Whats your fuel temps?

[Predator1]

What fuel temps do you guys see? I have a bosch twin sensor on my reg, and I've seen a max ever of 52C. Average of around 45 when cruising. I dont run a surge, with -10 feed and -8 return. Seem a bit high??

[Dose Pipe Sutututu]

On the track (as in a circuit not a 400 straight line) I've seen my fuel temps go above 65 degrees after 10 laps of Wakefield.

Day to day driving around town probably 30s to 40s, mind you I run PWM so both pumps in the surge are duty cycled. The DW200 lift pump however is just on factory wiring with the resistor deleted.

And no your fuel temp isn't that high.

[BK]

Not high at all. In the NT until I staged my two 400lph AEM external pumps with twin -8 feeds from surge with AEM 340lph in tank pump I was seeing 70 - 75 on the highway, ambients were above 40 though. After staging the 400s the temps came down under 50.

On the other 32 with PWM we had similar reduction in temp as Johnny suggested on a single Walbro 525lph pump.

[Predator1]

I forgot to say, that I run twin Walbro 285 pumps, and they are already staged via PWM. Max DC on the pumps is from memory under 80% even at under 100% tps.

Thinking of adding the Setrab fan assisted cooler.

[GTSBoy]

On 3/28/2022 at 9:23 AM, Predator1 said:

Thinking of adding the Setrab fan assisted cooler.

I wouldn't bother unless;

• You're having fuel temp related problems that you didn't mention, or
• You're going to change the way that you use the car that could/would lead to heat either increasing or being more of an issue, or
• You like introducing more points of failure.

[Predator1]

Yeah well I do have ect temp issues. Low speed it wont come down as fast, and at idle it will creep, even with a 2100cfm AC fan(Aux), so it feels like the fuels also heating up, hence this thread.

[Dose Pipe Sutututu]

I would not stage the pumps and duty cycle them together and ramp them up based on MAP (as the load axis).

At 100hz, the Walbro 450/460s don't like any duty under 40% they start to make an awful hum, however any higher they seem ok!

I suspect your pumps wouldn't be too far off that.

Part of the problem you have is 1x pump is always at full filt _ your lift pump. They're heating up your fuel unnecessarily. 

 

Also, if you have proper injector data and fuel data i.e. fuel temp vs fuel density vs. ethanol then there's no real issue with warm fuel.

This is how I've done mine (note must tuning shops will not do this, as customers don't pay them enough for their time - Link and MoTec have this predefined).

[BK]

On 28/03/2022 at 12:47 PM, Dose Pipe Sutututu said:

I would not stage the pumps and duty cycle them together and ramp them up based on MAP (as the load axis).

At 100hz, the Walbro 450/460s don't like any duty under 40% they start to make an awful hum, however any higher they seem ok!

I suspect your pumps wouldn't be too far off that.

Part of the problem you have is 1x pump is always at full filt _ your lift pump. They're heating up your fuel unnecessarily. 

 

Also, if you have proper injector data and fuel data i.e. fuel temp vs fuel density vs. ethanol then there's no real issue with warm fuel.

This is how I've done mine (note must tuning shops will not do this, as customers don't pay them enough for their time - Link and MoTec have this predefined).

I used your fuel density table you sent me and put it in the Elite before Simon tuned it at Morpowa last year, very handy 👍

[Dose Pipe Sutututu]

On 28/03/2022 at 2:23 PM, BK said:

I used your fuel density table you sent me and put it in the Elite before Simon tuned it at Morpowa last year, very handy 👍

no more silly AFR hunting at idle, regardless of fuel temp or big injectors  

Haltech is great, provided it's used properly.

[Predator1]

 

Funny you mentioned the hum noise, cos mine makes that too. I noticed in the logs stats, from memory my max Inj DC is around 38%.. So judging by that, my FP's sitting under 70%?? I think with PWM its the opposite?

What's your PWM setup?

 

On 28/03/2022 at 4:17 PM, Dose Pipe Sutututu said:

I would not stage the pumps and duty cycle them together and ramp them up based on MAP (as the load axis).

At 100hz, the Walbro 450/460s don't like any duty under 40% they start to make an awful hum, however any higher they seem ok!

I suspect your pumps wouldn't be too far off that.

Part of the problem you have is 1x pump is always at full filt _ your lift pump. They're heating up your fuel unnecessarily. 

 

Also, if you have proper injector data and fuel data i.e. fuel temp vs fuel density vs. ethanol then there's no real issue with warm fuel.

This is how I've done mine (note must tuning shops will not do this, as customers don't pay them enough for their time - Link and MoTec have this predefined).

 

[Dose Pipe Sutututu]

Interesting you've done yours off injector duty cycle, though not wrong it's interesting (to me that is).

Here's mine:

[Predator1]

Whats your PWM setup?

[Dose Pipe Sutututu]

On 28/03/2022 at 3:17 PM, Predator1 said:

Whats your PWM setup?

ooo I lied, I run it at 200hz

 

It's 100AMP Jaycar SSR, with flyback diodes on each Walbro 450L

[BK]

PWM on our white 32 GTR with the Walbro 525 pump. I run the same as Dose pipe with a Haltech / Kudom SY4086 100A SSR, but at 150HZ.

[Predator1]

On 28/03/2022 at 5:30 PM, Dose Pipe Sutututu said:

ooo I lied, I run it at 200hz

 

It's 100AMP Jaycar SSR, with flyback diodes on each Walbro 450L

Ah yeah so mines at 250hz, doubt that be an issue. The tuner didnt stick flybacks on my SSR which I always was a bit dubious about. I run the 100A SSR too. 

[Dose Pipe Sutututu]

Look at us, all so modern  

Love it - running all pumps full tilt all the time is stupid!

[Dose Pipe Sutututu]

On 28/03/2022 at 3:38 PM, Predator1 said:

The tuner didnt stick flybacks on my SSR which I always was a bit dubious about

You need flyback diodes, if not your SSRs would be ripping hot and will fail with time.

[BK]

On 28/03/2022 at 2:10 PM, Dose Pipe Sutututu said:

Look at us, all so modern  

Love it - running all pumps full tilt all the time is stupid!

I'd like to PWM the blue 32 with the twin 400 pumps, but can't be stuffed so it will stay staged. It works perfectly and probably draws less current than PWMing 2 pumps simultaneously. PWM on the primary external and keep the secondary staged if I can be bothered would be the go.

For Predator1 - absolutely use a flyback diode as above. I like the 1N5404 at 400v / 3A for a bit of overkill.

[Predator1]

Thanks guys. I'm just concerned about my tune. 

So safe to just stick 1 flyback across the SSR terminals that go towards my pumps? I think both pumps get their positive from the SSR. I'll have to double check.

[BK]

On 28/03/2022 at 2:26 PM, Predator1 said:

Thanks guys. I'm just concerned about my tune. 

So safe to just stick 1 flyback across the SSR terminals that go towards my pumps? I think both pumps get their positive from the SSR. I'll have to double check.

The best place for a flyback diode is at the load, so across the pump terminals ideally.

.