4100 Rpm fuel cutoff?

Trips · 07-06-2009, 01:00 AM

Well Like I got around to installing my Berk hfc's and noticed that at idle in park when I would rev to hear the difference from stock I couldn't rev past 4100 no matter how I tried. I looked in the owners manual and there it said that the engine would go into a no load fuel cutoff mode, I ask why not at a higher rpm like 6000 I believe that was the idle rev limit on my old 90 300zx can any one chime in on this and I know my fellow lead foot members out there understand what I'm talking about.

FricFrac · 07-06-2009, 12:20 PM

Put the clutch in and put it in first.... then you can rev to 7.5K before the rev limiter kicks in...

Phimosis · 07-06-2009, 12:40 PM

OP has auto trans.

wstar · 07-06-2009, 12:46 PM

I thought the limit was closer to 5K, but it could be 4100, I didn't pay that close attention. I haven't tried to figure out how to bypass the limit while sitting still. They probably designed it that way for a reason, perhaps because pointless very-high revving of an unloaded engine is bad for it (having load on the engine's output shaft probably stabilizes things a lot).

I've free-revved the engine up to 7K once when I first noticed this just to test, but I did it by shifting to neutral while rolling down the highway at 70mph. The limiter is definitely gone in that case. I don't know if it would be gone sitting in a parking lot in neutral with the e-brake off or not, it may also watch vehicle speed for all I know (as in, car < 10mph, rev limiter still active, or something of that sort).

Island_370 · 07-06-2009, 09:15 PM

Quote:

Originally Posted by Triple's

Well Like I got around to installing my Berk hfc's and noticed that at idle in park when I would rev to hear the difference from stock I couldn't rev past 4100 no matter how I tried. I looked in the owners manual and there it said that the engine would go into a no load fuel cutoff mode, I ask why not at a higher rpm like 6000 I believe that was the idle rev limit on my old 90 300zx can any one chime in on this and I know my fellow lead foot members out there understand what I'm talking about.

My owner's manual says that no-load revving of the motor near 4500 will cause cut. Maybe it is just that?

Trips · 07-06-2009, 11:45 PM

Quote:

Originally Posted by Island_370

My owner's manual says that no-load revving of the motor near 4500 will cause cut. Maybe it is just that?

I stand corrected. I just wish it were higher

davidyan · 07-08-2009, 02:25 AM

Its probably not a bad idea by Nissan to cut it short. Generally speaking, free revving the engine without any load will make it easier to float the valves since you can rev up so quickly.

07-06-2009, 01:00 AM	#1 (permalink)
Trips Administrator Join Date: May 2009 Location: Disneyland, Ca Posts: 8,732 Drives: 🔰 Rep Power: 10	4100 Rpm fuel cutoff? Well Like I got around to installing my Berk hfc's and noticed that at idle in park when I would rev to hear the difference from stock I couldn't rev past 4100 no matter how I tried. I looked in the owners manual and there it said that the engine would go into a no load fuel cutoff mode, I ask why not at a higher rpm like 6000 I believe that was the idle rev limit on my old 90 300zx can any one chime in on this and I know my fellow lead foot members out there understand what I'm talking about. __________________

07-06-2009, 12:20 PM	#2 (permalink)
FricFrac A True Z Fanatic Join Date: Dec 2008 Location: Victoria, BC Posts: 1,481 Drives: 370Z 300ZX 280ZX 240 Rep Power: 229	Put the clutch in and put it in first.... then you can rev to 7.5K before the rev limiter kicks in... __________________ '09 370Z - '93 300ZX Vert - '83 280ZX - '83 280ZXT -'81 280ZXT stroker - '72 240Z - Stillen CBE, HFC, G3, Grounding Kit, Sways // Swift Spring // H&R 15mm // 5% Tint // Clear Bra //

07-06-2009, 12:46 PM	#4 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	I thought the limit was closer to 5K, but it could be 4100, I didn't pay that close attention. I haven't tried to figure out how to bypass the limit while sitting still. They probably designed it that way for a reason, perhaps because pointless very-high revving of an unloaded engine is bad for it (having load on the engine's output shaft probably stabilizes things a lot). I've free-revved the engine up to 7K once when I first noticed this just to test, but I did it by shifting to neutral while rolling down the highway at 70mph. The limiter is definitely gone in that case. I don't know if it would be gone sitting in a parking lot in neutral with the e-brake off or not, it may also watch vehicle speed for all I know (as in, car < 10mph, rev limiter still active, or something of that sort). __________________ 7AT Track Car! Journal thread / Car setup details

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07-06-2009, 12:40 PM	#3 (permalink)
Phimosis Enthusiast Member Join Date: May 2009 Location: Oildale, CA Posts: 412 Drives: 2013 911 4S Rep Power: 416	OP has auto trans.

07-08-2009, 02:25 AM	#7 (permalink)
davidyan Base Member Join Date: Jun 2009 Location: CA Posts: 244 Drives: PG 370Z Sport 6MT Rep Power: 16	Its probably not a bad idea by Nissan to cut it short. Generally speaking, free revving the engine without any load will make it easier to float the valves since you can rev up so quickly.