View Full Version : Rev limiter peculiarity
brucebp
04-06-2013, 05:55 PM
If I rev hard when accelerating I can get to over 9000 rpm in the first four gears. In 5th I appear to be limited to 7500. The practical result of this is it becomes very difficult to overtake the more senile members of the Middle Lane Owners Club when your max is about 80mph. The ECU does not have an inbuilt 7500 limit so there must be a sensor telling it I am in 5th. Does anyone know where this sensor is located so that I might disconnect it. This should then give me a top speed in the nineties.
Steve_M
04-06-2013, 09:09 PM
The standard ECU has a built in speed limiter, it activates at 140kph (87 mph).
Some people have fitted a modified chip into the ECU to remove this limiter and also change some of the mapping.
I think others have added a speed sensor signal modifier which can be used to make the speedo read in MPH on the KPH scale and effected the change of this signal to the ECU.
brucebp
10-06-2013, 05:01 PM
The standard ECU has a built in speed limiter, it activates at 140kph (87 mph).
Some people have fitted a modified chip into the ECU to remove this limiter and also change some of the mapping.
I think others have added a speed sensor signal modifier which can be used to make the speedo read in MPH on the KPH scale and effected the change of this signal to the ECU.
Steve,
I have carried out extensive research (i.e. poked about on every internet site I could think of) but can't seem to find any mention of the sensor signal modifier you mentioned. Can you point me in the right direction. I don't really want to mess with the ecu as they seem a bit tender on the Beat
I have also been told by two chip suppliers their is no such car, which does not exactly inspire confidence.
thanks
Bruce
Dirk Schooner
10-06-2013, 05:54 PM
Bruce, I understand (know) it is possible to fit a unit external to the ECU, which requires splicing into 3 wires, you should be able to find the info online on this.
It does not change mapping, only removes the speed limit so it will go to 160 KPH.
Take a look at 'HKS Speed Limit Defencer - Type 1' you just need the correct wires from ECU, I think 12v, earth and the speed sensor, you also need to set the dip switches for honda.
fxdlidon
10-06-2013, 06:35 PM
You can actually do the same with an electronic speedo converter spliced into the ECU speed sensor feed. It just gives the ecu mph rather than kph pulses so the limiter will cut in at 140mph instead of 140kph - if you can get a Beat to do 140mph please tell us how :). It doesn't affect the fuel map as, I'm fairly sure, it only uses the speed sensor to detect whether the car is moving or not (for the neutral time out) rather than using the speed to change the fueling.
If it did anything else these speedo converters wouldn't work as the signal to the ECU comes from the speedo not, as it appears on the schematic, sensor-ecu-speedo. The wire itself runs past the ecu, up to the speedo, then back again. The signal wire doesn't match the colour in the wiring diagram as it's screened, I think the outer sheathe is white (there are 2 screened wires running there) but the core does match the colour in the wiring diagram.
Steve_M
11-06-2013, 12:45 PM
I have also been told by two chip suppliers their is no such car, which does not exactly inspire confidence.
Seach on this forum for "Project A chip"
brucebp
11-06-2013, 04:01 PM
Seach on this forum for "Project A chip"
Thanks for the help guys, i've got a converter on order and weather permitting will get it on this weekend. Also got some useful info about converters and VTEC engines on a site for other imports
http://www.infsq.co.uk/2007/04/honda-vtec-engagement-and-kmh-to-mph-converters/
might help someone else.
Bruce
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