RPM LIMIT ACTIVATION, HELP NEEDED ASAP

Hi, just after a little help, link storm g4+, my RPM limit is activating nearly 1000rpm lower than have set it, my undersatnding is the that control range in 200rpm before the set limit. all other limits are off its definitely rpm limit activating, have attached log file and screen shot of settings, any help really appreciated as racing tomorrow.

Cant see anything from a screenshot. Can you attach the actual log and your tune file.

I suspect you probably have trigger errors so there is a small spike in the RPM that is not captured due to the logging speed you have used.

Thanks Adam that does make sence, have attached files for you to view, thanks. Ill up the logging speed on the RPM and see if i can catch it. using a nissan 360 factory cas disc on nissan sr16ve engine so might be the case.

Yep, you have a trigger problem.

You can see a couple of spikes to 8400 in the log, dwell starts to get erratic anything above about 4000RPM and your trigger error counter is clocking up errors. The "max engine speed" statistic also confirms the ecu is receiving erroneous trigger info.

You can try turning on the "low resolution mode" in the trigger settings, this divides the tooth count down and sometimes can help (not often but worth a try).

Thanks for your help Adam and pointing me in the right direction, much appreciated, looks like i need to change the cas disc, cheers

hi Rowan, the Nissan 360 deg CAS is notorious for giving problems, particularly with larger cams. The ideal solution is to use a crank trigger system and use the CAS as a single tooth for sync. I've had reasonable success with a 24/1 trigger disc in the stock CAS for engines with mild cams.

Thanks Andre. Im using the crank trigger system on the my GTIR (sr20vet pretty much same spec as the one you built) but its just my GTI with the sr16ve giving me issues it still factory cams and factory engine so hopefully a trigger disc will sort it, its just a low budget race car so want to limt what i throw into it. changing the resolution helped (not fixed but made it better) and got me through the racing in the weekend. I also suspect the very light flywheel i put in it is also contributing to the issue. I have ordered a disc to try first.

If it's still running stock cams and springs then in my experience the trigger disc will be sufficient. I did that on an SR20DET with mild cams that had basically been impossible to tune due to erratic rpm above 5000 rpm and it was almost perfect with the new trigger disc. As an added bonus, with accurate (ish) timing I picked up something like 100 kw atw!