Aidan's loose oily bunghole actually runs a track lap
05-03-2016, 06:43 PM
#6802
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Also just purchased a Solid State relay so I can control the Walbro 400 with PWM instead of just always on.
Using this relay Hella Relays H41773001 - Free Shipping on Orders Over $99 at Summit Racing
its a negative control relay, so triggered by ground. Which means the standard Miata fuel pump output should work fine. I will jump the stock relay, (connect the fuel pump output from the MS to the tank wire, which will send the ground signal needed for the solid state relay), and wire this one in at the tank.
It's rated at 20amps continuous which is just above the walbro400 max current draw.
Using this relay Hella Relays H41773001 - Free Shipping on Orders Over $99 at Summit Racing
its a negative control relay, so triggered by ground. Which means the standard Miata fuel pump output should work fine. I will jump the stock relay, (connect the fuel pump output from the MS to the tank wire, which will send the ground signal needed for the solid state relay), and wire this one in at the tank.
It's rated at 20amps continuous which is just above the walbro400 max current draw.
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05-03-2016, 08:07 PM
#6804
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With a fuel pressure sensor and megasquirt closed loop fuel pump control 
At least that's the idea. Territory is somewhat uncharted.
At least that's the idea. Territory is somewhat uncharted.
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05-03-2016, 08:28 PM
#6806
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Scratch that. Not using closed loop. Just open loop. Probably with a few different set points.
Also not using that relay. Revisited some other threads and will be using a MOSFET.
Also not using that relay. Revisited some other threads and will be using a MOSFET.
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05-03-2016, 08:47 PM
#6807
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Is this in place of a mechanical regulator, or in addition to?
If it's in place of a mechanical regulator then I think you need closed loop, otherwise, changing voltage will change fuel pressure.
--Ian
If it's in place of a mechanical regulator then I think you need closed loop, otherwise, changing voltage will change fuel pressure.
--Ian
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05-03-2016, 09:05 PM
#6810
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Walbro 400. 1.**** making no horsepower. i don't need the thing running full speed all the time. I'm already going to be rewiring it back there so i'll use a solid state relay instead of a normal relay.
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05-03-2016, 10:07 PM
#6811
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Ok I revisited some of the Hella data sheets and its basically a mosfet with a heat sink, and a normal socket compatible pinout. So I will be using that.
The standard fuel pump relay is a positive control relay, which uses the AFM 12v signal. Which we jump at the AFM connector. And then the megasquirt output grounds the relay.
This will be different. I will still use the signal from the megasquirt, but I will jump the wire from the megasquirt directly to the fuel pump wire that goes to the tank. That will give me a signal wire for the solid state relay.
The relay will be wired directly to the battery and fuel pump with 10 gauge wire.
I will use the open loop pwm control. Find the minimum duty cycles that I can hit my desired fuel pressure at, and then add a bit of duty cycle to be on the safe side.
The standard fuel pump relay is a positive control relay, which uses the AFM 12v signal. Which we jump at the AFM connector. And then the megasquirt output grounds the relay.
This will be different. I will still use the signal from the megasquirt, but I will jump the wire from the megasquirt directly to the fuel pump wire that goes to the tank. That will give me a signal wire for the solid state relay.
The relay will be wired directly to the battery and fuel pump with 10 gauge wire.
I will use the open loop pwm control. Find the minimum duty cycles that I can hit my desired fuel pressure at, and then add a bit of duty cycle to be on the safe side.
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05-05-2016, 10:30 PM
#6814
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Track day was awesome. Car+driver was 3 seconds faster than October. And I only drove one event between now and then. Combination of tires, suspension, and a couple more cajones. I did a 1:33.6 last summer at full boost, and beat that today at low boost.
Had a blast chasing @oregonmon in his VVT swapped NA, at low boost I didn't pull very hard on him at all, maybe 75% throttle.
October
Today
Had a blast chasing @oregonmon in his VVT swapped NA, at low boost I didn't pull very hard on him at all, maybe 75% throttle.
October
Today
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