frebay

can someone explain to me torque steer? i was w/ my friends yesterday test driving a 6spd, and everyone including the dealer said the torque steer is much more noticable in the 6spd.

jyg tl 3

very noticable on 6mt, 270 hp. is really too much for front drive set up,. Lower hp cars like my 90 legend coupe with 160 hp, dio not exhibit such, In case of 6mt, which has LSD limited slip differential . the torque steer is more notiiceable as front wheels may get traction at different rates.

SlntSam

Torque steer is when you hit the gas and the car wants to steer you in one direction or the other. You sometimes have to fight the wheel to keep the car straight.

frebay

wouldn't that be an alignment issue?

neuronbob

Not really, as noted above, it's what happens when more power is applied to one wheel than another.

There are worse cars than the TL when it comes to torque steer. I mention, again, the new Maxima.

Formula 350

Lets see how good I do on this....

Think about the tires spinning under power. If you have a rear wheel drive car, the tires are 'fixed' on a solid axle (ie they do not change their orientation to the car). So, no matter how much power is being sent to the wheels, they stay parallel to the car.

Now lets move this to the front. The front tires do not stay parallel to the car (or we could only go straight). When you put power to the wheels, one or the other usually has more traction than the other. Therefore, the tire is trying to accelerate more than the other. This extra force tends to cause the wheel to pull in one direction or the other (depending on which wheel has the traction). It causes the steering wheel to turn. To compensate, you must hold onto the stearing wheel or slightly turn the wheel back from the force.

Try this where one wheel is on dry pavement and the other is in water. You should feel it a lot more then.

jdone

Owners or former owners of turbo-charged Saabs and Volvos know that torque-steer is no big deal. You automatically compensate for it without even thinking about it. It's only an issue under hard acceleration anyway, and I do mean hard.

chiawei

Not exactly.

torques steer only exist on FF cars. Because the output rod fron engine that connects to the front axle is not in the middle. Pict below

|--engine-----| where | denotes each tire, and --- denote axle.

Because the output from engine is the same no matter where it is connected to the axle. By law of physics, the short side will spin faster than longer side, hence the car will pull toward that direction.

Hence in my example above, the car would pull to the left.

On the rear wheel drive, the engine out put is connected to rear wheel through use of rear wheel drive shaft that connected to the rear axle at center. So equal length= equal rate of spin. Hence no torque steer.

Formula 350

The law of physics???

Show me where the law of physics says the short side will spin faster?? They are geared the same. If one was spinning 'faster' it would be spinning faster ALL the time and you would be smoking one tire.

Try again.......

ragin

LOL!!! Which law of Physics is this?

OK.. getting serious again..

well the only way I can see:

(A)|--engine--------------------|(B)

causing torque steer is if the WEIGHT causes tire A to get more traction than tire B.

Think of it this way, RWD has fishtail, FWD has torque steer and AWD is.... well, heaven.

partagas

Let me try my always overbearing luck at this. HANDLING:
1. 95.....BMW 330i
2. 80.....'04 TL
3. 80.....Audi A4 (for diferent reasons)
4. 70.....Infifniti G35 (dangerous)
5. 70.....Lexus IS300 (can't handle rough)
6. 65.....Lexus GS430 (power but understeer)
7. 65.....Turbo Volvos and Saabs (torque steer and undester galore. Only the Bmws, the Audi and the TL are acceptable. A little bit of torque steer -- Learn to love and live with it or get a BMW. As you know by now, I'm giving up the 30i to get the other amenities of the TL. None of the other cars will do.

chiawei

Obviously you have no clue. So let me explain this in detail.

1st of all, by design FF tends to have unbalanced driver shaft. Which means one side is always shorter than other. Thus torque tends to reach the shorter side faster than longer side.

2. suspension design principle. In all cars, the left and right side of suspension are mirror of each other. in simple word both work to counter balance each other so that you don't have to constantly adjust steering wheel. Because in all cases, both wheels contact traction with ground are not always the same.

3. Cause of torque steering. Torque steering is caused by torque generated along the kingpin axis. Hence, both engine torque as well as traction force on the tire will cause torque steer.

During hard acceleration, the engine torque differential between the two wheels are too great and too quick for suspension to do it's job, thus why you feel the pull of the wheel to one side. This has to do with unequal drive shaft length. It does not matter if they are geared the same. Becaue of unbalanced torque hence, the net effect to the wheel is one side is temporary faster then the other. Hence my explaination is correct.

Torque steer is temporary by nature as by the time, either the driver would manually counter turn the wheel or the traction control would cut in and reduce this temorary engine torque unbalance.

vipvop

hey partagas, what is understeer? does it explain why I feel like my 99 tl handles better than my girlfriend's '03 gs 430? I'm guessing it just refers to the fact you seem to have to turn the wheel a lot to make the car turn - ie, it doesn't feel responsive...

partagas

No, the GS doesn't torque steer. It's just not designed for balanced handling and it understeers horribly.

SCWells72

I'm not sure I'd say it understeers, either, at least not in the sense that a FWD car does. Understeer is when the driving wheels are also the steering wheels and can't be turned easily because of the various strong forces working against them going into a turn. There are several "at the extreme" handling issues when you try to dual purpose the same wheels for driving and handling. The main advantage of FWD/FE is that the weight of the engine is over the driving wheels for inclement weather causing them to slip less than, say, a RWD/FE car where there's very little weight over the driving wheels.

It's true that the steering on the stock GS430 is very light and the suspension dangerously soft for the power of the V8, so it's very difficult to induce controlled oversteer as you typically want with a RWD car.

Put the L-Tuned (or other firmer) suspension on the car and it's much more composed and consistent with the power of the engine. It's trivial to induce controlled oversteer with a GS430 when you have the right suspension.

Formula 350

Yes I do have a clue, but I am wondering if you do.

Lets review the quote that I left. Are you telling me that if I have one short shaft and one long shaft that the longer shaft will take longer for the torque to get to the end? That is what I am reading. That is completly wrong. If you have a two foot shaft and a one foot shaft and twist them at the same time with the same torque the power reaches the end of both shafts at the same time (except for any torsional loss, but this is so small it is not worth talking about) So saying that the shorter shaft put power to the wheel first is completly wrong, based on the laws of physics that is......

ragin

I had an 2001 Accord that had no noticeable torque steer. A 16 year old gal with No insurance pulled out in front of me on a highway and totalled my car.

I replaced the car with a 2002 Acoord. Same engine, basically the same car. The 2002 Accord has bad torque steer. The only thing that is different (that I know of) is the 2002's tires. The alignment is great. Only when power is applied does it veer left.

chiawei

That's because you did not know that drive shaft would twist before it turns. Hence the shorter side will alway twist and turn slightly earlier than the longer side. This is simple physics. It's harder to turn then it is to twist. Anyone should have known that.

That's why torque output reaches the shorter side wheel 1st then it does on the longer side wheels, hence resulting in the torque steer.

When torque is output to the drive shaft, the tendency is for the drive shaft to twist thus changing the kingpin angle. So during hard acceleration, shorter side will always spin sooner and faster until the suspension can correct itself and both side are spinning at same speed.

Formula 350

Decided to go looking in the web. Got this explanation. As you can see, it is not that the shafts are shorter that is the problem, but the other components in the system. So, I think we were talking around each other. The shafts, one being long and one being short in and of itself is not the problem. The torque applied to each shaft is transferred to the other end with little loss. So my physics remain the same.



Torque steer is when your engine is steering the car, not you. Pounding on the accelerator causes the car to twist the direction of the tire getting more torque. Torque steer is created from a moment or leverage arm created by the relationship between an imaginary line projected through the Kingpin inclination angle and the centerline of the tire. Kingpin inclination angle is the line drawn through the upper and lower ball joints on a multilink car and projected to the ground. On a McPherson strut car, it's the line drawn between the upper shock mount through the ball joint as projected to the ground. The distance from this point to the center of the tires contact patch is a moment arm or a leverage point where the torque can pull the steering off center. Another cause of torque steer is unequal length driveshafts. When the axles are not of equal length, the CV joints are at unequal angles. This allows more torque to reach one wheel than the other. Nonsymmetrical driveshaft angles (including equal axle length cars when cornering) and lengths are the primary cause of torque steer but the problem can be compounded by suspension, worn or loose control arm bushings, worn or loose tie rods, broken or loose engine mounts, engine movements, alignment, unequal tire pressures, and road surface. Denser engine mounts can keep the engine from shifting during acceleration. The Spec V has a lot of torque, which makes torque steer more noticeable than say a GA16DE, however it is not dangerous in itself.

sparky57

Not exactly. Although understeer tends to be more prevalent with FWD designs, it can occur with any drive combination, including AWD. It is simply the tendency for the car to go straight when you turn the wheel. Many cars and virtually all trucks have lots of it dialed in because it is considered inherently "safer" for inexperienced drivers. I like the NASCAR driver who described understeer vs. oversteer this way:

"Understeer is when you hit the wall with the front end and oversteer is when you hit the wall with the back end"

Not exactly a scientific explanation, but it serves well. My wife's S2000 has a pretty neutral state where either under or oversteer can be induced with your right foot. Older rear engined Porsches were inherent understeerers until you entered a fast corner and backed off the throttle. The weight shift and geometry change of the suspension caused the rear end to steer "out" and quickly you found yourself going the opposite way.

You can tune in or out degrees of understeer by changing the front to rear tire pressure balance, tire size, or roll stiffness using stabilizer bars. Larger front roll bars increase understeer; conversely, larger rear bars reduce understeer. Increasing front tire pressure, however, has an opposite effect as it reduces understeer. I'm amused when I see someone put bigger tires on the rear of a FWD car. It simply increases the amount of understeer. With an older Accord that had a bunch of understeer, I backed out some by running about 4 psi more in the fronts vs. the rears.

As been discussed by others, the nature of most FWD drive systems involves unequal length "half shafts". There are some Hondas and Acuras, however, that have equal length shafts to minimize that effect. In general, Honda has engineered most of the torque steer out of their designs. BTW, there is a similar phenomena experienced in propeller aircraft. It is aerodynamic effect caused by uneven lift of the prop blades that pulls the nose to the left on hard acceleration. It's called "P" factor, but manifests itself in a similar manner.

rw

partagas

My GS400 understeers like an SOB. I is a real pig going downhill through the chicanes from Yosemite.

chiawei

Actually you are wrong again. As i have explained from earlier post. There are many reason that torque steer occurs. Torque steering is simply a variaion of king pin axis. In fact your own post also mentioned that faxt that unequal length drive shaft allow more torque to reach one wheel than the other.

However, the explaination is wrong. The CV joint is at unequal angle during hard acceleration, however this is consequence of unequal torque application due to uneven length drive shaft. In addition, CV joint angle can also be changed by traction force applied to each front wheel (this occur quiet frequently in low speed for RWD). The CV joint in its nature state are symetric regardless of which side it is on. However, because of unequal length of drive shaft and drive shaft tendency to twist instead of turn cause the CV joint to become unsymetric between two front wheels, that's why differential torque steer occurs. Because more torque is being applied at faster pace on one wheel instead of the longer one.

Hence my explaination is correct. You just did not understand the reasoning behind it.

Let me explain one more time

Hard acceleration torque steer occurs when torque from the transaxle begins to turn the drive axles, the axles twist before they turn. The longer axle shaft will twist more before it begins to turn than will the shorter shaft. This additional twisting of the longer axle makes it begin to turn slightly later than the shorter axle. This condition is called torque steer. The so called uneven angle of CV joint is an effect of this uneveness of torque exist between two front wheels, not the cause.

gweempose

frebay,

You certainly got more than you bargained for when you posted this thread!

:lol1: :lol1: :lol1:

fla-tls

I completely agree with this post. There is no single reason for torque steer. It's a combination of driveshart lengths and angles, road conditions (i.e. bumps / less traction on one wheel), etc.

As far as over and understeer, understeer is just what it sounds like. You turn the wheel, and the car's front tires don't deliver all of the turning force to the ground. You end up plowing straight forward in extreme cases. It's worse on cars that have a high proportion of their weight in the front (FWD cars are at a disadvantage here because all of the drivetrain is up front).

Oversteer is just the opposite. The front tires grab and pull the front end around quickly. In extreme cases the back end will lose traction and you spin out.

svtmike

So, let's say I take your explanation as correct.

Take an unequal-length half-shaft setup. Split the long shaft into two shafts. The first shaft is connected to the output of the transmission, and ends at a point symmetrical to the output of the engine for the short half-shaft. I then put another half-shaft between the output of that shaft and the CV joint.

Of course, you know that this describes an equal-half-shafts setup.

I still have a longer transmission path for the torque on the long side, so if I accept and apply your explanation I should have as much torque steer, since I still have a longer set of shafts to twist.

In practice this setup significantly reduces torque steer, in direct contradiction to the application of your explanation. Can you explain this apparent contradiction in terms that even I can understand?

Mike

jyg tl 3

I think you are all getting way too much involved with torque steer alone, a major factor in the steering wheel turning when you apply power, may be action of lsd Limited slip differential grabbing at road surface causing uneven traction , hence wheel pull
this might be causing a good part of the
wheel pull.

Formula 350

That is one of the things I said a long time ago. Take the car to a place and have one wheel in water and the other on dry pavement. Floor it and you will get a lot of torque steer on almost any car. It is a traction thing on this example.

Fencesitter

This has been a helpful thread. But I can't find the dreaded torque steer on my Saab (I have the 250 hp one). Last night I tried hard acceleration with only two fingertips on the steering wheel, and the car went straight ahead, with no apparent pull either way. Could it be that the TCS (traction control) prevents/minimizes torque steer? I didn't try it with the TCS turned off.

chiawei

But then again, you would need a joint between those two shaft. Simple drawing below.

|left joint---engine---joint#1---joint#2|

The joint #1 would begin to counter balance. Hence reducing the uneven torque experienced by #2. Therefore torque steer is reduced but not eliminated because you still have longer travel than to the left side. But at least you now have one additional joint to compensate.

I do not see how this contradict my explaination. In fact , this still prove my point. Even with this setup, there are still going to be some engine torque steer because the momentum arm on the right side (my example) is still longer.

In addition, I have explained many times, there are many cause of torque steering. My explaination only applies to engine torque steer and nothing else.

jorgev

i thought this had to do with the limited slip diferential.. but my friends welded the LSD together.. both tires spin equaly.. but the car still pulls to one side.. the side fardest from the transmition. so i guess it has to do with that... i'm talking about cars with over 600 hp... fwd

BlueXTC

i totally agree with chiawei... the torque steer has to do with the length of the drive shaft from the engine. left and right drive shaft is not equal in length thus creating torque steer. ask any well trained honda mechanics, they'll tell u the same thing.