I understand that the front needs toe out, but on my picture of the specs, that .17 and .18 number, is that my toe out? Or because it's not negative this is actually toe in?
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Alignment setup
- Thread starter powerneedy
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Based on the arrows alone, it looks like toe in.
In comparison, the top photo shows "0.07" and the arrow is pointing outward. Looks like they might use an always positive sign convention and just go off the graphic.
You don't "need" toe out. Toe out will aid in cornering, but for daily driving, it will be "darty" as mentioned before. Think of toe out as unstable (wants to turn), and toe in as stable (i.e. doesn't want to turn). For DD, most of your driving is in a straight line. Which is likely why they've got you with just a tad tow in.
Lucas
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Toe is measured with a default of toe in, that is, positive numbers represent toe in, negative numbers are toe out.
You don't *need* toe out, but it helps with turn-in. Mild toe out will not make the car darty. Excessive toe out will. Your numbers are pretty tame, pretty close to zero, especially considering they are measured in degrees and not in inches or mm.
I'd recommend a *touch* of toe out, but realistically, you might not even notice the difference to get it realigned, unless you are extremely sensitive and are measuring tenths of a second on a race track.
You don't *need* toe out, but it helps with turn-in. Mild toe out will not make the car darty. Excessive toe out will. Your numbers are pretty tame, pretty close to zero, especially considering they are measured in degrees and not in inches or mm.
I'd recommend a *touch* of toe out, but realistically, you might not even notice the difference to get it realigned, unless you are extremely sensitive and are measuring tenths of a second on a race track.
jaja and dquarasr2, thank you for the responses, the previous posts were a little too vague, now I feel a little better about the setup and understand it more. The car drives wonderfully, I did notice that before it felt a little darty and now it doesn't, I do drive mostly on the street so it's a good stable ride for me now and the front camber change feels much better in the turns. Overall I'm very happy with the specs, just needed to know what changes do what to the handling so I know what to do next time.
numbers are only numbers..as you have described you like the feel so use this as a starting guide.The toe out is probably complimentary to the manual rack ...whereas the later eps units make it easier to turn the wheel even with neutral to slight positive toe.
Toe-In will probably improve the initial response and dartyness than toe out. Tires need to generate slip angles to generate cornering force. If you have toe-out, the outside loaded tire goes to neutral then builds to the direction your turning while toe-in already slightly preloads the tire in the direction you want to turn, but could be more nervous and darty in a straight line.
Just the 158 Mustang in GS. We didn't have a ton of speed during the race.
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Now I am confused. I understand your explanation about preloading the tire but I had always understood toe out to allow the outside tire to better follow the "longer" path , being on the outside, and that toe out promoted skittishness especially under hard braking.
The more i know the less i seem to know LOL.
That's the key right there
I remember reading a great summary from Comptech from the 90's based on their work with the Acura Spice cars. They said you want slight toe-out on the front axle in the NSX and as much positive caster as possible, as it will improve the turn-in feel of the car. Basically, they said the factory alignment settings for the front axle were perfect, except you should max out the caster.
For the rear axle, they said you want toe-in because of the NSX's rear suspension geometry and rubber bushings. Basically, on hard braking for a corner, the rear tires will "squat" and toe-out from the flex in the bushings. You want to leave some room so that the tires are still toe-in or at least at zero when this happens. This greatly improves rear-end stability on corners. That is why Honda spec'ed a 6mm total toe-in for the original 1991 NSX. Comptech recommended 8mm! Problem is, this chews tires and Acura got sued over tire wear. So, they relaxed the spec to 4mm.
I have personal experience with these settings on the track. After my winter refresh and new tires in 2012, Acura aligned to the post-lawsuit 4mm rear toe-in, which is what all dealer computers now say for the NSX. The car was downright nervous on the track and the rear never seemed to settle on corner entry. So, I took the car back and had them increase rear toe-in to 6mm (the original spec). Wow what a difference. Rear was completely stable and neutral through the turns. Amazing the difference 1mm on each wheel can make!
Of course, the other solution is to go to a non-compliance rear end and set your rear toe to almost zero. But, that is a lot more expensive.
For the rear axle, they said you want toe-in because of the NSX's rear suspension geometry and rubber bushings. Basically, on hard braking for a corner, the rear tires will "squat" and toe-out from the flex in the bushings. You want to leave some room so that the tires are still toe-in or at least at zero when this happens. This greatly improves rear-end stability on corners. That is why Honda spec'ed a 6mm total toe-in for the original 1991 NSX. Comptech recommended 8mm! Problem is, this chews tires and Acura got sued over tire wear. So, they relaxed the spec to 4mm.
I have personal experience with these settings on the track. After my winter refresh and new tires in 2012, Acura aligned to the post-lawsuit 4mm rear toe-in, which is what all dealer computers now say for the NSX. The car was downright nervous on the track and the rear never seemed to settle on corner entry. So, I took the car back and had them increase rear toe-in to 6mm (the original spec). Wow what a difference. Rear was completely stable and neutral through the turns. Amazing the difference 1mm on each wheel can make!
Of course, the other solution is to go to a non-compliance rear end and set your rear toe to almost zero. But, that is a lot more expensive.
I remember when I bought my NSX, it felt very nervous but as I had never driven one before I took it for granted that a mid-engine car would feel more nervous.
It was so bad that I spun on a downhill left hander corner before I knew what was going on.
When I changed my tires, I had the geometry checked and guess what: there was toe-in at the front!
With the proper toe-out at the front the car felt perfectly predictable.
Lately, I had the geometry checked and the computerized system wanted to create toe-in again???
Someone must believe that the NSXes need toe-in...
It was so bad that I spun on a downhill left hander corner before I knew what was going on.
When I changed my tires, I had the geometry checked and guess what: there was toe-in at the front!
With the proper toe-out at the front the car felt perfectly predictable.
Lately, I had the geometry checked and the computerized system wanted to create toe-in again???
Someone must believe that the NSXes need toe-in...
can I do anything to the alignment to remove the mid corner understeer?
I am max neg on camber and F toe out .3 and R toe in .6
I am max neg on camber and F toe out .3 and R toe in .6
Increase rear spring rate, stiffer rear sway bar, and/or increase rear tire pressure.
I think I might have had a slightly lower pressure in the rears.
I am running street tires, Pirelli pzero nero front and Nitto Invo (I think) rear. The rears are 265 on 18s so I suspect that the car just has too much rear grip.
Adding throttle would only worsen the understeer, I kind of telegraphed the gas to get the rear loose and regain the trajectory I wanted.
Can't wait to put back the stock 15/16 sizes - as soon as these tires wear out.
Hey, I managed anyways to keep the pace of a teenage TT-RS. Not bad for a granny! :biggrin:
I'm by no means an expert, that's where stuntman, coz, illwillem, etc can chime in with much better advice. But I cured a lot of my understeer problem with more negative camber in the front (went from -.7 to -2.0) and increasing the rake of the car slightly, I just lowered the front a tiny bit more. Start with little changes and see the differences they make, you can't do too many because then you don't know which ones are working or which ones could be working against you.
You can go back to stock sway bar in the front or stiffer one in the back, increase rear spring rate or reduce front spring rate, wider front tires (235 instead of 215), etc.
You can go back to stock sway bar in the front or stiffer one in the back, increase rear spring rate or reduce front spring rate, wider front tires (235 instead of 215), etc.
When i had Pirelli PZero's on the front and better tires on the rear i understeered like crazy, i had Falken 615 on the rear and the matching fronts never turned up so i did a few track days like that and had massive understeer now i run Dunlop Z11 and have never looked back. The Pirelli's are rubbish
Scam my, can you report more on the Dunlop ZIIs? What sizes are you running? How are they grip-wise, in the turns, feedback, etc?
They are a great all round tire and absolutely awesome on track real good feed back in corners, standard sizes 17/18 215 & 265
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