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My long promised blog

Enuo said:
*insert evil grin*
Click to expand...


Mr-Burns-evil-grin.jpg
 
I've been bodge hunting... anything remotely bodged has been fixed... funnily enough only wiring..
It has (as @enuo will be pleased to know) is all now crimped and heatshrunk. No more dodgy wiring for me :D
And H701 is now bodge free
 
h701micra said:
I've been bodge hunting... anything remotely bodged has been fixed... funnily enough only wiring..
It has (as @enuo will be pleased to know) is all now crimped and heatshrunk. No more dodgy wiring for me :D
And H701 is now bodge free
Click to expand...
I'll sleep easy tonight now :p
 
Cut springs and the facts. End of. No questions. That's it

First off I took a spring...its a 100lb/in spring with a 13.2in free length
Few dimensions
12.5mm material thickness (w/t)
335mm free length (f/l)
87.5mm closed length (c/l)
138mm diameter

Currently on H701 is a smaller 10.5in 113lb/in spring..
268mm f/l
81.25mm c/l
136mm diameter
And the same 12.5 w/t

Anyway to the cutting
The spring has 7 coils
So I calculated the height and spring rate
1 full coil off gives
296mm f/l
75mm c/l
And 117lb/in +17% (40mm)

2 coils off gave
240mm f/l
62.5mm c/l
And 140lb/in +40% (95mm)

Cant go no lower as I want to remain captive and my aim is 125lb/in

So 1.5 coils off
268mm f/l
68.7mm c/l
And 127lb/in +20% (67mm)

Its official... cut standard springs are better than lowering springs in terms of rate...

As more coil off ups rate I need to go less..
So 1.25 coils off
289mm f/l
71.8mm c/l
And 122lb/in +22% (46mm)

You could say 1/4 coil is 5lb/in but that's incorrect.. rate goes up the more of the coil is cut.
1 - 17%
1.25 - 22%
1.5 - 27%
2 - 40%

The rate machine cycled each spring 100 times continuously so they're well settled. No sign of sag of wear. They retained their rates

Now I fiddled and tweaked my numbers about.
Chucked H701 on the scales and I got the static l/r weight balance 50/50. Weighing a massive 220kg on each front corner. And 93kg on each rear corner. 57% front/rear balance which is about right :)

Looking at the roll centres on the car there's more weight transition from right to left than the other way round only by a small margin and the only way to counteract that is varying spring weights... I cut the springs accordingly to give the right rate. 1.15 and 1.25 coils was my selection in the end.
Shimmed the height to reset the crossweights to where I like em

Normally varying weights on the springs isn't that plausible... trimming the coils gives me that flexibility
So I got 50/50 static and now 50/50 dynamic... not done that before on mine so it should corner like a lunatic now on some rough surfaces :D

So in summary as much as I hate cut springs. Providing they're cut correctly they can be extremely efficient. I don't recommend going beyond the max shock length, so they can remain captive. Other than that they should serve you well providing you get the right height and rate from them
 
Cheers Andy, im glad i actually understood most of that :)

If i can get some rear springs of a car that normally supports a higher load & remove a few coils whilst captive the rate should be plenty stiff for a K11.

If nothing else it will give me an idea of what rear rates are best
 
Skinner_87 said:
Cheers Andy, im glad i actually understood most of that :)

If i can get some rear springs of a car that normally supports a higher load & remove a few coils whilst captive the rate should be plenty stiff for a K11.

If nothing else it will give me an idea of what rear rates are best
Click to expand...
No worries. Keep checking it as I add bits I've missed out :)

Hopefully it helps
Go for a longer spring to give you more room to cut coils
And remember rate increases when cut so get soft ones. Petrol springs over diesel springs etc :)
I've a whole load of things to play with now :D
 
McMicra said:
@h701micra

What about cut lowering springs?
Click to expand...
If the objective is higher spring rate then standard springs are better :)
Huggy444 said:
If they're progressive I'd of thought you'd get the same results, wonder what the Guru says
Click to expand...
Close. Your right but..
I had a play with progressive springs... where you have a 2 stage spring (I'll get a photo) if you cut from one side you increase the rate of that side only not the entire spring

Found one
1389122010930.jpg

If you cut from the top set you increase that rate but the already stiffer bottom set would remain the same

If that makes sense?

(That spring is upside down... but he's a special lad)
 
Yay corner weighting... I love corner weighting... with proper scales :confused:

I just wanted to chuck some info up here beforehand so when I throw up figures and info later you've got a base knowledge to relate to

Those WITHOUT coilovers do not fear you can still have adjustable suspension. H701s rally kit is shock and springs at the front. Cheap 6n coilovers aren't mega height adjustable as the shock is a fixed height but its still adjustable

H701 is already corner weighted properly so I'll note all adjustments down and then have another go with my £6 scales

Anyway...
Corner weighting part 1 static weight balance this is balance between left and right over each axle. Our objective is to get 50/50 left right balance including driver.
I know that when I sit in my seat my weight affects the rear slightly more than the front because my centre mass is behind the centre of gravity.. as will all of yours be. As it sits now I'd safely guess your CoG will be between your heater and your gearstick and near level with your clutch pedal

Once you've got 50/50 or as close as possible you go onto cross weights.
A crossweight is the weight of 2 corners.
There is 2. 'FR and RL' and 'FL and RR' as they start one corner and cross over to the other.
This is where we can calculate your front rear weight bias. I've always found 57% front has always worked best for our cars.
Why not 50/50? Well our cars are front wheel drive and they need weight over the wheels to gain traction and move. Too little and you wheelspin and understeer. Too much and you'll break traction under braking and get the all famous lift-off oversteer. This is also affected greatly by springs and shocks but lets forget them for now.

You can then adjust ride to wherever you feel comfortable. And set up your cross weights up where you're happy. Too low you'll bottom out and too high you'll increase your CoG and roll centres, this exaggerates weight transfer. If you've shocks n springs or static coilovers you're pretty stuck for height but we can adjust crossweights that's the main thing

Hope this makes sense this far folks
 
Last edited:
Right here we go.. my car has gained a few kilos... I thought if I wanna do this properly I need some unknown numbers. So I chucked a subaru box and rear subframe in (because I was also curious how much that'd weigh too :p so I suppose you could say these are nissanubarus figures almost

These scales on their own take 136kg apparently. I dropped a corner on one scale to see exactly how much it would take. Turns out they max out at 152kg (all the way round + 4 stone) but there was no damage to the scale even after loading it with 200kg plus (was 220 but I don't know now :p) Bonus points that we can't break them :)

Moving on... first things first.
Mark the centre
1389279297766.jpg

You'll need something to place on it to spread the load of weight evenly on the scales
Its one pic per post so I'll say see pic 2 and add it after
Once you've added that zero your scales if not make not of the weight displayed.

Find something that will hold the other 3 corners up at the same height. Chunks of wood, slabs etc all work well.
If you can't don't worry too much its less accurate but as long as it consistent that's all that matters (I didn't bother)

Jacking one corner means you'll get more weight on the scale
See pic 3 how weight distributes :)
Now jack the car up safely and lower it down onto your scale setup. Keeping the centre of the tyre over the centre of the scale
See pic 4

Do this for all 4 corners and note your weights down

That's part one :)
 

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