GM power steering pump to BMW steering box High pressure hose

[TipsyMcStagger]

My original question was specific to a steering box and not a rack. Maybe someone else more familiar with the LS --> BMW Rack interface can answer that.

Yeah, I know. But the thread title you chose is very relevant to my question.

Tipsy

[cooler breeze]

BUMP

The stock high pressure hose has a restrictor. With the fabricated lines we use on these swaps, it's not detrimental to eliminate the restrictor?

In my case, I'll be sending pressure from the GTO pump into the hydroboost unit and out of the hydrobosst to the E36 steering rack.

Tipsy

So can we revisit this a little. I've had my swap running fine for a few years now but i am on my second rack leaking. The first one didnt last long and it only had 110k on it. I swapped in a super low mile z3 rack. All as been fine for about 8k miles but now noticing it is leaking from the boots.
Must be the ls1 PS pump puts out too much pressure and like Tipsy was saying, most people have removed the factory restrictor. I am unfamiliar with this piece in the oem setup. What do you guys think?

[Liquidity]

I use a BMW pump.

[BillyDee36]

Bump. I’m interested in cooler breeze’s question

[AutoRotate]

I used a shim kit on the outlet side of my PS pump. I can't remember the name of the company, but I didn't want an over boosted feeling to the steering. Might help here too.

[TipsyMcStagger]

I used a shim kit on the outlet side of my PS pump. I can't remember the name of the company, but I didn't want an over boosted feeling to the steering. Might help here too.

I'll toss some fuel on this fire because I want to get educated;

After reading that AutoRotate couldn't remember the name of company that made his shim kit, I thought it might have been Turn One. So I did a quick search and the info pasted below (linked here) from Turn One's site was the top search result.

My setup (which might one day actually get on the road) is a GTO LS2 pump and all custom lines with no restrictor.


DEBUNKING THE SHIM KIT THEORY

Ever have light steering effort or twitchy steering? At some point or another, you probably have. It seems that somewhere along the line, a rumor started that the fix to this dilemma is to use a shim kit on the pressure relief valve to lower pressure in the power steering pump. Unfortunately, this is a myth.

Many believe that when a steering system feels over assisted the system has too much pressure and the fix is to install a shim kit. Installing a shim kit will reduce the pump's pressure capacity. However, if the pump's pressure capacity is set below the demand of the steering unit control valve, then the system will not operate properly. Installing a shim kit will require you to reduce the pump's pressure capacity so low in order to get the desired feel at high speed. This would result in giving you no assist under low speed maneuvering because the steering unit control valve demands more pressure. Running the pump under these conditions will dramatically shorten the life of the pump.

In actuality, if your system feels over assisted, it has too much flow. The control valve in the steering rack or box is sensitive to flow rate (GPM). When the control valve receives more flow rate than what it is designed for, it gets overly sensitive. This results in a system that responds too quickly and gives a light or over-assisted feel. The control valve in the steering rack or box essentially communicates to the pump how much pressure to provide the system. As outlined in our "Pressure vs. Flow" article, it is adjustments to the flow that improve your steering feel.

The proper way to gain steering feel is to use a properly sized Turn One flow restrictor. Not only is this an easier adjustment, but it will have no adverse side effects to the life of the pump. A properly sized flow restrictor will make the pump compatible with the steering unit control valve requirements. This will give the driver the desired steering feel without compromising the steering system.

[RulyLSX]

I have a very tiny leak on mine, but mine is due to only have the crush washer on 1 side :P lol need to get that fixed soon

[motorV8ed]

(Posting here as it seems most fitting. I realize it does not help OP's question.)

It seems that most swappers convert to AN-6 fittings and use new, braided or other high pressure line from pump to rack. I just spent a ton of time looking at adapters, hoses, etc. I happen to still have the GM-style high-pressure line. This is rubber, crimped to 3/8" Al hard lines on either end. I don't have the engine in the car at the moment, but it sure looks like the stock GM line will wind up close to the BMW steering rack position. Also, I should mention that both ends of the BMW steering rack have already been converted to AN-6 male fittings.

In the end, it seems to me that all I really need to do is cut off the GM M16x1.5 (I think) fitting, and use an AN-6 sleeve and nut, like that shown below (and construct a proper flare, of course). I can't believe it would be that simple if everyone is converting to braided high-pressure lines. Am I missing something obvious?

Thanks in advance.

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