Thread: VEry high revs

Well I was just in the parking lot of my work today shooting flames out of my exhaust for kicks, and just hearing the motor. Motor sounds really great, runs very strong. I try to get some video of the car revving and spitting flames, one getting up to about 12" long.

I look at my tach and I am noticing that I build about 3-4psi just free revving the engine. Cool. And I noticed that the engine was very responsive over 6K. Playing with the throttle a bit, I don't hit the rev limiter, but the MSS turns red to let me know I am over 7200rpm. All is good, so then I check to see what my max revs where hitting and I pooped myself.

9890rpm

I didn't hear any float at all, but the motor couldn't have been up that high for very long. The tach just simply could not keep up with the motor building boost on a free-rev over 7000rpm.

I don't know how far these VET cams can be pushed on stock 16ve springs, but something tells me that even 8500rpm cannot be safe lol. Motor runs great and no noises or anything, but I won't be free revving in boost anymore lol.

Let me say this again. 9890rpm, just shy of 10K!!!

I will post a pic of the MSS, and this is no joke.

I always thought the VE motors could be revved higher than a DE with springs and retainers. But you're saying this isn't the case?

TRIGGER ERRORS DETECTED!

I don't have springs or retainers. This is a stock SR16VE head with VET cams.

The MSS Reads 989. In case you didn't know, the MSS only reads 3 digits on the unit. 100 would be 1000rpm 350 is 3500rpm.

Electrical/trigger error. You didn't reach those engine speeds.

Ok, that sounds more reasonable. But what do you think caused it to have a trigger error?

Free revving it.

The CAS has so many tiny slots in it. When they move too fast for the sensors to make sense of it, it can seem to the ECU like much higher revs than what's really happening. Some ECUs can detect this. Basically it knows the engine can't go from 4k rpm to 9k rpm in one CPU cycle. Some ECUs don't detect it. Not sure what the Nissan ECU does.

Point being, the slots in the CAS went by the optical sensor so fast the ECU didn't get a clear signal.

Either that or noise in the CAS electrical lines (it is shielded from the factory to help prevent this).

It happens.

Weird. Has anyone else have this issue? The highest I have revved it before is 8500 hitting the rev limiter during a burnout.

If you had a log of the event it would probably show you climbing revs and then somewhere in the middle there'd be a single spike to 9,800 rpm and then the graph would go back down to where it should be and continue to climb.