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Number of wheel turns lock to lock?

Discussion in 'Gen 3 Prius Technical Discussion' started by Patrick Hook, Jul 16, 2024.

  1. Patrick Hook

    Patrick Hook New Member

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    I'd be most grateful if someone would be kind enough to let me know how many turns a Mk3 takes to turn the steering from lock to lock. I'm considering using a Prius rack on a project car, but never having driven one, I have no idea!
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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  3. Patrick Hook

    Patrick Hook New Member

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    Ah - that's useful to know - are there any markings on the rack to distinguish them, and what are the respective ratios?
     
  4. Patrick Hook

    Patrick Hook New Member

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    I've now discovered that the 15" models have more turns from lock to lock than those with 17" wheels, so my question here has now changed. Instead, it is either:

    'Can anyone tell me what the part numbers are for the rack and column for the 17" wheel models?'.

    or

    'Is there a different model designation for the 17"-wheeled cars?'.

    As ever, any help would be most appreciated!
     
  5. Tombukt2

    Tombukt2 Senior Member

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    Something like three or two and three quarters or 2 and 7/8 I believe A Prius rack on a project car you mean you want an electric rack You know the rack isnt electric the steering shaft is electrified there's a motor above your knees I'm guessing you know this so the input from the steering wheel goes through a motor assembly if you will right above your knees which turns a steering yolk which in turn turns the spleen shaft on the rack which moves the tie rod ends so it's essentially a manual rack so thinking a little backwards you might be able to take the steering shaft assembly and motor and the yolk and make that work to about anything you want within somewhat reason I imagine there's a weight limitation or something along that specifications for the motor and the steering effort and all of that stuff. You do know that TRW made a complete electric rack also not steer by wire or anything like that similar to the Toyota set up I do believe but I think it's all in the rack not in the steering column or shaft The guys that spend their time with the electronics on this car will be a long shortly to tell you something I'm sure but seems perfectly plausible to use in other carts etc I shouldn't really be an issue I'm not sure how much computer input and what not is needed or what exactly works the electric motor for the steering whether there's any computer aided business going on doesn't seem like it I've had a few of these in generation twos that do funny things It seems like the motor that's giving the steering boost is pretty cool it's like on some kind of geared shaft and if you have the wheels off the ground or if the car is on and ready you can move the steering wheel kind of quick and then backwards and you can feel gears kind of catching up with each other or something so there's something going on that provides some kind of feedback and all of this kind of business so then just fitting the steering column from a generation two or three Prius to whatever steering is already in the other vehicle If it's not power I guess or if this is a home built then it's not power the steering shaft should be able to turn your I assume rack in your built vehicle if all the splines will slip up.
     
  6. Patrick Hook

    Patrick Hook New Member

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    Thank you for your input - yes, I'm well aware that the power-assist is in the column, as I have one here. The car this is going in is a mash-up of a modern twin-turbo engine together with a classic '70's sportscar. I'll need the extra help with the steering because the tyres that are going on it are a lot wider than the originals!

    I have two problems though:

    1. I need to have both the column and the ECU for the same kind of motor (brushed/brushless), and although it appears that my ECU is for the brushless variety, I don't yet know what type my column is.

    2. Although the car is Italian, the rack itself was actually made by a British company where the accountants clearly ruled over the engineers. Consequently, every cost-saving feature was implemented - poor quality parts made on worn-out machine tools to out-dated designs. This resulted in a high rate of wear, and poor steering. While I'm more than capable of ripping it apart and machining up my own replacement bushes, etc., I'm toying with the idea of fitting a Toyota rack to on the end of the Toyota column, as I can be reasonably sure that it was designed and made properly. BUT - I need to know which models featured the lower lock-to-lock steering so that I can go and track one down!
     
  7. ChapmanF

    ChapmanF Senior Member

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    The gen 1 steering rack had the motor and torque sensor integrated, if you wanted a one-piece option. But the torque sensor in that one was prone to flakiness.
     
  8. Patrick Hook

    Patrick Hook New Member

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    Would a 2011 T Spirit (UK model) - which had 17" wheels, have the brushless column motor?
     
  9. Tombukt2

    Tombukt2 Senior Member

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    I don't know that's a good one I don't know when the brushless column motor started Heck I would think the one that's in a generation too would probably be a brushless DC column motor but I have no way to guarantee it I don't want to take it apart looking for brushes. And brushless or not they seem to rarely fail as in the motor not working usually a bunch of slop develops or something weird like that goes on I don't think the brushless would help with that.
     
  10. Patrick Hook

    Patrick Hook New Member

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    I assume the easiest way to tell if it's brushless would be to count the turns, lock to lock?
     
  11. Tombukt2

    Tombukt2 Senior Member

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    All you have to do is just look under the steering column then down literally and look up under the pedals and you'll see the round motor control system bolted right where the normal steering column bearing would be this thing replaces the steering column upper bearing and mount assembly and it bolts into the car almost in the same spacing You could fit this thing probably and a lot of what's already around and if you're building something custom the spacing should be very close to normal steering column mounts I don't think counting the lock to lock is going to tell me which steering system is in the car although I don't know what the straight up turns are on the regular power rack and pinion in like say a Corolla s which is the sport model I would imagine somewhere around 2.5 2.7 turns but maybe more
     
  12. Patrick Hook

    Patrick Hook New Member

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    Yes, the motor sits in my car just as you describe.

    As for the 'normal' (brushed) rack - that has something like 3.5 turns lock-to-lock, whereas the brushless one is 2.75, which is about what I need - hence why I'm so keen to find out the part number!
     
  13. Tombukt2

    Tombukt2 Senior Member

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    There must be some other way to identify or whatever this problem or situation I mean 3.5 versus 2 and 3/4 is a bit and just knowing if the rack is brushless I mean what are they marked like a DeWalt drill I don't think so so I'm not sure how that's going to really play out I thought most DC motors were brushless and things like this anyway but hey I really don't know anything about that kind of stuff to be honest about it so unless it's called out in the parts break down and how you'd find that out I just can't even imagine I know they're not marked like that so I guess you'd have to be able to look up the physical part number between the two different racks and I'm not sure how the brushless is going to come up I'm sure they don't replace brushes on these things and all of that they just replaced the whole motor assembly one can only hope but yeah that's pretty interesting I would think after some date somewhere they would all go to the lesser turn amount sporty or field whatever you want to call it and that instance.