yellow TCS signal light up at top speed

[austrian type-R]

hi!

I did a top speed run in the night of friday to saturday. Speed war 291 kph (181 mph) according to the odometer. Should be about 280kph (174mph) in real. On the Dyno it was exact 280kph too.

Driving for about 15 seconds at that speed suddenly the yellow TCS lighted up. When I stoped the high speed run I shutted the engine off and cranked it again (ignition on, 5th gear, clutch pedal releas). No problem so far. Anybody knows what that failure was?

thanks

 

[goldNSX]

I don't think it's a failure, it's pretty normal, no? The rear tires are loosing grip. Just switch the TCS off and take a video-camera with you next time. :tongue:

 

[austrian type-R]

the TCS was off. The green light "TCS off" gone and the yellow TCS came on!

 

[rbirling]

If the yellow light came on, I _think_ it should have saved a code. Try pulling the code and checking the manual.

 

[greenberet]

The yellow TCS failure light comes on whenever you go above that speed.

If you leave the traction control on, it seems to become active and prevent you from going faster. If you turn it off, you can keep accelerating, but the failure light comes on and stays on until you turn the ignition off. Next time you start the car, everything is back to normal.

It took me a lot of searching to find out what was causing the "speed limiter" effect. The green traction control light didn't flash at 7550 rpm, but power noticeably cut out every time I reached exactly that engine speed in top gear - just like it would with a speed limiter. In the other four gears, I could go to 8000 rpm. Phone calls to Acura, Honda, Autothority, Comptech, etc. were fruitless and dyno runs (in fourth gear) with fuel pressure gauges didn't help either. The cure turned out to be as simple as a push of the button to disable the traction control system. Now the speed limiter is the rev limiter.:smile:

 

[austrian type-R]

hm, does that mean I can not go faster than 290kph with an NSX until I change the gear ratio? A chip like SoS or Procar with more revs will also have this "cut-off" thing since the TCS is for sure another chip in the ECU?

 

[greenberet]

With a .771:1 fifth gear, a 1:4.062 final drive ratio, and 245/40 17 rear tires, 8000 rpm calculates out to 302 km/h. With the traction control on, my car runs into the wall at 7550 rpm, which works out to 285 km/h. I didn't try top speed runs while the car was stock, so I never found out how many rpm the car could pull with stock horsepower.

The traction control is not in the engine management computer, so I'd expect that you are going to run into this as long as you keep the stock traction control. I have an aftermarket engine management chip in my car and the programmer assured me that there is no speed limiter in it in any gear. Then again, Honda assured me there is no speed limiter built into the traction control, either.

From experience, however, whether I disable the traction control or not determines whether the car stops pulling at 7550 rpm or whether the yellow failure light pops on instead and the car continues accelerating.

 

[garyn]

I experienced the same problem with the TCS light coming on and no green tcs light. The engine would bog when accellerating at low speeds. My trouble codes were 5-1 and 3-4. I got a new main relay from Dali-$55.00 and the problem is gone. I thought it was tire pressure, wheel sensors, tcs module, etc.,but thanks to Briank the problem is solved. You might want to give it a try. Good luck!

 

[Hugh]

With a .771:1 fifth gear, a 1:4.062 final drive ratio, and 245/40 17 rear tires, 8000 rpm calculates out to 302 km/h. With the traction control on, my car runs into the wall at 7550 rpm, which works out to 285 km/h. I didn't try top speed runs while the car was stock, so I never found out how many rpm the car could pull with stock horsepower.

That wall you're referring to is mother nature. A stock NSX is capable of about 167MPH. This speed is limited by drag. I don't have all the fancy schmancy formulas in front of me but it's going to take at least a doubling of the stock horsepower to get the top speed up another 25 - 30 MPH. How much horsepower do you have? 285km/h is 177 mph. It would probably take at least 400 to 450 HP to reach that speed according to the my cranial abacus and total lack of the correct formulas.

 

[greenberet]

Without getting into any fancy schmancy formulas, my car pulls to 8000 rpm in fifth gear with the traction control off and 7550 rpm with the traction control on.

If you have the formulas, I'd love to hear how many horsepower an NSX needs to get to those speeds. An NSX has an unusually small frontal area (1.78m2) and combined with a decent coefficient of drag (0.32), it has less wind resistance than most other sports cars. But if you can calculate it, go for it!

As to how many horsepower my car has - I don't know. The dynamometer the car was on in Virginia while the engine management chip was being programmed said 408 hp. Which I cannot believe. A dynamometer here in Austria said 192.5 kW (which, using my cranial abacus, should be about 265 rwhp) and that sounds more realistic for a 3.0 V6.

In any case, if you research or calculate how fast cars can go that have the same coefficient of drag times frontal area, let me know. Or come to Europe, we'll hit the Autobahn, and given a long enough straight, hit the wall at 8000 rpm in fifth.:smile:

 

[MvM]

I have run at top speed several times, always with around 280-285 kph on the clock but never had this problem (it's been a while so I don't remember the rpm on the dash).
I am running 17" wheels in front and 18" in the rear.
What wheels and tires are you using. I am not sure, but I can imagine that it might make a difference.

Also, I have been told that the NSX will reacht it maximum speed (or keep it) only with the TCS off. But I have never been able to verify this.