Pirate4x4.Com : 4x4 and Off-Road Forum

Pirate4x4.Com : 4x4 and Off-Road Forum (https://www.pirate4x4.com/forum/index.php)
-   General 4x4 Discussion (https://www.pirate4x4.com/forum/forumdisplay.php?f=16)
-   -   The 4500 steering that won a national points Championship (https://www.pirate4x4.com/forum/showthread.php?t=2183906)

jr4x 10-28-2015 10:58 AM

The 4500 steering that won a national points Championship
 
I know there is both a go fast steering thread and a recent thread inquiring about our steering. We have been hounded about our secret steering all this year so I am about to drop the secret, but first. In previous years racing we were breaking 1 to 2 steering boxes and pumps per race with a traditional ram assist steering setup. After racing a season with both Ultra4/DirtRiot and getting on the podium 6 times in 8 races. This year we did all that on the same parts we started the year with at KOH.

I am going to start by giving credit where credit is due, this thread is going to be long winded so if you don't like it hit the back button now. I have waited to do this because there are going to be people arguing against what I am saying despite the fact that I can prove what I am saying works. I wasn't willing to start this thread until I was good and ready to field such retarded comments as "but so and so said this" I don't care what any one has ever told you, it may very well have been wrong. The most important information I got in all of this came from Hydrodynamic right here on pirate. I have had long conversations with Jeff from Howe, Tom Allen and Lance Gilbert with PSC. Hydrodynamic (name is Jeff) was the one that could explain to me what I needed to understand. The thing I couldn’t wrap my head around was that a servo is not an orbit valve, but provides the same hydro service via a differential pressure between mechanical input and mechanical output forces.

The class we race in requires a mechanical connection between the steering wheel and the wheels, no full hydro. Our very first desert race ever was the 2012 KOH Every Man Challenge. While in 3rd place in that race the Scrambler broke its first of about 15 steering boxes with hydro assist that lead me to the end of the earth and back on all things steering. I have been working on a solution to regular hydro assist for about 4 years. We were at the Ultra4 Reno National Finals last year and broke another box on the front row in our prelim destroying our chance at a podium. Later a friend of ours Clay Gilstrap ran one of the fastest qualifying laps in 4400. Where he hit a rock so hard as to explode a tire, the tire balls, and a forged Method wheel. Without damaging any of the rest of the car. His is a Tribe4x4 built IFS rig with a Howe trophy truck rack. It occurred to me that the IFS rack is literally just a different configuration of ram assist. I began by reading the whole go-fast steering thread and anything ram assist related I can find. After talking to all the big steering manufacturers I decided to abandon traditional ram assist for our race car. There are people racing and doing well racing with regular old ram assist but for us it had to go. I wanted to figure out how to get the power of full hydro while staying class legal with a real mechanical connection. The willy’s race truck had been built around the steering in the first place so we kept our box and just modified it.

http://i268.photobucket.com/albums/j...ps99f1a8bc.jpg

A power steering box is a small ram assisted rack & Pinion unit all by itself. The rack doubles as a ram shaft as well, the pinion being the sector shaft, the box having its own steering servo on the input side of the box. There is a tiny little port that runs the length of the bottom of the box from the front of the piston to the servo. For the piston to move forward all the fluid in that cavity has to return to the servo through about an 1/8th inch hole several inches long. This hole cannot be adequately opened up where other ports in the box can be. In an event where the vehicle plows into an immovable object at speed the wheels trying to move the internals of the of the box faster than fluid can evacuate the small port leads to a momentary hydrolock event and leads to the sector shaft twisting off, or breaking the teeth off the sector shaft.

http://i268.photobucket.com/albums/j...ps0f3e75bd.jpg
http://i268.photobucket.com/albums/j...ps83717b5e.jpg
http://i268.photobucket.com/albums/j...ps6b9a1e39.jpg
http://i268.photobucket.com/albums/j...pse62c01fe.jpg
http://i268.photobucket.com/albums/j...ps4bd49976.jpg


The secret is don't bother calling sweet. Call Howe. Sweet specializes in circle track and street setups meant to run a maximum of a 1 inch rams. Howe buys servo's from sweet and modifies them. The whole trick is three parts that are volume matched to each other, the pump servo and the ram. These 3 part numbers are all the right size for perfectly smooth 2 1/2 turn lock to lock steering. I use PSC for the pump but Howe sells an equivalent one, we have ran both. But the modified PSC pump in this application is $200 plus the pulley and works fantastic. With this pump and servo the Howe ram requires more fluid displacement while creating the same pounds of steering force on the steering knuckles. Howe's 2 1/2 inch rams have smaller shafts which means more fluid displacement. This is the servo that Howe uses on the trophy truck rack. A friend of ours bought a stock servo straight from sweet to run in conjunction with a cable setup similar to the poison spider 4500 rig from the first EMC, and it doesn't work right. So even though its 200 more dollars from Howe than from sweet it really does matter. This is what we won the national points championship with and I insist it’s amazing. You will have to figure out the pulley size you need for yourself. We run a ford engine and our crank pulley is about half the diameter of an LS crank pulley.

Pump part number SKU #: PSC-SP1200X-8-12
TC series Extreme Duty PS Pump-SP1200X : Pump Systems and Components, Universal Pumps | PSC Motorsports - performance steering components

Ram part number SKU #: SCX2212K1
XR Series 2.5" Double Ended Race Cylinder | PSCMotorsports.com performance steering components, power steering

Servo part number P# - 725 with a 200# torsion spring
Control Valves | Parts Categories | Howe

http://i268.photobucket.com/albums/j...psqhw4gk43.jpg

86chevyjoe 10-28-2015 11:17 AM

Awesome!!!! Thank you for letting us in on your success :smokin::beer:

Juicysluice 10-28-2015 11:36 AM

Thanks for coming out of the closet! Being from a dirt track background, I fully understand how your system and the components work. Really there's not much to have to wrap your head around concerning the basic function of each part. I dig it.

Bebop 10-28-2015 11:48 AM

Awesome tech !

Thanks a lot for sharing.

jr4x 10-28-2015 11:49 AM

Next up is pumps. The P in P pump is for POS! A lot of guys already have p-pumps and don't want to change them. There are a lot of reasons you shouldn't waste your time with one. Less PSI and less GPM first. Second is the shaft bushing. A p-pump doesn't have roller bearings for the input shaft where better pumps (any pump is better) have roller bearing inputs. The p-pump just has a bronze bushing so the belt tension wears the shaft into the same spot on the bushing all the time.

This is where I most diverge in agreement with both PSC and Howe. Call them up and talk pumps, they will be both try to sell you some crazy high volume trophy truck pump as high as 9.5 gpm. I insist that its not only not necessary but actually nets a negative in our steering systems to have more volume than you can use.

So our new set up runs a 4.5 gpm pump at 1650 psi, which is the exact same gpm and psi rating as the high flow control valve from Howe. At the dirtriot national finals we ran for 1 hour on the roughest course other than KOH that we ran all year. Through tight trees and nasty rocks. At the end of that brutal race our fluid temperature was 90 degrees. No matter how hard of a demand we place on the rig you can shut the car off and hold onto any part of the steering system with your bare hand. No matter how fast you turn the wheel with your hand the steering never doesn't keep up with you. The ram can move the wheels faster than you can outrun the hydro system with the mechanical side.

I know people running full hydro systems with trophy truck pumps that the steering system gets so hot that you could weld with it. The higher PSI and higher GPM the pump is the more engine power it takes to run it. Where is that fluid going? If a normal orbital valve can only use 5.5 gpm the pump is bypassing internally the remainder of its produced fluid volume. That fluid doesn't get to run through the cooler before returning to the reservoir. Any time pressure is made heat is also made. So if your pump is making more fluid than you can use, that hot fluid re-enters the pump and is immediately re-compressed and more heat made. It can recycle hot fluid to the point that the pump gets so hot the bypass spring loses its spring rate. Bypass goes full open, now recycling only hot fluid and the steering fades if not goes away completely.

JohnnyJ 10-28-2015 12:12 PM

Interesting. We've been pondering changes to get through mechanical steering in 4500, and had looked at your build thread earlier this year.

We had figured that the same servo howe sold with the big money rack would be the ticket, but didn't want to risk the time/money on R&Ding something.

Thanks for sharing. Will be interesting to see how many 4500s will have this setup come february.

jr4x 10-28-2015 12:41 PM

Quote:

Originally Posted by JohnnyJ (Post 33984314)
Interesting. We've been pondering changes to get through mechanical steering in 4500, and had looked at your build thread earlier this year.

We had figured that the same servo howe sold with the big money rack would be the ticket, but didn't want to risk the time/money on R&Ding something.

Thanks for sharing. Will be interesting to see how many 4500s will have this setup come february.

I know of 6 other vehicles in various stages of install at this very moment.

generalee7 10-28-2015 12:49 PM

You mentioned something about your pump being a modified TC pump from PSC, what modifications need to be done or is this a PSC secret?

As for the sweet valve from Howe, I wonder if they can be made to have more turns (4-4.5) for street driven rigs. And as for feel, I imagine this feels more like a full hydro setup than hydro assist with a box, am I correct?

FORDTECHGURU 10-28-2015 12:52 PM

anybody got pictures? I got boxes..

[email protected] 10-28-2015 12:54 PM

Very nice. As a bonus this will work great on the street with big tires.....

IslandPath 10-28-2015 12:55 PM

Loved the explanation in person at Reno, sounds like you guys went thru a ton of steps to do something that hasn't been done before.
Very cool, love the out of the box thinking and moving the sport forward.

Also loved the Lasagna! You guys rock!

Wilson 10-28-2015 01:12 PM

What parameters did you use to select the correct pulley size for the pump? Were you looking at max shaft speed or something else?

Weasel 10-28-2015 01:17 PM

I was looking at Woodward servo valves last year and talked to the guy at their shop for a brief bit. He was sorta helpful but not much as it wasn't really an application he used this system in.

[email protected] 10-28-2015 01:21 PM

In to find out what are the mods we need to do to what box?

generalee7 10-28-2015 01:28 PM

Now that I think about it, maybe the turns lock to lock is still determined by the box since its the only mechanical link. Someone correct me if I'm wrong :D

boing. 10-28-2015 01:38 PM

I am sure the ratio of the box (turns lock to lock) has to be pretty close to the volume of the ram divided by the output volume of the servo...

Otherwise the ram and box would fight each (of which the ram would win every time), that and he needs the resistance of the box to make the torsion bar work and intern the ram to work...

hurleygo3 10-28-2015 01:50 PM

Thanks for all the info. Are you running a mechanical box, or did you gut the servo out?

gtxracer 10-28-2015 01:56 PM

Quote:

Originally Posted by generalee7 (Post 33985874)
Now that I think about it, maybe the turns lock to lock is still determined by the box since its the only mechanical link. Someone correct me if I'm wrong :D

Quote:

Originally Posted by boing. (Post 33986010)
I am sure the ratio of the box (turns lock to lock) has to be pretty close to the volume of the ram divided by the output volume of the servo...

Otherwise the ram and box would fight each (of which the ram would win every time), that and he needs the resistance of the box to make the torsion bar work and intern the ram to work...

I believe the servo, in conjunction with the pump, pushes fluid to the ram at the rate of steering input from the wheel/shaft. It is then limited by the mechanical input of the box, the steering stops, or the ram, whichever comes first. Obviously, a rock could also stop it, but all of that force is transferred to the ram instead of the box since the ram is the controlling entity in the system.

If I'm correct, then the box can be used to dial-in lock to lock. I just started researching this system last week, so I may be incorrect but that's how I understood the entire system.

muddnutt 10-28-2015 01:59 PM

The Willys is a dream to drive. The ram takes the load and unless you turn the wheel it wont let the front steer only on super hard impacts turning the steering wheel a little bit. The steering wheel feedback is better than with the conventional box to us.

muddnutt 10-28-2015 02:03 PM

Quote:

Originally Posted by hurleygo3 (Post 33986274)
Thanks for all the info. Are you running a mechanical box, or did you gut the servo out?

We built the car around the scout steering box so we could have a very long drag link to help with bump steer. John can tell you how but we modified the box servo. No fluid passes through the steering box except that it is filled for lubrication.

HydroDynamic 10-28-2015 02:50 PM

Cool to see so many people going this route. And all it took was one person to try something different.

generalee7 10-28-2015 03:28 PM

Quote:

Originally Posted by gtxracer (Post 33986386)
I believe the servo, in conjunction with the pump, pushes fluid to the ram at the rate of steering input from the wheel/shaft. It is then limited by the mechanical input of the box, the steering stops, or the ram, whichever comes first. Obviously, a rock could also stop it, but all of that force is transferred to the ram instead of the box since the ram is the controlling entity in the system.

If I'm correct, then the box can be used to dial-in lock to lock. I just started researching this system last week, so I may be incorrect but that's how I understood the entire system.

Yeah this makes sense. Thanks!

Now curious about the torsion bar options since Howe offers quite a few different ones. Stiffer torsion bar for more road feel? Lighter torsion bar for less feedback into the steering wheel if the tires were to jam into something (big rock etc)?

jr4x 10-28-2015 03:34 PM

The box part of this I will get done and posted tomorrow morning. I realized that I am missing a couple pictures to adequately show how we handled the box itself. So know that it's coming.

vetteboy79 10-28-2015 03:35 PM

Correct on the box determining the lock-to-lock; the servo has nothing to do with physical turns. It only sends fluid to the ram when you're demanding a different steering position than the box is currently in (a torsional difference between the steering shaft and the box input).

As mentioned above, a servo is a completely different device than an orbital, which has a fixed amount of displacement per revolution.

I'd also be interested in knowing what you ended up with for the steering box itself. I had another idea long ago when this concept first came up, but I'll leave that discussion until more people get a handle on how this works. :)

ZAG 10-28-2015 03:42 PM

its just the same system as normal steering box has but its just outside the box:laughing: same could be done with normal box just plug the box piston ports and hose it to external ram...............


All times are GMT -7. The time now is 08:38 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 ©2011, Crawlability, Inc.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.