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Hi
I have been doing a bit of reading on the subject of suspension and wish to settle a couple of points.

1.If one had coilovers then stiffer than OEM sway bars would not be necessary as they would detract from the effectiveness of the independent suspension? And in fact decrease grip?

2.If one had stock suspension or stock shocks with stiffer springs - then stiffer sway bars would be of benefit?

The above applications are for road/track, not autocross.

Curious as to what peoples opinions / gained knowledge might be.

thank you

Chris

The stock suspension is very optimised for the levels of grip stock street tyres have.

If you go stiffer the car will not body roll as much so its likely that the weight transfer wont work properly and your cars camber will not be used, infact the camber without body roll leads to less tyre on the road, a smaller contact patch.

Sways only help to flatten the car if the springs are not stiff enough, however they lower weight transfer without the need to stiff springs.

As you say, stiff springs and stiff sways are usually not good.

Remember, roll stiffness needs to be proportional to grip of the tyres. So stiff springs and sways works of you have big grippy slicks. But the lack of body roll/contact patch due to camber in the suspension stuffs you if you have stiff everything but niot enough grip to still achieve body roll.

Dann

What Dann said. I have stock suspension with Whiteline adjustable sway bars set soft front and mid rear. The car is flatter and more responsive through corners and "feels" like it has more grip, especially on the road. On the track? I've followed a stock NC (with a better driver) on track and yep, lots of roll for him but he was out gripping me with both of us on road tyres.

I have no idea what mine would be like with semi-slicks but suspect it would work a lot better.

Chris,
As Dan said, really stiff is no good, you need to strike a happy medium between wallow and ironing board stiff.

A NC with stock shocks, slightly stiffer springs like the Kings or Eibach and a set of upgraded adjustable sways will handle great.

Once you go to stiffer coil over springs, along with heavier bars, you won't get the body roll and therefore enough negative camber thats required for the track so you need to increase your static negative camber to compensate for this. You also need to check what negative camber your tyre manufacturer recommends.

The winning time attack car at Eastern Creek this year was setup by Spinning Wheel with "soft" settings to keep the wheels on the ground. I followed Ralph on Sunday and watched as his front wheel lifted off the road on tight corners. To my knowledge mine doesn't do this and I was able to close through most corners on him. He pulled away after the exit but that's due to the 4.1 diff.

I've run mine with stock bars and coil overs for most of the last two years. I then added the adjustable rear bar on full soft to get more oversteer ar the Creek. Last meeting with the 1:09 lap, the adjustable bar was back on the front but so too was a lot of camber.

Charlie Brown wrote:Chris,
As Dan said, really stiff is no good, you need to strike a happy medium between wallow and ironing board stiff.

A NC with stock shocks, slightly stiffer springs like the Kings or Eibach and a set of upgraded adjustable sways will handle great.

Once you go to stiffer coil over springs, along with heavier bars, you won't get the body roll and therefore enough negative camber thats required for the track so you need to increase your static negative camber to compensate for this. You also need to check what negative camber your tyre manufacturer recommends.

The winning time attack car at Eastern Creek this year was setup by Spinning Wheel with "soft" settings to keep the wheels on the ground. I followed Ralph on Sunday and watched as his front wheel lifted off the road on tight corners. To my knowledge mine doesn't do this and I was able to close through most corners on him. He pulled away after the exit but that's due to the 4.1 diff.

I've run mine with stock bars and coil overs for most of the last two years. I then added the adjustable rear bar on full soft to get more oversteer ar the Creek. Last meeting with the 1:09 lap, the adjustable bar was back on the front but so too was a lot of camber.

Phil, Dann, JBT, Thank you for that. I am running Ohlins coil overs with the stock bars. I have the coilovers pretty much on the factory recommended setting and I'm well happy with the cars behaviour
on the road and track. I don't have very aggressive camber settings that I know of, I'll check with my mechanic next time. But he did tell me it is set as a compromise between highway driving and track driving conditions. The car is a bit lower, but not much. I do not have the knowledge to change any settings myself and would probably ruin the cars handling if I did.

BTW I was watching your car for a few laps the other weekend and was quite impressed.

I have seen a number of cars, generally not mx5s, that have suspensions so stiff that they can sit with one wheel in the air while negotiating a driveway. I always wondered what was the point.

From the replies above, I gather there isn't.

thanks all for the advice, much appreciated !

chris

Glad the OP is happy, but I'm slightly confused.

So the answers seem to be:

Q1: If one had coilovers then stiffer than OEM sway bars would not be necessary as they would detract from the effectiveness of the independent suspension? And in fact decrease grip?
A1: You are asking the wrong question, you shouldn't even have coilovers unless you have sticky slicks. Go back to stock springs otherwise you will lose all grip and slide off the road.

Q2: If one had stock suspension or stock shocks with stiffer springs - then stiffer sway bars would be of benefit?
A2: No, it will stuff up your handling. Go back to full stock.

If you are running stock tires then with the exception of alignment leave the suspension stock.

Dann

barge wrote:Glad the OP is happy, but I'm slightly confused.

So the answers seem to be:

Q1: If one had coilovers then stiffer than OEM sway bars would not be necessary as they would detract from the effectiveness of the independent suspension? And in fact decrease grip?
A1: You are asking the wrong question, you shouldn't even have coilovers unless you have sticky slicks. Go back to stock springs otherwise you will lose all grip and slide off the road.

Q2: If one had stock suspension or stock shocks with stiffer springs - then stiffer sway bars would be of benefit?
A2: No, it will stuff up your handling. Go back to full stock.

My above questions were to confirm some things I was unsure about. IMHO the Ohlins enhance the cars handling, but if you went overboard with the settings then well, you'd be wasting your time and get into the situation of A1.

In terms of Q2, I don't have that set up.

thank you
chris

Shock absorbers do not affect what we have said. Assuming they are not damped stupidly good quality shocks will always help where as springs are springs and the right rate has been given to you by the manufacturer for stock Tyre levels of grip.

Dann

NitroDann wrote:Shock absorbers do not affect what we have said. Assuming they are not damped stupidly good quality shocks will always help where as springs are springs and the right rate has been given to you by the manufacturer for stock Tyre levels of grip.

Dann

No argument about that!

c

um ok, so will you take your Ohlins out?

Dann, the problem is that spring rates are not chosen by the manufacturer to maximise grip with the stock tyres. Spring rates are chosen to maximise sales.

That is true, the mx5 is sold as the best handling sports car money can buy this side of a Ferrari.

Guess what that means?

Dann

NitroDann wrote:That is true, the mx5 is sold as the best handling sports car money can buy this side of a Ferrari.

Guess what that means?

Dann

That Ferraris are too expensive!

NitroDann wrote:Shock absorbers do not affect what we have said. Assuming they are not damped stupidly good quality shocks will always help where as springs are springs and the right rate has been given to you by the manufacturer for stock Tyre levels of grip.

Dann

Rubbish!
The springs are a compromised fitted to maximise sales.
Soft enough to give a smooth ride but too soft to maximise handling.
Hard enough to give good handling but not hard enough to effect ride.

OEM tyres are good.. There are plenty of road legal tyres in stock sizes that will generate enough grip to overpower the stock suspension and cause handling problems.
mainly too much roll which effects tyre contact

Sailor wrote:

NitroDann wrote:Shock absorbers do not affect what we have said. Assuming they are not damped stupidly good quality shocks will always help where as springs are springs and the right rate has been given to you by the manufacturer for stock Tyre levels of grip.

Dann

Rubbish!
The springs are a compromised fitted to maximise sales.
Soft enough to give a smooth ride but too soft to maximise handling.
Hard enough to give good handling but not hard enough to effect ride.

OEM tyres are good.. There are plenty of road legal tyres in stock sizes that will generate enough grip to overpower the stock suspension and cause handling problems.
mainly too much roll which effects tyre contact

Bridgestone RE050A (std tyre for NC) = combined with stock suspension, gives the best performance for that regime.

So better tyre (and also wider tyre?) = exposes suspension limitation

Stiffer suspension = maximises handling, as long as tyre is up to coping with it.