuring gear and prototype engine management system.

> So why not eliminate the tires, and mechanically couple the axles or
>steel wheels to *something*?  

Indeed, why not? Assuming that you're not going to use it for tuning up
many different cars in one day, just your one & only project car. I don't
think rollers are possible for most of us. Neither me, nor any of my friends
have a pit across the garage floor for the rollers. The frame of this "hub 
coupled"
device should probably carry the weight of the car rear end by the hubs to 
avoid 
large angles at the axle joints. This approach would also make less noise. The
tyres against the rollers makes one #¤%& of a racket at 240+ Km/h!

A modular approach with the dyno part hooking into a test frame should make
it possible to share the more expensive parts between several users on a
time-share basis. Then the test frame can be anything from rollers to a
simple engine test stand.

Someone seems to be doubtful whether this has something to do with DIY-EFI.
It seems pretty clear to me that dialling in an EFI by the seat of your pants
requires a well calibrated bum. (I)  So..you need a DYI-dyno!

Regards
Einar

--
einarp at ade.no  ( Maserati Biturbo Spyder )