Electric Boost for towing? - 1993 F150 4x4 5.8L

E

efloth

New member
Hello! What amazing and fun projects! I am impressed by the results I have seen here so far. I am tempted to try electric boost, but my situation is a bit unique. I have a rig that has a built 351W making somewhere around 400HP at the crank. AFR 165 Heads, Trick Flow stage 1 cam. I have custom tuned the factory speed density ecu myself. I have 80lb injectors and am running e85 through 340lph fuel pumps (front 19gal and rear 38gal tanks)

The truck pulls amazing in nearly all circumstances. The only exception is I regularly tow 7K pounds up a several 15-17% grades. In these situations, I do not have enough gears to run at the ideal 3-4k rpm with the torque converter locked. Unlocking the converter works but shoots trans oil temps over 250 degrees! The cam doesn't really kick in until 3k RPM and in 2nd gear I need a bit more power to climb between 2-3k RPM.

Said grades are several miles long so I would need boost for minutes at a time but rarely. Is that even possible without melting the motor and or wires? I have a bunch of 20ah LTO cells and could make a 20 cell 48v pack. I don't think I need more than a few lbs of boost to make the little more power I need.

I looked at belt driven superchargers but centrifugal would be inefficient to make boost early and the older roots style kits are no longer available. The thought of having boost only when needed is exciting!

Any thoughts or input is greatly appreciated.

Eric
 
A very rough calculation is 1.5kw per L displacement per 1000rpm for 0,5bar boost, In you case that would equate to about 13kw @ 3000rpm for 0.25bar boost (3.6lbs). That will require 270A so I would say that is possible if you find the right supercharger with the right cables and battery cooling. It certainly will be a challenge though
 
Thanks for that math. If I am thinking correctly 20 2.3v 20ah LTO cells would make a roughly 1kwh pack so could run 13kw for between 4 and 5 minutes. The cells have a max 10c discharge rate so may be limited to 10kw discharge which would give a little more runtime.

Questions:
1. Can one castle hobby motor/Hobbywing Esc's handle 10kw continuous for 5 minutes? Would it need cooling?
2. How to properly implement a bypass when not in boost. Are there any good examples out there?
3. I am clueless on if the Speedmaster P-2 would be properly sized supercharger for a lower power/boost/rpm scenario.
4. Since the ford has a dual 61mm throttle body does it make more sense to just go dual superchargers?
 
Not sure if that ESC could handle 300A for 5min you would have to look at the spec
Bypass is not too difficult but does require some engineering and a control system. I made one on my twincharged application (have a look on this forum)
You need to look at the compressor map of whatever you want to use to se if it will be able to handle the airflow and boost requirement.
Your problem maybe finding a suitable motor that can run 13kw continuous and still be small enough. Just need to do some surfing around.
 
300A continuous is in the specs here:
www.hobbywingdirect.com

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Maybe the dual motor or something like this would be cool. https://www.aliexpress.us/item/3256805803418693.htm
 
Do you think this would work for the bypass? Not sure how fast acting it needs to be.

https://www.ebay.com/itm/374878557942

Just to make sure I get the logic:

Under normally aspirated conditions both intake tracts are open (or should sc tract be closed?). When switching to boost the normal air filter tract is closed off preventing boost escape. Is that all there is to it besides timing these events correctly?

I'd assume one could start spooling the SC as the valve is closing as to not choke the engine.
 
If you make a T section upstream of the valve then normal operation it is open and the air will pull from atmosphere and through the stationary supercharger. When you want boost, shut the valve and the ait will only be drawn through the supercharger
 
The motor on that is only 5kW so you would need at least 2 of them, probably 3 to achieve the desired results. Also I am dubious that that system would be capable of running flat out for minutes at a time reliably
 
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