Amps/injectors

Discuss which Sensors work best with these ECUs and share how you are using inputs and outputs
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

Alex DTA wrote:I didn't say the pot wouldn't work, just that I'd do it with the regulator.

Interesting stuff, either way.
But with the regulator being regulated.....that has to be a negative as you lose any means of monitoring voltage and offering corrections based on voltage ?

And given the low loads and duration....a pot or similar should pose no problem ?

After all, we use such pots as sensors/inputs routinely. Whether TPS, trim pots in the tuning box, pots for traction or launch. Same deal really, just playing with voltages
Rob Stevens
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Re: Amps/injectors

Post by Rob Stevens »

Stevie, thing is with the supply being un regulated, the voltage would go up and down with the load on the ecu, I think the current could vary by 2A depending on what it was doing at the time,
Your example of a TPS output isn't relevant as the output goes to a very high resistance input and draws next to no current.

I'm not about to test it but I suspect the ecu would be fine on 16v, I recall Allan telling me that they had survived 24v in the past.
Alex DTA
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Re: Amps/injectors

Post by Alex DTA »

The ECUs are generally OK up to 18 V, but that's for short periods. 24 V must have just be a spike!
They were never designed with a constant 16 V, so I can't say it would be safe.
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

Worst case scenario...what damage might be caused from overvoltage on a 16v system then ?

ie, would be be catastrophic damage, or a simple/cheap fix ?
Rob Stevens
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Re: Amps/injectors

Post by Rob Stevens »

I'd imagine output driver failure due to over current, but this would be mitigated in a small way by the reduced dead times. On the S40 would definitely overheat with no heatsink.
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

But at a higher voltage, surely less current is likely to pass ?

I'm sure some alternator based 12v systems have run at nearly 15v ?

So a step to a battery based 16v, with no charging system shouldnt be too much more as voltage would never actually exceed the 16v, and may drop a little during the run.

Just curious if it'd be an expensive risk, or cheap risk to the ecu itself to just run it all at 16v

Although I recall years ago, MAD ran some big power amp to power most aspects of the ecu systems on their Sierra, so they would always see a stable 14v regardless of battery voltage.

Another version of a similar idea.
Rob Stevens
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Re: Amps/injectors

Post by Rob Stevens »

No it's simple ohms law
I(current)=Volts/Resistance
Example
12v/6ohm = 2A
16v/6ohm = 2.7A

My cars run at about 14.4v so as you say not much difference to 16v without an alternator.

So these 16v batteries if lead acid must have 8 cells and if charged from an alternator would charge at 19.2v clearly too high for the ecu
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

But again...often it is a total loss system. Battery only, no charging system on the vehicle.
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

2 options extend from this ( well probably more )

Run entire system at 16v, and more than likely it will be fine.

Run the system at a normal 12v, and find a suitable power amp to run the injectors at a stable higher voltage. This would also negate the need for ecu based voltage corrections for voltage at the injector. Because there wont be any.

I guess the likes of the Kenne Bell Boost A Pump and other similar devices would offer enough power for injectors only for this, even if that was not their intended purpose. Although I think their base model runs at 17V ?
Or variable models as high as 22V

And they offer them in 40A capability, so should even cover a lot of those atomiser injectors.
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

As an update to this.

This was the device I'd seen before used on a car to ensure the important systems had rock solid stable voltage. Seems it can be set up to 16.25V and handle around 100A
Although for ecu, coils, injectors etc it would never need 100A.

But if it provided a perfectly stable voltage, then any voltage corrections in the ecu would become irrelevant as injector dead times would never change due to voltage.

http://www.jacobselectronics.com.au/raceaccuvolt.htm

https://www.youtube.com/watch?v=FFGqf5VQvuI
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