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Originally Posted by churchx
+0.7 front, and +1.2 rear toe-in .. that's in what measurement unit?
If in degrees, way too much.
If in inches, according to this (with 24.62" tire diameter) even worse, +2.65dg front, +5.59dg rear, but i doubt something THAT off may go unnoticed or even set that much.
If in mm, +0.12dg front, +0.22dg rear. A bit too much in front, normal in back.
Understeer or oversteer balance is about which car end has more grip vs other. There are several ways of skinning cat, as in - to add or remove grip to one end of car, to change car grip bias.
For example, to add grip - softer springs, more toe-in, softer rollbars, less air pressure in tires, more negative camber. For less grip - stiffer springs, stiffer rollbar, higher tire pressure, less camber.
Just toe-wise i usually aim/ask to dial on twin for zero front toe, and slight toe-in rear (+0.15dg to +0.25dg total toe in (halve that if per wheel. "+" means toe-in, "-" - toe-out)).
Stock alignment for these cars: at front each wheel 0dg camber, 0.0 toe, rear each wheel -1.2dg camber, +0.2dg toe-in. It's a bit understeer-ish bias.
Most "fix" it by adding front negative camber (which also makes better tire wear on track instead of just ripping outer side as if on stock alignment), extent to how much camber optimal depends on use type (DD only or track), with dialing toe close to "stock" of zero front toe and slight rear toe-in (for some stability under accelerating out of corners, or to ease handling when accelerating in straight if/with wheels spinning (eg. if low grip such as wet/snow/ice)).
Simple to aim camber values for closer to neutral/less understeer-y grip balance might be - by 0.5dg more front camber then rear.
What use your car sees? (just daily driving? pushing a bit more? track driving?)
What camber adjustment means your car has? (twins as stock have only toe adjustment. Aftermarket coilovers may have front camberplates. For rear camber adjustment aftermarket LCA might be needed).
P.S. Also remember that "hard" to get rear out might not be just because of grip balance .. but also because if tires may have more grip in general. PS4 have much much more grip then stock Primacies. You really have to push them to loose grip .. not so easy when driving within speed limits and not hooning dangerously, just driving together with rest of traffic. Need to push more (eg. on track), or loose grip in other ways (driving in wet, or do driver inputs to overcome available grip). Understeer or oversteer .. it's more about when one pushes to limit, which end of car looses grip first. With grippier tires you have overall grip limits much higher, not just rear but also front. |
I assume the measurement is in mm.
So good to know that the toe isn't ridiculous.
Car is a daily, but I still want it to have some fun on some back roads.
Yes, the front coilovers have camber adjustment. Perhaps on my next alignment, I'll get more negative camber and less toe.
I've only experienced the car with Pilot Sport 4 (The older tyres on the stockies were PS4, but obviously much more worn).
I'm not really sure how though that I'm getting to the end of the grip level of the 86 so quickly.
I've been on track twice now (with my other car) and never had this issue, as well as in a honda on back roads.
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Originally Posted by ZDan
Power-on understeer is a normal phenomenon. Despite Fast & Furious "physics"... Get on the gas, load up the rears and unload the fronts, the car is going to push. Up to a point anyway, but given 2.0 liters of n.a. fury, for us power-on OVERsteer isn't so much an issue usually...
Proper driving technique is to trail-brake on corner entry, maximum steering input near apex, on the gas at exit with enough turning already done that you don't have to get OFF the gas to point the car.
That said, your toe numbers look fine (assuming millimeters!), but you could run less. Could run zero toe all around and that would generally reduce understeer a bit, particularly knocking the rear toe down from 2.4mm. Which isn't excessive but from zero to half that is the range I like to be in for rear toe, with zero front toe.
You could run a lot more front camber (assuming coilovers have camber adjustment). Street-only and desiring less understeer I'd try at least -2 degrees front camber, could run more than that and still be streetable, up to, say, -3 degrees.
AS for damping adjustments, go by manufacturer recommendations, but usually you adjust from full *stiff*, not full soft. I.e., the reference point is to screw the adjustment needle all the way in (clockwise), and then count clicks out from that point. Usually the steps between the first clicks out result in bigger changes in damping, and you get to a point where more clicks out doesn't do much.
But again, technique is probably a big reason. If you're in a corner in anything higher than first gear and just smash the throttle, you're gonna get understeer in general, unless in low-grip conditions.
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Yeah, I'm just surprised that the car is able to over grip the front tires and "slide" so easily.
My old honda with a K24A3, never felt like this and it was one Bridgetone Re003s on 225/45/17s.
Obviously different setup and what not, but being FWD the way it understeered during a corner still didn't "slide" out or anything.
Especially seeing as the 86 is a RWD, I just don't really understand why it's doing this.
In my NB MX5 it's a completely different beast. Yes, obviously a lot less power, but it's actually not that far off when you look at power to weight figures.
I might have to meet with some local 86 owners to get them to feel it.
Just something that I thought was quite odd.
And also it just feels weirder then usual understeer. Like the front "slides".
Perhaps I'm overthinking this a bit too much.