leman Posted March 23, 2021 Report Share Posted March 23, 2021 I have been playing around with the Bump steer function on my Hunter alignment system and have to admit I'm confused with the results. I recorded a graph with standard track rod ends on an MX5 MK1 then swopped the rod ends to the R Package types that are designed to negate bump steer on Some specials Mazda did. I can see adifferent curve on the graph but am struggling to interpretation what I'm seeing, Can you shed any light on this Tony? Quote Link to comment Share on other sites More sharing options...
Tony Posted March 23, 2021 Report Share Posted March 23, 2021 Hi Has the car been lowered? Quote Link to comment Share on other sites More sharing options...
leman Posted March 23, 2021 Author Report Share Posted March 23, 2021 Hi Tony, Yes it has been lowered, its approximately 320mm center of wheel to wheel arch. I have had these rod ends for years and was interested in seeing on my machine the difference between the two types. I'm looking at the graphs and my logic is saying the standard rod ends had less bump steer, or am I interpreting the results wrong. Quote Link to comment Share on other sites More sharing options...
Tony Posted March 23, 2021 Report Share Posted March 23, 2021 Has the car actually suffering from bump steer. Quote Link to comment Share on other sites More sharing options...
leman Posted March 23, 2021 Author Report Share Posted March 23, 2021 Yes when compressed hard it would, but I honestly have not drove this car for at least 4 years. This was just basically an experiment to see what the Hunter machine could actually do and whether it was useful info or not. I was hoping to record the curve with the standard rod ends then compare the curve with the Mazda R Package rod ends. The solid lines on the graph are the R Package rod ends and the dotted lines is the comparison standard rod ends. The Hunter manual does not really expand on the Bump steer featue. I'm obviously out of my depth on this feature Quote Link to comment Share on other sites More sharing options...
Tony Posted March 24, 2021 Report Share Posted March 24, 2021 There is an explanation in the "training" feature in the Hunter. I've only used the feature once?..... Basically all you are doing is confirming what you already know. To explain.... The track-rod-end has an orbit with the ability to retain the tow without influence. In an ideal world the track-rod-end ( pick-up-point ) should maintain the centre pin within the orbit range of motion. Personally i would use one of these to re-centre the pickup point All these do is allow you to centre the pick-up-point and then adjust the toe. Also, i find the customer is uneasy with figures and graphs and all they really want is a solution. Quote Link to comment Share on other sites More sharing options...
leman Posted March 24, 2021 Author Report Share Posted March 24, 2021 Thanks Tony, I will look in the training feature its not something I even thought of looking at because the training videos on my machine are inactive due to the machine being a VW/Hunter machine and the electronic key for that was never installed. I have admin access to the Hunter software so I can still access the training just not directly. The wheel alignment machine is just for my own personal tinkering in the man cave so the graph was for my own weird inquisitive nature, so no customers. Quote Link to comment Share on other sites More sharing options...
Tony Posted March 25, 2021 Report Share Posted March 25, 2021 Thing about the keys i fully understand. My guys have to work on any car so information is power. We interview the customer to narrow down the path we need to take? I give them an hour normally to prove the condition no matter what the car albeit a Fiesta or Ferrari. The only additional time is allowed is if we need to remove the under tray. No domestic car should suffer from bump-steer, so we are serving the modified car. Geometry laws applies to all cars give or take a bit of tweeting. Obviously the radius of the lower arm and steering arm should be the same during bump and droop and the orbit of the track-rod-end has to be uninterrupted. We can chart the level of bump-steer but i found it a wast of time because it's a visible condition the operator should be able to conclude without mapping. I sponsored three cars in the BDC which had nearly zero bump/ droop, the centre of gravity on the coilovers was way to low since the driver wanted seven degrees of negative camber The radius of the lower arm, steering arm and the SAI/ KPI was visibly wrong, i warned him but he insisted. In competition miss-information is rife, but he wouldn't listen.... The car went to Portugal for a drift display and crashed on the first lap? Quote Link to comment Share on other sites More sharing options...
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