Another '05 STi article...

[dustinr]

http://www.channel4.com/4car/road-t...rx-sti/sti.html

[MikeK]

http://www.channel4.com/4car/road-te...x-sti/sti.html

I think your link is b0rked

[dustinr]

Originally Posted by MikeK

http://www.channel4.com/4car/road-te...x-sti/sti.html

I think your link is b0rked

OOPS! ...thanks for the fix...

[sperry]

Um, that's for the euro-spec STi.... I'm still interested in some definitive white-paper type info on the '05 US STi having something other than the latteral-G sensor that the '04 already has.

[dustinr]

Originally Posted by sperry

Um, that's for the euro-spec STi.... I'm still interested in some definitive white-paper type info on the '05 US STi having something other than the latteral-G sensor that the '04 already has.

I have seen the 2004 STi service manual and it has information on the Lateral G sensor but nothing on a Yaw-Rate sensor. I have also seen the service manual for the USDM 2005 STi and it has information on both the Lateral G sensor and the Yaw-Rate sensor. I have the 2005 info. on .pdf and I also have the Subaru VDC booklet on .pdf which also talks about use of the Yaw-rate sensor in Subaru's that have VDC and TCS. I attempt to attach them but if it doesn't work give me your e-mail and I'll send the info. to whom ever.

[dustinr]

Tried to attach the VDC Reference booklet but it wouldn't accept it... It's 4.2 MB.

[sperry]

If all this stuff is in the STi, I'm surprised Subaru isn't pushing it in the sales literature.

[Kevin M]

Both of those documents refer to the "yaw-rate and lateral G sensor." I'm still not convinced it's not just the lateral G sensor with a new name.

Also, VDC is apparently just traction control, 99% of which ysstems result in slower lap times. It does seem to counteract both over steer and understeer, so maybe it's better than most. I can say for certain though that it's not an equivalent to the Evo's AYC.

[dustinr]

Originally Posted by BAN SUVS

Both of those documents refer to the "yaw-rate and lateral G sensor." I'm still not convinced it's not just the lateral G sensor with a new name.

Also, VDC is apparently just traction control, 99% of which ysstems result in slower lap times. It does seem to counteract both over steer and understeer, so maybe it's better than most. I can say for certain though that it's not an equivalent to the Evo's AYC.

If you look at the Service manual for '04 they only mention a Lateral-G sensor not a Later G & Yaw Rate Sensor like the '05 manuals. I also have a .pdf of the VDC training booklet which describes separately what the Lateral G and Yaw Sensors do. Granted it's not AYC but it's not far off; AYC controls the torque to each of the rear wheels allowing one side to get more torque than the other...On the Subaru's the Yaw sensor allows the car to better recognize understeer/ oversteer and instead of controlling the torque bias between the rear wheels the Subaru system applies small amount of brake to any one of the 4 wheels that it feels will help reduce the stray from the intended path of travel...ie if understeering it will apply brake to both of the inside wheels. And who convinced you that 99% of traction control systems make for slower lap times? It's well documented and proven (even in Formula 1) that traction control systems make for faster lap times; I think you have confused the dislike of traction control systems by some race drivers as meaning they are slower...they are not. There's even a video put out by the Japanese where they took a Ferrari 360, Porsche twin-turbo and Sky-line GT-R and put traction control to the test. They all lapped faster with traction control turned on despite the drivers not liking traction control. Formula 1 uses electronic traction control and if anybody knows how to get faster times it's F1 teams, if TC was slower it wouldn't be used.

[Kevin M]

You're confusing banned Formula 1 traction control systems with the kind of traction control Federalized, street-legal vehicles get. I will hold out for the possibility that the new VDC may have the ability to improve traction for motorsports purposes, but mostly it's so people don't get the "I have AWD, I'm INVINCIBLE!!!1!1!!!!" mentality in the winter and plow into curbs, cars, farm animals, and lakes.

[dustinr]

Originally Posted by BAN SUVS

You're confusing banned Formula 1 traction control systems with the kind of traction control Federalized, street-legal vehicles get. I will hold out for the possibility that the new VDC may have the ability to improve traction for motorsports purposes, but mostly it's so people don't get the "I have AWD, I'm INVINCIBLE!!!1!1!!!!" mentality in the winter and plow into curbs, cars, farm animals, and lakes.

Taken from the FIA web-site...


Although built to perform slightly different purposes - in ordinary cars ensuring stability under everyday use, in Formula One delivering the maximum amount of power to the road at all times - the fundamental principles remain very similar.

Formula One cars are massively powerful. Even with the grip of modern racing tyres and the assistance of aerodynamic downforce, they are still capable of 'breaking traction' or developing wheelspin up to very high speeds, especially under the loads imposed by cornering. This is inefficient, slows the car down and can damage tyres. Traction control therefore gives drivers a competitive advantage.

To understand traction control it is best to consider the 'traction circle'. The tyres of a Formula One car, like any car, can only offer a certain amount of grip. This can be the longitudinal grip used for braking and accelerating in a straight line, or the lateral grip required for cornering - or a combination of the two. Judging the exact 'mixture' of acceleration and cornering grip that can be extracted from the tyre is one of the hardest tasks faced by a racing driver - too much will result in a 'power slide', too little will see the car putting in a slow time. And it is in this that traction control is of the greatest assistance to drivers.

Not that traction control gets rid of the need for driver skill. The highly 'aggressive' systems on a Formula One car will allow a car to operate very close to the edges of the tyre's capability. But simply travelling around every corner on full throttle would have a very serious impact on the tyres' life and require more frequent pit stops. Discretion is still called for.

Traction control is not new to Formula One motorsport. It has been around in various guises since the 1980s, and cars like the 1992 Williams-Renault FW14-B which took Nigel Mansell to his Driver's Championship title were even more electronic-packed than the current cars - featuring computer controlled active suspension in addition. After a long period during which traction control was banned, the FIA decided to re-allow its use at the start of the 2002 season as it was becoming increasingly difficult to prove that ECUs (Engine Control Units) were not being used to replicate traction control functions.

As with systems on road cars, Formula One traction control works by a comparison of wheel and track speeds, the information gathered by electronic sensors. If the wheel is travelling quicker than the road it is passing over then the engine will be progressively throttled back to prevent wheelspin. Until recently the system was also vital to the 'launch control' mechanism which allowed drivers to make optimum starts. This has been outlawed for the 2004 season.

The role of traction control in Formula One racing is an ongoing source of debate, with critics arguing that driver skill alone should regulate the amount of power transferred to a car’s rear wheels. However, others have argued that any ban on such systems would be difficult or impossible to police and traction control remains legal for 2004.

[Kevin M]

You completely missed my point- I know all about the banned traction control systems. What I was saying is that any USDM production-car traction control is NOT designed for faster laptimes- it's designed for fewer crashes. The STi in showrooms now *might* be faster with the VDC active, but I will believe that when a professional driver goes around a racetrack faster with it than without it. That has nothing to do with competition systems.

Read the first line of my last post again:

Originally Posted by BAN SUVS

You're confusing banned Formula 1 traction control systems with the kind of traction control Federalized, street-legal vehicles get.

I'm not debating the merits of FIA-style traction control. I'm talking about electronic nannies to keep stupid Americans from crashing their car because they think they can do what they want in bad conditions.

[dustinr]

Originally Posted by BAN SUVS

You completely missed my point- I know all about the banned traction control systems. What I was saying is that any USDM production-car traction control is NOT designed for faster laptimes- it's designed for fewer crashes. The STi in showrooms now *might* be faster with the VDC active, but I will believe that when a professional driver goes around a racetrack faster with it than without it. That has nothing to do with competition systems.

Read the first line of my last post again:

I'm not debating the merits of FIA-style traction control. I'm talking about electronic nannies to keep stupid Americans from crashing their car because they think they can do what they want in bad conditions.

I agree with that statement in the case of SUV's and station wagons but the TC systems that come on sports cars do aide in faster lap times. Where as a good driver can make a mistake and correct for it, or slide the car around and still have control it still doesn't make for faster lap times, TC by not allowing these things to happen although maybe not as fun do account for faster lap times. Regardless of how tuned a drivers senses are and their skill level they can never match the speed and response of dedicated systems of sensors and actuators that can allow a car to be driven to it's exact enevlope and not cross over. I'll try to find the video of the Japan test where they were attempting to do exactly what you claim, they thought they could lap faster with traction control turned off and they ended up proving they couldn't.

[doubleurx]

Faster,Better, More!!!!!!!!!!!!!

[sperry]

Originally Posted by dustinr

I agree with that statement in the case of SUV's and station wagons but the TC systems that come on sports cars do aide in faster lap times. Where as a good driver can make a mistake and correct for it, or slide the car around and still have control it still doesn't make for faster lap times, TC by not allowing these things to happen although maybe not as fun do account for faster lap times. Regardless of how tuned a drivers senses are and their skill level they can never match the speed and response of dedicated systems of sensors and actuators that can allow a car to be driven to it's exact enevlope and not cross over. I'll try to find the video of the Japan test where they were attempting to do exactly what you claim, they thought they could lap faster with traction control turned off and they ended up proving they couldn't.

That's a pretty general statement. I guarentee a Group N STi is faster on gravel with the ABS and TC turned off. Those systems are designed to keep the car in line, and keep your car from sliding, both of which are necessary things to go fast on gravel. The same is true for some tarmac situations.

Plus, the way the TC works on the new STi seems to use braking to create yaw moments (rather than L/R torque split like the EVO's AYC). Braking is never the ideal way to control a car at the limits of traction. I can imagine a system like that applying the brakes during a high speed sweeper that would put the rear-end of the car in front of the nose... and I'll guarentee that spinning is not the fast way around any race track.

The bottom line is that the system in the STi is not designed for at the limit race driving, it's designed for street use. I bet an experienced race driver with all the ABS and TC turned off will destroy the lap times of an experienced street driver with all the aides turned on.

The only time TC and ABS are really advantageous in racing is when the systems are specifically designed for racing. And like most things, what's good on the race track isn't all that good for the street... race brake pads, race suspension, race tires, etc. all make a car more dangerous on the street.

[dknv]

Originally Posted by sperry

I can imagine a system like that applying the brakes during a high speed sweeper that would put the rear-end of the car in front of the nose... and I'll guarentee that spinning is not the fast way around any race track.

It would be interesting to know whether that RX8 driver at Fernley had his TC on or off.
I know on an autocross course, my laptimes are slower with TC on. It's possible this is not the case on a road course - I'll have to see what the RX drivers are saying on the other boards.

[MattR]

In an unrelated/ related note...Saturday, I ran one run at autocross with my diff set at "open/rear"...Can you guess which one it was? It really does effect how quickly the car snaps around a turn.

[subarudedude]

sti fo evah