Power steering delete question

[priapism]

So I disabled the power steering (looped it) and I'm wondering how heavy is normal. It seems excessively heavy--I can barely turn it at a stop, it takes both arms and some body english. I don't worry too much about parking the race car (heh) but I feel like it's dulling my reactions when I have to countersteer in tighter corners.

I opened the rack up and twisted the steering back and forth to drain some fluid, but not all of it. Is this the way to do it?

How heavy is "normal"? Is this normal?

[jlevie]

Without power boost the steering will be extremely heavy when stopped or at low speed. Less so at higher speeds. What you have done makes it as good as it is going to get.

[lambo]

Sounds about right, especially in a track car with wide sticky tires.

[Vivek]

I have 205's and a 330mm wheel. It's heavy at a stop and pretty hard to turn (although possible). As soon as you're moving its much better but you can still tell it's gone (which is what I like).

[KVF]

As others had stated, what you're feeling appears to be the norm. There is a certain appeal to having deleted my power steering for street driving, but it seems like an extremely inefficient way to go around a race track. The additional driver input required to make transitions, tight corners, and intentional oversteer correction is off the charts.

[priapism]

As others had stated, what you're feeling appears to be the norm. There is a certain appeal to having deleted my power steering for street driving, but it seems like an extremely inefficient way to go around a race track. The additional driver input required to make transitions, tight corners, and intentional oversteer correction is off the charts.

That's how I felt about it, and fatigue in enduros. But apparently it sucks up quite a bit of power, and in a spec series you need as much as you can get. Guess I'll be hitting the weight room.

[jlevie]

That's how I felt about it, and fatigue in enduros. But apparently it sucks up quite a bit of power, and in a spec series you need as much as you can get. Guess I'll be hitting the weight room.

There are a number of opinions about the power consumed by the power steering system, but I don't think it is as much as most folks think. Maybe about 1hp max.

On a race car the tradeoff is driver fatigue versus the power loss. I've run my Spec E30 for a number of years w/o power steering, but have come to the conclusion that the increased fatigue isn't worth the power difference and am in the process of re-installing the pump. It may not be universal, but the pro cars I've seen all have power steering...

[priapism]

Last I got out of the car I was thinking I should reinstall it, so we'll see if I still feel that way after we start racing. I don't have direct power comparisons because I did a head gasket and top end at the same time the PS was deleted.

Also, I heard 5hp. That seems excessive...

[KVF]

5 hp does seem excessive. Out of curiosity, I'd love to see some before & after dyno numbers on a pwr steering delete.

[Smelser]

I was thinking in the neighbour hood of 3HP, but on a 100HP engine, thats a 3% gain!! another option is to leave the resevoir and route the hoses to the resovoir, this allows the oil to move freely without any kind of "back pressure" from forcing out of one side and to the other. it moves freely enough to keep the rack lubed and use the fluid it needs.
we race on dirt and I have found that on "rack" cars, the P/S is not needed. however when dealing with "box" cars, the power steering is greatly needed. we have bent a steering colum in the car once (chevy) with the engine off turning the wheels. but it moves so much nice with a rack when your moving, you almost NEVER have to turn the wheels when stopped on a race track. unless you goofed and are geting back on the track, then at that point your lap is screwed anyway.

[jlevie]

I lean towards the lowest numbers just from a consideration of how the system works. When not turning the pump is putting work into the fluid and the pressure relief valve is open and when turning that work is partially used in moving the wheels and relief valve may be closed. In either case the pump is doing the same amount of work (consuming about the same amount of power). If you dump a lot of power into the system then it has to come back out as heat as not much of that work goes into turning the wheels at speed. Since an E30 doesn't have, or need, a power steering system cooler, there must not be all that much work done on the fluid which means the pump isn't drawing all that much power.

I have a recollection of someone actually testing this on a dyno. They made a few runs, then cut the belt. The difference was on the order of 2hp, which is pretty close to the uncertainty of a chassis dynomometer.

[Smelser]

we also pulled the fan and just run an electric. I wonder how much it draws on the engine as well?!?
then add an underdrive pulley and the alum alt pulley. wonder if all 4 would amass to 10 hp or sit closer to 7.
any thoughts?

[jlevie]

The engine fan draws very little power with car at speed and when the fan clutch is good. On a race car an electric fan should have a driver switch and to protect further a thermo switch. The fan is not normally needed in a race. When neither the HVAC nor headlights are operating the alternator power requirement is minimal. Thus on a race car the remaining parasitic draw is primarily the water pump and it may be considerable. Note that BMW and others have gone to computer controlled electric pumps on recent production to reduce that parasitic loss.

As a WAG, I'd suspect the gain from the above being more like 2-3hp under normal race conditions.

[seatown88]

So I disabled the power steering (looped it) and I'm wondering how heavy is normal. It seems excessively heavy--I can barely turn it at a stop, it takes both arms and some body english. I don't worry too much about parking the race car (heh) but I feel like it's dulling my reactions when I have to countersteer in tighter corners.

I opened the rack up and twisted the steering back and forth to drain some fluid, but not all of it. Is this the way to do it?

How heavy is "normal"? Is this normal?

I would drain the remaining fluid. Any although the system is not fully closed the fluid still may be compressing in the rack creating stiffer steering. With a fully drained and plugged rack I have no problem with fatigue during a 30 minute race in my PRO3 car which potentially produces more ultimate grip. Corrections are shouldn't dulled as shown in the video below.

As others had stated, what you're feeling appears to be the norm. There is a certain appeal to having deleted my power steering for street driving, but it seems like an extremely inefficient way to go around a race track. The additional driver input required to make transitions, tight corners, and intentional oversteer correction is off the charts.

I think its more about driver preference. There is a lot of personal opinion out that any you need to figure out what works best for your driving habits. My personal opinion is that I prefer to drive a race car without powersteerning because there is more dynamic feeling in a system without the hydraulic assist to dampen it all. I find that any additional driver input is negligible, transitions and corrections are more precise because of the improved connection between my hands and the front wheels.

The video is from the first weekend out with my car this past year. I was struggling with a poor/no actual setup on the car and played with finding the ultimate grip of the car.


As far as horsepower concerns, I would have to agree with jlevie that the increase in performance is probably not large enough to make much of a difference.

However I also view the powersteering deletion as a method of simplifying the race car and removing a potential system failure that could lead to a DNF

[yeaseth]

Also I noticed when I increased my caster I felt it harder to counter steer as well, and that is with power steering. I ran no PS for about a week just to try it out and it sucked for counter-steering and autocrossing. I like having my PS