How to ...?

[rado76]

Hi everyone
Could any one help me with an advice?
I've got new Brain Crawers cams 272* with springs and retainers kit for my MR2 3SGE engine.Everything will be in place these days (including adj. cam gears) and i am planing to use Map Pro Scan to adjust the ignition and fuel. Can you pls tell me your opinion and if you could tell me also how to rise the RPM limiter ( not sure if it is possible with electronic like that)? It is not stand alone (for now and i hope that we will be able to do all the set ups. Can you recommend me some software for adjusting the limiter or if i could directly play with the stock ECU?
Thanks a lot and all the best

[mrturrari]

You can overclock the ECU to raise the rev limiter. Take the cover off the ECU and see what frequency the crystal is. It's the silver cylinder sticking off the board with two legs. It should be 12Mhz or 16Mhz depending on how new your engine is. Then order a new crystal from Digikey or elsewhere with a clock that is higher by the percentage you wish to raise the rev limiter over stock. You probably won't be able to go much higher then 20-25% without also raising the voltage and doing some cooling. 8% and 12.5% are pretty common but with 272 cams you will probably want it higher. After you overclock you just need to add more fuel and timing with the piggyback to get things back safe because this tricks the ECU into thinking it is at a different RPM then it really is. I am doing this on my 5sfe and have a 22.5% overclock letting me rev to 7700rpms. On a 3sge you won't need as much because the red line is higher to start with.