Thread:

recommended efi for aluminum 632 with psi screw blower

Originally Posted by BOOSTPOWER

Lol! Like unchained mentioned. Any system can work if the tuner knows what's up. Some have better resolution/or control ability per say.
We have maps for every system known for just about every marine/auto engine. We can also convert maps from one system to others.
Anyway, they all pulse from say 1% duty cycle to say 80% duty cycle, however I would not recommend pulsing any injector much over that. It will overload the injector driver and cost you $$$$$$$$$


Sent from My Boostpower Marine Efi Beacon.

I know you do a lot of big, high dollar efi builds, but I don't agree with what you said about the injector drivers. Everything I have ever read on the 80% rule is not for keeping a driver from "overloading", I've never seen or heard of this, other than when someone tries to use peak and hold injectors on a saturated injector driver circuit. The 80% rule is for fuel control, above about 80% until you reach 100%, it is very difficult to properly control the fuel flow as the mechanical movement of the pintle itself cannot go from fully open to fully closed in the amount of time given when the injector is pulsing at over 80% D/C. This causes the pintle to begin to close but before it can is already opening again, causing inconsistent fuel control. Inconsistent fuel control is the last thing you want to happen when at 80% D/C as you are likely at peak power, when engine damage can occur if a lean condition occurs.

I have seen a couple of issues that have occurred where a driver went 100% D/C on an entire bank of injectors when the ignition was turned on (not running obviously). The injectors got smokin hot after a significant amount of time at 100% D/C with NO fuel flowing, and yet there was no injector damage or driver damage caused. I've also seen random failures to injectors drivers, but none that were proven to be caused by duty cycle.

I say all these things because I am curious why you say that over 80% duty will damage the driver? Have you seen these failures before that were traced to D/C? Were they isolated to a specific ECU brand? Was it with saturated or peak and hold injector circuits? I'd just like to hear you expand on your info.



Andrew

Originally Posted by Unchained

I ran a set of Bosch 160# injectors at 100% DC for a couple seasons and had no problems with it.
They just went static. The target A/F ratio on E85 just happened to be right on at 100% DC 28# boost.

The holding current is considerably less than the opening current on a low impedance injector.

I have since switched to Atomizer 225# injectors and the DC is down in the 75% +- range.
The Atomizers are a better running injector than a Bosch IMO.
They just cost 3x the price.

this is exactly my point. once you reach 100% the fuel control is perfectly consistent, and lucky for you it happened to create an AFR that didn't make the engine go boom! If your WOT would have been in the 90-95% D/C likely you would have seen AFR constantly moving around to the point that you couldn't ever get a solid reading at WOT, which is exactly what you don't want! But never have I seen injector drivers fail due to high duty cycle. That's why I'm asking about the statement.



Andrew

Originally Posted by Hass828

How much does a set of those babies cost ? $$$$$$$$$$$$$$$$$$

quit


you already know how much they cost! Your google search works just as good as mine...

we know how you love your carb....no need to tell us again






.........but, if you want to know a little something about efi.....

Originally Posted by Unchained

I ran a set of Bosch 160# injectors at 100% DC for a couple seasons and had no problems with it.
They just went static. The target A/F ratio on E85 just happened to be right on at 100% DC 28# boost.

The holding current is considerably less than the opening current on a low impedance injector.

I have since switched to Atomizer 225# injectors and the DC is down in the 75% +- range.
The Atomizers are a better running injector than a Bosch IMO.
They just cost 3x the price.

How are those injectors performing?

Originally Posted by cstraub

Doing a 650CID PSI boat engine and we are going with Holley Dominator.

I have good maps for this setup along with any others. Let me know.


Sent from My Boostpower Marine Efi Beacon.

Originally Posted by ap67et10

I know you do a lot of big, high dollar efi builds, but I don't agree with what you said about the injector drivers. Everything I have ever read on the 80% rule is not for keeping a driver from "overloading", I've never seen or heard of this, other than when someone tries to use peak and hold injectors on a saturated injector driver circuit. The 80% rule is for fuel control, above about 80% until you reach 100%, it is very difficult to properly control the fuel flow as the mechanical movement of the pintle itself cannot go from fully open to fully closed in the amount of time given when the injector is pulsing at over 80% D/C. This causes the pintle to begin to close but before it can is already opening again, causing inconsistent fuel control. Inconsistent fuel control is the last thing you want to happen when at 80% D/C as you are likely at peak power, when engine damage can occur if a lean condition occurs.

I have seen a couple of issues that have occurred where a driver went 100% D/C on an entire bank of injectors when the ignition was turned on (not running obviously). The injectors got smokin hot after a significant amount of time at 100% D/C with NO fuel flowing, and yet there was no injector damage or driver damage caused. I've also seen random failures to injectors drivers, but none that were proven to be caused by duty cycle.

I say all these things because I am curious why you say that over 80% duty will damage the driver? Have you seen these failures before that were traced to D/C? Were they isolated to a specific ECU brand? Was it with saturated or peak and hold injector circuits? I'd just like to hear you expand on your info.



Andrew

The injector drivers are load driven and load sensitive. Some ecm's have low amp drivers ( like less then 4 Amps) this makes the ECM struggle to perform on most low imp peak and hold injectors. Think of it as overloading the circuit the breaker pops! When the injector drivers go bad, weird things happen until full ECM failure. So being that we deal with so many ECM brands, our in house protocol is to not run injectors over 80% if possible. They are happy there with the brands we test often (Delphi, Deka etc)
Yes, above 80% there is also fuel control issues depending on injector mfg.
And yes, we have seen failures and that is what initiates the testing we perform over the past 25 years.
Thanks 👍


Sent from My Boostpower Marine Efi Beacon.

Originally Posted by BOOSTPOWER

The injector drivers are load driven and load sensitive. Some ecm's have low amp drivers ( like less then 4 Amps) this makes the ECM struggle to perform on most low imp peak and hold injectors. Think of it as overloading the circuit the breaker pops! When the injector drivers go bad, weird things happen until full ECM failure. So being that we deal with so many ECM brands, our in house protocol is to not run injectors over 80% if possible. They are happy there with the brands we test often (Delphi, Deka etc)
Yes, above 80% there is also fuel control issues depending on injector mfg.
And yes, we have seen failures and that is what initiates the testing we perform over the past 25 years.
Thanks 


Sent from My Boostpower Marine Efi Beacon.

4 amp drivers?? WOW! I suppose there probably isn't any way you are going to out the brands that have problems, (that is a problem for a circuit that is suppose to run an ultra low resistance injector!) because I would put money on it (like I said in my first post) that it is isolated to 1 or possibly 2 specific brands and also only with peak and hold injectors/drivers. I would even put money on it that the problems are with a big name brand.....that's just how it always seems to go.

I'm sure most people think I'm a broken record, but this is exactly why I am strictly a Megasquirt user. I can see every single thing about the circuitry, software, code....everything about them! There are no secrets, or proprietary time bombs ready to bit a $2,000+ hole in your wallet. You know what you are getting, and if you spend some time with them you can make them do anything you want.

Obviously the 80% rule is something that's worth living by, but with the massive amount power people are making with boosted engines, I find so many people don't realize that going too big can be just as bad, especially when considering a lake/cruiser boat.


Andrew

Thanks guys! Each system
Has its pro's n con's for sure. We have run every one known and have our opinions. Bottom line is run what your research convinces you to run and master the software. Enjoy!


Sent from My Boostpower Marine Efi Beacon.