IW STi Forum banner

Do you ever accelerate in the midst of a turn and ....

14K views 61 replies 46 participants last post by  Major Anarchy 
#1 ·
Curious if others get this too. If you are in the middle of a turn and get on the gas does your STI seriously push to the outside of the turn? Just curious. Mine has always done this. If I am in the middle of a turn and I get on it then I NEED to turn the steering wheel at the same time in order to maintain my current direction. If I don't turn the wheel when I push the accelerator down then the car will immediately push to the outside.

Just curious. Any explanations? The best I could come up with was that when you hit the accelerator you get 65% to the rear wheels which causes the push?

t
 
#27 ·
RE: Rota rims and Nitto tires

ZenBoy said:
Sands said:
Open diffs don't do this, which is 99% of all RWD cars out there.
My RWD car sure doesn't do this, and it's got Positraction.

My 2000 2.5RS didn't do this, and it had a limited-slip rear differential.

The difference between those cars and my STi, at first glance at least, is that the STi has a limited-slip front differential as well.
The rate of lock up totaly depends on the ramp angles of the plates in the diff. So just because a car has a LSD doesn't mean it will behave just like another car with an LSD.

If you have a car wtih a posi rear end, which if I'm not mistaken is a locker, I'll bet it's a muscle car. Without any other info, I'll bet it will understeer like a pig with or without the posi rear end. (Does the posi need to be locked manually?) Provided you don't power oversteer that is. :lol:
ZenBoy said:
mccullpl said:
I figured it was the front diff starting to lock under power (or unlock when letting off the gas)., forcing the front wheels to try to turn at the same speed...I'm certainly not an ME, but it kinda makes sense to me. It would also explain why nobody notices it on a rear drive car, or a WRX. (no front diff).
I think mccullpl has spelled out what I've been thinking as well - it's the limited-slip front diff. Under throttle, the diff is starting to lock up when it has enough torque distributed to it. This would also explain why adjusting the torque bias to the rear of the car helps the problem so much.
Zen
Try going through the same corner at the about same speed (say 45 mph or so) a few times with the following conditions (needs to be a fairly aggressive corner and DCCD in auto):
1. gearbox in neutral, just coasting
2. gearbox in gear, foot off the clutch and trailing throttle
3. gearbox in gear, foot off the clutch and neutral throttle (just enough to not slow down, but not loading up the gearbox)
4. in gear, really hard on the gas

What you should feel:
1. Should be totaly transparent and shouldn't feel the diffs at all
2. Front diff should start to stiffen up a little since the engine brake will put a load on the front lsd. Should start to push and you'll feel the center diff move torque around.
3. Line should be tight and car should rotate, but you'll feel the center diff move torque around
4. Get ready to counter steer! Power totaly overcomes the front diffs tendency to lock - but since you're under power, all the wheels are pulling, not slowing the car down.

(I found a pdf file with a more technical description of the DCCD action, but I can't track it down right now - which is what I'm basing the info on above)

From my track experience (all on a e39 bmw) the hardest thing I've had to learn was to get on the gas sooner and harder then I thought the car could do. The rear end will dig down and get more grip then you thought, all without making the car push. In fact it rotates better. You get the right amount of lateral slip in the rear tires to rotate the car, even though the front end it unloaded (which normally will make it loose grip)

The sti is the same, but the car expects you to drive in a certain way. The computer needs to have a certain progression of brake, transition and power.

The best way to describe it is to drive the car like a FWD car on entry and a RWD car on exit - but you have the FWD half to pully you out of an oversteer on exit. [edit] the difference to a non-lsd fwd car to the STI is the trailing throttle will tend to stiffen up the front LSD, which promote push, so you need at least a neutral throttle to free it up (or out of gear, which is stupid if you're on the track) [/edit]
 
#29 ·
going around the skidpad at autocross school, the instructor said I would find my car's limit when my car started understeering with additional throttle. Most cars act that way at the limit, but perhaps in differing amouts. I found that I could steer my way around the pad with throttle: add throttle and the turn radius would increase, lift throttle to pull the nose back in. Someone suggested pulling the e-brake at the limit, but I was pretty sure that would result in more fun than I was interested in ;-)
 
#30 ·
Well, I think I found a good source of information for driving technique for my STi.

I went a HPDE at Watkins Glen this weekend with my STi and found it to be a very forgiving car. I over cooked a couple of corners and just outta instinct I squeezed back down on the gas and poof back on line and in control, but a bit messier in the shorts department. My car is totally stock in the suspension, but still managed to hustle it around the track very quickly and very smoothly. I had some good comments from other instructors that I was really movin the car. Which "turn on air pump" boosted my ego. E46 M3's E36 M3's E30 M3's no match for AWD and 300hp. Some were on track tires and I suspect many were first timers at the track. I had been to the glen before and felt very comfortable with it. I went from intermediate group to advanced group and found it easier to driver in the advanced cause we all were at the same skill level. Roughly. I must say the car is incredible, but it's the last time this year for the track for it. I have a 325 as my permanent track car so we'll see how that goes in July at the Glen.
 
#31 ·
This is a GREAT thread.
I have found that after intalling the Pinks/Tops & f/r sways......esp the sways, the car is alot harder to upset incorner. Much more confidence. I agree totally with hammering hard in corner, if you get scared you while in a bit hot your done. Kinda like a 911.
 
#32 ·
WE_R_ND said:
If I get on the gas hard, no it doesn't do that. If you learn to be more aggressive with our throttle you will notice the car doesn't do it. I used to be the same way as you. Then one time I got pissed and just floored it. The car squated as the weight transferred to the rear and outside then just turned through the corner. If your light with your throttle input the car will understeer as described above. If your more agressive the weight transfer can actually benefit you.

BING! plus you feel the pressure on ur body when u jam the gas, its rather nice.
 
#33 ·
ZenBoy said:
What I find so disconcerting is that with its more driver-centric orientation, the STi does this and my MY00 2.5RS didn't do it at all. If I applied the throttle in the midst of a turn with the 2.5RS, it just held the line I already had and accelerated. With the STi, the car aggressively pulls itself straight (that is, to the outside of the turn).
It sounds to me like what you and the original poster are experiencing is torque steer. The reason you don't feel it in your 2.5RS is that it doesn't have a front LSD and 300hp.

Some have said the 'fix' is to be more aggressive with the gas pedal. The problem is that once you're in that situation, giving it more gas won't help (again assuming I understand you correctly). What you really need to do is rotate the nose of the car a bit more towards the inside of the turn, *then* get back into the throttle. Lift throttle oversteer might be a good choice under the described circumstances. There is also the old tried and true method of turning the wheel ;)

Cheers!
 
#34 ·
Albanianimpreza said:
BING! plus you feel the pressure on ur body when u jam the gas, its rather nice.
I forgot to add something after I learned it. Since that post I've attended a few driving schools and learned more about the car. I suppose I should post my last track experience sometime soon. Anyways, I've since played with how I want the diff, and learned that auto creates so much artificial understeer that I hate it. The only way to drive this car is with the power dialed to the rears all the way. I promise everyone, if you try it and your aggressive with the throttle and also smooth you won't get understeer or oversteer. You'll also never leave the car in Auto at the track again. If I ever go out for a session and forget to hit the button I realize it even on the warmup lap, it makes that big of a difference. Just try it. If your driving the car right you'll be smooth and never get oversteer. Keep in mind, I'm usualy trailbraking just a bit then getting on the gas after I've got it pointed and full throttle by apex. You'll then get a tighter line then you would think which is perfect. You then start dialling out the steering and the car jumps out of the corner. It's great!
 
#35 · (Edited)
Anyways, I've since played with how I want the diff, and learned that auto creates so much artificial understeer that I hate it. The only way to drive this car is with the power dialed to the rears all the way.
I tried playing with the DCCD on my last track day (Fri.), and I noticed the same thing with it turned all the way to the rear. There did seem to be less understeer. BUT, I also was slower out of the corners than in auto. Since I wasn't timing my laps I don't have times as proof, but I do pay attention to shift points. My shift points were quite a bit later when turned to the rear, meaning I was slower coming out of the corners. I didn't change anything else in my driving. Brake points, turn in points, apexes, were all the same.
 
#36 ·
i never really have that much of a problem with taking corners with my cars, i dont really do that whole regular turning anymore, its all about drift. lol, but to be honest, if u do throw it all to the rear isnt it just like a RWD? or almost? theres probably some lag, from engine to back, or id think so, stick with it auto
 
#37 ·
I get the same sort of sensation from my '05. I notice it most while on the highway, if I am in a turn and give it just a little more gas, the car will push to the outside. If I am in the same turn at the same speed and let off the gas, the car pulls sharply to the inside. Turn in this instance is very relative. I'm talking highway curves, 65 MPH. Obvoiusly in this instance there is little steering input before changing throttle position. I have never had another car do this. My last three cars were front drivers with Limited slips. '03 MINI S w/ Quaiffe, '01 Integra Type R w/ factory helical diff, '99 Civic Si w/ Kaaz clutch type diff. None of them exibited the same behavior. I'm used to the very planted feel of those cars, and this takes a little bit of the fun out of driving the STi. Would alignment settings help? Swaybars? Springs? I really want the planted feel. Turns with more steering input, I have no problems with.
 
#38 ·
Chayse - sway bars front and rear, or at least front, will drastically reduce how hard the car tucks in under lift-throttle. It likely has to do with the toe-curves (how much toe changes based on suspension compression).

Of course lift-throttle will always transfer more weight onto the front tires, increasing their grip, but adding sway bars makes it much less unsettling.

SS
 
#39 ·
CGMDan said:
I tried playing with the DCCD on my last track day (Fri.), and I noticed the same thing with it turned all the way to the rear. There did seem to be less understeer. BUT, I also was slower out of the corners than in auto. Since I wasn't timing my laps I don't have times as proof, but I do pay attention to shift points. My shift points were quite a bit later when turned to the rear, meaning I was slower coming out of the corners. I didn't change anything else in my driving. Brake points, turn in points, apexes, were all the same.
Something changed because I gained a ton of speed coming out of the corners. I was able to dial out so much sooner and the car would just leap out of the corner. I was probably on average moving my shift points about 50ft earlier. To me, that's alot. I have another school coming up this weekend so I'll check both speed and distance.
 
#40 ·
Thanks Scott. I've been reading your other handling thread with some interest.
 
#41 · (Edited)
Having taken my Integra GS-R to the Infineon raceway a couple of times, the instructor told me to use throttle steer to drive the car through some of the turns. It sure is counter-intuitive to newbie track drivers like me, but man! what a rush! Can't wait to drive the STI on the track now! :lol:
 
#43 · (Edited)
WolfPlayer said:
Curious if others get this too. If you are in the middle of a turn and get on the gas does your STI seriously push to the outside of the turn? Just curious. Mine has always done this.
I absolutely agree with your assessment of the stock car's handling and and I think it is better to adjust the car than your driving. In fact, I have felt this with every stock Subaru I have driven (WRX's and Legacy GT's), and it almost stopped me from buying this car. I only bought the STI when I was convinced I could fix it. (I came very close to buying an EVO instead.)

My first mod was a Whiteline Comfort ALK and max - front camber (-0.8 for my car) and it just about eliminated this problem. Amazing how much a simple mod could improve a car. I have since done some other handling mods, but for me the ALK has been the best improvement. (By the way, I drove my car with a bigger rear sway (22) and a stock front, and it drove horribly. Again, just my opinion. I am currently using a 22 front and a 20 rear and it is ok.) Keep in mind that an ALK can be a problem for autocross classification, if that matters to you.

That said, I have been in some STI's with modified suspension (but no ALK) that have overcome this issue, so there are different ways to fix the handling. (That said, I still felt these cars would have driven better with an ALK.) To me, there seem to be two basic problems. 1. The front end anti characteristics (as in anti dive and and anti lift). 2. The stock springs are not well matched to the stock struts.

Scott, from Subaru of Gwinnett has a great thread on handling in the suspension section right now.

Again, all of this is just my opinion. There are lots of different driving styles and car preferences, so it depends on the person. Still, I think you described exactly the reason why the EVO has been winning all the shootouts. Hope you find this helpful.

Jeff

Edit: Do not take this post to mean I am against working on driving technique; I am definitely for any such work. I just feel this car greatly benefits from some basic handling mods.
 
#44 ·
I'm not going to get into all the suggestions, but the original poster's experience is counter to mine.

my 04 tightens its line when I get on the gas coming out of a corner.

By the way, my sti requires a very different technique than my Wife's Miata. The Miata doesn't understeer much at all.

So trailbraking deep into corners is an option. The sti plows like the Pig that it is if you brake deep while turning. Better off accomplishing the braking before the turn, drive around the turn.

Then concentrate on getting on it HARD and EARLY and letting the "beauty of all wheel drive" allow you to come charging out of that corner harder than you've ever done before.

Don
 
#45 ·
Guys - I'm new and naive - but would altering tire pressure F/R make a difference here?
 
#47 ·
donmei said:
my 04 tightens its line when I get on the gas coming out of a corner. ... Don
Of course it does :) Mine does too. Most people aren't really paying attention to what I am saying. I'm not talking about driving the car correctly. I am specifically referring to a behaviour that manifests itself when NOT driving the car correctly. If I am on the throttle throughout the whole turn the car is great and pulls me through ... just like you said Don. This is how the car should be driven and this is what makes this car so potent. The behavior I am referring to is if you are in the middle of a turn ... not really on the gas at all ... and THEN you get on it. The car will pull to the outside. This is because the front diff is partially locking up. The outside front wheel will slow down as it begins to accept power and the front diff does its job. This slowing down of the outside wheel WILL cause you to pull to the outside .... but you will only notice it when you are going from no power to adding power. This is just the nature of the car and this is the nature of how the front diff works. The problem isn't the car ... it's that you shouldn't be driving the STI by using no throttle until the middle of a turn. I know this. I was just making note of it here to see if other cars do this too.

t
 
#48 ·
WE_R_ND said:
I promise everyone, if you try it and your aggressive with the throttle and also smooth you won't get understeer or oversteer. You'll also never leave the car in Auto at the track again. If I ever go out for a session and forget to hit the button I realize it even on the warmup lap, it makes that big of a difference. Just try it.
I haven't been to the track yet (next Sunday 7/31 . . . can't wait) but I was at the skid pad yesterday and have to say I figured this out pretty quickly there. Obviously the cornering is much tighter and speeds lower, but I found that in auto mode, there was no way for me to know what to expect from the car. I brought the back end around on the figure 8 twice in auto mode. With the DCCD all the way to rear, I was able to get consistent. For me, as a novice, that may just be part of the learning curve. Some other setting may be better, but for now I want to master one predictable set of circumstances before I start changing things, or having it in auto where the car changes things for me on the fly.

This is a great thread!!
 
#49 ·
Thread resurrection warning....

WolfPlayer said:
Most people aren't really paying attention to what I am saying.
Glad I found this thread. I noticed the very same behavioir when I first got the STI and posted in the drivertrain forum because I thought it was an issue with the diffs. Like you, no one really seemed to understand my complaint and gave me alot of "driving technique" advice, blah blah. The effect is very prominant and easy to reproduce at slow speeds. Its not understeer, but it feels similar. It feels like I'm fighting the wheel, along with the somewhat floaty feeling in the front. I was surprised I seemed to be the only one on the thread that was experiencing it.

The last car I had was FWD with an open diff and throttle application during mid corner would cause the nose to dive deeper into the corner tightening the line. In some cases a little steering input toward the outside of the corner was required to keep a consistant line. This made transition to the STI far worse as the behavior was just the opposite.

Since my orignal post about this issue, I have experimented with the heavier throttle application approach to solving this. And yes, much to my surprise, it actually does work pretty well. But since I won't be taking most corners on public roads at 10/10th, I still want to improve the initial power-on mid corner feel (again its not understeer). It sounds as of the best solution is the ALK which is designed to improve the geometry under power (and braking).

Any follow up comments about this issue, specifically the impact of the ALK are appreciated.
 
#52 ·
Trust me it's there. Subaru builds it into the cars for "safety". I guess it is safer to understeer then oversteer, but not nearly as fun ;). Nothing a stock front sway with a 24mm rear can't fix though :devil:. Smash the throttle in the middle of a turn and out goes the rear.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top