Rev Limiter Testing

BriSCA F2 would like to thank Bill Batten, Neil Langworthy and Mike Priddle, for their combined efforts in arranging for the #740 BriSCA F2 Stock Car to be taken to Omex Technology for a day of investigation and testing, in relation to issues that have occurred since the introduction of the Pinto Rev Limiter.  Omex have duly provided the following report of the investigations that took place.

The car was supplied with two wiring configurations made by the team;

·         “Standard”. i.e. the car’s original (pre rev limiter) wiring. Used to give a base-line comparison of how the engine is running normally.

·         “Rev Limiter”. Wiring completed by the team using the sub-harnesses supplied with the Rev Limiter.


The engine was run with the car stationary with both of the setups. Results as follows;

·         “Standard”. A poor earth initially gave a running problem, but once this earth was fixed the engine ran without fault as expected.

·         “Rev Limiter”. The engine showed no fault.


As we had the car available for the day we tried to replicate the fault by running on the Omex rolling road. Results as follows;

·         “Standard”. No fault.

·         “Rev Limiter”. No fault.


Two more Rev Limiters that had been reported as faulty units were brought with the car and were run on the rolling road. Neither of these units showed any fault.

To further prove that the Rev Limiter was definitely not acting, the car’s own Rev Limiter was modified with an LED which would light when the Rev Limiter is acting. Several runs were made on the rolling road and the LED never lit. The Rev Limiter was then returned to standard configuration.

Although the results of the testing showed no faults we wanted the car to leave Omex with known good wiring in case there were intermittent problems causing the faults that the team had reported. As the installation of the Rev Limiter wiring had been completed using standard “red plastic splices” the quality of the connections could not be checked from the outside. Therefore Omex decided to strip the harness and rebuild. In stripping the wiring it was found that the Rev Limiter wiring had been crimped onto corroded cable from the amplifier (black box) which would have given high resistance joins. The crimps themselves were good and correctly made, just onto corroded cable. The corroded state of the cable is an overall black tarnish of the conductor. It would be understandable that someone not involved in wiring could see this as a normal state as the tarnish is so uniform. These crimp joints were clearly working correctly whilst at Omex but had potential to cause a fault for the team and so another amplifier connector was used with new terminals and cable installed into the housing by Omex.

BriSCA F2 have been supplied with a cable that allows the Rev Limiter to be completely removed without the associated wiring being removed, so should the car show a fault at the track the Rev Limiter can be easily removed proving whether the fault is related to the limiter or not, and if it is a Rev Limiter related fault it allows the driver to complete his race meeting without the Rev Limiter.

So in summary, the reported fault was never replicated during our day of running, but some questionable wiring connections were found and replaced. We await results of this car running on track.

Omex remain committed to helping to overcome any problems that drivers have experienced since the introduction of Rev Limiter, and would welcome a car being presented to them with a fault, so that investigations can be carried out.  Accordingly, any driver who has a fault and who is willing and able to make their car available at Omex in Cheltenham, is encouraged to contact BriSCA F2 with full details of the fault so that Omex may solve it.

As a note to engine builders who may be concerned about Omex running their engines on the rolling road, we did so under the supervision of a BriSCA F2 representative, did not record any power figures so cannot make comparisons between engines, minimised use of the engine, and kept in contact with the driver via the BriSCA F2 representative throughout.

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