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Login to post Forums » Grassroots Motorsports » Be So Kind As to Elucidate the Causes and Cures for Torquesteer

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Dec. 17, 2011 6:45 a.m. DaewooOfDeath HalfDork

How does torque steer work? I thought it was a function of the transmission shifting in relation to the hubs. I heard that unequal length axles make it worse and that squishy motor/tranny mounts aggravate it.

Given my assumptions, it would make sense that torque steer would be most severe in first gear. This doesn't match my experience. At low speeds, full throttle and first gear the steering weights up slightly and pulls left very slightly. However, at higher speeds in fifth gear it pulls noticeably on trail throttle.

What gives?
Dec. 17, 2011 8:37 a.m. 92CelicaHalfTrac SuperDork

That sounds more likely to be bad bushings or similar. This is the daewoo, right? Does it make enough torque to have torque steer?
Dec. 17, 2011 9:02 a.m. DaewooOfDeath HalfDork

It's got brand new poly bushings all through the suspension and it did this on the stock bushings too.

It might not even be torque steer. It just feels floaty when I lift off the throttle at speed and then tightens back up when I step on the gas.

And yah, I know. Just talked to a guy who has done several Daewoo swaps and he said the 1.5, regardless of what they rate it at, usually does about 70 whp.
Dec. 17, 2011 9:12 a.m. Luke SuperDork

I've never actually experienced torque steer (can't even get my Saab 900 turbo to do it), but the best demonstration of it I've seen is Jeremy Clarkson in his RS Focus test. Heading straight, he takes his hands off the wheel and nails the throttle, and the car veers dramatically off-line. So maybe it's not torque steer at all .
Dec. 17, 2011 9:33 a.m. carguy123 SuperDork

DaewooOfDeath wrote:

It might not even be torque steer. It just feels floaty when I lift off the throttle at speed and then tightens back up when I step on the gas.

What you describe sounds more like low tire pressure on one side.
Dec. 17, 2011 10:05 a.m. novaderrik Dork

the axle on one side is generally much longer than the other, so it will "twist" up more and spring back harder when the tension releases.
Dec. 17, 2011 10:13 a.m. Trans_Maro Dork

Moving the drive wheels to the rear where they belong generally cures torque steer problems.

Shawn
Dec. 17, 2011 10:27 a.m. integraguy SuperDork

Car manufacturers have tried to correct/engineer out torque steer using many different methods, some of which can't be done on a grassroots budget. Example? When the driveshafts on a front wheel drive car are of different lengths, some manufacturers will make the shorter driveshaft heavier than the longer one. Way back in 1972 VW/Audi figured their negative offset steering radius...thingee, would have the added benefit of not inducing torque steer. As the owner of a 1974 Audi, I would say there were barely sucessful. Borderline grassroots would be a limited slip diff...assuming there is an application for your car.
Dec. 17, 2011 10:29 a.m. z31maniac SuperDork

^My MazdaSpeed 3 had an LSD...................torque steer was absolutely BRUTAL in that car.
Dec. 17, 2011 10:42 a.m. bravenrace SuperDork

novaderrik wrote:

the axle on one side is generally much longer than the other, so it will "twist" up more and spring back harder when the tension releases.

This is a common misconception about how torque steer happens. The real cause, which is in fact related to different length half shafts, is that when torque is applied to the shafts there is a moment arm created. Its the different angles of the shafts that creates different moment arms that is the primary cause of torque steer. That's why even cars with equal length half shafts can expereince torque steer in certain situations where the shafts are different angles due to suspension travel. Is there twisting? Possibly. But any effect from that is minimal.
Dec. 17, 2011 12:45 p.m. corytate HalfDork

from what I understand it is the power taking the shortest route to the wheels, putting more power to the wheel with the short axle? not even close to being sure about that though. drive a speed 3 to find out about torque steer=]
Dec. 17, 2011 1:33 p.m. 92CelicaHalfTrac SuperDork

DaewooOfDeath wrote:

It's got brand new poly bushings all through the suspension and it did this on the stock bushings too.

It might not even be torque steer. It just feels floaty when I lift off the throttle at speed and then tightens back up when I step on the gas.

And yah, I know. Just talked to a guy who has done several Daewoo swaps and he said the 1.5, regardless of what they rate it at, usually does about 70 whp.

REALLY feels suspension/steering related rather than torque steer.
Dec. 17, 2011 4:26 p.m. jimbbski Reader

That condition can also occur due to incorrect caster as in the caster is not equal side-to-side or one side of the suspension can move more then the other.
Dec. 17, 2011 6:26 p.m. HappyAndy HalfDork

Luke mentioned the SAAB 900 turbo's lack of torque steer, must be a c900, the axel shafts are equal length & the diff is nearly dead center.

I've owned quite a few c900 turbos, and even driven a friends c900 race car that had to be over 250 hp, none of them torque steer. There is also supposed to be something about geometry of the double wishbone front suspension that gives them additional resistance to torque steer.

SAAB ng900s OTOH have "normal" transverse FWD drivetrains with off center diffs, unequal length drive axles and mac-strut front suspensions. They do torque steer.

So I guess the moral of the story is to. convert the Daewoo to a double wishbone front. suspension and move the diff to the center and the problems will go away.
Dec. 18, 2011 2:05 a.m. DaewooOfDeath HalfDork

carguy123 wrote:

DaewooOfDeath wrote:

It might not even be torque steer. It just feels floaty when I lift off the throttle at speed and then tightens back up when I step on the gas.

What you describe sounds more like low tire pressure on one side.

I checked that. 35 psi all around.
Dec. 18, 2011 2:07 a.m. DaewooOfDeath HalfDork

92CelicaHalfTrac wrote:

DaewooOfDeath wrote:

It's got brand new poly bushings all through the suspension and it did this on the stock bushings too.

It might not even be torque steer. It just feels floaty when I lift off the throttle at speed and then tightens back up when I step on the gas.

And yah, I know. Just talked to a guy who has done several Daewoo swaps and he said the 1.5, regardless of what they rate it at, usually does about 70 whp.

REALLY feels suspension/steering related rather than torque steer.

I've been through the suspension a couple times now and haven't found anything. Guess it's time to check the steering.
Dec. 18, 2011 2:09 a.m. DaewooOfDeath HalfDork

HappyAndy wrote: So I guess the moral of the story is to. convert the Daewoo to a double wishbone front. suspension and move the diff to the center and the problems will go away.

Haha, this makes me smile!
Dec. 18, 2011 2:35 a.m. 7pilot Reader

Cause: Driving wheels at front of vehicle. Cure: Driving wheels at rear of vehicle.

m
Dec. 18, 2011 4:31 a.m. DaewooOfDeath HalfDork

Next project is going to fix that problem. I'm just hoping the next project gets built in a big pimpin mechanical engineering department at a college that runs a semi pro racing team.

(Please hire me, Joongbu, pleeeaaaaseee!)
Dec. 18, 2011 6:40 a.m. Schmidlap HalfDork

You mentioned that the suspesion has all new poly bushings and the car did this with stock bushings as well. Did it do it when it was new or did you just notice it recently? My 1999 Cougar had this problem when it broke one of the engine mounts (it had 4 engine/trans mounts) so you may want to look at that too. I think my problem may have been limited to lower speeds though but I can't remember for sure.

Good luck with the job search!

Bob
Dec. 18, 2011 7:01 a.m. DaewooOfDeath HalfDork

When it was new I was 13!

Did your Cougar stop doing it when you fixed the motor mounts? I have some seriously crappy mounts right now, but I'm changing them all out for this rock hard plastic composite stuff during the engine swap.
Dec. 18, 2011 8:34 a.m. 92CelicaHalfTrac SuperDork

DaewooOfDeath wrote:

When it was new I was 13!

Did your Cougar stop doing it when you fixed the motor mounts? I have some seriously crappy mounts right now, but I'm changing them all out for this rock hard plastic composite stuff during the engine swap.

That can certainly do it as well.
Dec. 18, 2011 11:45 a.m. kb58 HalfDork

My analogy:

Take two pieces of PVC water pipe, one 1 foot long and the other two feet long. Put the end of one in your vice and grab the free end with ViceGrips - and twist. Repeat with the other one. Note that the longer one is easier to twist, and there you have it. The engine is putting equal twisting force through different-length axles. The longer one "winds up" more, so less torque ends up going through it. Because more power is going though one axle, the car pulls to one side.
Dec. 18, 2011 11:47 a.m. iceracer SuperDork

One attempt was to divide the longer shaft into two parts. The inner shaft being mounted rigidly to the engine block. the outer shaft was then the same length on both sides. My ZX2SR had this.
Dec. 18, 2011 12:57 p.m. 2002maniac HalfDork

In my experience FWD is the main cause of torque steer. I stick to RWD to avoid the issue.

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