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Discussion Starter · #1 ·
I am going to build my own front IFS and have a few questions that I need answers to. I understand that in order to get the ackerman right I have to get the pivot point on the rack to intersect an imaginary line through the top and bottom wisbone pivot points. If this is the case and lets say the rack I have is a little short can I move the bottom wishbone in towards the centre of the car or if the rack is a little long can I move the upper wisbone pivot point out in order to get these pivot point to be in the right place ? And now the second question how do I determine the ride height that I want the car to sit at ? when putting this IFS onto the main frame rails ? :tup:
 

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I was under the impression that th Ackerman angle was to do with the imaginary line from the center line of the rear axle through the king pins/ ball joints and beyond and the steering ends had to be some where on that line

IE if in front of the Axel the tre's would be closer to the wheel but if wee behind the would be closer to the center of the car

And i found this out through help from Kev and Langy and i think one of em did post up a diagram on the NSRA

But that was for my beam axle and not 100% what the difference would be for wishbones

I MUST TYPE FASTER LOL
 

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Discussion Starter · #5 ·
Thanks for the replies as you can see I got mixed up with this and I ment bupm steer so is what i stated correct and can I overcome the issue I mention by the method I explaned ?:tup:
 

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Thanks for the replies as you can see I got mixed up with this and I ment bupm steer so is what i stated correct and can I overcome the issue I mention by the method I explaned ?:tup:
Sorry, but this type of question says that you need to do much more studying before contemplating doing this yourself. The wishbone pivots ,there lengths relative to each other and the angle they mount at all play a huge part in how the suspension works(or not), so until you have that sussed you can't just move things around until it fits.

Too big a subject to explain it all in one go. Loads of books on this so go read one, then read it again.
 

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Sorry, but this type of question says that you need to do much more studying before contemplating doing this yourself. The wishbone pivots ,there lengths relative to each other and the angle they mount at all play a huge part in how the suspension works(or not), so until you have that sussed you can't just move things around until it fits.

Too big a subject to explain it all in one go. Loads of books on this so go read one, then read it again.
well put, having built a few sets of a arms it is not as easy as you may think if you start moving a arms in in or out top or bottom you will throw out all the geomatry i can see what you are attempting to get your rack to fit but you need to no a lot more,there are several book,s to look at, i had one about raly cars that was very good ithink it was celled how to make your car handle? hope this helps im not trying to negative but as i said there is alot to no:tup:
 

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Just a quick question along similar lines.....if the vehicle was to be changed from steering box to steering rack, would I be correct in thinking that the steering arms do not need altering as the Ackerman angle remains correct?:S (standard factory suspension)
 

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Yes, but rack conversions are a whole other ball game especially on a Mac strut car if you wnat it to handle as well as just turn the wheels in the correct direction.

If you want to set up an IFS , read books about IFS , if you want Mac strut do the same , likewise beam axle. Ackermann is about the only interchangeable spec amongst them, each has it's own needs and settings.

Check out the UKhotrods techs section for a basic overview re requirements for IFS.
 

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Simplest system which I have used successfully on my 34 coupe is the Locost one, 'Build a car for less than £250' book shows you all you need to know.
 

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Have a look at this drawing. If all this doesn't line up correct, you ends up with a rather crappy IFS.
I know there are lots of IFS' out there that don't, but if you want the handling advantages from it, you have to build it correct. As you se, most of the fastening points refer to each other, and changing one point often lead to the change of other points as well.

Usually it is better, cheaper and safer to use a kit or at least use an IFS from a donor car.

 

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If you really want to mess with your head get a copy of "race and rally car source book" by Allan Staniford ISBN 0 845429 984 X lots to read and fail to understand:incheek:
Chaley
 
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