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 »

eg, this says it will output 12v, and max 2A.

If the ecu is not handling ignition loads or any injector current etc then it shouldnt be using anywhere near 2A ?

http://www.hobbytronics.co.uk/s18v20alv ... -regulator

The only downside to this would be losing the ability to log battery voltage ( which is seen as ecu voltage ) and any compensations you may want to apply based around any changing voltages.


or perhaps a simple large wattage resistor might drop ecu voltage enough...but retain the above features.
Alex DTA
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ECU Model: S40 Pro
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Re: Amps/injectors

Post by Alex DTA »

If you have the Fuel Tech driver boxes already, you don't need to supply the ECU with 16v.
The signal from the ECU will go to the FuelTech driver box, which can run at whatever voltage it needs. There won't be an offset then, as the FuelTech driver box will deal with that.

You can then run the ECU at normal voltages. 14v is fine.
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

Alex. A lot of drag guys these days run 16v systems. In the US that's both battery and alternator.

Although a lot of the drag specific guys will just run a 16v battery in a total loss system. So ALL aspects of the car run at 16v. Injectors, pumps, coils etc etc.

This has obvious power advantages for these components....but then there is the need for any other affected parts to be happy with the higher voltage.

In this case, that may be the ecu.

As the ecu itself would draw very little current, what sort of size/type of resistor might be useful to drop the ecu to around 13-14v so it can remain safe, but also be aware of any volt drops, and ability to log voltage ?
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

I guess for some flexibility....something like this would allow the user to choose the voltage to the ecu ?

https://www.ebay.co.uk/itm/150-Ohm-150W ... 0005.m1851

But it would still be relative to input voltage, and not a stable regulated output ?
I use a pot like that myself, albeit smaller for the LED dash illumination on my car. ( it's actually the same rotary pot my welder uses for wire speed..hence i had a couple lying about to try lol )

Or if happy with a simple fixed output setup, Jaycar offer this

https://www.jaycar.co.uk/dc-to-dc-step- ... e/p/AA0236

Running a 16v battery and total loss system for drag use, I'd think battery voltage would be very stable throughout a run anyway ? So compensations for varying voltage might be less concern ?
Alex DTA
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Re: Amps/injectors

Post by Alex DTA »

Interesting. I don't have much exposure to high level drag stuff, so this is a learning experience.

If it was my car, I'd use the Jaycar style transformer to power the ECU.
Then use the FuelTech injector drivers, and IGN1A coils (or similair amplified coils). That means the ECU is completely isolated from all high voltage systems. Assuming they've been built correctly, the 4 V offset won't be a problem.
The ECU can then supply the 5 V rail for the sensors.
Any solenoids that require the ECU to trigger them would have to be powered by the transformer.

Why are people using 16 V?
The coils won't charge more, just quicker. Injector dead times will reduce, but those can be catered for in the ECU. I can't imagine RPMs are at the point where big dead times are an issue, even with batch injection. Sequential would solve that.
What am I missing here?
katana
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Re: Amps/injectors

Post by katana »

Maybe a lot don't run alternators so total loss battery drain even over 10 seconds is a lot! When I was bike racing, the electrical load comprised maybe 8-10A ignition, 15-20A Nitrous system inc. fuel pump and maybe another 5-10A for c/case vac pump with a few more amps for tach and warning lamps. We used to use Drill plug-in packs 14.4v. Add in a lot of amps for injection and high amp fuel pumps and drain gets excessive quickly?
rocar
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Re: Amps/injectors

Post by rocar »

We use 16v so we do not use alternator and the big 500lbs billet atomizers are recommended 16v with 90psi base pressure and small difference in voltage will make many difference in fuel as I'm using two on each cylinder

Do you think lowering voltage with a resistor will end with stable voltage.
How much amps on the ecu ? do this vary ?
Alex DTA
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Re: Amps/injectors

Post by Alex DTA »

OK

I would not simply put a resistor in series. Do it properly with a good quality step up/down transformer. If you're investing properly in the rest of the system, why skimp on the part that controls everything?

The S80 will draw between 1.5 and 2.5 amps with amplified coils on, and no injectors.
This will increase if the ECU has to drive any other outputs.
stevieturbo
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Re: Amps/injectors

Post by stevieturbo »

There's no reason why the adjustable pot shouldnt work ?

Using a regulated device like the Jaycar, you lose any ability for voltage based corrections.

But ultimately it is as Roger says. 16v will run the ignition better, it will operate the injectors better/faster, it will run the fuel pumps better.

And it means it's easy for these guys to get good electrical power....without the need/weight for an alternator at all ( although you can get 16v alternators too )
And when running very large injectors like the atomisers....you need all the help you can get, and again as they run at much higher pressures than the average user.

The example above with the 500lb injector....Yes, that is EACH injector approximately 5000cc.

A far cry for some when their entire engine might only ever need a fraction of that.
Alex DTA
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Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
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Re: Amps/injectors

Post by Alex DTA »

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

Interesting stuff, either way.
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