utkinpol

>more gentle on throttle application

that is the most usual suspect - despite all efforts still too 'digitized' inaccurate overhurried slamming of pedals - as a simplest explanation is usually the most obvious one. m96 engine more than enough of torque and it is quite easy to push out...
speaking of NHMS - 2 places where I had it repeatedly happening were transitions in those 2 final corners before main straight. in the rest of the track I do not think I ever had my front to slip. i really hate that spot as it is almost near the wall down there, if you spin there close to redline on 3rd gear it will be quite ugly.

well, i guess it will simply take more seat time. thanks for a great response, it actually helps a lot to build a proper mental picture of what to think of regarding all this.

Sterling Doc

When corner entry is done right, I am managing some slip all the way through it. If there is any time the car feels completely planted throughout the whole process, I've left some time on the table. If I blow through the effective slip angle window, and either end of the car is outright sliding, well that's too much, and fixing that mid corner costs time as well (at best).

When I'm braking initially, I'm feeling for threshold, and can usually feel the car moving around just a bit, as each individual tires probes over/under that limit.

As I trail off the brake and turn in, I feel the car start to develop slip in rotation, as Joe describes above. Before this goes too far, I have to get back on the gas to equalize slip angles front and rear midcorner (maintenence throttle, or in an 8V 944 pretty much WFO). Managing those transitions so as to keep the car smoothly in an effective slip angle through the entire process is key. With a 944 on Toyo's, that slip angle is significant, and a whole lot of fun when you get it right.

I don't reach that driving Nirvana all that often, but thinking about it this was makes it more clear where I'm leaving time on the table.

utkinpol

i probably was overdriving my front tires, I just try to understand why from this conversation as from what I feel I do everything 'kinda' right. i think.

or may be those v700 kumhos sets I was using last season were just sh$tty tires. I liked them for AX, they are sticky but may be on a track they were simply getting too hot before main straight and it was a cause of understeer there. go figure. tires were started shaved to 5/32th, rears still have 2/32th and look equal left 2 right but right front got totally bold and corded in the middle, left front had 1/32th left. kinda weird pattern to get fronts corded before rears, it got to be an overdrive sign just i was not overdriving them.
this season as I will cord what is left i will switch for RA1 in 245/335, will see how that will work. for AX 245 will probably feel quite bad after 265 v700.

quickxotica

Utkinpol, I hate trying to get into specifics on a forum like this where there are so many things I don't know about your car, but if you are running 335mm rear tires it should not be a surprise that the fronts scrub on corner exit and wear out first. You would have to carry crazy speed into and through a corner to make such a staggered set-up take & hold remotely equal F/R slip angles... The kind of speed that's no fun since it leaves no room for error. A less staggered setup (i.e. a narrower rear tire) might be worth considering if you want a more neutral handling balance. I can only imagine that the understeer at AX speeds must be a real issue with 335 rears.

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M758

Yes that is very much possible. However I believe what you are trying to achieve in both cars is same, but different in how you do it. I tend to drive my car to create a bit of an oversteer at corner entry. I achieve this any number of ways, but the most reasonable seems to be by taking advantage of weight transfer rather than changes to the static set-up. I take advantage of weight transfer by specifc throttle, brake and steering inputs. The exact pattern of those is dependant on alot of factors and will not be the same for a 944 or a 997.

The intersting thing is that despite all the differnet corners I have driven they all seem to favor a slight oversteering condition at turn entry. It can be slow hairpin or fast sweeping turn. I think the reason is little extra rear slip helps the car turn allowing you let the car do the work . If you have a hint of understeer at turn in you have to fight the car all the way. The challenge is using the rear as you limiting end at turn make it very easy to spin off track. The good thing for an experienced driver is if you exceed your rear grip at turn in by using weight transfer to the front you can get back on the gas to restore weight transfer to the rear.

Cheyenne

In situations like this I just account for how much the front grip loss is likely to affect my trajectory and turn in a touch more initially, so that as load is shifted off the front it has the freedom to flop around a little, but I stay on the correct line.

Are you making a lot of corrections to keep the front in line while this happens, or just tip-toeing and hoping the front doesn't wash out? I would expect a lot of work happening at the front to try to keep up with the rear, pretty much constant corrections, or committed drifts as QX alluded to.



I thought m758's post captured a lot in a very nice way. Every corner is a small spin starting to happen, then being 'captured'. But in a long and fast enough corner, you have to lean on the front more, so if you can't ride rear end slip all the way around your only option is to be comfortable with the car suddenly pointing to the outside of the corner, and giving yourself enough room to recover. I don't like to push it in places I'm not comfortable being 5-10 degrees off my path of travel for a second or two.

utkinpol

i used to drive a miata a bit so it helps me to understand what you speak about a little better but for real it takes a lot of effort to learn what to do and how to handle this heavy 997 ***. it is a lot of fun nevertheless, otherwise i would get rid of this car already, but it seems i will stuck to it for a while as it is indeed quite fun.
one way or another it makes sense to me what you say.

like what i was saying to begin with - i do same thing with pre-loading front outer side at the corner entrance as in AX it is the only possible way to get a 'fast in' otherwise your nose will keep going straight despite your best steering intentions, issue is with transition on the way out. i think what was told about brake-gas transition is the culprit as I definitely get right foot of brakes before I start on a gas and that it probably enough for front springs to come up and loose just enough grip for front start slipping. i will need to work on that later on and practice a bit to compare one to another.

quickxotica

100% agree. This is well-stated. Now, the caveat is of course that the actual slip angle you refer to as "slight oversteering condition at turn entry" will probably but much larger in a car with 45-series sidewalls like the 944 than in a modern 911's that has 30-series sidewalls in back. The extra stiffness & lack of twist in the super-low profile tires dictate that the rear slip angle that is optimal for a 944 would be a "whoops" in a 997. Nonetheless it's true that the desired turn-in balance as described above is the same... it's just the details that vary, like so many other things, from car to car.

All our cars are imperfect mechanical objects that demand nuance to reach their limits. Learning to read the car to find out what it needs to get from 85%of its potential to 95% is half the fun/challenge.

Good thread so far.
John

M758

My comments really apply to corner entry. If the corner is long and you have long steadt state period you need to look at it differently. In a long accelerating corner a little understeer is good. It allows you the option of lifting to tuck in the nose. If you are part throttle then you can stand a slight bit of oversteer since more throttle will catch the back and push you out and lift tucks it in. In my 944 very few corners are not full throttle even long ones. So I work to dail out understeer as much as possible to limit scrub, but never so much as might cause me to lift.

M758

There is one corner which is a slow hairpin. I brake in a straight line and if turn after I get off the brakes the car simply won't turn. I need turn the wheel hard before the front end comes up.

I had been assuming you are already trail braking into a corner so at the time you get off the brakes you don't need to do any more turning. You are just holding on to the car to pull it out.

Maybe I am not understand this right.

Cheyenne

I think we're mostly saying the same thing.

One alternative to lifting to tuck the nose in, is to work the steering as if you were correcting oversteer to the opposite direction that you're turning. Short, sharp turns of the wheel to "toss" the front end over a bit more, but without so much scrub as to make it as bad as lifting. Different compromises for different situations.

Of course, if you lose nerve and lift at the same time you're doing that...

mdrums

I've given you many point by's going into corners and watched you fly through them with both inside wheels off the ground. I was scared for you!

cello

No, sorry for the confusion. The point being made was that our cars will tend (track and grip dependent, of course) toward OS during that pause between coming off the brake while TBing thru corner entry to apex. The key to sit the rear is to quickly but smoothly get back on throttle (maintenance or progressively, corner dependent) as the above posters have already noted.

I too am confused tho by your posts. The bolded quote in your original post referenced a lightened front end but that Poster was clearly speaking to the post TBing to apex throttle application phase of the corner. Re-read, carefully, his (excellent tongue in cheek) post. I thought that was what you were speaking to. When/how to stop rotation and get on power.

Subsequently you seem to indicate that your issue is more of a light front end by way of US. Your car has a modded suspension so I assume you have a track alignment (set with the track tires on) that was performed by a party that knows these cars and dialed it away from US toward 'neutral' handling, correct??

If so, it is not that easy to US (at DE speeds) these cars without a bad line or misjudging entry speed/brake modulation or being pretty coarse on throttle input thereafter. If that is the case, double check your line and re-read the very good posts above.

333pg333

Yes, that's a big stagger even for a 911. I have read of guys tracking their rear engine cars with square setup which I found a bit surprising, but I'm sure you could regain some more balance if you brought that stagger a bit closer.