23 replies to this topic

[01smartc]

Hi all,

As you may know I race the Smart Performance hillclimb car. Over the winter we are doing some development work, one of the areas we are looking to improve is the front subframe/suspention, I have been having problems with getting it to handle how I like it and its just so bloody heavy!

So ive been looking at the Zcars front subframe with the thought of putting it in the racer with our 1380cc 16v Twincam engine.

Just got a few questions

Does it handle better than the std subframe on coilovers?

How heavy is it? Is it lighter than std?

Would it be worth while on our all out, gta win next year racer?

Cheers

Chris @ Smart Performance

[wtverouden]

Hi Chris,

The Z-cars subframe is 10 kg lighter than the standart mini front subframe. It will absolutely handle better than the standard one on coilovers. It'll get rid of any bumpsteer you usually experience with the standard subframe.

Visit chris and he'll show you the difference, the handling is stunning.

cheers Pim @ holland

[Paul Wiginton]

A standard subframe is 13kg, are you sure Z cars is 10kg lighter?

I fabricated my own subframe this year, I designed a top wishbone into it rather than a top arm (mirroring the bottom wisbone and its angles.) This massively reduced front end lift on accellerating and improved grip. The Z cars has a similar arrangement so I believe will help.

Bumpsteer is to do with the angle of the steering arm so replacing the trackrod end with a rosejoint end and a spacer made to the appropriate thickness will help eliminate this.

The coilover arrangement on Z cars will reduce unsprung weight which should aid grip.

Paul

[wtverouden]

To my knowledge a standard front subframe weighs 30 kg.


pim

[Paul Wiginton]

Is that built up?

[Paul Wiginton]

Ooh, hold on, my lightened std subby was 13kg bare, a standard fully built up subby is 50kg, my new subby is 6.5kg bare

[Zcars Richard]

the front subframes are lighter when you weigh all the ancilliaries as well as the basic frame
the angles of the arms are different so help keep the wheels in the right place on the tarmac
weve not sold any to full on racers so i cant comment on the end result only that the theory is correct
they certainly have better wheel travel and rising rate than a stock set up so everything points to a better amount of traction and control
chris

[R1minimagic]

I found with my Z cars front subframe that I lost all steering feel at low speeds (up to about 40 or 50mph) compared to a standard mini front subframe, but it got better at higher speeds, has this been eliminated now?

If so, what was the cure?

[hazpalmer14]

isn't that because as you push harder the wheels are pushed further into the ground giving more grip and handling in the corners

[AllanMcD]

I found with my Z cars front subframe that I lost all steering feel at low speeds (up to about 40 or 50mph) compared to a standard mini front subframe, but it got better at higher speeds, has this been eliminated now?

If so, what was the cure?

That problem sounds like you didnt have enough front wheel weight eg you needed to lower the front or raise the rear.
The lighter your car is the more important weght distribution is.
Allan

[R1minimagic]

The corner weights had been set up by a local Mini Miglia racing team and they said they would be happy with the corner weights i had on their race cars, so nothing to do with that.

Chris told me at the time that he knew about the problem and was working on some cures for it, including fitting a quick rack.....

Edited by R1minimagic, 17 December 2009 - 12:35 PM.

[AllanMcD]

The corner weights had been set up by a local Mini Miglia racing team and they said they would be happy with the corner weights i had on their race cars, so nothing to do with that.

Chris told me at the time that he knew about the problem and was working on some cures for it, including fitting a quick rack.....

A miglia has the engine in the front.
Even the F1 boys need to change there cars to get them to work when they have plenty money and experience.
My car is ace but it needed a fair bit of teaking to get there and it never understeers even in the wet.
If it understeers you need more weight on the front easy.
Ps I have beaten a few Radicals so its not in my head.
Allan

[R1minimagic]

Doesn't matter where the engine is, the idea of corner weights is to get the particular car as well balanced as possible, that was what they were meaning, not my car had the same corner weights as a Miglia, that would be impossible!

Any car can be made to understeer or oversteer, just depends on the driver!

[AllanMcD]

Doesn't matter where the engine is, the idea of corner weights is to get the particular car as well balanced as possible, that was what they were meaning, not my car had the same corner weights as a Miglia, that would be impossible!

Any car can be made to understeer or oversteer, just depends on the driver!

Its the balance front to rear that needs seting to fix understeer or oversteer.
Allan

[R1minimagic]

Chris seemed to be aware of the problem at the time, and as I said, he was experimenting with fitting quick racks.

You don't need corner weights setting up if you are only driving at 40mph, optimising corner weights improves your handling when you are driving at or close to the limits..

Edited by R1minimagic, 17 December 2009 - 05:52 PM.