… the motor is in the back all your gonna do is plow (understeer) if you try to push it at all.
I have to disagree, with respect. Common misconception.
Understeer? My car is one of the best “turning in” (no understeer) cars I have driven. At any high speed it never understeers. Only at very slow speed sharp turns.
At high speed a small drift will stain my pants and I will find Jesus, but all this laundry work and conversion is needed because of slight oversteer, not understeer.
When you have the weight near the back, the front tyres have a longer moment arm to pull the nose around. The front tyres have less work to do to pull the nose around. No understeer. Better. Force x distance = Moment
Also, with the NSX all the weight is concentrated in one lump near the middle (slightly to the back), so the polar moment is “less”. Means the car will turn better, easier for the front tyres to do their turning work.
Polar Moment,:
Take a weight-lifting dumbbell. Hold it in the normal place in the middle of the thin part. Now rotate it by spinning your wrist. Hard to do because the weight is concentrated in the extremities. Wrist hurts. It doesn’t turn easily.
Now take the same dumbbell and hold it upright vertical standing up in your hand, with you hand grasping one of the weights at the end. Twist it around the axis. Much much easier, even thought the weight is exactly the same.
That is polar moment (simply put). And mid engine cars have a better “weight distribution” (partially, that just means lower polar moment) giving them better turn in. Less understeer.
Less work for the front tyres to do to turn the car around.
But, just like nsxtasy said, because of the same thing, when the back end goes out, it can go quicker too, for the same reason.
Because there is less mass sticking way out in the extremities. So it goes quicker, sometimes too quick for the driver.
If there were lots of weight in the trunk and lots in the nose, it could not “snap out” as quickly, and feel more like a sedan car, easier to feel it going out, doesn’t “snap out” as quickly.
However in this case once it got moving out, it would be harder for the tyres to regain grip, harder to “bring back” so I don’t suggest putting cement bags in your car to reduce “snap out”.
Unless it is snowing and you need to get up a hill, but THAT is something else entirely.
It is NOT that there is less weight over the front wheels so it understeers more.
Wrong wrong wrong. Common misconception.
If that were the case, try putting a few bags of cement in the nose and see how badly it turns in then. Make sure your insurance is paid up.
No, a lighter weight front end will always steer better that a heavy weight front end (unless there is deep water on the road).
And mid engine cars have less weight in the nose so they turn better, steer quicker, turn quicker. That is why pure racing cars have no engine in the front. Better turning.(also they put it in the middle to have lower (better) polar moment too. Two benefits for the price of one).
If you get understeer on the NSX, in a slow sharp turn in the rain for example, like maybe in a hairpin, it is because the castor and King Pin Inclination in a sharp turn causes the tyre to “lean over”. (Although you could say the kg/mm2 (pounds per square inch) on the tyre contact patch is more, so better in the rain, but the tyre is not made for running on the edge…lets not go into that here).
They gave the NSX more castor in their suspension design compromise to help compensate for the King Pin Inclination, return steering and behavoir on bumps, they decided on for good handling. All front suspension is a compromise. The consequence of all this is to make the steering wheel harder to turn, so they gave it an extremely low steering ratio, all a compromise.
Also, when bigger diameter, wider tyres are fitted, the scrub distance is changed, usually for the worse. This changes the cars feel. A lot of you have wider wheels set further outwards. This reduced the scrub distance making the steering feel like you are driving on ice. Not as good handling feel.
Unless you stay with 6.5 inch wide wheels (stock), and set them further out with spacers or less offset (centre line of wheel moved outwards), and keep the KPI the same, then the handling should stay as the Honda engineers settled on.
Of course with bigger diameter wheels/tyres, then the car will sit too high so you have to lower it with coilovers, then the car is running in “bump”, so the handling will again be different that the Honda engineers meant it to be, mainly with more pronounced “bump steer”. So compensating with strong anti roll bars is a good idea, so the car don’t lean so much, effective lean geometry will be more than normal because the car is in “bump”.
But then if you put strong anti roll bars on, then you can drastically change the car’s handling with respect to oversteer and understeer.
So, again, unless you understand ALL this (and there is more) then don’t change things to get better handling. You can’t function when you are in the dark.
So next, the King Pin Inclination causes the tyre to ”lean over” even further when you turn when you have changed to wider and larger diameter tyres. Because the KPI is fixed, the scrub distance changes.
You probably have noticed that formula cars have almost zero KPI.
Well, the fast ones anyway.
Because they have very smooth tracks. (older formula cars had more KPI because tracks were rougher, driver’s wrists like it when there is more KPI on rough tracks, less wrist and arm strain). So when they turn, their wheels/tyres don’t “lean over”. That is why you hear about drivers complaining about a particular race track being “bumpy”, poor bunnies. Their wrists and arms have severely noticed the bumps more than you will on a street car. Because they have almost zero KPI.
Anyway, you have to understand all this and more before you can change the wheels and tyres, and consequently the ride height, on a car like the NSX.
Maybe that is why some of you have understeer or oversteer problems.
Maybe that is why many stock cars will beat cars with different sized wheels.
Not maybe, actually.
Personally (in my stock NSX, stock wheels and tyres, ugly as hell it looks, but better handling) I have had mild oversteer, almost spinning sometimes when I push the car at just too fast a speed around a corner. Then the back end breaks out in a nice predicable way.
Very very quickly oversteers, (result of low polar moment) but predictable.
Never spun it accidentally.
Also on the Nurburgring this has happened several times and motorway on-ramps. On the Ring, it is many times at Adenauer Forst because it is suddenly slow and sharp, so the handling changes drastically (see above) confusing/upsetting my small brain.
I find it is not the correcting that is the problem, it is the “snapback” correction that is the problem because the steering is a too slow ratio.
Haven’t tried Spa yet, but when I do I won’t be going fast through Eau Rouge. MvM, Nick from v/d Poel Honda in Hulst told me about THAT experience…
Man, it is so complex but simple. You have to understand everything about suspension before you can “design” your own (which is what you are doing when you fit bigger tyres/wheels).
Anyway, maybe that’s why there are so many different experiences about spinning from person to person.
