MFI to EFI Conversions

[jackson51]

Have been reading posts about converting MFI to EFI with modified original MFI components. Lots of solid info on the process. JP Novak discussed using BMW injectors and polymide (sp?) fuel lines in one of his threads - which were very informative, thanks.

By now, some of these conversions have been running on street and track for some time and a few miles. Would like to hear about your experiences with the conversion process itself and longer term use.
Also have a some questions:

What fuel pump(s) were used to replace the factory MFI pump, safely and reliably?

What other modifications or components were needed for the fuel delivery system? Filters, pressure regulators, fuel distributors?

Added fuses or relays?

What would you do differently having lived with a converted car?

[rsrguy]

Me too... I just ordered Jamie's kit and will be collecting the rest of the parts necessary to work the conversion.

[jackson51]

That’s great… good luck. Hope you have the time and inclination to update your progress!

[rsrguy]

The first hurdle is the throttle bodies and stacks... I guess it's not the easiest or as cost effective as I was hoping to get them up to snuff..

[Henry Schmidt]

Two question:
First: How do the electronic injectors respond to the proximity to the head [head temp transfer]
Second: How do the electronic injectors respond to the high vacuum on closed throttle deceleration ?[IE: trail braking]

[rsrguy]

Jamie?

[winders]

Originally Posted by Henry Schmidt

Second: How do the electronic injectors respond to the high vacuum on closed throttle deceleration ?[IE: trail braking]

Would the vacuum be any higher than with direct to head ITBs that have the injectors 1/4" away from the head intake port?

I don't see why the vacuum would be much different...if at all.

[Neven911]

Originally Posted by Henry Schmidt

Two question:
First: How do the electronic injectors respond to the proximity to the head [head temp transfer]
Depends how you insulate them I expect

Second: How do the electronic injectors respond to the high vacuum on closed throttle deceleration ?[IE: trail braking]

EFI injectors are metered by time open which is why you regulate the fuel tine pressure to a fixed amount above manifold pressue - so a full 1 atmos vacuum should not be an issue

[Henry Schmidt]

Originally Posted by Neven911

EFI injectors are metered by time open which is why you regulate the fuel tine pressure to a fixed amount above manifold pressue - so a full 1 atmos vacuum should not be an issue

I understand that some electronic fuel injectors function perfectly well under high vacuum environments but my concern was if ALL electronic fuel injectors function equally well. If they do, cool.
Same with the heat concern. Do electronic fuel injectors respond well in high temperature environments? Direct to head injectors are subjected to extreme heat generally well above 250 degrees.
I was not and am not stating any facts just asking questions.

[dannobee]

Electronic Injectors are cooled by the fuel going through them, so nothing special is needed there.

Engine vacuum isn't a problem, and in fact, the injectors are often turned off under engine braking conditions.

EFI is vastly more tunable than MFI. It might take you awhile if you're learning it all on your own, but it has the capability of giving the best driveability under all conditions.