Unpredictability

[JMoraru]

My car makes about 450rwhp. I have steeda springs, koni yellows, adj panhard, and brace.
Michelin pilot sport tires(295/35r20 and 255/35r20). A problem I have had forever is my car grips pretty well, especially with the steeda and koni set up, but once it breaks loose its like a whole different animal. The rear becomes very very hard to predict and control. It's like an on and off switch. Once it loses traction it feels like it instantly wants to come around on me.I know I'm putting decent power down, but I feel like its something handling related. Would lca an brackets target this?

 

[Mike K]

Yes and a watts link would help. You could also try different sway bar settings/ sway bars. That's about my extent of knowledge on this subject.

 

[Whiskey11]

Yes and a watts link would help. You could also try different sway bar settings/ sway bars. That's about my extent of knowledge on this subject.

This to me sounds more like tire behavior more than lateral location and LCA geometry.

I don't have any experience with the breakaway on the tires, but some tires are very abrupt on their breakaway and don't recover very easily. Like some R-Comps can be "GRIP GRIP GRIP GRIP GRIP, YAY! WE ARE SPINNING!!!!!" with no warning at all except the inevitable spin.

 

[sheizasosay]

Counter-steer and throttle control would be my first guess. It's a whole, whole, whole lot easier and hands down better, to get to know your car on a road course with an instructor. Trust me...I thought I could drive because I could slide my car around and counter it, but you will be HARD-pressed to push the limits on the street.

You might want to read a review on Michelin Sport tires that you got and see if anybody talks about a "no-notice" break-away. I don't know if Michelin Sports are the same as Pilot Sports, but the Pilot's are put on a throne and revered. Tire Rack probably has a review of it. If it turns out to be a normal characteristic of the tire, then I would start thinking about a road course with an instructor.

It's really hard to know what is up without knowing your skill level. What sway bars are you running? And to be fair, I thought simliar of my mustang at only 300hp when I first drove it. Now I think it actually handles pretty good. "Driver mod" was the biggest improvement for me.

PS-where a diaper on your first outting.

 

[JesseW.]

i'd think tires. also, if the LSD is on the way out in the car, it makes for a wild ride when one tire is spinning and the other isn't, also makes it break traction really easy when one tire is seeing all 450 hp. i fried an LSD at an autocross, making the same power as you, and it was damn hard to drive. a true trac solved that and the rear seems a lot more planeted. i do not have relo brackets as no one is sure if they are class legal until my scca letter gets answered, but it should't make that much of a difference as far as it kicking out sideways under power

jack a rear tire off the ground, parking brake off, wheels chalked, and see if you can spin it by hand. if you can the lsd is bad. if you can't, go check the other side. its easy to check and rule out. (note: doesn't work with aftermarket helical style lsd diffs, only clutch type, and those will start to move with enough force applied.)

 

[fdjizm]

My car makes about 450rwhp. I have steeda springs, koni yellows, adj panhard, and brace.
Michelin sport tires(295/35r20 and 255/35r20). A problem I have had forever is my car grips pretty well, especially with the steeda and koni set up, but once it breaks loose its like a whole different animal. The rear becomes very very hard to predict and control. It's like an on and off switch. Once it loses traction it feels like it instantly wants to come around on me.I know I'm putting decent power down, but I feel like its something handling related. Would lca an brackets target this?

How is this not a common problem with anybody in a high powered rwd car?
You lose traction, you lose the cars ass most of the time.

You want your car to handle correctly while you're burning the tires?
I so confuz.

 

[DTL]

Something that helps me when I'm losing my mind trying to sort out a handling quirk is to ask one of my friends at the track to take a few laps in my car. As with many other things, a fresh perspective can be a big help.

 

[EGNARO]

How is this not a common problem with anybody in a high powered rwd car?
You lose traction, you lose the cars ass most of the time.

You want your car to handle correctly while you're burning the tires?
I so confuz.

I think he is referring to not having any warning of it occurring.
Or maybe he means sometimes at X rpms it breaks loose and sometimes it's at X-200 rpms when it breaks loose


Sent from my iPad using Tapatalk HD

 

[Full_Tilt]

Some tires are forgiving, some are not.

You should feel what slicks are like. It goes from lots of traction to ice.

 

[JMoraru]

The tires are michelin pilot sports. I love how they grip, but i do think they either grip or let go. They dont like to slide.
Im sure i could be a better driver, but this car especially is very hard to let the rear come out on. Not confidence inspiring at all. I mean it hugs the road pretty well, but when it breaks loose it feels like i hit an ice patch.

I know its a whole different animal, but i had an STi and after one day in that thing i could drive it harder and slide it more than i can this car after over 5 years of driving it.I did things in that care i wouldnt even dream of attempting in the mustang. I knew exactly where it was going to go. I do think it was easier to slide on stock wheels and tires(nonsupercharged). Im not trying to drift by any means, but id like to know what the hell it is that i cant feel comfortable sliding this car.

 

[fdjizm]

Sounds like you could change a few things about driving, even in a 600whp you have to have some throttle control.

 

[JesseW.]

if it has the stock lsd in it, you really need to check it. mine went out at 35,000 miles, and it makes it a huge handful to drive

 

[jmauld]

I know its a whole different animal, but i had an STi and after one day in that thing i could drive it harder and slide it more than i can this car after over 5 years of driving it.I did things in that care i wouldnt even dream of attempting in the mustang. I knew exactly where it was going to go. I do think it was easier to slide on stock wheels and tires(nonsupercharged). Im not trying to drift by any means, but id like to know what the hell it is that i cant feel comfortable sliding this car.

It doesn't take any skill to drive an awd car, in fact, in the hands of an untrained driver they will reinforce a lot of really bad habits.

What are your shocks set at? Are they blown? I have a similar setup as you, except no supercharger, bilsteins instead of Konis, and star specs instead of the pilot sports and my car slides very predictably.

 

[JMoraru]

I think im at 2 1/4 turns front and 2 turns back(from soft). they only have about 8000mi on them. same problem with stock shocks and bmr springs. i also think its tire. i LOVE how they grip, but im sick of being too scared to have a little fun.

Yes i understand throttle control and im sure that doesnt make it any easier per say, but i feel like that isnt really the problem. my friend also agrees that my car is very difficult to predict in a rear slide. it either wants to grip or slide like ice.

 

[zquez]

The michelin pilot sport tires are known to have snap oversteer (what you describe) until you get some heat into them. Chances are that you will not be able to get the heat required for them to tame down unless you're on the track and even then, you'll need to give yourself at least a lap or two to heat them up. They are very similar to slicks in this way.

 

[fdjizm]

I think im at 2 1/4 turns front and 2 turns back(from soft). they only have about 8000mi on them. same problem with stock shocks and bmr springs. i also think its tire. i LOVE how they grip, but im sick of being too scared to have a little fun.

Yes i understand throttle control and im sure that doesnt make it any easier per say, but i feel like that isnt really the problem. my friend also agrees that my car is very difficult to predict in a rear slide. it either wants to grip or slide like ice.

I have a fix.

Stop getting into rear slides.
I really hope you're doing this shit on a track.

 

[Whiskey11]

I think im at 2 1/4 turns front and 2 turns back(from soft). they only have about 8000mi on them. same problem with stock shocks and bmr springs. i also think its tire. i LOVE how they grip, but im sick of being too scared to have a little fun.

Yes i understand throttle control and im sure that doesnt make it any easier per say, but i feel like that isnt really the problem. my friend also agrees that my car is very difficult to predict in a rear slide. it either wants to grip or slide like ice.

Aren't there only like 3.5 turns on the Koni's total? I would back off the rear adjustment half a turn and see what it feels like and if the problem goes away.

I still think it's the tires, personally.

And yes, AWD will make heroes when set up halfway decent. These cars will always require a lot of finesse to drive well, that is why it is rewarding to drive. You can set these cars up to be "turn, point, and mash gas" but it's a driving style that is extremely expensive (think tires and wear and tear on the drivetrain, specifically the differential) and not always the fastest.

 

[Norm Peterson]

Koni yellows only have 2-1/4 turns of total adjustment in them. Dial some out of both ends, taking more out of the rear.

Where do you live and/or what kind of temperatures are you experiencing?

The Pilot Sport PS2 is not intended to be driven in near-freezing temperatures, through snow or on ice.

Frankly, the grip of summer performance tires at temperatures below about 45°F sucks. It's a huge point of discussion for a certain other make when fitted with the latest and greatest Gen 2 Goodyears, and I stop running my "3-season" max performance tires as soon as I notice tire slip getting too easy.


Beyond that, I think you need to look at your wheel and tire package for something other than tire mfr/model/summer.

What inflation pressures are you running (f and r)?

How wide are your wheels?


Norm

 

[Vorshlag-Fair]

Michelin pilot sport tires(295/35r20 and 255/35r20).

While better geometry for the lowered car always helps, and better dampers are probably in order, the 20" wheels and short sidewall tires aren't doing you any favors. The shorter the sidewall gets, the stiffer the spring rate of the tire becomes, and the twitchier your car will handle.

The 2011+ Mustang GTs come with 40 series 19" tires and 50 series 18" tires. Running an ever shorter sidewall increases the "squirreliness" factor. Our two street cars have similar suspensions - remote reservoir monotube adjustable coilovers with much higher spring rates - and that makes them a little trickier to drive. But our red 2011 on a 275/40/18 tires is easier to fling around than our black 2013 on 295/35/18 tires. The 275mm tire is 1/2" taller in diameter than the lower profile, 35-series 295mm tire, and it all ends up in the sidewall. The taller sidewall rides better and is easier to drive, too. Factory Mustang tires are over 27" tall...



The two sets of race tires above are another example in sidewall height. One set, the size I normally race with on track, are 315/30/18 Hoosiers. We just picked up a set of similar 295/40/18" Hoosiers. Both sets are brand new. We're going to test both tires back to back at our next NASA Time Trial event, to see if the taller 40 series tires are easier to drive and more forgiving. I suspect they will be, from similar tests we've done in the past. Of course the 1" wider 315's will probably be faster, but that's not what we are testing - we want to see if the taller tire is EASIER to drive, just like you are struggling with on the street. See more about this in our 2011 Mustang Project Build Thread, linked in my sig.

So my suggestion for easier performance driving to the OP is..... ditch the twingos. Get into some 18x10" wheels (we make some, so do many others) and shoot for a 26.5" to 27" tall tire. 275/40/18 is a really good choice.

 

[claudermilk]

This to me sounds more like tire behavior more than lateral location and LCA geometry.

I don't have any experience with the breakaway on the tires, but some tires are very abrupt on their breakaway and don't recover very easily. Like some R-Comps can be "GRIP GRIP GRIP GRIP GRIP, YAY! WE ARE SPINNING!!!!!" with no warning at all except the inevitable spin.

Agreed, it sounds a lot like tire to me too.