Nunco, you almost sound intelligent sometimes. Are you bipolar, by any chance?

 

dont know it til you've tried it.. ive got better throttle response then any other year s2k ive driven

 

[QUOTE=JonBoy,Feb 3 2010, 08:11 PM] Nunco, you almost sound intelligent sometimes.

 

It's already been mandated by the Feds. There's an FMVSS that requires a vehicle stability program (Honda calls theirs VSA) on all new vehicles in either the 2011 or 2012 model years, I forget which.

You can't have VSA (or whatever you want to call it) without computer control of the throttle.

 

That's not true. My 1999 Mustang had individual cylinder shutdown in addition to brake control at each wheel as part of the stability control system. And I have no proof that the system was new in 1999.

Even with a mechanical throttle, the computer can reduce flow or shut down individual fuel injectors as well as spark to individual cylinders. The fact that the throttle is wide open is moot when the computer refuses to fuel the cylinders or give them spark. And the computer can just as well feed each cylinder whatever volume of fuel it wants and trigger the spark whenever it wants even if the throttle position is not condusive to the ECU's wants.

That said, not all ECU's are designed to control those parameters on a per cylinder basis. In the past certain companies gang-fired the injectors regardless of where that cylinder was in the four-stroke cycle. And computer-controlled spark has not always been oriented around firing only the cylinder that needs it. Any company that asserts that it is impossible to have a stability control system without throttle-by-wire is trying to cover up their crude computer control system. They might not even know their system is crude compared to the competition.

I'm guessing the reason the S2000 got VSA at the same time they got throttle-by-wire is because Honda could not justify a new ECU without incorporating a series of advancements all at once. Sometimes it's not an issue of know-how but an issue of cost-effectiveness. But to be fair, sometimes cost-effectiveness limits know-how.

 

VSA is more than Throttle and brake control. VSA monitors steering angle,Yaw/Pitch rates. It's not stability control, it's stability ASSIST. VSA doesn't keep a car from doing anything, it assists it on it's intended path. While VSA may not necessarily require DBW to work, DBW probably helps it work a whole lot better.

 

Call it whatever you want, the system on Mustangs only intervened when the system detected the car slewing sideways. Wheelspin in a straight line was ignored for the most part. If both tires were on slick ice, it will retard the engine to the point that with the gas floored it would keep running but the car would go nowhere in first gear in a manual transmission. A nice trick, but no system can create traction when none exists. That's why the Mustang TCS can be shut off entirely so you can get up an icy incline with some wheelspin, if you are a good driver with throttle control.

Southern state drivers are alerted by text to call a tow truck/taxi at that point lol.

Bottom line, the idea that such a system requires throttle-by-wire is silly. Throttle-by-wire is motivated by EPA mileage numbers. If you can remap the throttle opening to torque production based on pre-mapped algorithms, you can make the car more efficient by only delivering the torque demanded by throttle position (50% thottle = 50% torque, not 50% throttle opening) since throttle position and torque delivery is not necessarily a 1:1 relationship. Lower rpms actually demand a smaller throttle opening than high rpm operation for the same torque delivery. You can feel this in a loaded big truck, where you notice that flooring the gas can actually result in less apparent acceleration than part throttle at lower rpms. You might be dumping more gas at WOT, but it isn't always resulting in more acceleration than 75% throttle.

 

i agree. and yeah calling VSA (stability assist)is no different than DSC (stability control which also measures yaw, and pitch, and wheel speed)

thats simply Honda marketing jargon, everyone has a different name for essentially the same system. how aggressively they tune said system is of course a different story. but both 'stability assist' or 'stability' control is basically using the cars ABS system to individually brake the wheels based on the target parameters of data.

I will admit in a sporty RWD car I am probably not a good enough driver to benefit by turning off the system, but in an easy to drive FWD car these systems always hinder the cars performance. especially once you have put stickier tires on the car and you can safely go past the limits of the stock parameters and the system is constantly fighting to keep you in check.

 

I said the same about a week ago in the Toyota thread. Not a fan of DBW.

 

A lot of people have complained about the responsiveness of TBW. I don't think that's a TBW problem so much as a problem with the exact implementation. For example, both the MINI and the old Contour were reported to have throttle hang after you let off the gas. What is really happening in both cases is the intake system is feeding a bit of extra air into the engine before the motor revs down in an effort to save on emissions. The TBW MINI does this by cracking the throttle for a moment after you let off the gas. The mechanical throttle Ford did this with an idle air bypass valve. Different systems, same result. It's not that TBW can't be responsive. In fact in turbo cars it can improve rather than hurt throttle response. It can help spool up the turbo by over opening then backing off a bit when you have requested some additional throttle. Believe me that's better than old school turbo lag.

Fundamentally I think TBW is perfectly fine. However, that doesn't mean all TBW is good.