Stamp EFI

garfield at pilgrimhouse.com garfield at pilgrimhouse.com
Sat Jun 27 13:33:32 GMT 1998


On Fri, 26 Jun 1998 23:56:24 -0700, Sandy <sganz at wgn.net> wrote:

>Most of the automotive high perf injectors will require the CS453 (4/1).

I used to think the same thing, until I started using them (we use both;
we have a TBI injector as the "5th/7th element" for redundant backup on
our KISS EFI system 4/6-cyl boxers) and studied the spec more carefully.
Here's a quote from a salient paragraph on the 3rd page of the data
sheet.

"Automotive injectors at present time come in two types. The
large throttle body injectors have an inductance of about 2.0 mH
and an impedance of 1.2ohm and require the CS-453 driver. The
smaller type, popular world-wide, has an inductance of 4.0 mH
and an impedance of 2.4ohm and needs about a 2.0A pulse for
good results, which can be met with the CS-452. Some designs
are planned which employ two of the smaller types in parallel.
The inductance of the injectors are much larger at low current,
decreasing due to armature movement and core saturation to the
values above at rated current."

>One other side note, the cherry driver
>is a low side switch and the lm1949 ends up being a high side switch.

I dunno how you can say that, dude. The darlington's a low side switch;
yes, the 1949 drives the darlington from the high side, but
whatsdatgotta do with anything? The 1949 was never meant to drive
anything all by itself anyhoo, so you end up at exactly the same place
as the cherry drivers as far as "driver-side".

Gar




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