Overboosted steering with hydroboost setup

[cactuss4]

I was trying to figure out a solution and it appears Borgeson has a pressure reducing kit, however since I'm not running a rack (one of the main reasons it was created), I'm not sure if I'm barking up the wrong tree:

12:1 Saginaw steering box
hydroboost
hydroboost capable power steering pump (dual inlets) (so no T's in my system).
Willwood Master Cylinder, brakes, prop valve etc.

Brakes are awesome, I love them!



However my steering is overboosted and I would prefer a bit more feedback or resistance than I'm getting.

I'm slightly concerned that going down my path and reducing the pressure at the power steering pump, may cause me some unforeseen issues.
There are 3 washers and the instructions cite that using all 3 washers will get the pressure down to about 800 or so (I guess perfect for a mustang rack and pinion), but obviously 800 is a bit low for the hydroboost system (I say obviously with a bit of uncertainty if that's in fact true.).

Before I rip my power steering pump apart, figured I would come in and see if anyone solved the overboosted steering with a hydroboost, saginaw steering box. And if I should be looking elsewhere first (there is obviously the adjustment on the steering box (nut and hex), but again not sure if I should touch that

Appreciate the suggestions (but no . I won't get rid of the hydroboost

Thanks
Tory

[D-Man]

What steering box, what pump, and what pump valve do you have?

[dontlifttoshift]

Those shim kits shouldn't exist. I stole this from here. https://www.turnone-steering.com/blo...essure-vs-flow

PRESSURE VS. FLOW
Fact or fiction? There are a lot of myths surrounding power steering and its functions. Most of these myths revolve around the power steering pressure and flow rate settings.In this article, we discuss power steering pressure and flow rate and their respective functions in the power steering system.

There are two distinct functions that the power steering pump is designed to perform. The first function is to deliver a constant flow rate to the power steering rack or box control valve. The flow rate will determine the sensitivity of the control valve when input is applied through the steering wheel. In conjunction with the control valve design, a given flow rate will result in a given steering feel and performance. Adjusting the flow rate is a fine tuning adjustment of the steering system and is not considered an all-inclusive adjustment.

The second function of the power steering pump is to provide enough pressure to assist the driver in overcoming steering load. The pump only builds pressure when it is required to by the steering rack or box control valve. The power steering pump’s maximum pressure should be set at a minimum of 200psi above the system operating pressures. For example, if the system’s requirements are a 1000psi, then the pump’s maximum pressure should be set at 1200psi or above.

Each system is unique and its requirements may be different. This is a generalization of the dynamics of the power steering system to help our customers further understand how the steering system operates. Tuning of your steering system is a delicate matter and should be done only under the guidance of a qualified technician. If you have any questions or need assistance, please feel free to contact our technical service department.

The problem you run into with a Hydroboost is that it wants 2.5 to 3 GPM and most performance steering boxes and racks want 2 gpm. You have to pick. Tell us more about your pump.

Related: The saginaw boxes aren't exactly known for their great feedback and feel.

[groho]

Having recently used a similar tuffstuff kit to reduce my pump pressure for autocross (was percolating the fluid). I can say it does make a difference. It's an easy change, but my suggestion is don't get so aggressive. There's a pin and spring inside the piston that appears to act as a relief and youre changing the pressure point of the valve by extending or shortening that pin and spring. 800psi is a fairly large drop from 1200psi. You're gonna notice it most at slow speed, idle. Don't be surprised if you make more than one attempt to reach the feel you want.

[WallaceMFG]

Call these guys, they can get you sorted out: http://www.jonesracingproducts.com/

We told them about the setup on our car and they built us a pump with the proper flow valve for what we had. They're also one of the few places that actually use new pumps, not re manufactured pumps. Most of the times the flow valve is too big in the pump causing aerated fluid, noise, and sensitive steering.

Our 69 Chevelle has the same hydroboost/ box setup as your car and it drives great. We had our original steering box re-geared to a quick ratio and the torsion rod changed for more road feel. We ended up buying the pump mentioned above from them after having issues with several off the shelf options. They will sell you the proper flow control valve if that is all you need.

[cactuss4]

What steering box, what pump, and what pump valve do you have?

[COLOR=#000000]

Saginaw Jeep steering box 12:1, I don't have a specific model, but I could climb around looking for a PN if required.

ACDelco 20756715 GM Steering Pump
ACDelco 178-0854 GM Power Brake Booster Assembly

Hopefully this helps you point me in the right direction.

Thanks



- - - Updated - - -

Call these guys, they can get you sorted out: http://www.jonesracingproducts.com/

We told them about the setup on our car and they built us a pump with the proper flow valve for what we had. They're also one of the few places that actually use new pumps, not re manufactured pumps. Most of the times the flow valve is too big in the pump causing aerated fluid, noise, and sensitive steering.

Our 69 Chevelle has the same hydroboost/ box setup as your car and it drives great. We had our original steering box re-geared to a quick ratio and the torsion rod changed for more road feel. We ended up buying the pump mentioned above from them after having issues with several off the shelf options. They will sell you the proper flow control valve if that is all you need.

Okay will keep this in my back pocket if I end up being told to get a new pump Thanks!!

Tory

- - - Updated - - -

Having recently used a similar tuffstuff kit to reduce my pump pressure for autocross (was percolating the fluid). I can say it does make a difference. It's an easy change, but my suggestion is don't get so aggressive. There's a pin and spring inside the piston that appears to act as a relief and youre changing the pressure point of the valve by extending or shortening that pin and spring. 800psi is a fairly large drop from 1200psi. You're gonna notice it most at slow speed, idle. Don't be surprised if you make more than one attempt to reach the feel you want.

Thanks, ya figured if I felt something with 1, I could continue, but was trying to bypass the entire mess piece . (twice) and bleeding the steering (twice)

[D-Man]

Ok, Jeep Cherokee 600 steering gear with GM 2500/3500 pick up pump and hydroboost. Your gear only needs maybe 1200 psi and your pump is pushing 14 or 1500. A non-hydroboost valve, as strange as it might sound, usually works. Like 90% or better. I know because I've helped scores of jeep guys do hydroboost conversions and usually they first try their factory pump with a T fitting. So if you happen to have an old non-hydroboost pump laying around try using it's valve in your 20756715. Don't swap in a non-HB pump though. If the valve doesn't have enough flow you'll know when you try to stop and turn at the same time. Also early valves pre-1980ish won't work as they use a flare instead of o-ring hose fitting. If you don't have a valve or if it doesn't work (no harm/cost in trying) then you can start in with the mods.

[D-Man]

Also, since this is pro-touring after all, how much caster do you have?

[cactuss4]

Also, since this is pro-touring after all, how much caster do you have?

I think I'm running -2 caster., not a ton.

And re pump, ya I've got a non HB power steering pump sitting in one of my boxes. Okay, ya can totally just swap those I guess! Good suggestion, thanks!!

[D-Man]

Yes, you can swap them. Remove the pressure hose from the pump and then unscrew the fitting.
4+ degrees of caster will give you better steering feel, less wandering, less vague, better return to center.

http://www.gmtruckcentral.com/articl...rsteeringmods/
https://www.hotrod.com/articles/1209...ower-steering/

[cactuss4]

[QUOTE=D-Man;1296881]Yes, you can swap them. Remove the pressure hose from the pump and then unscrew the fitting.
4+ degrees of caster will give you better steering feel, less wandering, less vague, better return to center.

Thanks ya, mine is actually +2, can probably increase that (I've got about an inch of shims in each upper A-arm Will take a look after my power steering pump fun. Luckily the one I have in a box is for a 90 pickup truck, so it has the right part I believe, so will try that first before I take things further apart and add washers.

Thanks again
Tory

[cactuss4]

Well the truck pump definitely has a smaller orifice than the one I pulled out. Although smaller orifice in my head, tells me higher pressure, not lower pressure, but based on my reading my initial thoughts are bassackwards. So this may be the ticket. Going to drive and see what it feels like. Was able to do it all in the car actually.

"The larger orifice provides maximum steering assistance while the smaller provides maximum steering feel. If it’s too heavy, increase the orifice diameter; if too light reduce it."

[cactuss4]

Yep that helped. I'll drive it a bit more before deciding if it needs a bit more tuning, but yes changing that def put it in the more acceptable column for sure..

Thanks again!

[dontlifttoshift]

The smaller orifice limits the gallons per minute or the flow. Any increase in pressure will be between the pump and the restriction or orifice. A smaller restriction would raise pressure if there wasn't a relief valve in the system, the relief valve pressure is what you change when you add the shim kit.

[D-Man]

Yep that helped. I'll drive it a bit more before deciding if it needs a bit more tuning, but yes changing that def put it in the more acceptable column for sure..

Thanks again!

Good to hear. Donny is correct the orifice controls volume. You can check the size with index drill bits.
Pressure will only get you so far. To get really good feeling you'll need more caster (usually different upper a-arms) and maybe a different torsion bar in the steering gear. If you notice anything strange with your brakes post up as this is of course a safety issue and a little complex.

[cactuss4]

Good to hear. Donny is correct the orifice controls volume. You can check the size with index drill bits.
Pressure will only get you so far. To get really good feeling you'll need more caster (usually different upper a-arms) and maybe a different torsion bar in the steering gear. If you notice anything strange with your brakes post up as this is of course a safety issue and a little complex.

Yep will do, I'll spend some more time driving and see, but my initial drive around the n'hood, didn't alert me to any negative changes in the brake feel, but I've not really put it through it's paces yet, but I think this was a good change, I'll look at the other pieces next as well. I've got tubular A-arms but a mild alignment, I (well shoot I have the paperwork around here somewhere, one sec (elevator music> ...... AHH here it is, okay not as bad of shape as I indicated

Left RIGHT
-1 CAMBER -.90
4.75 CASTER . 5.20
,01in TOE . .01 in
8.8 SAI 9.3 (no idea what this is
7.8 . Included Angle 8.45

Cross Camber -.10
Cross Caster -.46
Total Toe -.01

So how does that look?

[dontlifttoshift]

Alignment looks good. I wouldn't change a thing.

[Hydratech®]

https://www.summitracing.com/parts/hdt-ps-101

http://www.lateral-g.net/forums/showthread.php4?t=29580

Slalom? Crank it up for max assist / fastest response. High speed road course? Turn it way down. Street / Strip? Tune in as desired. Yes, it adds complexity and expense, but VERY cool to be able to simply pull over and change your steering feel with the flick of a knob.

In your case (since you like the braking actions and only want to change the steering), feed the brakes full power, and then install this valve between the hydroboost and the steering gear (downstream of the hydroboost unit) (to only blow off the pressure / volume the steering gear receives).

[dontlifttoshift]

Nope. I have thrown a handful of those in the garbage. Volume is the problem, not the pressure. It was just proven in this thread.

[Hydratech®]

Hmmm.... sorry I posted... you guys already have all the answers...