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Making coiloversDeleted
@Deleted
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Jan 23, 2019 19:59:11 GMT
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I'm researching how to make coilovers for my Anglia by utilising its original struts. It will be powered by a 2.0 zetec and not used on track - maybe only a straight 1/4mile occasionally but mainly road.
Without wishing to come across as a dunce I need some help and guidance.
The cutting and welding side of things is covered, whats confusing me is trying to establish what length inserts, springs and rates I will need.
I want to lower the car by probably 2" (tbc). Is it simply a case of finding new inserts 2" shorter than standard inserts (if I'm lowering by 2") and also buying springs 2" shorter than standard, I will need to also determine the spring rate - without actually knowing I would just purchase springs which are a bit harder than standard, rightly or wrongly.
Also I see lots of talk of adjusting the ride height with coilovers but I'm guessing by welding the threaded coilover tube to my struts, il only be able to adjust the preload? to be fully adjustable i.e for ride height as well, the bottom of the strut would need to be threaded to enable the complete coilover to be wound up or down?
Providing I can establish what ride height I'm happy with I don't mind not being able to adjust the ride height.
Preload? When assembling the coilover do you set any preload, or just wind the collars up to hold the spring against its top seat?
I suspect, obvious to some on here but not me!
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Jan 23, 2019 20:25:18 GMT
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The length of the insert affects the amount of jounce or vertical travel you have before the top of the insert hits the top mounting and can affect the overall travel (i.e. a longer insert will generally give longer overall travel). for a 2" drop with stiffer than standard springs you would normally be fine with the standard length of damper.
The spring will be a fixed length for a given weight pushing down on top of it so the adjustable lower seat will raise and lower the vehicle, it will also affect the pre-load as you suggest though normally you would specify the pre-load at the mid point of adjustment and use the adjustment to set the ride height.
Spring rate is very much a combination of judgement, personal choice and how you want the car set up, very stiff make it awful to drive on the road but can improve grip on smooth tracks. To soft and it will wallow all over the place, you also have to consider the balance front to rear which will affect the understeer / oversteer balance (anti roll bars also come into this), how much it dives under braking and the effect of traction and brake balance. What you suggest is not a bad idea, if you are starting with a pretty standard road car , going up 25% in rate front and rear is not a bad place to start though the best idea is probably to find out what others have used to give the results you want.
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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Making coiloversslater
@slater
Club Retro Rides Member 78
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Its a good idea to do the conversion and then fit the strut to the car, position it at your desired ride height and actually measure the length of springs you need. Remember to allow for the weight of the car on them ofcourse. You can calculate how much they will compress if you know your corner weights and spring rates but if you don't then just make an estimate. Usually a good guess is fine as you have lots of adjustment in the platforms to correct for a spring that is an inch too long or short.
For the inserts, again you have some leeway. For a 2ins drop you would probably get away with standard length inserts. You could fit shorter ones if you shortened the whole strut tube. You would gain some bump clearance and will get less 'droop' too. (It might pick the front wheel up in corners with less droop which looks good and can be desirable on a race car but i doubt it matters on your road car..)
To select your spring rate it's a good idea to ask around and see what other people with simlar cars think. I can tell you what we use on our anglia touring cars but it wont help you on a road car. It all down to preference, some people want a road car to be like a race car and some people want it to ride like a boat. Make a choice and if it's wrong be prepared to change. Springs are cheap really and are not hard to find 2nd hand.
No there's no 'preload' as such. The car sits on the springs which sit on the adjustable platforms so as you adjust the platforms the car ride height raises and lowers. You can use the platforms to adjust corner weights but the ride height will change at the same time. If you raise one corner it will take more of the weight of the car etc.
Hope that helps a bit.
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Last Edit: Jan 24, 2019 3:20:32 GMT by slater
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Making coiloversDeleted
@Deleted
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Jan 24, 2019 15:50:49 GMT
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Thankyou to kevins and slater for good solid answers.
Next question, and I may be overthinking this, I'm not sure.
edited as I was getting confused reading back what Id written,
With the car at rest how much is a shock/coilover in compression (I'm not talking about the spring but the shock/insert) - i.e how much more travel does it have available in compression and rebound, example has it got 2/3 available travel in compression and 1/3 left in rebound???
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Last Edit: Jan 24, 2019 17:54:11 GMT by Deleted
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Jan 24, 2019 21:43:55 GMT
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Last Edit: Jan 24, 2019 21:45:32 GMT by nomad
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slater
Club Retro Rides Member
Posts: 6,390
Club RR Member Number: 78
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Making coiloversslater
@slater
Club Retro Rides Member 78
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Thankyou to kevins and slater for good solid answers.
Next question, and I may be overthinking this, I'm not sure.
edited as I was getting confused reading back what Id written,
With the car at rest how much is a shock/coilover in compression (I'm not talking about the spring but the shock/insert) - i.e how much more travel does it have available in compression and rebound, example has it got 2/3 available travel in compression and 1/3 left in rebound??? Thats probably not far off.
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