electro-hydraulic steering

[hoveringuy]

I briefly mentioned this in the Mk60 post, but when I ran the independent rear brake lines I also ran the 3/8 AN6 tubing for a trunk mounted pump unit (highlighted red). My motivation is that even though I mostly got the PS temps under control at the track and it feels great, 275F is still pretty warm and it will decrease my rack life and it still likes to vent. Plus, having just the alternator as my only belt-driven accessory is glorious! Also, 2hp! (or 5... depending on who you ask)

The front is literally just two hoses that connect the tubing to the rack. So clean!

Still working on the final configuration for the rear, but the AN6 bulkhead fittings pop-up in the corner of the trunk giving me lot of flexibility. I had though of just mounting the pump in the back of the trunk, and I could, but I think I'll take the opportunity to relocated the battery back there (going to an Optima 35 at the same time to save 8lbs...).

I'll have a combination of hardlines and softlines to put the pump in the battery tray. I'll mount it vertically at first, using the stock battery tray, and eventually make it horizontal so it will sit under a cover. (The Mazda pumps work really good for this because they have remote reservoirs) Pictured is a Volvo pump.

I've already got the speed controller circuitry figured-out and it's just a $20 Arduino board that I will upgrade to also respond to Vss.

All of my old front PS stuff, including Chase Base reservoir, pump and brackets weighed like 12lbs, the pump weighs about 15lbs.

This is all un-doable so if it sucks I'll let you know...

[hoveringuy]

trunk..

[Panici]

Subbed for updates.

Have always thought trunk mounted accessories would be great.
Weight off the nose, parasitic drag off the engine, clean engine bay.
Depending on how global warming goes, might explore a trunk A/C setup in my E30 eventually.

Possible to use one of the modern tiny LiFePO4 batteries and squeeze it in there with the pump?

I experimented with one 9 years ago at the track. It was just a bare RC pack with no specific provisions to be charged by a car's electrical system.
Apparently there are commercial solutions for cars available now.
It had absolutely no trouble cranking the engine over.

[hoveringuy]

Panici Yeah, briefly, but a Braille is pushing $6-700 and I don't know how well it would work with a high-draw pump (although the fuel pump draws 8 amps or more, the PS pump is about that at idle and only 15-20 most of the rest of the time)

A 30lb Optima isn't a porker and I can upgrade once the PS is proven.

The Optima mounting tray just bolts to the trunk floor and is easily removable.

I suspect Ill be learning a lot from this and making future adjustments

Love the RC battery!

[Victell]

...Possible to use one of the modern tiny LiFePO4 batteries and squeeze it in there with the pump...

I've considered using a LiFePO4 battery, but putting up front to save weight on the long rear-to-front positive cable.

[hoveringuy]

I've considered using a LiFePO4 battery, but putting up front to save weight on the long rear-to-front positive cable.

yeah, I'm planning on downsizing that to a #2 welding cable. I think the cable was originally intended to allow the car to start when it's -40. It's massive overkill, but it will only save a pound or two.

[moatilliatta]

Waiting on electric AC compressor's to get more popular. I’d love to stash on in the battery compartment.

You could also probably put an anti gravity battery back there also with the pump.

[hoveringuy]

You could also probably put an anti gravity battery back there also with the pump.

What do I need to know about LiPo batteries?

I know a standard trickle charger is wrong, I don't want to invest $700 for a battery to have it ruined for whatever reason.

I mainly don't the "don't use with a lead-acid charger...", but my car is a lead-acid charger!

[Panici]

What do I need to know about LiPo batteries?

I know a standard trickle charger is wrong, I don't want to invest $700 for a battery to have it ruined for whatever reason.

When I looked into using an RC battery pack, my concerns were operating temperature range, charging rate from alternator (charging the batt too fast), balancing individual pack cells, (and perhaps most importantly) thermal runaway.

Here are a few notes from my build thread:

Battery is a "ZIPPY Flightmax 8400mAh 4S2P 30C LiFePo4 Pack" and weights just 2.1lbs!
The rated burst draw is 40C, which works out to 336A for cranking.

Believe it or not, it cranks the car without issue. I took 42.5lbs out of the car by switching to this battery. (1.4lbs of that was for the battery tray and battery expansion box)

The LiFePO4 packs are a lot better then Li-ion and other lithium based compositions [LiPo] for fire/explosion risk, but there is still a risk.

I was testing an unprotected pack meant for a small RC car.
I am making the assumption that these issues have been addressed with a commercial product designed for a car, but I have not followed the technology.
Certainly they give you some idea of what questions to ask of a manufacturer.

[moatilliatta]

It’s not that hard to charge LiPo. Defiantly not a cheap battery,

CTEK - 40-206 MXS 5.0 Fully Automatic 4.3 amp Battery Charger and Maintainer 12V https://a.co/d/aaQoVa7

[Panici]

It’s not that hard to charge LiPo. Defiantly not a cheap battery

The concern I had was over charging via the alternator, and balancing the pack in situ.

Would be a PITA if you need to disconnect the battery from the car to hook up a balancer.

[moatilliatta]

hoveringuy

By the way is that goodridge 910 hose on the soft lines?

How do you like it, a local shop has a crimper for it?

[hoveringuy]

hoveringuy

By the way is that goodridge 910 hose on the soft lines?

How do you like it, a local shop has a crimper for it?

Yes, sir! 910 Aramid.

I send the measurements to Pegasus Auto Racing and get the hose back in a few days.

Quality stuff!

[hoveringuy]

The concern I had was over charging via the alternator, and balancing the pack in situ.

Would be a PITA if you need to disconnect the battery from the car to hook up a balancer.

I've been eyeballing the AntiGravity in the U1 form-factor. It has the built-in charge electronics that monitor cell balance, over and and under charging, temperature and state of charge. It would sit nicely sideways at the rear of my battery tray and I'd easily have room for a pump and a battery, and the combination would still weight 17lbs less than my current battery!!

[Panici]

I've been eyeballing the AntiGravity in the U1 form-factor. It has the built-in charge electronics that monitor cell balance, over and and under charging, temperature and state of charge. It would sit nicely sideways at the rear of my battery tray and I'd easily have room for a pump and a battery, and the combination would still weight 17lbs less than my current battery!!

Looks like a good solution, except for the pricetag. Ouch!


I've used a small (sealed lead-acid) motorcycle battery in my Miata before.
It was able to crank over the 1.6L I4 in the summertime, but not nearly as strongly as a regular size battery.
Miata also has very low electrical draw, whole car has a total of 17 fuses (including the main).

I can't see that working for a six cyl, and especially since you'll be adding electrical load.