Alec,


After the first test I pumped them up to 38 PSI on the front (whilst still hot)

This made the steering a little less pointed and induced understeer but I was at least not sweating after the third run on the next test!

My steering column has a little play in it which probably doesn't help as it must wind up a little.

Other option I guess is roller top mounts - though I don't know how much advantage these really give and are quite pricey.

PAS rack without the PAS? That's what the rally cars had - might have to start going down the gym, or driving the car more!


James

What you need is a quick manual rack and lots of bhp , LSD and narrow rear tyres so you can steer with right foot

I've got a Spit ratio rack in there at the moment

The slaloms were unfairly tight and I don't think LSD would have helped - everything else was fine - but the slaloms were almost impossible in the big saloon without PAS - had to go at walking pace.

LSD would nice - FTD car had as LSD and you could see it helps a lot.

Hello James,

is this car predominately a road car with the occasional bit of competition use? The problem with making a car suitable for, such as Autosolo is that it makes the car more uncomfortable for road use. I'm sure the steering geometry could be altered to lighten the steering (less castor maybe?) but would compromise normal road steering.

Incidentally I usually run at 35 psi on my road car.

Alec

It's like I've always said, a big saloon with PAS is far nicer than one without.

The power assistance coupled with the quicker ratio rack makes the car a lot more agile. A Triumph PAS set up in good condition should feel lovely, a knackered one will be horrid.............

The column mounted ones would be a lot of work but just using an electric motor to drive the Triumph pump may be a good option?

I'm sure the hydraulic pump must eat a few horsepower and some moderns (Honda, Vectra, Astra) use a normal PAS rack, but with a electrically driven pump.

Bingo! An PAS pump that you can switch off! And get those horses back.

I know nothing comes for free and the current drain when using the pump will be high. But maybe if you're only using the pump for parking, a larger alternator (and the extra HP it uses)
won't be needed?

I believe these pumps, however, run at a much lower pressure, around 120psi. I wonder what effect this would have on the assistance?

Has anyone any experience of using a PAS rack without the hydraulics?

The other advantage of using a electric pump, is that it can fitted anywhere (or almost!)

What do you think?

The rally cars used PAS racks without the power.

I bet they are pretty damned heavy!

The idea of turning it off certainly appeals.

I am pretty sure they produce more than 125psi... I think its more like 400-500 - which sounds scary to me.

If you just disconnect drive to the PAS pump won't you be working against hydraulic pressure? Certainly when my rack pipes sprung a leak on a journey and hydraulic fluid was spraying out everywhere, I just cut the drive to the pump with a knife and carried on - trust me, I needed arms like Arnie just to turn the wheel, even at moderate speed. It was bearable at anything above 30-40 miles per hour, but below that was a nightmare. At parking speeds it was next to impossible.

If the rally cars used non-powered PAS racks then they must have been sans pump and hydraulic fluid I'd have thought.

If you simply add an electric motor and associated bracketry, you still need to keep the pump, rack and pipes, therefore you'll be adding weight. The net result might well be a reduction in performance.

The electric pump will replace the engine driven pump, shouldn't weigh more than a few pounds over the old engine driven pump.

As you say, over about 30 mph, the PAS isn't needed, so a pump you can switch off and only use at parking speeds will free up some horsepower.

And my understanding is that a engine driven pump takes 5 or more hp, even when you don't need the PAS, i.e. when driving down a motorway!

I know the ecomodders (people who mod cars to give max fuel economy) throw away the engine driven PAS pump ASAP!

Andy

And then I can fill the space left by removal of the engine driven PAS pump with a supercharger!

Just got to have a nice win on the Lotto first!

Andy