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| Re: rack and pinion steering in 1200 ute |
Subject: Re: rack and pinion steering in 1200 ute
by wards on 2009/3/20 8:40:08
hi guys , i have been doing a rack conversion in my 1200 ute and have found some info that might be usefull ,you decide.
As mentioned the bump steer is the issue because to get it right the rack im using is 500mm between the pivot balls on the inner tie rods (this is with the lower arm pivot bolt moved out 20mm per side) I also have s14 struts and stub axles so the steering arm geometry is a bit different to a standard 1200, but ackerman is another story , anyway i achieved 0.4 mm of toe out in bump and was happy with that.
the rack its self was a manual rack out of a nissan micra cut down to suit, it worked but had too slow ratio (3.75 turns to move 125mm). Then i modified a power steer rack from same model micra this was a huge task involving making a new rack shaft to get the spacing between the rack teeth and the hydraulic piston close enough to get 120mm of travel and stay 500mm between pivots ,and after all that 3.0 turns lock to lock , better but not good enough for a car with such short wheelbase ( i was advised by some very smart racecar builders that short wheelbase cars are very twitchy and to have the fastest steering i can so catching a slide can be done with out having take a second bite at the steering wheel) Take 3 a power rack from a mazda 929/ mx5 it has the fastest ratio of all 2.25 turns for 125mm rack travel and again i am remaking the rack shaft to fit the teeth and the hyd cyl in the desired length. Hope this can short cut your development but this project is not for a novice, as i've said in a previous string i have changed my approach several times as i descovered plusses and minuses in my geometry , sorry for the long answer hope it was worth the read.
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