Rack And Pinion exploration

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dislexicdime
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Re: Rack And Pinion exploration

Postby dislexicdime » 30 Dec 2015 12:31

Maybe your engine should be turbo
L series only have one header!

i need another garage mine is full of part's

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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 30 Dec 2015 14:04

dislexicdime wrote:Maybe your engine should be turbo



Trust me I've been thinking about that!
I liked Hainz better...... Can we trade back?

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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 29 Jan 2016 18:41

We are still working on the rack and pinion. So close to having prototypes in our cars. I goal is to have them in for our last autocross event! We got the steering linkage mocked up. Seems to work fine. Also Sam ordered a front sump L series oil, it just came it a few days ago. So close!!!

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Didn't have the right drill bit, so we just interpolated it with a 5/8 end mill. then welded.

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The top of the U-joint originally had a bearing on it when it was in the toyota. Sam found this bearing which is a slip fit the black deals are shaft colars to hold the bearing in place. We then slight the steering column tub and used a hose clamp to secure the bearings outer race. It worked out great so we are going to order a nicer clamp.


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I liked Hainz better...... Can we trade back?

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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 13 Feb 2016 20:56

We have a goal set, the last auto cross is one month from now. We want to drive both are cars with the prototype rack setup in it. Seems like an easy goal... Well after getting all the bump sorted out we realized that the steering would be terribly slow. The rack travel is less than the box. We wanted faster steering! So the only option was to make new steering knuckles. The knuckles dictate the amount of ackerman by moving the inner tie rod pivot point inboard. Which in effect changes the bump..... Serious rabbit hole!!! We decided to go with neutral ackerman, 100% or whatever you want to call it. The good news is Sam figured out how to get us 2 turns lock to lock! Zero bump, added caster, neutral ackerman! While he was doing that I drew the power steering bushings haha. I was busy with some family stuff that week or I wouldn't have been more involved. :) To give you an idea of how different a steering knuckles can be, the left arm is off a 300zx and the right is off a 510.



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I liked Hainz better...... Can we trade back?

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bertvorgon
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Re: Rack And Pinion exploration

Postby bertvorgon » 14 Feb 2016 08:18

I put shorter steering arms on my car! :D
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 14 Feb 2016 08:55

How do you know they didn't mess up the ackerman? Or the bump steer? I know people use the 280zx arms as "quick steer arms" I also know the 280zx had an option for power steering which made the car come with a steering box. I'd like to compare the steering knuckles of the zx rack vs box cars.
I liked Hainz better...... Can we trade back?

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duke
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Re: Rack And Pinion exploration

Postby duke » 14 Feb 2016 12:36

Did you guys ever measure the ackerman for stock steering arms? Just from looking at the location of the ball joint hole I wouldn't be suprised if they had less than 100%. Also, it would seem to me that the ball joint location on the stock arms would make the scrub radius pretty bad.

I can't wait to see what you guys come up with.
Duke Schimmer

'72 2-Door 510
"Simplify and add lightness."

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Byron510
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Re: Rack And Pinion exploration

Postby Byron510 » 14 Feb 2016 18:25

icehouse wrote:How do you know they didn't mess up the ackerman? Or the bump steer? I know people use the 280zx arms as "quick steer arms" I also know the 280zx had an option for power steering which made the car come with a steering box. I'd like to compare the steering knuckles of the zx rack vs box cars.



The 280ZX's actually had three versions - manual rack, power recirc ball and power rack. I personally have no idea what changed as far as distance goes, but I can ask someone who may know and report back....

Byron
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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 14 Feb 2016 18:26

Yes Duke we measured it, well Sam did. I was busy that week so I couldn't head over to his house to help with the data gathering. I think it almost does have 100% I think he checked it with the LCA's pulled forward. It seems since the steering box and idler arm travel in an arc it helps add in ackerman. We talked about moving the ball joint location, but we don't want to move to many things at once. Even if it adds up on the computer it may not be worthing doing all of it on our cars. So we are going to prototype some stuff then do some upgrades. Such as moving the ball joint location.

I also am going to make the tallest bump steer spacer that will fit in my car just to see what it feels like. I don't see a reason why not to.
I liked Hainz better...... Can we trade back?

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bertvorgon
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Re: Rack And Pinion exploration

Postby bertvorgon » 16 Feb 2016 17:03

I asked Andy what he did for my bump steer, as it was a long time ago. He remembered putting the short arms on, then bending up and back the arms. I do know that I have a good bump curve and that my ackerman, according to Andy, got better. I do also know that my car turns in very well and that on very violent bumps it does track with no issues.

Other than that I am no help, as the angles of the dangle are beyond my scope.

In a perfect mathematical world, I'm sure there is a point that everything happens as it does in text books. In our real world, we can strive for the best compromise of settings, which, as I have seen in my car have worked very, very well for a lot of years. I have not touched my suspension now for I would say about 30 years. If anything, on street DOT slicks, my rear springs have sagged just a bit and the car feels more predictable that it ever has, go figure. It's all about weight transfer ultimately IMHO.

Good tires, no, lets say GREAT tires make up for a lot of deficiencies in the subtleties of our cars. When you consider that we have turned grocery getter's into some formidable sports cars, and then BEATEN same, is a testament to the engineering that has been done by the group of us.

I watch with major interest to see what you come up with Jeff, maybe taking things to the next level.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 18 Feb 2016 13:01

Yeah Keith I don't know if what we come up with will handle as well as what you and Andy have done! I personally just want it to feel like my S13, sable at high speeds and not be so jumpy in the rutty freeways. Sam is going to run a manual rack I picked up a power unit. Did you Toyota corolla have power steering? If so I'm sure it felt nice.
I liked Hainz better...... Can we trade back?

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Byron510
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Re: Rack And Pinion exploration

Postby Byron510 » 18 Feb 2016 19:15

Byron510 wrote:
icehouse wrote:How do you know they didn't mess up the ackerman? Or the bump steer? I know people use the 280zx arms as "quick steer arms" I also know the 280zx had an option for power steering which made the car come with a steering box. I'd like to compare the steering knuckles of the zx rack vs box cars.



The 280ZX's actually had three versions - manual rack, power recirc ball and power rack. I personally have no idea what changed as far as distance goes, but I can ask someone who may know and report back....

Byron



Jeff, just to follow up. I did pose this question concerning the 280ZX steering arms; the consensus was that all three versions of steering had the same steering arm, so the ratios of the manual rack, power rack and power recirc ball must have been engineered the same. Unfortunately no quick fix for the quicker steering arm.

Byron
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icehouse
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Re: Rack And Pinion exploration

Postby icehouse » 18 Feb 2016 22:05

Byron510 wrote:
Byron510 wrote:
icehouse wrote:How do you know they didn't mess up the ackerman? Or the bump steer? I know people use the 280zx arms as "quick steer arms" I also know the 280zx had an option for power steering which made the car come with a steering box. I'd like to compare the steering knuckles of the zx rack vs box cars.



The 280ZX's actually had three versions - manual rack, power recirc ball and power rack. I personally have no idea what changed as far as distance goes, but I can ask someone who may know and report back....

Byron



Jeff, just to follow up. I did pose this question concerning the 280ZX steering arms; the consensus was that all three versions of steering had the same steering arm, so the ratios of the manual rack, power rack and power recirc ball must have been engineered the same. Unfortunately no quick fix for the quicker steering arm.

Byron


I doubt the knuckle were the same. If they used the same knuckle the ackerman, steering radius and steering speed would all be changed going from the rack to box. I'd look into it more but we are just going to make a custom knuckle. For those reasons and the outer tie rod runs out of articulation because the stock arms are twisted the wrong way. Which works to our benefit making arm flat will gain us travel and make it simple to machine.


We have only 3 weeks until are last event and I want to run the rack setup. So I'm going to be very busy the next few weeks making parts!
I liked Hainz better...... Can we trade back?

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bertvorgon
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Re: Rack And Pinion exploration

Postby bertvorgon » 19 Feb 2016 07:14

What castor are you running? We run 5.5 minimum and the the time when I was solo'ing full time I ran just over 6 degrees. I ran either ZERO TOE or, at full combat time, I ran a gnats eyebrow of TOE OUT, which helped the car turn in as the courses got tighter.

YUP..it is a bear to steer in the parking lot, but, it makes the car very stable at high speed and in terms of solo use, induces MORE negative camber in tight solo turns, which really gives the front end bite.

My AE86 was one of the best steering cars I have ever had! It was slightly power assisted, yet was TOTALLY lineal, no over or under boosting steering input. If I could have that on my 510 I would think I have died and gone to heaven.

I did my own suspension the AE86, basically I duplicated the settings of the 510 up front. #300 springs, pulled as much castor into it as I could, camber I left stock as it seemed to be ok. I put the 5 way Illumina shocks in there and ran at #4 for summer driving. That car worked very, very well

I have mentioned this before also, believe it or not. With that much castor, at some points on the course, it was better to just almost let go of the steering wheel, and let the self centering action of the high castor, straighten the wheels, faster that I could reef it back. It became one of timing, but, it worked a hot damn at times. It also made the car dead stable at speeds over 120 - 130 MPH.
"Racing makes heroin addiction look like a vague wish for something salty" - Peter Egan

1973 2Door Slalom/hill climb/road race / canyon carver /Giant Killer 510
1968 Vintage 3HP Mini Bike
1971 Vintage 13' BOLER trailer

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Dave Patten
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Re: Rack And Pinion exploration

Postby Dave Patten » 20 Feb 2016 11:47

bertvorgon wrote:With that much castor, at some points on the course, it was better to just almost let go of the steering wheel, and let the self centering action of the high castor, straighten the wheels, faster that I could reef it back. It became one of timing, but, it worked a hot damn at times. It also made the car dead stable at speeds over 120 - 130 MPH.


I ran a ton of caster in my ITC 510. I never measured it, but the top of the strut was moved back about 1" and the TC rod was shortened a little more.

While racing it at Lime Rock Park (Lakeville, CT) I lost traction on the back end of the car creating a massive oversteer condition. My guess is I was doing around 100 MPH, exiting the Downhill Turn going onto the front straight. I turned opposite lock to correct for it. With the car at nearly 45 degrees to the correct path of travel, I clipped the track-out curb with my left rear. This was just enough to stop the rotation of the car and immediately (and violently) turn it in the opposite direction.

SO at 100MPH what else can you do to take out 1+ turns of opposite lock instantly but let go of the steering wheel and let all that caster straighten out the car. I did just that and the car responded and I was saved from a nasty spin to continue down the front straight.

I tried auto crossing the car with this set-up and ended up with arm pump worse than you’d get motocrossing. Lots of caster is great for high speed stability, terrible for parking lots.
Dave Patten
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