Synchro rev problem.

toñinz

My 370z might have a problem with its Synchro Rev, it always happens in the same conditions, while driving in 2nd gear and 20 mph then full throttle till 7500rpm, change to 3rd gear, again full throttle till 7500 rpm, change to 4th gear full throttle again..... till approximately 120mph.

In those conditions, the synchro rev stop working and the yellow warning comes up in the dashboard, syncro rev stop working till I stop the engine and restart it again.

I´m a little bit worried about this as I don't know if it's something normal in all 370's or if it's a problem of my unit. Has it happened to anyone?

I have the following mods:
Titanium Amuse exhaust, Nissan Frontier 4.083 Final drive, 265/35 R18 rubbers at the front and 285/35 R18 at the rear.

WhiskeyHotel

Well, I can say that mine does not do that. The warning light means the computer thinks something's not right. Maybe something to do with your final drive ratio? Just a guess.

6MT

WOT might have something to do with it.

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Andrew

2009 370Z Sport/Touring 6MT sold
2013 Honda Civic Si coupe D/D

Davey

I think that's a good guess.

If the computer is programmed to read the mph and figure the RPM it needs to match the speed based on a table, yours is all wrong due to the final drive, and it MIGHT be "in spec" up to a certain speed (since it would be off by a percentage) just like your speedo becomes less and less accurate (off by more MPH) the faster you go.

red6spd

Cant tell if your being serious. I hope your not


Its the gears. The gears throw the synchro rev off very slightly, just enough for the computer to sense a problem. Since the SRM works on upshifts as well every time you shift the computer senes a problem and eventually turns the system off letting you know there is a problem. For now your just going to have to live with it, thats the price you pay and one of the biggest reasons I dont wanna do gears.

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esfourteen

its your 4.08 final drive gear thats affecting SRM. jnaut has experienced the same issues.

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6MT

Yep, I was being serious. That and those ratios "probably" are the issue. Without the WOT condition, there was no issue, right?

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Andrew

2009 370Z Sport/Touring 6MT sold
2013 Honda Civic Si coupe D/D

ChrisSlicks

WOT is irrelevant, it is the RPM calculations going wrong at the high end of the rev band thanks to the messed up ratios. Theoretically the SRM could be reprogrammed to new ratios but I don't know if anyone has that figured out.

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red6spd

Stop it ok. Drving the car at WOT does not affect the SRM at all. If you think so maybe you should stay off the gas ok

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2010 Base+Sport 6spd: Stillen G3, FI Non-Resonated CBE, FI Non-Resonated Test Pipes, UpRev Tuned, Custom 24R Oil Cooler, JDM Rear Fog-OEM Harness.
???Whp ???WTQ (Will find out come spring time)

ShinyBlueZ

K I didn't want to start yet another SRM thread so I wanted to ask my question on here (I don't think anyone's ever had this feeling of mine):

When I manually heel-toe, the car feels glued to the ground the entire process.. no problem at all. However, I've tried the SRM a handful of times, and each time the same thing occurs. Coming up on a turn I would begin braking, then while still on the brake, I would downshift and the throttle would blip like it's supposed to. However, it feels like when I let off the clutch pedal, the brakes ease off on their own, or the car stays in neutral for 1 or 2 seconds longer. The feeling of your tires gripping the road is almost completely gone. I've tried re-engaging the clutch more quickly and more slowly.. and the same thing happens each time.

It feels like the car is kind of just 'floating' there and it's quite unsettling and doesn't inspire much handling confidence. I 'could' just turn it off and heel-toe myself, but I sorta wanna use the 'high-tech' function if it's there (also mostly because if it's a problem with the SRM on my car in particular I wanna sort it out while still under warranty). I've heel-toed in a few other cars with no issues so I don't 'think' it's my technique.. but maybe I'm doing something wrong here with the SRM? Any tips/ideas/suggestions? Thanks dudes!

cossie1600

It is all in your head. I have a datalogger to monitor the decceleration, S mode is not letting your brakes off

LafitteZ

Yea sucks to be you bro. It may be some crazy problem that no one will ever feel unless they drive it everyday and they will never figure out or admit to because no one else is reporting. It's just one of those things that someone has to drive the car all the time to feel. Been there done that man. I had to end up selling the car I had on of those phantom problems. Good luck tho hope you get it sorted out. I'd be willing to bet it has to do with the gears tho. The ecu is a really sensitive tool.

ShinyBlueZ

no.. I know by default SRM isn't programmed to let off your brakes lol

I was just wondering if anyone else had this experience while driving with their SRM on. It's definitely not in my head. It's the same floaty feeling as if you picked up speed in your car, then kept your foot on the clutch and let the car coast along in neutral for 3 or 4 seconds. That's how it continues to feel for ~2 seconds, after I downshift and let the clutch back in while SRM is on. I can't turn in and accelerate with the car in that state lol Like I said.. I could just turn it off and manual heel-toe is perfectly fine.. but so many people say the SRM is so smooth and enhances the driving experience.. that it made me wonder if perhaps my SRM is faulty

Maybe I'll just have to take it in and ask the Nissan guys if no one else here has ever experienced what I'm talking about hehe Thanks anyways guys!

ChrisSlicks

I have experienced your issue on track, but only with high RPM downshifts. High RPM downshifts under heavy braking generates compression drag in the engine which increases the chance of locking up the rear wheels and engaging ABS. Depending on what the ABS controller feels like it may reduce overall brake force to compensate.

So, save your downshifts for later in the braking. It doesn't sound as cool but the car will work better.

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ShinyBlueZ

Ahhh what you said sounds extremely likely! It's because I was testing the SRM to see how it reacts that I was downshifting early and before more braking.. and that's why when I did it myself it doesn't do that. Cool! I'll try downshifting at the proper time and see how it goes. Thanks for the explanation dude!