Z YA LTR

iTrader: (1)

Is reapetedly bouncing off the rev limiter a bad thing. I mean, if you go into a slide and are gasing it, and it keeps bouncing, will that hurt the motor? I did it a little bit last night but it didnt happen for too long. When I realized it was bouncing I feathered the throttle and the car gained traction. Which I didnt want to do but oh well. Thanks for any insight.

--Josh

12SecZ

YES it is VERY bad for your engine and should be avoided.

PhoenixINX

Try to avoid doing it, but the limiter is there for a reason.

Your motor is fine.

AxionF117

The rev limiter is to protect you from over reving your car, its their to save your engine not break it.

azrael

it's a very bad situation. While the rev limiter IS there to "protect" your motor from overrevving, the way that the rev limiter works is actually very bad for the engine.

From what I've heard, the rev limiter on the Z works by stopping fuel spray, which ends up creating a lean condition in the cylinder (bad news for engine health). Other cars cut the ignition, which is a much safer way to do it, IMO, although bad for emissions. I find it hard to believe the Z works this way, but that's what I've heard people say on this forum. I'm still waiting to obtain a service manual to confirm this 'fact.'

jesseenglish

It definitely works that way. According to page EC-27 of the FSM

I can verify the deceleration thing because on deceleration my wideband O2 pegs out lean at the max 45:1 AFR. The thing is we really don't know whether it completely cuts off, or just partially cuts fuel. If it completely cuts fuel, it's harmless because there is no fuel in the cylinder to burn.

azrael

it's probably a 100% fuel cut, because I really can't believe Nissan would allow a potentially dangerous partial-lean condition. EGTs would probably blow through the roof.

However, ATI warns strongly against bouncing on the rev limiter. Maybe this is just related to the added dimension of boost and the piggyback kludge computers/AFCs/FPRs or whatever they use?

Z YA LTR

iTrader: (1)

Well, thanks for the info. I know what the rev limiter does. I just didnt know how harmful it was to reapeatly bounce off of it. I know when people are drifting they are usually bouncing off the thing like crazy. But they have BUILT engines and mine is just stock.

--Josh

AxionF117

well maybe its bad for a supercharged application, did they specifiy the exact reason? That sounds pretty lame if you can't do dounts or burnouts in a supercharged Z.

joust75

iTrader: (1)

The rev limiter in action may create a lean condition, but I think with 100% full cutoff is too lean for detonation or any type of combustion.


A couple thoughts on this:
1.Perhaps ignition is cut in addition to fuel shutoff. Considering the VQ is ULEV this is a likely scenario.

2. (with the scenario where the ignition continues to function at cut off) Perhaps it is not advisable to bounce the rev limiter with a supercharged motor because the stock injectors are the only ones cut off and the aftermarket injectors that are not governed by the factory ECU continue to spray. That will be enough gasoline to allow combustion and cause a dangerously lean condition!! Not knowing how the fuel shutoff is initiated this is just speculation of course!