Spring rates for Nitrons ....
Discussion
I agree with the can't/difficult to compare argument. The problem is that there are so many variations out there which various people claim to be the optimum and are clearly not. Many drivers will drive round their settings and be quick despite their cars.
There are no magic formulae and everything is a compromise. Touring usually means two up with a weight loaded car. The weight balance will be radically different from that of a car on a track with one occupant and no luggage and light fuel. That means that one setting will be compromised whichever way you look at it.
The most important question to ask is what is the problem I am trying to solve? What is limiting the car's behaviour? Is the front or rear too soft? How much roll is there? Does the car yaw about. Get some piccies/video of the car and look at the what the car is doing and then decide how much to increase fronts and backs etc. It takes time but the effort is worth it. It might take several iterations of springs but they are cheap.
There are no magic formulae and everything is a compromise. Touring usually means two up with a weight loaded car. The weight balance will be radically different from that of a car on a track with one occupant and no luggage and light fuel. That means that one setting will be compromised whichever way you look at it.
The most important question to ask is what is the problem I am trying to solve? What is limiting the car's behaviour? Is the front or rear too soft? How much roll is there? Does the car yaw about. Get some piccies/video of the car and look at the what the car is doing and then decide how much to increase fronts and backs etc. It takes time but the effort is worth it. It might take several iterations of springs but they are cheap.
As mentioned on another thread here, you also need to watch the ride heights too.
I had lowered mine too much at the rear, which induced a lot more roll sensitivity. (This is due to the angle the wishbones adopt, in relation to horizontal/chassis.) Having gained a bit of rear ride height, it all feels a lot more controlled.
As Steve says, it's all down to trial and error, and at the end of the day, personal preference.
The good thing about Nitrons though, is that most of this is not too difficult to alter, even between runs at a ciruit.
I had lowered mine too much at the rear, which induced a lot more roll sensitivity. (This is due to the angle the wishbones adopt, in relation to horizontal/chassis.) Having gained a bit of rear ride height, it all feels a lot more controlled.
As Steve says, it's all down to trial and error, and at the end of the day, personal preference.
The good thing about Nitrons though, is that most of this is not too difficult to alter, even between runs at a ciruit.
HarryW said:
HarryW said:
Johno,
in a garage awaiting 'some' work.
harry
Indeed .... still there, but there is progress .... that progress will result in the necessity for the new dampers... The old are knackered anyway and were due a change, but I might aswell do the whole lot at once.
Should see it back in time for Touring in Scotland at the end of July/August !!
Drop me a mail and I will expand.
who stole your LE badge
harry
I did !!! Got it back from Leven a couple of weeks ago and it looks sooo much better ...... and was nearly as bad as the stone chips on the front ...
You'll like the spec when you talk to Mike and Paul I think .... must give 'em a call today actually ....
If it helps anyone I have just had my Chimaera (Eibach) springs measured at work. The fronts are ~275 lb/in and the rears are ~200 lb/in.
Unfortunately the machine can only measure 2 inches of displacement as it was designed for valve springs. As they are dual-rate springs this therefore doesn't take into account the stiffness change after the first part goes coil-bound.
Unfortunately the machine can only measure 2 inches of displacement as it was designed for valve springs. As they are dual-rate springs this therefore doesn't take into account the stiffness change after the first part goes coil-bound.
really? still got a touch (not much)of mid corner understeer i'd like to loose, bit squeally too.
was gonna go up another 50lb all round. maybe its too stiff. looking at photos suggests its about right.
first though, i've got a set of road slicks. gonna see how it works out with them first.
any thoughts?
>> Edited by Guillotine on Friday 2nd July 22:39
>> Edited by Guillotine on Friday 2nd July 22:40
was gonna go up another 50lb all round. maybe its too stiff. looking at photos suggests its about right.
first though, i've got a set of road slicks. gonna see how it works out with them first.
any thoughts?
>> Edited by Guillotine on Friday 2nd July 22:39
>> Edited by Guillotine on Friday 2nd July 22:40
Guillotine said:
really? still got a touch (not much)of mid corner understeer i'd like to loose, bit squeally too.
Tried accelerating harder through the corner? Mild understeer is generally good for exit speed as long as you have enough torque available to get through the understeer hump.
feathering thru (turn in to apex) at the mo...am pretty fast thru anyway and car is set up to accelerate from apex with a good balance.
turn in is good, so not too much top worry about.
getting on the throttle earlier would just make me run wide on understeer.
got about 2 derees neg on the front. May be running the nitrons too stiff (17)
turn in is good, so not too much top worry about.
getting on the throttle earlier would just make me run wide on understeer.
got about 2 derees neg on the front. May be running the nitrons too stiff (17)
Changing your driving style can make a big difference to transient handling problems. In general, with a more powerful car it is worth taking a slightly later apex. This means your entry speed is lower but you can accelerate earlier which more than makes up for it on the way out. Since the car would normally be set up to be nicely balanced under acceleration, this also means the car is more neutral more of the time. Finally, the lower entry speed and late apex means you have earlier visibility of hazards in the corner and are travelling slower when you see them. If you don't already use this approach, it would be worth giving it a try.
peter,
with you on all of that, but when up against cars that are faster thru the corners, caterfields etc, i need to protect my apex under braking, which incidentally is greatly improved with the AP 4 pots / nitrons.
as you say, the earlier you can get on the trottle the quicker the lap time, but if you have another car taking the apex the slowing your exit you've lost all round.
i've tried to improve turn in and braking to reduce this without compromising the exit and i feel i'm nearly there, but as we know that last bit is the money shot (and where the real skill lies
)
smooth in, heel and toe and early throttle is the key IMHO but protecting the apex really pays off when up against other nmakes (ins porkers,ferraris and nobles).
with you on all of that, but when up against cars that are faster thru the corners, caterfields etc, i need to protect my apex under braking, which incidentally is greatly improved with the AP 4 pots / nitrons.
as you say, the earlier you can get on the trottle the quicker the lap time, but if you have another car taking the apex the slowing your exit you've lost all round.
i've tried to improve turn in and braking to reduce this without compromising the exit and i feel i'm nearly there, but as we know that last bit is the money shot (and where the real skill lies
) smooth in, heel and toe and early throttle is the key IMHO but protecting the apex really pays off when up against other nmakes (ins porkers,ferraris and nobles).
Sorry, thought you were talking about road driving, didn't realize you are racing! Don't know the whole answer, but I think the front/rear roll balance will need to be set to avoid excessive oversteer under power, this will normally mean you do get some understeer when coasting/accelerating gently. There are some techniques you can use to cope with this. In terms of driving style, avoid spending time in the understeer hump, instead of opening the throttle gradually hold off (keeping a tight line) until you can afford to accelerate hard enough to overcome the understeer. This may mean you lose ground at the apex (so what're they going to do, go over the top?) but you can avoid washing out from understeer which gives you more width to make use of all that power. Also you can set the car up for transient oversteer by softening the front dampers a little. But you do have a tough choice to make because going defensive on the way in will compromise your overall speed, for you more than for the other guys.
but there's an old racing maxim... if you're not braking or accellerating, you're wasting time!
however,
this is "non-competitive" stuff, trackdays etc but generally against the same guys with the same cars (as mentioned). been developing the car for the track over the last four years. some stuff has worked, some hasn't.
but you know how it is once you're out there
Le mans in a couple of weeks followed by Dijon. as usual will be up against caterhams, nobles, elise/exige, GT3 etc so its a case of racing those you can and getting out of the way for those you can't. ie Radicals / ADR etc
god they're quick
cheers
hoping the road slicks will help!
>> Edited by Guillotine on Sunday 4th July 14:42
If you are running slicks then your current settings will need to be radically changed to get the best out of them. That means taking camber off and increasing the spring rate dramatically. The better grip will increase body roll which means that the suspension has to be stiffened to cope and then the camber is not right. Took about 3 months to dial the 520 in when I switched.
Gassing Station | Griffith | Top of Page | What's New | My Stuff