8 replies to this topic

[Pops_Guild]

I’m pretty happy with perf of my bog standard Cooper SPi so aside from doing the obligatory exhaust and K&N (done) I don’t want to change the engine spec to improve perf.

From the various weight reduction stuff I see from the KADs of the world, it’s not cheap to do but I am genuinely interested in the knowledge here on whether it actually makes a difference to perf/handling and what sort of weight difference it actually makes.

Thoughts?

[nicklouse]

like what?

 if you have not done anything to the engine you will see very little change elsewhere.

 

other than needing to soften the dampers.

[unburntfuelinthemorning]

Lowering the unsprung weight should improve the ride comfort and help the wheel stay in contact with the road surface better when cornering over bumps in theory.  Having not done this in practice I too am interested to know what difference it makes.

 

If you're after a handling improvement though you'd probably get more bang for your buck by fitting solid front subframe mounts, renewing the springs, putting decent dampers on and optimising the suspension geometry.

[DeadSquare]

It revolves around inertia, and the effort that the spring has to exert to return the wheel to its desired position after a deflection.

 

The softer the initial spring rate, the better the suspension is able to keep the tyre in contact with the road, and as nicklouse says, damper rates can also be softer with lower unsprung weight.

[mab01uk]

You might also be interested in this technical article in link below by Keith Calver:-

 

Wheels & tyres - Bigger wheel fitment consideration 

"Bigger wheels/tyres means more (un-sprung) weight to control when encountering road surface imperfections (bumps/pot-holes)."

https://www.calverst...-consideration/

Edited by mab01uk, 26 October 2019 - 12:25 PM.

[Spider]

I've found changing the Sprung to un-sprung Ratio does make a difference and surprisingly so.

 

The ride is way better, for one. I felt the handling was a little improved too, but I didn't do back to back checks on this aspect alone to say it that's where it came from.

[DeadSquare]

I've found changing the Sprung to un-sprung Ratio does make a difference and surprisingly so.

 

The ride is way better, for one. I felt the handling was a little improved too, but I didn't do back to back checks on this aspect alone to say it that's where it came from.

The irony is that the more the car is lightened, the worse the ratio gets.

[unburntfuelinthemorning]

A lot of vehicles are more comfortable when more weight is carried which does the same to the ratio as lightening the unsprung weight.  However, more sprung weight doesn't help the handling.  My van was very comfortable when I picked up an A series engine and gearbox but the steering response was terrible.

[smudger068]

I think in terms of cost their is not a massive amount to be gained. And their certainly is better things you could spend your money on first.

They are normally parts for people who are in competition were by that point everyone is trying to gain that small advantage.

To be honest if their was a greater margin to be had from them everyone would be fitting them. Like protech dampers/engine parts etc. Not saying you would not notice anything fitting them but you would have outlaid alot of cash.

Edited by smudger068, 27 October 2019 - 06:40 AM.