Question about FWD cars and high Torque

How do Honda (and others) tuners manage to get very high torque to the ground and not twist the drive shafts into pretzels. Not to mention the effect on torque steer.

 When Ford/Lincoln dropped the Intech V8 on the fwd Continental they detuned it supposedly for fear of torque steer and the strength of the powertrain. GM did the same when it dropped the Supercharged 3.8 V6 into some of their cars. Now the 3.8 V6 was the same engine that powered the Grand National with a  turbo but nowhere as powerful as the RWD set up.

So are all those people on You Tube proclaiming that their Civic hatch back produces 500 hp lying or how are they getting around the destructive forces on their drivetrain and avoid torque steer specially in real life conditions, or any competition other than drag races?

Inquiring minds want to know.

You can make incredible HP at super high RPM without a boat load of torque.

OK I get it high rpm in the case of the Honda while the Ford/GM cars plenty of low end torque. That seems to work for the NA engines but what about those with aftermarket turbos?

I don't think driveaxles are the issue. BMW and Porsche can put down some incredible power numbers (and torque) through axle shafts that are not much larger than that in FWDs. Taming torque steer is a different animal. The best way is through equal length shafts, as Chrysler did in their turbo cars, but that can be a real packaging nightmare.

You also have to look at the Honda tuner making 500hp, he does not have to worry about 10 year/100,000 drivetrain warranty.

Torque steer builds character.

Maybe semantics, but the axle shafts seldom fail.  The CV joints shatter quite regularly.

I think one of the bigger challenges is launching a high horsepower fwd car without rattling the tires, the gears, the engine, your teeth... Rock solid engine mounts help, and also make the car quite unpleasant to do drive.  Pure torque applied smoothly is not that tough on parts.  Chatter the tires, and E36 M3 breaks at 100 horsepower.

My 3800 cars all seem to destroy transmission mounts long before the axles fail.

fortee9er said:

How do Honda (and others) tuners manage to get very high torque to the ground and not twist the drive shafts into pretzels. Not to mention the effect on torque steer.

 When Ford/Lincoln dropped the Intech V8 on the fwd Continental they detuned it supposedly for fear of torque steer and the strength of the powertrain. GM did the same when it dropped the Supercharged 3.8 V6 into some of their cars. Now the 3.8 V6 was the same engine that powered the Grand National with a  turbo but nowhere as powerful as the RWD set up.

So are all those people on You Tube proclaiming that their Civic hatch back produces 500 hp lying or how are they getting around the destructive forces on their drivetrain and avoid torque steer specially in real life conditions, or any competition other than drag races?

Inquiring minds want to know.

 

The Continental (and the Taurus it grew out of) were more or less biggiesized Tempos.  Their steering geometry sucked and there were more soft squishy bushings in the drivetrain than there should have been.  Engine mounting was by four mounts under the drivetrain to the subframe, which was also rubber bushed, as opposed to modern practice where you hang the drivetrain at the front and rear end (relative to engine, not chassis)  and then have one or two torque mounts to control rocking back and forth under load.  So basically it was a recipe for undesired drivetrain motion, which is a large contributor to torque steer.

And - nitpick - the turbo Buick was a completely different engine from the transverse front-drive.  Technically the head gaskets and timing cover gaskets might interchange.   Much different blocks, significantly different heads, WAY different computer control systems.

There has been a tremendous amount of "well that didn't work" in FWD drivetrain geometry over the years. They all become pretty much undriveable unless you're going absolutely straight at some HP level. Finding that is kind of fun. For what it's worth, you can't put 500lb/ft of torque through street legal 275 width tires on a regular road at street legal speeds in pretty much anything, FWD or not. The fuse in the system is always traction. 

Ford uses/used some trick engineering in the Revoknuckle and GM the Hiper strut.

Mazda used SWAS to limit torque in low gear and a jackshaft. For mine I found the tune to bring the torque on in a more linear fashion helped a lot more with the drivability than either of those.

Otherwise the other points were made.

Streetwiseguy said:

Maybe semantics, but the axle shafts seldom fail.  The CV joints shatter quite regularly.

I think one of the bigger challenges is launching a high horsepower fwd car without rattling the tires, the gears, the engine, your teeth... Rock solid engine mounts help, and also make the car quite unpleasant to do drive.  Pure torque applied smoothly is not that tough on parts.  Chatter the tires, and E36 M3 breaks at 100 horsepower.

This.  I've seen someone blow up a CV joint with a too-aggressive clutch drop in a Civic with less than 100hp. 

The other factor is that RWD CV axles don't have to deal with steering.  Handling that much angle makes the outer CV MUCH weaker on an FWD car.

I doubt that they're lying, but it may be for a drag race application where steering isn't as relevant or it just might be plain undrivable at WOT on the street and it was built as an engineering exercise/for bragging rights.

My overall impression of the torque steer issue is that it's massively overblown because most of the time it happens it means there is something semi-obviously wrong with the engine mounts or suspension bushings that just isn't being diagnosed and fixed. 

Vigo said:

My overall impression of the torque steer issue is that it's massively overblown because most of the time it happens it means there is something semi-obviously wrong with the engine mounts or suspension bushings that just isn't being diagnosed and fixed. 

I am kinda in the same boat here.  When i had my turbo grand prix, there wasn’t much issue with torque steer.  But it had good bushings up front  and poly engine/trans mounts all around.  It just kinda put the power down or spun the tires.  Nothing unpredictable.  

Knurled:  I remember feeling like such a fatty ordering biggiesize fries from wendy’s back in the day.  

Knew a guy that had a modded Mazdaspeed 3 - he said that it got really hairy when he took it above 300 bhp.

Vigo said:

My overall impression of the torque steer issue is that it's massively overblown because most of the time it happens it means there is something semi-obviously wrong with the engine mounts or suspension bushings that just isn't being diagnosed and fixed. 

Well,there's two kinds of torque steer, there's the torque pull from the drivetrain going cockeyed, and then there's the steering kicking around as the various forces bobble around between negative-feedback and positive-feedback loops.  (Sometimes it turns harder and sometimes it straightens itself out, depending on the Ouija Board principle)

Funny, when people laud old 911 steering, they say the steering wheel "writhes in your hand", but the steering jumping around like an excited dog on a leash in a front driver is considered unsporty.  I always thought the torque steer in a light grunty front-driver is kind of neat.

Knurled. said:

Funny, when people laud old 911 steering, they say the steering wheel "writhes in your hand", but the steering jumping around like an excited dog on a leash in a front driver is considered unsporty.  I always thought the torque steer in a light grunty front-driver is kind of neat.

It's funny.  I find torque steer far more annoying if I'm just driving the car than if I'm actually beating on it.  A bit of torque steer while hooning it around some corners?  Kinda fun and entertaining. 

Torque steer on the highway with the cruise set when the car throttles up for a hill?  Pisses me off to the point of pretty much refusing to ever daily a FWD anything. 

Good description!

I also remember now a C&D article about one of the hyper SAAB 9-5s, and they noted that while it was the same drivetrain as in the then-current hyper 9-3, the larger 9-5 didn't have nearly as much torque steer.  The additional weight on the chassis damped out the juggling forces nicely.

Diff and alignment settings make a huge difference. If it's only putting power to one wheel it doesn't matter how much power it has. 

As far as destructiveness, let's just say you get good at replacing axles. LOL

A friend of mine had a turbo hatch putting low 400's to the wheels. Most of the time the tires would just spin, but the 2nd gear torque steer was violent when boost and vtec kicked in. 

Sadly it was stolen before we could do much development. 

In reply to Knurled. :

the 9-5 also had a better chassis than the 9-3. the NG900 and first gen 9-3 need braces to tighten up the front end to be able to put the power down. Notably this includes a brace for the firewall mounted steering rack. my old NG900 turbo was SCARY when boost kicked in and the wheel wanted to steer you into the nearest kerb

Torque steer on the highway with the cruise set when the car throttles up for a hill?

That should never happen if the thing is working right. Even as a professional technician who has driven untold cars in all states of disrepair, i have never experienced that. 

Vigo said:

 

Torque steer on the highway with the cruise set when the car throttles up for a hill?

That should never happen if the thing is working right. Even as a professional technician who has driven untold cars in all states of disrepair, i have never experienced that. 

Ever driven a gen 5 Camry with a V6?  The torque steer in those is pretty noticeable.  Going from coasting down a hill to climbing a decently steep hill on the highway definitely requires a slight steering correction as the power comes on.  It's nothing massive, but you certainly couldn't take your hands off the wheel and have the car stay straight as it throttles up.