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Coilover droop


Toddy415

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Hey guys does anyone know how to get more rear suspension droop for a cert? My coilovers dont have enough droop even when fully extended the only thing I can imagine working is put a softer spring in so it sags a bit more at ride height. Coilovers are bc golds. 

I thought about a shorter spring but if its the same spring rate then the lower spring seat just moves up so shock is still in the same position therefore will still have same issue. 

Any ideas or am i missing something? 

Cheers

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37 minutes ago, Toddy415 said:

Any ideas or am i missing something? 

What's the car and are they body adjustable? 

The correct way to get more droop is to add keeper/helper springs to your setup. It's easy to do, and if your coilovers are body adjustable there should be plenty of adjustment (body adjustment changes the total length of the shock). 

Here's the process I would follow: 

  1. Remove springs and run suspension through its whole sweep with the wheel and tyre on.
  2. Take note of how much clearance you have at full compression (if any). You should aim to have the tyre as close to the wheel arch as possible at full compression for optimal handling.
  3. Make sure there's enough clearance for the bump stop to compress a little for big bumps (10mm minimum gap between tyre and inner guard). Use the shock body adjustment to set this height.
  4. Jack the car up and see how far it droops. Measure the distance between the centre of the hub and the wheel arch at both ends of the sweep to give yourself an idea of total available droop travel.
  5. Install your main spring (no keeper) and drop the car on the ground. Set your desired ride height for cert using the spring perches. The spring will probably be un-captive after this. 
  6. Once ride height is set, jack up the car again and see how far the spring is from being captive. This will give you an idea of how long your keepers need to be.
  7. Install your keepers with spring locaters between the keeper and main spring 
  8. You will need to drop the spring perch to account for the compressed length of the keeper plus the thickness of the locater to get the same ride height
  9. ??? 
  10. Profit

If you don't have enough perch adjustment, you might need a shorter main spring. 

 

Hope that helps. 

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6 minutes ago, Truenotch said:

What's the car and are they body adjustable? 

The correct way to get more droop is to add keeper/helper springs to your setup. It's easy to do, and if your coilovers are body adjustable there should be plenty of adjustment (body adjustment changes the total length of the shock). 

Here's the process I would follow: 

  1. Remove springs and run suspension through its whole sweep with the wheel and tyre on.
  2. Take note of how much clearance you have at full compression (if any). You should aim to have the tyre as close to the wheel arch as possible at full compression for optimal handling.
  3. Make sure there's enough clearance for the bump stop to compress a little for big bumps (10mm minimum gap between tyre and inner guard). Use the shock body adjustment to set this height.
  4. Jack the car up and see how far it droops. Measure the distance between the centre of the hub and the wheel arch at both ends of the sweep to give yourself an idea of total available droop travel.
  5. Install your main spring (no keeper) and drop the car on the ground. Set your desired ride height for cert using the spring perches. The spring will probably be un-captive after this. 
  6. Once ride height is set, jack up the car again and see how far the spring is from being captive. This will give you an idea of how long your keepers need to be.
  7. Install your keepers with spring locaters between the keeper and main spring 
  8. You will need to drop the spring perch to account for the compressed length of the keeper plus the thickness of the locater to get the same ride height
  9. ??? 
  10. Profit

If you don't have enough perch adjustment, you might need a shorter main spring. 

 

Hope that helps. 

Cheers for the reply ill sit down and get my head around that. Car is a r34 coupe and coilover height is adjusted by winding shock body up or down in the bottom mount spring perches stay put. 

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1 minute ago, Toddy415 said:

Cheers for the reply ill sit down and get my head around that. Car is a r34 coupe and coilover height is adjusted by winding shock body up or down in the bottom mount spring perches stay put. 

Do you have a pic of the shocks? You should be able to adjust the body length and the spring perch if they’re the style I’m picturing.

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4 minutes ago, Truenotch said:

Do you have a pic of the shocks? You should be able to adjust the body length and the spring perch if they’re the style I’m picturing.

Yea sorry yip you can adjust spring perch too, I was meaning for your main height adjustment you just use bottom mount 

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3 minutes ago, Toddy415 said:

Yea sorry yip you can adjust spring perch too, I was meaning for your main height adjustment you just use bottom mount 

This is only partially correct. The only reason to adjust the body instead of the perch is to keep the spring captive when making adjustments. It’s worth noting that doing this could also limit your bump (upwards) travel by causing the tyre to hit the wheel arch under full load (depending on total shock length etc).

Adding shock length as required, lowering your spring perch and installing keeper springs should allow for lots of droop travel while still retaining enough bump travel.

Droop travel is more important than compression travel in some situations like big bumps and drop offs. 

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Rear coilover on the right of image. Cletus I tried that last night and it was pretty much already no preload so there was no change. Currently have 30mm droop. Cert guy said it needs to be 40mm and plenty of people have come back with it fixed but only suggested a shorter spring might help. 

D_08_BR_RS50SHRINKEDSHARPENED.jpg

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@Toddy415 - here's a simple guide from MCA suspension on how to gain droop travel with coilovers like yours: https://mcasuspension.com/technical-section/Ride-Height-Adjustment

 

MCA don't talk about keeper springs because they don't run them in their race cars. Your springs will need to be captive for a cert, so you'll need to add a keeper spring with enough travel to allow for the extra droop (which also means dropping the spring perch a little further to account for the compressed length of the keeper). 

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2 minutes ago, Truenotch said:

@Toddy415 - here's a simple guide from MCA suspension on how to gain droop travel with coilovers like yours: https://mcasuspension.com/technical-section/Ride-Height-Adjustment

 

MCA don't talk about keeper springs because they don't run them in their race cars. Your springs will need to be captive for a cert, so you'll need to add a keeper spring with enough travel to allow for the extra droop (which also means dropping the spring perch a little further to account for the compressed length of the keeper). 

I read that the other day but got put off by spring not being captive haha but makes sense when you add keepers ill get into shed tomorrow afternoon and have a play. 

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Yeah I'll measure up the keepers in the FD tomorrow and if they're the right diameter we can whip those out to try in the 34 first to ensure that's what we're after before you commit to buying some even though it's likely thats the deal. 

Markku/Clint, would you suggest running some in the front also and getting to 50mm Droop as per the MCA guide? 

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40 minutes ago, kyteler said:

Yeah I'll measure up the keepers in the FD tomorrow and if they're the right diameter we can whip those out to try in the 34 first to ensure that's what we're after before you commit to buying some even though it's likely thats the deal. 

Markku/Clint, would you suggest running some in the front also and getting to 50mm Droop as per the MCA guide? 

@Truenotch I Just adjusted rear as per suggestions and it worked so now have 50mm droop (with springs un captive so will need to get some keepers). Thanks for your help guys much appreciated as I got myself overly confused. Good to know for the future as well. 

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6 minutes ago, Toddy415 said:

@Truenotch I Just adjusted rear as per suggestions and it worked so now have 50mm droop (with springs un captive so will need to get some keepers). Thanks for your help guys much appreciated as I got myself overly confused. Good to know for the future as well. 

Good stuff. 

You can get keepers in a few different lengths. Get some that give you as much travel as you need with a little left over (so the keepers are always slightly compressed). This will give you more flexibility for ride height changes in the future and also means you can adjust your ride height from the spring perch, instead of the lower body. 

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12 minutes ago, Truenotch said:

Good stuff. 

You can get keepers in a few different lengths. Get some that give you as much travel as you need with a little left over (so the keepers are always slightly compressed). This will give you more flexibility for ride height changes in the future and also means you can adjust your ride height from the spring perch, instead of the lower body. 

I was just about to ask the spring is only 15mm un captive it wont matter if the keeper is pretty much fully compressed even unloaded will it?

I guess i can adjust it all a bit anyway so its not fully compressed anyway. 

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54 minutes ago, kyteler said:

Yeah I'll measure up the keepers in the FD tomorrow and if they're the right diameter we can whip those out to try in the 34 first to ensure that's what we're after before you commit to buying some even though it's likely thats the deal. 

Markku/Clint, would you suggest running some in the front also and getting to 50mm Droop as per the MCA guide? 

IMO it will be a good idea to have a decent amount of droop in the FD. I did a shitload of R&D for my MX5 suspension mods last year and found that droop travel and good urethane bump stops are both key to good suspension for the road and track. MX5's are pretty limited in compression when slammed and I assume FD's are similar. Adding good bump stops and utilising droop travel are two tricks to maximise road holding ability. 

 

Just now, Toddy415 said:

I was just about to ask the spring is only 15mm un captive it wont matter if the keeper is pretty much fully compressed even unloaded will it?

Your keeper springs will need be a bit open at full droop - just enough to allow for that extra 15mm of travel. You can buy keepers from 25mm up to 70+mm in length. 

I would recommend something like this: https://www.trademe.co.nz/motors/car-parts-accessories/performance/suspension-braces/listing-2000560762.htm?rsqid=f6b126ce4b604edab9abc14c8ddcb068

keepers.jpg.bbfb1e3edef31d0d53086ad75f912349.jpg

 

40mm uncompressed length, 15mm compressed length, 3mm retainers. This would give you loads of room for adjustment and more than enough extra travel. You'll need to drop your spring perches by an extra 18mm from where they are now to account for the compressed spring and retainer, so they'll work well as long as you have that adjustment available. 

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3 minutes ago, Truenotch said:

IMO it will be a good idea to have a decent amount of droop in the FD. I did a shitload of R&D for my MX5 suspension mods last year and found that droop travel and good urethane bump stops are both key to good suspension for the road and track. MX5's are pretty limited in compression when slammed and I assume FD's are similar. Adding good bump stops and utilising droop travel are two tricks to maximise road holding ability. 

 

Your keeper springs will need be a bit open at full droop - just enough to allow for that extra 15mm of travel. You can buy keepers from 25mm up to 70+mm in length. 

I would recommend something like this: https://www.trademe.co.nz/motors/car-parts-accessories/performance/suspension-braces/listing-2000560762.htm?rsqid=f6b126ce4b604edab9abc14c8ddcb068

keepers.jpg.bbfb1e3edef31d0d53086ad75f912349.jpg

 

40mm uncompressed length, 15mm compressed length, 3mm retainers. This would give you loads of room for adjustment and more than enough extra travel. You'll need to drop your spring perches by an extra 18mm from where they are now to account for the compressed spring and retainer, so they'll work well as long as you have that adjustment available. 

Cheers man much appreciated

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