Dyno-Less tuning?

[Raymond C Drouillard]

On Thu, 21 May 1998 22:36:31 -0400 "Thor Johnson" <thormj at earthlink.net>
writes:
>> >Brief recap... this is a 68hc11 EFI (fuel only) for a Honda
>> >CBR600 motor.  All homemade stuff.
>> >Calculates base PW based on MAP, all other sensors totally
>> >ignored (incl RPM)... batch fired at #1 intake stroke.  How
>> >important is RPM (considering I'm injecting 1/rev anyway)?
>>
>> It wouldn't be important at all if your volumetric efficiency remained
>> constant at all speeds.  Of course, we know that this isn't the case.
>> The amount of fuel injected needs to be reduced in the areas that have
a
>> low volumetric effieiency.  Generally, this means the low speeds where
>> the cam overlap reduces volumetric effieiency, and the high speeds
where
>> there simply isn't enough time to gulp a cylinder full of air.
>
>  How much does VE generally change on a high-performance engine like
this?
>  (1000-13500 RPM, 100HP rated)

Do you have the torque curve for your engine?  The volumetric efficiency
follows that (approximately).

>
>> I bought a cheap used laptop to do my tuning.  It's an old 486 DX2 50
>> (50/25).  With the Holley, I could actually go as primative as a 286.
>> How primative can you go?  Maybe you can find someone with an old 386
>> laptop that is gathering dust.
>
>Gotta look.  My cheap laptop service agent wants $150 for the NiMH 
>batteries.
>
>> Do you have an automatic?  The torque converter makes a dandy static
>> load.
>
>Its a stick (stock xmission), but I'm intrigued.  Can you use the torque
>converter outside of an auto-trans?

I never thought of trying.  It would probablly be some work to fabricate
it.

I used it up to the stall speed, and I didn't do it for very long.  I
didn't want to heat it up.

>
>> I don't know what you are using as an ECU.  In the holley, there is a
>> table that is used to specify extra enrichment when the throttle is
>> suddenly opened.
>
>How is the table organized?  Is it just a number or ?

It is a three dimensional graph.  The independant variables are throttle
angle and RPM.  The dependant (Z) axis is the amount of compensation
(increased injecter volume)

>
>> BTW, there is another table that specifies extra enrichment when the
>> engine is colder.
>
>... gonna worry about that next.... got all these sensors & dunno what
to do
>with them.
>
>> I wrote some programs in Foxpro that I used to statistically anylize 
>the
>> data and use it to tune the engine.  If you want, I can send them to 
>you.
>>  You'll have to modify the code to use your data, though.
>
>Definitely.  Couldja post it on the FTP, or you could email directly 
>to me.
>If thormj at iname.com doesn't work, thormj at earthlink.net will.
>
>Muchas Gracias,
>Thor Johnson
>thormj at iname.com
>
>

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