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How much drop do you put in the lf from ride height when you are tying the lf up with a cable? Thanks
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When do you want it to lift off the ground?
Just because the LR is ON the ground doesn't mean it is carrying a load or providing a steering advantage. Chaining/cabling it up isn't going to change anything except when it leaves the ground. It isn't going to hold the LR DOWN.
If you're looking to keep more load on your LF, chaining it to the chassis isn't going to help.
In other words...this isn't why Davenport is winning races. -
Sure made mine turn in better.Comment
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I have found it takes a little sidebite away and adds some drive. You will have to experiment to see what you like. I gave gone away from it.Modern Day Spec Wedge RacingComment
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A chassis builder told me one inch before spring unloadsComment
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load
Originally posted by Matt49 View Post
Matt49
have you ever done any work on a pull down rig?
there are advantages to limiting LF down travel, this is all I am at liberty to say.I think there should be lifeguards in the genepool.Comment
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We use it on asphalt quite alot it has merit. We just talked to rocket two weeks ago no mention of it call this week and ask them about it, oh yeah yeah buy this, do this and set it to this......Comment
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I didn't ask if davenport was doing this. ThanksComment
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I didn't ask if Davenport was doing this. ThanksComment
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The only way that tying the LR suspension to the chassis will keep the left front wheel from coming off the ground sooner is if there is enough unsprung weight there to change the center of gravity of the entire car and/or prevent additional weight transfer from left to right.
That plays into what MBRacer said about less side bite and more drive. But aren't there a million other ways to do that? Just saying...
And the Davenport comment was a joke so lighten up. It you pay attention you'll see that a lot of recent threads seem to be taking stabs at figuring out what Rumley might be doing so I was having fun with it. Nothing personal.
Anyway, that's my best explanation of how tying the LF to the chassis might "work" but again I think there are better ways to accomplish the desired result without using logging equipment. Namely with shocks and front end geometry.Comment
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Not trying to start a pissing contest here but...Originally posted by Matt49 View Post
Do you have any data to support your explanation, or is it just how you believe it might work?
I have seen the data from a pull down rig. There is no denying hard data.
No log chains were harmed in the making of data...lolI think there should be lifeguards in the genepool.Comment
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No pissing contest here either. I really enjoy these discussions. There are certainly many ways to skin a cat.Originally posted by JustAddDirt View Post
That being said...
Does a pull down rig do anything that emulates lateral weight transfer? The answer to this (which is no) is the reason I've never been a fan of pull down rigs for vehicle dynamics analysis. It can help you in evaluating dynamic positioning (camber curves, roll centers, rakes, etc.) but not wheel loading. Emulating car attitude does not emulate wheel loading. It is impossible to emulate lateral forces on a race car with equipment in a shop. This is why data acquisition is coming into our sport. Because it is needed if you want to beat the guy that has the EXACT same car as you.Comment
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Was wondering if pull down rigs could tilt on 2 axis to load rt side and frt or rear then it may get interesting. Then they may be able to figure out the math to show centrifugal wt/gravity,depending on speed, corner circumference, approx wheel load/traction etc to get closer. But that just makes for more homework.Comment
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If you have data acquisition, and know were each of the 4 corners are at any point on the track, along with pull bar and or lift arm positioning, and pinion angle, you can simulate what the car is doing at those positions. then start changing things when the car is at attitude, you can simulate the wheel loading.I think there should be lifeguards in the genepool.Comment
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You can get the attitude of the car where ever you think you're going to learn something on a pull down rig. What you can't do is emulate lateral weight transfer. How do you get weight to come OFF of the LR on a pull down rig to simulate corner entry? You don't.
How do you emulate the wheel rate changes that are introduced by anti-squat when the car is accelerating? You don't.
How do you emulate the wheel rate changes that are introduced by anti-dive when braking? You don't.
And perhaps the most fundamental place where a pull down rig fails to provide meaningful data is because the tires aren't rolling. Load at the contact patch is HEAVILY influenced by scrub and that can't be simulated on a pull down rig.
If you want to do some serious testing, something like this is the cream of the crop:
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