Switchable power steering idea
 

Hello. I found this forum by chance the other day and I have to say I'm very impressed with the level of knowledge and experimentation. I hope to learn a lot from everyone here. After losing the PS belt on my old volvo the other night, I had an idea for switchable power steering. The PS pump in this car runs off a V belt from the crank. When the PS belt let go, I couldn't tell any difference in the amount of steering effort at anything above 20mph. The pump has a built in bypass for just such an event. But at a standstill its almost impossible to turn the wheel.
This gave me the idea to use a electric clutch type pulley from an AC compressor on the PS pump hooked up to a switch in the dash. This would allow me to turn off the parasitic drag from PS pump when cruising on the highway or any other long stretch of road, then switch it back on when I get into low speed city traffic or maneuvering around a parking lot. I could swap in a complete manual rack from an older volvo but I really don't like the 4.5 turns lock to lock with the giant steering wheel. My 95 dodge neon has manual steering with 4.0 turns which I don't mind so much because its a much lighter car. The PS rack in the Volvo 240 on the other hand is only 3.0 turns lock to lock with very precise and weighty feel.
A couple of articles I read on electric power steering all claim 5% improvement in fuel economy over conventional hydraulic PS. I think this modification could accomplish the same thing. What do you think? Has anybody else tried this?

This volvo 240 has been converted from a fixed fan to electric cooling fan, a large rear belly pan and all synthetic fluids. It currently gets between 20 to 26mpg with a 4 speed automatic (non lock up torque converter). EPA rates the car at 18/23 with automatic transmission. As soon as the weather warms up I'll be installing a 5 speed manual transmission I have sitting in the back yard and swapping the 3.73 differential for a taller 3.31 ratio. If i can get the volvo to 25 city, 30 highway I'll be very very happy. Anything more will be icing on the cake. I'm also considering a light pressure turbo since the parts already exist for this 4 cyl engine all over the junk yards. The stock 2.3 litre NA red block engine makes a pathetic 114hp with very healthy low end torque.
I already have base 95 neon with no PS or AC which routinely returns 35-40mpg so I don't need to get too crazy with the volvo.

The 2 speed electric cooling fan came from a later volvo with relays and temp switch in the lower radiator hose. Its an extremely reliable and quiet system.
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On the right you can see the PS pump pulley in question. The AC compressor pulley is just below. I removed the AC belt because the system is leaking. The old viscous clutch type fan was mounted directly on the water pump pulley.
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Volvo started using aerodynamic (sort of) belly pans under the engine over 30 years ago. This design could be substantially improved with a completely flat sheet of aluminum from the air dam back to the front cross member.
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I fabricated this rear belly pan out of an old plastic floor mat, the kind you under wheeled office desk chairs. Its ugly but effective. On my volvo 960 wagon it increased mileage from 25 to 28 highway tested over many many long road trips at my usual 70mph cruising speed. Very effective and cheap. Despite being a 3500lb, 6cyl 200hp,automatic, the 960 is blessed from the factory with 3.31 locking differential, lock up torque converter and a 10.7:1 compression ratio on 87 octane. The engine runs 2000rpm at 60mph. City mileage can fall as low as 17 mpg when I really step on it.
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Junk yard 5speed ready to go into the 240. Total cost with pedals, driveshaft, flywheel, new clutch and other ods and ends = $250.
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Welcome, tjts1. Looks like you have some good ideas yourself and not afraid to dive in. We can use that around here. I am a 3 month memeber of GS myself. Have you posted your Garage and Gaslog info yet?

I don't really keep a gas log because it doesn't vary that much. I can pretty much predict what kind of mileage I'm going to get based on what kind of driving i do over the span of one fill up. Also I don't really drive for efficiency although I do like to keep my cars as efficient as possible. I still do the math at every fill up (odometer miles/gallons at the pump) just to make sure everything is running properly.
The 240 came with mud flaps are all 4 corners from the factory. Do mud flaps have a significant affect on highway mileage? I live in California where we don't see any snow and little rain. The drag coefficient of the Volvo 240 is .40. The 960 wagon is a little better at .36.
I think the biggest gain can be had in underbody aerodynamics. Another 960 owner had several hard panels for the belly pan fabricated out of aluminum. The car gets 31mpg with the 6cyl, automatic and 3.73 axle ratio. I hope to do the same.
https://new.photos.yahoo.com/ajspgh@s...60762359627784

some people remove there mirrors on there car for a little increase in fe. so i would guess that mud flaps would help>

tjts1, welcome :)

re: ac clutch switchabe power steering, tricky but doable, if you can fit the ac pully on the PS pump, and It'd be nice to automatically turn it on below 20mph or so but a switch would be fine for starters.

I don't know if the AC clutch will last but a couple spot welds will get the pump turning again :)

Sometimes I miss my Volvo 760, but not as frequently as I used to. That 1984 had the PRV designed, odd-fire, 90 degree angle, wet sleeved, V6 with a whopping 100kw / 134 hp toting around the same 3400 lb brick as your 960. However, it had the same four speed automatic without lock-up as your 240. It averaged 20 mpg (with a one time 27 mpg, all highway, 55 mph trip) but had only an 11 gallon fuel tank. I was stopping each 200 miles to fill-up!
My present Passat TDI does 200+ miles before the needle comes off the 'full' mark.

Ah the Peugeot/Renault/Volvo V6. Quite possibly the biggest atrocity inflected by the French on Swedish people. I'm pretty sure the last PRV powered Volvo was unceremoniously crushed a couple of years back, and the world is a better place for it.

Wow that sounds like a horrible engine/car combination and I've never even heard about it. Probably rates up there with the 3.3l I6 that was optioned in the early eighties mustang.

Keep us updated on the switchable PS. Most co's offer speed sensative power steering via an electric motor or hydraulic system iirc, but this would be awesome for road feel, as well as economy. It can even give a workout by staying off all the time! :D

Nice to see you again. For those here who don't know me, I drive an '89 240 about 600-700 miles/week. I've also done an electric radiator fan conversion, inspired by posts by tjts1 on the Vovlo msg boards.

tjts1, did you consider or do any aero mods under the 240? The rear treatment on the 960 is real nice; I think the very different exhaust layout on the 240 will force a very different rear treatment, if one can be done at all.

For the 240, maybe a second belly pan located to the rear of the factory one?