[Diy_efi] sequential injection timing

[Mark Claywell]

Hello,
 
Most of my testing has been on an eddy current (Schenk) dyno with a digilog
controller or on a DC dyno. The DC dynos were WW2 vintage, but upgraded
with newer load cells. Calibration was done every few months (up and down).
You might be suprised that you can pick up an old eddy current or DC dyno
for not much money. The DC dyno's are however massive, for their absorbtion
size. You'll likely spend more money on the controller. I know some people
use LABVIEW and make their own controller using that, which can be cheaper,
but takes more screwing around. 

Many of the times I wasn't worried how much power was being put out, just
what tuning parameters were worse or better. During one tuning session you
can just play with parameters at one site and read the change in output
torque. You can measure the gain even with a skewed calibration, as long as
you realize that you can only know that the percentage changes are good,
and that the actual power numbers are not. In a small change (<%5) the
output of the load cell is very linear and you can look at percentage
changes and get useful data without worry of calibration. That's how I can
measure 2% gains. 

> I'm impressed that you can measure 2% gains. Most of us can't get access
=
> to engine test facilities with that level of accuracy, or operators who =
> know how to extract it, at least here in UK.
> 
> It would seem we have run into the usual problem of what is available to
=
> the Big 5, race teams and the like and what the DIY-er can get hold of =
> injector wise, viz: there are some advanced technologies out there, but =
> few of us can afford them or manage to get them to work properly. Net =
> result being that for 90% of us the injectors we use work best (for =
> power) in batch mode.
> 
> Every so often one escapes. The current Audi Le Mans car springs to mind
=
> as it uses direct injection. Audi only uses DI in its most amaemic =
> little shopping trolleys, but its highest HP engine also uses it, and =
> ignoring conventional wisdom have gained more HP and more fuel =
> efficiency than the competition. Net result, they are almost invincible =
> at the moment. As no-one else has managed to emulate this, one might =
> infer that this is a non-trivial thing they have done.=20
> 
> Meanwhile we have to wait for the trickle down, unless we have direct =
> access to the technology
> 
> Bill
> 
> -----Original Message-----
> From: ext Mark Claywell [mailto:clay0052 at umn.edu]
> Sent: 30 July 2002 04:49
> To: diy_efi at diy-efi.org; diy_efi at diy-efi.org
> Subject: Re: [Diy_efi] sequential injection timing
> 
> 
> 
> 
> > Only if you're worring about CAFE, and the EPA.  In the real world it
> aint
> > no big thing, feel free to review the archives.
> 
> I consider a 3% gain in power something to get excited about. Running
> 100octane race gas I have found 2-3% gains in some small motorcycle
> engines. Alchol fuels are more sensitice to EOI. However, I agree that =
> how
> much power will vary with EOI, is very much largely engine and injector
> dependant.=20
> 
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