Adding fuel and pulling advance for dry nitrous

[Efi Guy]

I'd have to look at it again but I think you can control the nitrous solenoid with the PWM output via a high current driver
In the AUX 2Ana2 box.

Let's assume that Allan gets his head around the principle of adding fuel with millisec

Control nitrous relative to mph
So input would be undriven wheel speed then column 2 add the fuel enrichment in ms -column 3 take out some timing (in degrees if poss)
Then put the duty cycle of the solenoids in the last column.

Add the second input as TPS above 90% so if you bottle it and lift it deactivates.

Figuring the duty cycle v jet size v enrichment would initially be tricky but once you had a base setting most could be calculated/extropolated. eg 10ms at 50% duty should equal 20ms at 100% ( deadtime of solenoids would need to be sussed as those things are not that responsive)

Strange that someone couldn't figure out that with a fixed orifice and fixed pressure (nitrous jet) you have fixed flow yet they decide that it's better to have the enrichment as a percentage which alters along the fuel curve.

Just need to figure a way of deactivating the whole thing without having to plug in a laptop-the nos solenoid is not a problem but you don't want enrichment every time you go above 90% TPS

further edit-I'm thinking as I go along here.

Might have to bring ANA 1 into it for the trigger and use another relay from the main arm relay to disarm the whole lot= certainly do able

[ignitionautosport]

Gotcha - do you know if you need a diode on it for an inductive load? Going to be controlling the nitrous solenoid.

No idea... I didn't bother at the time.

[Jon K]

I'd have to look at it again but I think you can control the nitrous solenoid with the PWM output via a high current driver
In the AUX 2Ana2 box.

Let's assume that Allan gets his head around the principle of adding fuel with millisec

Control nitrous relative to mph
So input would be undriven wheel speed then column 2 add the fuel enrichment in ms -column 3 take out some timing (in degrees if poss)
Then put the duty cycle of the solenoids in the last column.

Add the second input as TPS above 90% so if you bottle it and lift it deactivates.

Figuring the duty cycle v jet size v enrichment would initially be tricky but once you had a base setting most could be calculated/extropolated. eg 10ms at 50% duty should equal 20ms at 100% ( deadtime of solenoids would need to be sussed as those things are not that responsive)

Strange that someone couldn't figure out that with a fixed orifice and fixed pressure (nitrous jet) you have fixed flow yet they decide that it's better to have the enrichment as a percentage which alters along the fuel curve.

Just need to figure a way of deactivating the whole thing without having to plug in a laptop-the nos solenoid is not a problem but you don't want enrichment every time you go above 90% TPS

further edit-I'm thinking as I go along here.

Might have to bring ANA 1 into it for the trigger and use another relay from the main arm relay to disarm the whole lot= certainly do able

You're forgetting though that I could be doing 45 mph in 5th gear and 2000 RPM... too low to inject nitrous. Needs to be RPM based not speed based. If I made it most safe, I would have to pick a speed at which my RPMs in fifth gear would be > 3200, so then I'd have to pick 70 mph... and then I could never spray in firsts or second gear.

[Efi Guy]

Well you don't have to use MPH and you can easily add "active only above xxx RPM"
I'm not sure what you are trying to achieve but if you are dropping to 2000 rpm when you hit 5 th then you ain't on the drag strip or you need to try harder

[stevieturbo]

Fit an accelerometer, and use it into an Ana input.

If acceleration drops below a certain level....add more gas

[Jon K]

Well you don't have to use MPH and you can easily add "active only above xxx RPM"
I'm not sure what you are trying to achieve but if you are dropping to 2000 rpm when you hit 5 th then you ain't on the drag strip or you need to try harder

The whole point of this is to have a "I don't gotta think about it" strategy for nitrous. If I need to worry about what MPH I am doing etc., then I might as well just run a button on the dash.

[stevieturbo]

The thing is, far too many people in the US cannot think of anything outside 1/4 mile usage.

There's a lot more to fast/fun cars than just a drag strip.

[Efi Guy]

All the people I know who used nitrous on the road either had mishaps or got fed up of refilling . It's attractiveness for road use is limited unless you like showing off the fancy bottle to impress the chicas

[Efi Guy]

Well you don't have to use MPH and you can easily add "active only above xxx RPM"
I'm not sure what you are trying to achieve but if you are dropping to 2000 rpm when you hit 5 th then you ain't on the drag strip or you need to try harder

The whole point of this is to have a "I don't gotta think about it" strategy for nitrous. If I need to worry about what MPH I am doing etc., then I might as well just run a button on the dash.

"I don't gotta think about it" and nitrous only ends up one way

[stevieturbo]

All the people I know who used nitrous on the road either had mishaps or got fed up of refilling . It's attractiveness for road use is limited unless you like showing off the fancy bottle to impress the chicas

I agree, for a road car is is almost pointless, and bottles do not last long enough.

But I think among other things, Jon wants to use it to spool the turbo earlier. For that alone it can be very useful, and would use only small amounts of gas.

And a large shot can only be of use if the car has sufficient traction, hence the simple off/on isnt as relevant and why progressive control is so popular these days.
If the ecu can do that all the better, saves buying and wiring in more crap.

If the ecu cannot do it satisfactorily...then maybe it really isnt worth the hassle at this time.