Synchro Rev Problem

Nissan 350z / Nissan 370z technical discussion forum: Maintenance, performance, installations, modifications, how-to's and troubleshooting.
OldDudeLA
Posts: 2
Joined: Fri Jun 21, 2019 1:12 pm
Car: 2016 370Z Sport Tech

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I recently purchased a very low mileage 2016 370Z Sport Tech with the Synchro Rev feature (which is great). The car was barely driven and is a cream-puff with 8800 miles and a clean CarFax and other report.

Over the last couple of months the Synchro Rev has malfunctioned 2 or 3 times. I'll be up-shifting and I believe I may have missed or hesitated up-shifting (not sure) and the Synchro Rev will race the engine RPMs up to about 7k before I disengage it by clutching again. One time the engine gave a loud pop which is weird because everything is stock and this is the 4th Z I've had over many many years and the engine never popped.

Has anyone else experienced such anomalies and should I be concerned about it?

TIA!


amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

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I don't know spit about anything called synchro rev but if the pop happened as the car revved that high it may be only an OEM rev limiter kicking in. Mostly the rpm just cuts clean with no drama but occasionally when the cut happens just right the engine gets caught right at a plug firing and it causes a misfire to backfire. Normal if that is what happened. The cut kills the occurring spark as it develops to be weak and then the burn slows way down to have part of the ignition still going on as the exhaust valve has begun to open. The burning continues then in pipe and if slow enough even extends to intake overlap to backfire into intake.

amc49
Posts: 1183
Joined: Mon Jun 19, 2017 7:24 pm
Car: '11 Nissan Versa
'17 Nissan Altima

Post

Just went and learned about synchro rev. No way is the electronic TB moving that fast to be able to instantly hit various speeds that quick, the ignition I'd bet a million is being cut in there as well to get to the rpm needed much quicker in some cases as the TB hurries to catch up. Meaning both TB is adjusting and rpm limiter are being used there, and even more reason to pop every once in a while. The system may well have rpm limiter ability to soft damp/set the rpm to hold it at even levels instead of the more brute force simply cutting all ignition. Like the drag cars all use now to go to instant preset rpm launches.

If limiter used like that you will always have the ability to pop occasionally when it is active.

OldDudeLA
Posts: 2
Joined: Fri Jun 21, 2019 1:12 pm
Car: 2016 370Z Sport Tech

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@amc49: Thanks :)


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