Never ending fuel pump drama

[GTSBoy]

2 minutes ago, cabramatta said:

I'll chuck a clamp meter on it at the same time and figure out whats happening at different settings to get a good understanding.

Clamp meter will probably tell you lies. PWM DC looks a bit like AC (because the voltage is going up and down rapidly), but it is not AC because the voltage never goes negative and the current never reverses direction. But because it looks like AC, and it is happening at high frequency, at can cause wierd reactive effects. Just be warned that you might learn things that are....confusing. Because they aren't necessarily real.

[MBS206]

23 hours ago, cabramatta said:

Appreciate the detailed response! It's all new technology to me and your suggestion for reducing DC and finding sweet spots seems like a great approach.

 

I'll chuck a clamp meter on it at the same time and figure out whats happening at different settings to get a good understanding.

 

Will report back with my findings when I get around to it to help anyone in the future that will be in the same situation as me 😁

Clamp meter is pointless.

Unless you're trying to keep average current under a set value for some weird reason (maybe you undersized your wiring?), then you'll get no useful info.

What you're really trying to target is the flow of fuel coming back to the tank.

You want some, but not a lot.

You also want to make sure fuel pressure remains stable.

 

So, fuel pressure gauge, and fuel flow gauge.

Set it up from that.

[Dose Pipe Sutututu]

This is what I've done, add DC until it meets my fuel pressure requirements and above 4500 at over 1bar of boost, I send its mum with 100% DC to both pumps.

I'll post up a table soon when I'm free.

[Dose Pipe Sutututu]

I remembered wrong, but was close though

1Kz setting because those Jaycar SSRs don't go any faster, 1x pump per SSR with flyback diodes & heatsinks. In saying that, the heatsinks are overkill. Just on an alloy plate is more than sufficient. You'll find without a flyback diode, your SSRs will heat up big time and also die prematurely. 

I've been running the two same SSRs since the last motor, no issues, car does 2 hour straight drives in summer once in a while and gets punished on the track. Nothing melts, no hot messes, etc.

 

 

[Predator1]

20 hours ago, Dose Pipe Sutututu said:

This is what I've done, add DC until it meets my fuel pressure requirements and above 4500 at over 1bar of boost, I send its mum with 100% DC to both pumps.

I'll post up a table soon when I'm free.

Hows your fuel temps? I had big issues with fuel temps running 2 285's.

[Dose Pipe Sutututu]

13 minutes ago, Predator1 said:

Hows your fuel temps? I had big issues with fuel temps running 2 285's.

Driving around town in summer, probably like 50°C tops.

Went for a 2 hour drive before in summer, somewhere in the 60°C

Mind you, I have 3x fuel pumps. 2x 460L 1x DW200

[Predator1]

7 minutes ago, Dose Pipe Sutututu said:

Driving around town in summer, probably like 50°C tops.

Went for a 2 hour drive before in summer, somewhere in the 60°C

Mind you, I have 3x fuel pumps. 2x 460L 1x DW200

Toasty! I was around the same. Around 50 but with a fuel cooler. Got my tuner to dial down the pumps and its so much better.. i think last time I drove it was around 35-40 during summer. PWM makes a huge diff. I have the 1 PWM controller running my feeds.

[Dose Pipe Sutututu]

I'm going to run hard lines front to back in the future.

That should help dissipate a bit more heat.

If not, a fuel cooler might be next