DIY_EFI Digest V1 #298

[Matthew Beaubien]

This is all quoted because I have a little to say to each person, so don't
flame me ;-).

> >>I just got my '70 302 Ford running with the Holley Projection 4DI ECU.  This
> >>is a batch fire MAP system.  The cam is a high lift (.550"), medium duration
> >>(224 at 0.050"), hydralic roller from Crane.  The system indicates that at
> >>least a -50% correction is required at idle, 700RPM, to get the mixture
> >>correct if the stock 302 look up table is used.  The injection volume table
> >>is based on RPM and MAP signal.  

If you're using the stock table, the FI will run way too rich. Your vacuum
will be less than a stock engine (because of the cam) and the computer
sees less vacuum as more load = more fuel. If you lower the fueling
requirements in the maps, drivability should improve a whole bunch. One
indicator of how close your map is to what the engine needs is the O2
correction. You stated that the O2 correction was -50% at idle. This is
telling you that even cutting the fueling requirements it thinks you
should have by 50%, it is still running rich. It takes a long time but if
you have enough patience, you should be able to make it work ok.

 
> Oh no! Not a Holley! I hope you don't have the 4Di. That system is
> terrible. The one with the knobs on it is much better. I recently worked
> on a 93 Liconln Town car with a big block 605 in it. Carbs didn't work
> too well so they put on the digital Holley system (4Di). Damn thing
> would barely run.
> Holley just didn't put enough control into the thing (like how much RPM
> you can add in hi-cam mode). They try to use a standard O2 sensor for
> wide range control. Put a scope on it and it was WAY off. I will
> eventually put an EEC on it to get it to run right. Car is real strange.
> Canary yellow, BIG wheels/tires and probably 600 HP. When I'm driving it
> around people just laugh....until I push the throttle a little bit!!!

The fuel map you were using with the 4Di was probably way off. Something
must not be right if the carbs didn't work properly (too big, not enough
vacuum, etc?). If anything, it probably has too much control making it
difficult to tune.

I would say the Holley FI with the knobs (Projection) is even worse than
carbs. A friend of mine spent _hours_ on a dyno with a Projection on a
kids 383 and could not get the thing to run right. The thing would kill
holes at the bottom from running too rich and lean them out to near
critical temps at the top (or vice-versa). It would bog when it was leaned
on no matter what. The "Projection" manifold was one sorry piece wrt
distribution. Holley tech guy said it hadn't been dynoed but was "based"
on ZZ3 manifold. Holley eneded up buying back the system and giving my
friend with the dyno a Holley performance package with heads, cam etc.
Another strike against Projection is the fact that Summit stopped selling
it because people had too many problems with it (not only tuning but
reliability). They ended up bolting on a 750 on a Victor Jr and gained 20+
ft-lbs _everywhere_ compared to the best Projetion runs (even on the
Victor Jr.)

I don't know how many people have checked out other FI setups but from
talking to people "in the know", Accel's DFI seems to be about the best
(especially on forced induction engines) for the price. There's also the
FI setup that doesn't require a laptop to program. It has a knob where you
can adjust the mixutre +/- 50% while driving to get the map to where you
want. It's called SDS and there hompage is www.sdsefi.com. I know a few
people that have used it with decent success. The wiring harness is a
little lame but it works pretty good and is affordable.


Matt.
mbeaubie at gpu.srv.ualberta.ca