Comprehensive Steering Information Thread

[Bry5on]

If the pulsation were associated with the hose expanding and contracting:
1) I’d expect it to be such a high frequency that it would be hard to notice and
2) you could mitigate it by putting the restrictor closer to the pump/hard line

Given that you can feel it, my guess is that you’re feeling the pressure regulator open/close. It’s a bit of a gamble, but you could try the reverse of shimming the pump regulator to force it to operate at a bit higher pressure, though you’d change the assist level.

[heinzboehmer]

Car is now aligned and everything is bottomed up. overall it is a nice upgrade, however, I had spoken to soon and there are some pulsations when you are close to 70% of the track travel to either side.

In the M3cutters forum there are some details about the fix LPSR came up with, it explains why 02'topaz is having heating issues. They are adding a secondary restrictor within the high pressure line, not sure where, but this would limit oil flow which will create extra heat and slow down cool down in heavy duty such as track or auto-x.

The pulsations are not bad, but are noticeable to any enthusiast, that said, the feel of it is so nice, that right now it is not enough of an issue to put me off. I still have my OE rack and can go back to it at anytime.

Maybe in my case the modified line is ok as I don't track the car, and the fix maybe ok for street and even canyon road usage (question mark on that one), however, I am not convinced the pulsations are a problem perse.

From what it was stated on the other forum, the pulsations come from swealing and contracting of the hose, I would need to look into this from a fluid dynamics point of view, and rather than a restrictor, a slight different diameter, or even a braided line design may also solve the issue, even a different length and routing can be alternatives to explore.

Since the pulsation does not happen during normal driving, I don't think this is an issue, however, I can see this being a problem if you auto-x the car as the rapid wheel movement will result in flow disturbance.

LPSR is in Australia, right?

I wonder if LHD vs RHD has anything to do with this. Length of the hydraulic lines is different between the two, so the resonant frequencies should be different as well. Maybe not as noticeable in the RHD cars?

Besides tuning the resonant frequency of the hydraulic lines, changing the diameter of the pump pulley could drive the frequency into a range that's unreachable during normal driving. Unsure if you could keep the pulley a reasonable size though, some math needed here for sure before continuing with the speculation.