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HR's rev limiter

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Old 09-25-2007, 05:28 PM
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350Zimo
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Default HR's rev limiter

well , i have heard that the Z's rev limiter is kinda silent , doesnot really make frequent high-pitched clinking like other cars' rev-limiters. however the another night i played around alot in my Z , and i hit the rev limiter in second gear, it felt dead and it took a second till it responded again the way it is suposed to, even after i up-shifted. is that normal , are the 03-06 Z's rev-limiters the same, what scared me is that i expected it to scream like nuts, but the car just as i said felt not alive.
Old 09-25-2007, 07:01 PM
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VitViper
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It's a soft limiter. The ECU just closes the TB's, IIRC.
Old 09-27-2007, 07:00 AM
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drivesolo
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I need a little help in understanding this....

In my '03, I was under the impression that the rev limiting method was that the ECU cut the spark to the engine. As a result I could get the needle to 'bounce' off of the rev limit.

I haven't taken tried it on my '07 yet, but is it no longer a spark cut-off?
Old 09-27-2007, 07:04 AM
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Sharif@Forged
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The 03-04's use a harsh fuel cut to limit revs. The 05-07's use the throttle body to control the rev limit. This is why it feels soft and gentle, as the TB closesly slowly towards redline.
Old 09-27-2007, 08:25 AM
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Skorch
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Originally Posted by Sharif@Forged
The 03-04's use a harsh fuel cut to limit revs. The 05-07's use the throttle body to control the rev limit. This is why it feels soft and gentle, as the TB closesly slowly towards redline.
So at redline is the throttle body just starting to close, or does it start just past it?
Old 09-27-2007, 08:47 AM
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Originally Posted by Skorch
So at redline is the throttle body just starting to close, or does it start just past it?
It gradually closes a couple hundred RPM away from the actual redline, and the maintains an angle that allows the engine to gently maintain its redline. You can floor it all you want, and the sensation is the engine just stops accelerating.
Old 09-27-2007, 08:57 AM
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Skorch
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Originally Posted by Sharif@Forged
It gradually closes a couple hundred RPM away from the actual redline, and the maintains an angle that allows the engine to gently maintain its redline. You can floor it all you want, and the sensation is the engine just stops accelerating.
Yeah, I'm very familiar with the sensation... I was just curious about that actually happens when I reach the redline. Thanks!
Old 09-27-2007, 10:03 AM
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Shabib67
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Is there anyway to overcome this like an ecu reflash or something?
Old 09-27-2007, 11:19 AM
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ColoradoClark
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Originally Posted by Shabib67
Is there anyway to overcome this like an ecu reflash or something?
Why would you want to rev your stock HR past the stock rev limit?
Old 09-27-2007, 11:58 AM
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Skorch
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Originally Posted by ColoradoClark
Why would you want to rev your stock HR past the stock rev limit?
Why do people raise their rev limiters to begin with? To access their peak power for a longer time, assuming peak power is made at redline. Stock or not, it would still make you go faster. Now the question is, would it be safe to do so... I doubt an extra 500 rpms would hurt, but I'm not willing to experiment on my car.
Old 09-27-2007, 12:14 PM
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Riley07
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I wonder if there would be any real benefit from raising it..it seems to drop off right before redline, but could that be the throttle closing???
Old 09-27-2007, 12:15 PM
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Originally Posted by Skorch
Why do people raise their rev limiters to begin with? To access their peak power for a longer time, assuming peak power is made at redline. Stock or not, it would still make you go faster. Now the question is, would it be safe to do so... I doubt an extra 500 rpms would hurt, but I'm not willing to experiment on my car.
Peak power on almost every production car is prior to redline, so extended the rev limit would not serve much purpose on a stock engine, other than creating a lot of heat and stress. Now, on the lower revving 6600rpm engines, some people like a slightly higher rev limit for drag racing, which tends to keep the engine in the power band between shifts.
Old 09-27-2007, 12:35 PM
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So does the HR make its peak power in the 1st 2nd and 3rd gears at 7500 or lower? And if it is indeed at 7500, would there be a benefit to increase the rev limiter to say... 7600 to compensate for imperfect shifts and decrease the chances of hitting the rev limiter?
Old 09-27-2007, 03:13 PM
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The HR rev limit doesn't kick in til about 7500-7600 rpm. There's a solid pull all the way to redline before any kind of power loss or loss of acceleration happens.
Old 09-28-2007, 10:48 AM
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03redlineZ
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Originally Posted by Sharif@Forged
Peak power on almost every production car is prior to redline, so extended the rev limit would not serve much purpose on a stock engine, other than creating a lot of heat and stress. Now, on the lower revving 6600rpm engines, some people like a slightly higher rev limit for drag racing, which tends to keep the engine in the power band between shifts.

Can the stock valve springs handle the 287Hp motor revving to 7100Rpms on extended use???

Sharif, do you think a stock block tuned appropriately with a Greddy TT kit with a raise in rev limiter on the non rev up motor could handle it?
Old 10-02-2007, 06:12 AM
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first350
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another reason for wanting a higher Rev limiter setting is for Track/AutoX...I've raised my Rev limiter for autoX b/c it's basically allowed me to stay in 2nd gear for 98% of all courses I see - not having to shift to 3rd or bounce off the rev limiter creates faster times!
Old 10-02-2007, 07:03 AM
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03redlineZ
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Originally Posted by first350
another reason for wanting a higher Rev limiter setting is for Track/AutoX...I've raised my Rev limiter for autoX b/c it's basically allowed me to stay in 2nd gear for 98% of all courses I see - not having to shift to 3rd or bounce off the rev limiter creates faster times!

+1 to that... also when I run 0-60 times 2nd gear cuts out at 58-59MPH!! So without shifting would lower the 0-60 times...

(Sidenote) Your car looks familiar did I sell you the clear sidemarkers for your car, first350??
Old 10-02-2007, 12:16 PM
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alexfair
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my new nismo license plate frame boosted my redline to 9,800rpm
Old 10-02-2007, 01:42 PM
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Originally Posted by 03redlineZ
+1 to that... also when I run 0-60 times 2nd gear cuts out at 58-59MPH!! So without shifting would lower the 0-60 times...

(Sidenote) Your car looks familiar did I sell you the clear sidemarkers for your car, first350??
yeah, I have your old clear corners on - luv 'em!


Originally Posted by alexfair
my new nismo license plate frame boosted my redline to 9,800rpm
guess that means my sponsor stickers adds 50WHP ...now I just need the driving ability to use it
Old 10-03-2007, 11:44 AM
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when shifting at the redline, the 07 falls out of the power band a little bit, even raising the rev limit a few hundred rpm's would help cause it would put u back in a better spot in our powerband, just like shariff said

shorter gears like vitviper has help to, but i'm just a fan of long gears, cant' help myself, there is something about going into second at 55 and not having to shift instantly


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