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MagicMike

CL FP Speed on a return style (regulator) setup?

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Has anyone tried this? Does it work?

Got my pumps running via SSR, and while adjusting FP Speed duty %. I can obviously see fuel pressure (and differential pressure) changing slightly with pump duty with regulator base unchanged from staged pump config. I can turn regulator seat pressure up to keep base pressure same while reducing pump duty.

Which got me thinking about some kind of feedback loop control of pump speed as opposed to open loop control.

Initial thoughts were GP PWM such as below, for argument sake say that 50% gives me 300kpa differential.

59dae41318420_GPPWMsetup.jpg.26453903cc4d4cf18b5fc7028cc7e99d.jpg

59dae4241b36f_GPPWMtable.jpg.9cfab135b5f967b7c58d94d329a41d20.jpg

 

Have not taken this further than the hoist, is it worth spending any more time on? Or closed loop FP Speed an option? Or just stick with open loop?

Ultimate goal is minimum fuel circulation while retaining suitable pressure as demand increases.

 

School me please.

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Andy from adaptronic has a good  video on FPR slope which you may find interesting. 

I messed around with trying to reduce fuel flow all over the map and IMO not worth the hassle. I ended up just reducing the flow to 60%DC at idle and cruise to reduce pump noise. 

Fuel temps still get above 40deg, only way I can reduce this further is to run a fuel pump like the Weldon's. Where the fuel does not run through the fuel pump motor.

 

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32 minutes ago, Ducie54 said:

Andy from adaptronic has a good  video on FPR slope which you may find interesting. 

I messed around with trying to reduce fuel flow all over the map and IMO not worth the hassle. I ended up just reducing the flow to 60%DC at idle and cruise to reduce pump noise. 

Fuel temps still get above 40deg, only way I can reduce this further is to run a fuel pump like the Weldon's. Where the fuel does not run through the fuel pump motor.

 

Yeah I have seen his stuff on FPR's, and his testing is what prompted me to go with the FPR2000.

Noise isn't an issue with the 2 x 460's in tank, it is the temp I am trying to keep under control. So you are just using open loop FP Speed?

Be very interested to hear if anyone has used CL on a return style layout. I can't see why it wouldn't work, but what do I know...

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I would stick with open loop.  In closed loop with a regulator in the mix also I think you possibly could end up with some odd interaction going on under certain conditions.

 

55 minutes ago, MagicMike said:

Possible to show GP PWM DC% in logging? Or only status?

Unfortunately not at present.  It is a common request and I have been pushing hard to get this added though so hopefully you will be able to one day...

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I'm using the FP speed in open loop for the 1st pump and a 2D GP PWM table for the 2nd pump. Using injector DC% as the axis. 

I haven't needed the 2nd pump just yet as Ive got 16volts to the pump.

What's the highest fuel temp you have seen?

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Slightly off topic but perhaps relevant to the intentions of this thread.

I did some tests with a thermal camera, with the fuel pump running and the engine turned off. 

In this case, what heats up the fuel is/was when the fuel flows through the hot fuel rail bolted to the head, and then circulating down to the fuel tank and back through hot fuel rail again and so on.

Which is even worse when you have a surge tank to the fuel rail, which is probably why people think its the pumps making all of the heat.

If you slow down the speed of your fuel pump, and the fuel is flowing slower through the fuel rail then you're still transferring the same BTU of heat. (Half as much fuel flowing for twice the time through the hot rail)

If I leave the fuel pump running with a cold engine, it took something like half an hour to increase by 5 degrees. 

But with the motor running the fuel temperature increases almost immediately. 

Insulating the fuel rail from the heat of the head and I never had fuel temp issues again.

post-5967-0-00828600-1479289556_thumb.jp

Fuel rail is dark blue item near the left hand side after insulating it with thermal paint, and putting plastic washers under the bolts that hold the fuel rail to the head.

EDIT: 

Found a pic of a close up of the fuel rail, you can see the hot bolts (now insulated) against the rest of the rail (darker colour)

xdambpl4.0yl.jpg
 

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14 hours ago, Ducie54 said:

I'm using the FP speed in open loop for the 1st pump and a 2D GP PWM table for the 2nd pump. Using injector DC% as the axis. 

I haven't needed the 2nd pump just yet as Ive got 16volts to the pump.

What's the highest fuel temp you have seen?

In my current config, I have seen mid 50's. Old surge tank/fuelab setup I saw mid 60's!

It would be great to have axis configuration of the open loop FP Speed table, 3D even.

14 hours ago, Davidv said:

Slightly off topic but perhaps relevant to the intentions of this thread.

I did some tests with a thermal camera, with the fuel pump running and the engine turned off. 

In this case, what heats up the fuel is/was when the fuel flows through the hot fuel rail bolted to the head, and then circulating down to the fuel tank and back through hot fuel rail again and so on.

Which is even worse when you have a surge tank to the fuel rail, which is probably why people think its the pumps making all of the heat.

If you slow down the speed of your fuel pump, and the fuel is flowing slower through the fuel rail then you're still transferring the same BTU of heat. (Half as much fuel flowing for twice the time through the hot rail)

If I leave the fuel pump running with a cold engine, it took something like half an hour to increase by 5 degrees. 

But with the motor running the fuel temperature increases almost immediately. 

Insulating the fuel rail from the heat of the head and I never had fuel temp issues again.

post-5967-0-00828600-1479289556_thumb.jp

Fuel rail is dark blue item near the left hand side after insulating it with thermal paint, and putting plastic washers under the bolts that hold the fuel rail to the head.

EDIT: 

Found a pic of a close up of the fuel rail, you can see the hot bolts (now insulated) against the rest of the rail (darker colour)

xdambpl4.0yl.jpg
 

Totally in line with this thread. I have tried nearly everything to insulate all my fuel system from everything hot (cool tubes and heat shields everywhere!), and while I have made some gains, I'm going to have to revisit isolation as opposed to insulation. I will have to have a closer look, but I don't think I can get away with inserting some washers, I fear it will raise the rail too much and unseat the bottom.

20170727_232629.thumb.jpg.5934c6e50b5e80c1337963865e1b91c3.jpg

That is the general idea. Same all under the car and up the firewall etc.

13 hours ago, Ducie54 said:

Mike have see the Injector dynamics PRI videos. Worth a watch if you haven't  

 

Thanks for the link, I watched a couple last night, some good info!

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53 minutes ago, MagicMike said:

Totally in line with this thread. I have tried nearly everything to insulate all my fuel system from everything hot (cool tubes and heat shields everywhere!), and while I have made some gains, I'm going to have to revisit isolation as opposed to insulation. I will have to have a closer look, but I don't think I can get away with inserting some washers, I fear it will raise the rail too much and unseat the bottom.

In my case, the fuel rail is on plastic upstands that hold it up away from the head - But the bolt that goes down through the top touches both the fuel rail directly and the head of the engine. So it was conducting heat through it. If your fuel rail is held in place by anything metal straight from the rail to head then you'll be getting stacks of heat transferred that way.

Not the same situation for every type of fuel rail though I guess. 

Out of interest, is your fuel tank steel or plastic?

A lot of cars that now have factory plastic fuel tanks have a fuel cooler on the return line as they're no longer able to radiate heat out through the fuel tank.

But yeah leaving your fuel pumps running while the engine is off is a way to isolate the temperature increase from either engine heat or fuel pumps etc. 

Thermal camera is a cool toy but a cheap IR gun can still give you some good comparative info. 

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Yes, my rail is held in place with the upper plenum bolts unfortunately. Tank is steel, and I have a ducted cooler on the return line, which is great while the car is moving. My temps are highest when stopped on the side of the road looking at logs etc (haven't ventured out into traffic yet).

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No such luck having room to swing a cat like you!

Seriously considering re-plumbing the return line via the front of the car for some more room, but I am a bit nervous about putting fuel lines in the impact zone.

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I struggled to make it fit. There's 2x 3.5" magnaflow mufflers back there. In a dirty pulsar too

 

Here's a screen grab you may find interesting. Fuel temp into the rail is hotter than the fuel return. BOSCH temp sensor in and ethanol temp sensor on the return tho.

Fuel temp Diff.png

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That is interesting. My logs show the opposite. Oem in rail sensor and cont. flex sensor in the return but before the fuel cooler. Typically 2-5degs hotter on the return. Could be down to different sensor types I guess,  who knows.

In other news, I test drove open loop control of the 2 pumps in parallell 2night (via SSR PWM). Worked well. Laptop went dead before i could try anything else.

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Great discussion.

I usually Setup just a GP PWM table with map vs rpm. 

What's your guys expirience with tuning for fuel temp variations. How big is the influence to the knock limit?

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