Tuning my 450 in steps

[bob-in-dav]

Re: Tuning my 450 in steps

Where do you get a 20mm bar from? - aftermarket tuner?

Got mine on ebay from Ultra Racing - they were discounted for a while - paid about £110

[Kapt. Q]

Re: Tuning my 450 in steps

As i understand it the fortwo's arnt the best for handling and look like they would have a lot of roll and potentially tip at highet speed due to the height and tiny dimensions.....i could be wrong as i've never driven one personally. If this or some of it is true why would you want to make it a lot faster than it was meant to?
Fair do's on a roadster and forfour as they handle brilliantly and unless something goes seriously wrong you aint tipping a roady

When you spend some time and too much money sorting the suspension, wheels and tyres they can be little go-karts and tipping over is a non issue (you'd swap ends long before you could get side ways G forces high enough to tip it). Their suspension is basically the same design as the roadsters.

Cheers!

Ps. A 20mm rear anti roll bar would be too big. Ultra Racing only do 14 & 16mm versions.

[tolsen]

Re: Tuning my 450 in steps

451 models do not have any rear sway bar but still handles well. Better fitting special position or acceleration damping sensitive shocks for better comfort and handling if these can be sourced.

[Kapt. Q]

Re: Tuning my 450 in steps

451 models do not have any rear sway bar but still handles well. Better fitting special position or acceleration damping sensitive shocks for better comfort and handling if these can be sourced.

The roadster also has no rear bar (or provision for it).

Reducing under steer should be approached cautiously when dealing with a very short wheel base.

Cheers!

[bob-in-dav]

Re: Tuning my 450 in steps

Kapt.Q

Oops! You are absolutely right - it is a 16mm bar I got and not 20 - doh!

I was also going to fit lowered springs during that session in the workshop but decided that just doing the roll bar would give me feedback on that modification first.

[Thrumbleux]

Re: Tuning my 450 in steps

Got mine on ebay from Ultra Racing - they were discounted for a while - paid about £110

Didn't think it was an OEM fitment! (Even a 16mm bar)

Reducing under steer should be approached cautiously when dealing with a very short wheel base.

Cheers!

A move from 11mm to 13mm even, has a noticeable effect.
Stiffer rear bars should shift the balance more on a lowered car than one running at standard ride height.

[Kapt. Q]

Re: Tuning my 450 in steps

On a side note, anyone looking to radically improve comfort on our rubbish roads in the 450 should simply replace the rear springs with the roadster ones, I tried this as an experiment on my daily driver and was amazed at the result, it also eliminates rocking.

Cheers!

[Thrumbleux]

Re: Tuning my 450 in steps

On a side note, anyone looking to radically improve comfort on our rubbish roads in the 450 should simply replace the rear springs with the roadster ones, I tried this as an experiment on my daily driver and was amazed at the result, it also eliminates rocking.

Cheers!

Picking up on your side note... What do you mean by 'rocking'? Pitching, tail squat, or something else? Are the Roadster springs softer? (Implied by greater comfort). But softening the rear springs on a fortwo or anything else that brings the rear springs closer in stiffness/frequency to the fronts also makes the car pitch. Confused!

[Kapt. Q]

Re: Tuning my 450 in steps

Picking up on your side note... What do you mean by 'rocking'? Pitching, tail squat, or something else? Are the Roadster springs softer? (Implied by greater comfort). But softening the rear springs on a fortwo or anything else that brings the rear springs closer in stiffness/frequency to the fronts also makes the car pitch. Confused!

They are stiffer but car behaves better on rough roads & speed bumps. They also seem to sag less so neutral position of body is higher allowing slightly more travel (I estimate about 15mm), but my originals were quite old. I was very surprised by the ride quality enhancement as it was not what I was aiming for. Soft springs do not always make for a good ride if it means the suspension is always bottoming out. I found it remarkable how well they work with the front spring rate. If anyone wants to try it, the springs are very cheap.

Cheers!

[tolsen]

Re: Tuning my 450 in steps

They are stiffer but car behaves better on rough roads & speed bumps. They also seem to sag less so neutral position of body is higher allowing slightly more travel (I estimate about 15mm), but my originals were quite old. I was very surprised by the ride quality enhancement as it was not what I was aiming for. Soft springs do not always make for a good ride if it means the suspension is always bottoming out. I found it remarkable how well they work with the front spring rate. If anyone wants to try it, the springs are very cheap.

Cheers!

Thanks Captain.
Yes, the standard rear 450 suspension setup does not have much effective travel before bottoming out so I think I'll go ahead and try out this modification. You say the Roadster springs are very cheap. Perhaps somebody that have lowered theirs will have a pair of standard rear Roadster springs they can afford to part with for a reasonable fee?

[Kapt. Q]

Re: Tuning my 450 in steps

Thanks Captain.
Yes, the standard rear 450 suspension setup does not have much effective travel before bottoming out so I think I'll go ahead and try out this modification. You say the Roadster springs are very cheap. Perhaps somebody that have lowered theirs will have a pair of standard rear Roadster springs they can afford to part with for a reasonable fee?

Excellent, I look forward to your review. Perhaps you will more accurately measure height change than I did?

Cheers!

[tolsen]

Re: Tuning my 450 in steps

Excellent, I look forward to your review. Perhaps you will more accurately measure height change than I did?

Cheers!

Details of standard rear springs as follows:

Roadster round bar diameter 10.25 mm, length 239 mm
Smart 450 round bar diameter 9.5 mm, length 245 mm.

Coil diameter is similar but varies a wee bit between spring manufacturers but typically 99 mm.

Number of coils is same. The obvious benefit when fitting standard rear Roadster springs on a 450 is reduced material stress in spring due to the larger bar diameter. This should in theory lead to less chance of spring breaks. All my failed rear springs have snapped off at lower end usually starting as a fatigue crack. My most recent spring break was yesterday. This is number 10 or 11 since I got my Cabrio almost 12 years ago.

I've placed an advert on this site for a pair of Roadster rear springs but no replies so far. Might go for a pair of Suplex 19265 springs. They come with a stupid two years guarantee (springs for life in my case) and only cost about GBP 18 each postage included.

[problemchild1976]

Re: Tuning my 450 in steps

VX220 turbo!

It's how the lotus should have been powered

On my 450 pulse I had eibach lowering springs and spaced out 16" wheels on 195 tyres and it handled very well (keep the yaw sensor busy)

No matter what you do to the fortwo, it's not gonna be hot hatch fast. But it will shock some people off the line

Good luck but as evil says, you don't need to spend thousands on aftermarket parts, just buy wisely based on the advice of those who know and have been through it all already.

JJ

[Kapt. Q]

Re: Tuning my 450 in steps

They come with a stupid two years guarantee (springs for life in my case)

Are you poorly? I certainly hope not!

Cheers!

[tolsen]

Re: Tuning my 450 in steps

Are you poorly? I certainly hope not!

Cheers!

None of my Smart springs have lasted longer than two years. With a two years guarantee at least I will get another set or my money reimbursed when they break.