ptrhahn

Is fuel temperature even a real serious issue? I can't imagine adding all of those (potential failure) connections and vulnerable elements if it isn't causing problems.
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Peter '93: IRP Streetport w/ Turblown BW 8374, Bosch 044, JRZ/Swift coilovers, StopTech BBK, Raceshop rollbar, Sparco EVOs, BBS RGR street wheels, Technomagnesio/CCW track wheels. 440hp/400tq @16psi


When you start to get cavitation at the fuel pump I would guess you notice it and fuel temps become an issue.

You probably have that problem with the '044 if you let the tank level drop to 1/4 tank I would imagine. I did dailying my FC with '044. Of course on track I had to have a full to 3/4 tank not to get starve- so fuel temp wasn't an issue then.

 

It is also very critical on E85. This is some of the reasons why some people do returnless, or semi-returnless systems. To try and cut down on sending hot fuel back to the tank. The fuel loses density the warmer it gets and you start getting vapor issues with enough heat and cavitation.

 

Extended drive time, like hr+ causes pump cavitation from heat in surge tank. This happens on one or both pumps and happened on fuelab and on my 3 rotor.

It's not to the pt where you'd notice it on fuel pressure gauge, but rather you can just hear the pump get much much louder and begin to have noises of passing air.

This is actually extraordinarily common and often overlooked. Many think in tank pumps or larger surges w pumps mounted inside is a solution. Or PWM pump speed. While all of this helps we still can't escape The reality that big engines with aluminum rails right next to downpipe and turbo will carry heat into the return line eventually causing the pump inlets to cavitate. The only way to directly attack the issue is insulate the rails and cool the fuel. Speed control or pump staging can help but the issue still occurs eventually. It only takes 120+ degrees of fuel temp

I want to be able to drive 3hrs or sit in stop go traffic without ever worrying about too much return heat

 

What about the seat of the pants heat? I'm sure a 4" exhaust isn't exactly cool.

 

 

hahahahahah

these are insane. Imagine wearing those to the pool.

 

So crazy how the pumps go nearly completely silent when the overflow to the main tank is slightly squeezed and the pressure is increased in the surge to only 1-2psi

I don't think the extra, high pressure reg. I have here on the shelf would work as the lowest maintainable pressure is 30psi which would affect the base fuel pressure. But with 1-5psi increase by squeezing the return line, the pumps go nearly silent and sound as if they are accelerating, all while not affecting the overall fuel pressure at the rails.

This leads me to believe, that it can only benefit the pumps and further reduce any chance of cavitation or even need for staging during long low load driving by simply adding a TINY bit of pressure to the surge.

I've ordered a 5psi crack-pressure rated check valve to install inline to the tank, to test this out. Probably overkill at this point, but why not go insane. Also need to get around to wiring up the e85 sensor and dual boost a-pump setup so we can go for 20v and major fuel for e85, while monitoring fuel temps.

After this weekend show is over, the flight will be booked for the tuner. Tune and then transmission.

 

If fuel is anything like coolant, increasing the pressure has been shown to increase the boiling point and help prevent cavitation.

 

Lol so used a autozone compression hose clamp, the one with the little hand adjustment ear. Wrapped the hose in a little E-tape, turned it a few times, and can manually dial in the surge tank pressure. set it to 3psi, pumps go from scream to nearly inaudible! Can't believe the difference. Uploading a vid soon.

Anyone having loud or cavitation issues on a surge tank must do this.

 

This solution has been posted on the forum before. I believe he has posted in this thread actually. Has a repu and solved his cavitation issues years back by slightly adding pressure to his surge tank using a low pressure regulator

 

I don't think I saw how the fuel is plumbed, but bout a heat sink in the rear of the cabin/trunk instead.
Picture
http://www.radiumauto.com/Assets/Pro.../20-0221_2.jpg

Product Link
High Flow Fuel Filter Kits

 

Here's the link for the 3psi FPR.


Although I must say I do prefer your autozone hose clamp idea. same thing in theory

 

Yes sir, thats exactly the guy (kevinbtz) on here. So glad he discovered this. He's using a 044 making nearly 550rwhp. He was having fuel pressure drop at high rpm from cavitation in traffic. I just hadn't had a chance to hook something up to keep the pressure increased for long enough to see the before/after affects

 

Def thought about a regulator, but I've found a check valve that should open at 5psi which should keep pressure there without being as cumbersome as another regulator...we shall see

 

can anyone link me or show me how you would plumb in a FPR for the surge tank?

thanks

 

I suspect the fuel pumps are "running at the end/right of the curve". Which means they are running wide open with little load on the motors despite being regulated. They are bypassing a lot of fuel.

By adding a restriction in the return line, you are raising the load on the motors and moving your operating point on the pump curve up.

Try measuring the amps on the motors before and after the restriction is in place.

https://www.slideshare.net/bin95/143...psonendofcurve

These rules apply to centrifugal and positive displacement pumps.

Note comments about heat and cavitation.

 

The return line is not the same return coming from the rail, its just the overflow line out of the surge tank back to the main fuel tank. By restricting this return line ever so slightly, the surge tank is now pressurizing, which is the same as pressure-feeding the inlets of the 044 type pumps.





This is from a vendor's website, on recommended installation of the 044. So it seems to me the people with super loud 044's (aem 380 is same type of pump), is because the pump is not designed to scavenge so much as its made to push fuel.

 

 

So this is the issue you thought might be the cause of my pressure drop on my 20b. Seems more like a high rpm issue? Am I wrong? My pressure just completely drops off as soon as you touch the throttle? Would the issue be resolved after everything has cooled back down? If so not my issue.. It was same deal next morning. I have not had a chance to check it out though yet as engine is out. I was wondering if it could be a fuel tank breather issue? Blocked or one way valve wrongly fitted when it was all replaced maybe? Anyway.. All in my own thread discussion.. If anyone has any points to make!

 

This isn't that severe. Yours sounds like bad filter and or clogged pre-filter

 

Update on fuel system:

Ran it for over an hr last night. Pumps are super happy!

 

"the surge tank is now pressurizing"

???

 

yes sir dialed in at 5psi, which pressure-feeds the pumps. I gotta get this before/after video made, its so crazy the difference between 0psi, and 5psi on the sound of the pumps

 

First shot of the splitter with wheels down.

Ready for the drive to its first show.

Front is raised way up, lowering it back down when it arrives

 

mazzei,
#1:
do you have more details of the front splitter?
I am curious which materials, mounting, etc. you used.


also, #2: I honestly can't read through 45 pages to figure it out, but this is going to be a track car IIRC, so how do you plan to keep the IATs in check with no intercooler? meth? I'm sure you already have this accounted for, as you're ripping on the car now, but I was wondering. every FD track car I've seen has had issues controlling the IAT (including my two previous FDs with various setups)