E85 & Fuel pressure sensor location LT GenV

[takid455]

Any specific locations needed for these? Corvettes have the Fuel Pressure in the rear. Is there a known optimal location?

Would like to keep them next to each other mainly due to wire routing.

[randy]

My fuel pressure sensor is in the y block 12” after my dual pumps. My e85 se sir is up by the fuel rail. I didn’t want to restrict fuel so I also have a y block at the firewall from my 1/2” feed. Two -6an going off it to each fuel rail and the drivers side rail I have my e85 sensor in line

[takid455]

How restrictive is the E85 sensor? Would something like this be a good idea?

https://www.amazon.com/dp/B08PFCDHHN...Y7FGZ8QMC3XJ68

Are you running a return system/ adjuatable regulator?


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[andrewb70]

Originally Posted by takid455

How restrictive is the E85 sensor? Would something like this be a good idea?

https://www.amazon.com/dp/B08PFCDHHN...Y7FGZ8QMC3XJ68

Are you running a return system/ adjuatable regulator?


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The bypass is a good idea if you are planning on big HP...like over 1000HP

Andrew

[mikels]

http://foreinnovations.blogspot.com/...el-sensor.html

I have run OE E85 Continental sensors in many builds - splitting the -8 (1/2") fuel feed line into dual -6 lines going to each rail and having sensor on one -6 feed line.

Long story short - even without splitting, unless making some very seriously big power numbers, the pressure loss through the sensor is much less than portrayed.

Of course, I am an engineer and from Missouri - so 'show me' data is how I like to operate!

Also - I am a HUGE fan of returnless systems using PWM pump control (Carl @ VaporWorx) and stagging pump(s) as needed for flow capacity. Solves so many issues and has worked flawlessly up to ~1800hp applications on E85.

Fuel pressure sensor (low pressure) should be mounted near the tank (fuel pump outlet) to minimize 'noise' in pressure of system from injectors. Reason OE's put them by fuel sending unit in tank. Flow losses from near tank to by engine increase with fuel flow rate (is actually calibrated into OE systems) but with well designed systems can be kept to very small loss - and no detrimental effects on engine operation.

David

[OLDFLM]

Another vote for Carl @ VaporWorx!

Used his components on a GM fuel module in a Rick's Restomod tank on my Firebird and it's been flawless for over a year since the first start up!

Tuning done by Andrew (@andrewb70) aka DrEFI!

[CarlC]

Thanks to Dave for chiming in on issues that can create bald spots for those of us that have enough hair to pull out.

As port injectors and mechanical pumps (LT engines) open/close they send pulses into the fuel. These pulses (high and low) can be picked up by the fuel pressure sensors, and the PWM control system will react fast enough to chase them, hence creating a wildly changing fuel pressure. The controller is essentially turning completely on/off as it chases the pulses.

Mounting the fuel pressure sensor in the rear allows the flexibility of the lines and the column of fuel to act as a pulse damping system. In rare cases where the pulses/fittings/lines/injectors/etc. all "line up" just right the system still chases the pulses. In these cases a Radium Engineering pulse damper cures the troubles.

We have instrumented the pressure loss in a 3/8"/AN6 typical fuel line system. Using my Camaro as the test mule, there are a total of 14 interfaces from the point where the #1 sensor is mounted at the outlet of the pump and the #2 sensor is in the rail + the length of lines. Datalogging was done with HPTuners with separate inputs that allow for monitoring both sensors and to track them with MAP readings. With about 625FWHP supercharged + CTS-V fuel module, the total pressure loss is 2.2psi at WOT. From an AFR standpoint that delta is hard to measure with commercially available equipment and easily taken care of in the tune.

Why the MAP vs. fuel pressure comparison? MAP changes are the first practical and accurate change in the engine that will trigger a change in fuel demand. For a PWM returnless system the changes in volume and pressure can only occur with a change in pump speed. There are valid concerns that the pump speed cannot change as fast as the engine demand/MAP. From a MAP vs. fuel pressure response standpoint, we have found that it's a non-issue. The electric pumps spin up fast enough that there is no concern with them keeping up with engine demand. We're talking less than a few engine revolutions at 6000rpm for the pumps to track with MAP. This has proven out over the last 11 years with zero feedback from customers/tuners of any kind of lean spike due to pressure drop-off due to reaction time.

[takid455]

Good info.

Compiling data, it seems the pumps can provide fuel & changes of pressure fairly quick. Regarding the alcohol content, unless you do a drastic change (switch 93 to E85), I don't see a huge difference in placing the sensor. Do agree based on research/ data by others, a bypass isn't need unless big power/ very high fuel flow is being made.

Pressure sensor placement seems to have a slightly different impact depending on placement. As Carl mentioned, there wasn't a huge difference in pressure between the front & rear placements. I would say the injector pulsing would have a greater effect. That being said, I'm thinking of running this fellow:
http://www.radiumauto.com/Fuel-Pulse...Kits-P751.aspx

or

https://www.ebay.com/itm/TAARKS-Fuel...-/192917450409


..up on the firewall with the pressure sensor . This will solve the pulsing issue, pressure sensor mount issue as well as a place to run the hard line to and continue with flex house to the engine.

The radium uses MAP to adjust pressure. Looks like that is for boosted applications. For the LT1 w/ fuel pres module, I would leave the port to atmosphere?

If the above needs revising, I'm here to learn.