Optimistic Tachometer
10-09-2011, 09:16 AM
#1
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Tachometer reads high
I Have a 07 G35 with just an intake and a COBB tuner.
I have been playing around with this COBB tuner and noticed the revs on the tachometer are higher than the digital readout of the COBB. For instance at 3000 on the tach was only 2880 on the COBB. At 5000 on the COBB was 4800 on the COBB.
What I am getting at is the engine is only at 7200 when I think I am shifting at 7500.
Shifting at or near 7600 on the tach has never put me in the rev limiter, and this is why. So I am thinking the limiter is closer to 7900 on the tach. Maybe this is a saftey mechanism from the factory for those who have no fear of redline.
Has anyone else noticed this on their G or Z?
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I have been playing around with this COBB tuner and noticed the revs on the tachometer are higher than the digital readout of the COBB. For instance at 3000 on the tach was only 2880 on the COBB. At 5000 on the COBB was 4800 on the COBB.
What I am getting at is the engine is only at 7200 when I think I am shifting at 7500.
Shifting at or near 7600 on the tach has never put me in the rev limiter, and this is why. So I am thinking the limiter is closer to 7900 on the tach. Maybe this is a saftey mechanism from the factory for those who have no fear of redline.
Has anyone else noticed this on their G or Z?
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10-09-2011, 01:47 PM
#6
Keeps me in the powerband on the 1-2 shift, car is faster that way. There is more power from 75-8 than there is from 5-55. I'd rather spin 1st a little higher and be in a better part of 2nd gear. Dont need to rev that high for the other shifts since the gears are closer.
10-09-2011, 01:52 PM
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Keeps me in the powerband on the 1-2 shift, car is faster that way. There is more power from 75-8 than there is from 5-55. I'd rather spin 1st a little higher and be in a better part of 2nd gear. Dont need to rev that high for the other shifts since the gears are closer.
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10-10-2011, 12:11 PM
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10-10-2011, 01:22 PM
#10
It honestly has nothing to do with nitrous. Look at the RPM spread between 1st and second gear. When you shift at 7300 or so, before a 7500 limiter hits, you land around 5K in 2nd, a bit low in the powerband. There is a slight lack of power before you really get into the cams at 5.5+ and have the meat of the powerband back until the next shift. Only place this happens is 1-2, as all other gears have a closer spread. You can shift to third at 7600rpms and land at nearly 6K.
I don't spray in 1st, car spins tires on motor anyway, but carrying the gear all the way to 8K allows me to hit 2nd gear in a better part of the powerband and help lower the torque hit from the nitrous when it activates (torque gain from nitrous falls as rpms raise) so the tires don't break loose in 2nd.
Regardless, the falling power from 7500-8000 is still more than the climbing power from 5000-5500, especially with test pipes and other restriction lowering mods that don't strangle the engine at high rpms as badly as stock. I agree in other gears, there is not much reason to push the car any higher, and I usually don't.
Besides, the car sounds great at higher rpms
I don't spray in 1st, car spins tires on motor anyway, but carrying the gear all the way to 8K allows me to hit 2nd gear in a better part of the powerband and help lower the torque hit from the nitrous when it activates (torque gain from nitrous falls as rpms raise) so the tires don't break loose in 2nd.
Regardless, the falling power from 7500-8000 is still more than the climbing power from 5000-5500, especially with test pipes and other restriction lowering mods that don't strangle the engine at high rpms as badly as stock. I agree in other gears, there is not much reason to push the car any higher, and I usually don't.
Besides, the car sounds great at higher rpms
Last edited by Italianjoe1; 10-10-2011 at 01:27 PM.
10-10-2011, 01:25 PM
#11
Further, delaying the shift on a pair of evenly matched cars almost always makes the car slightly faster. The added momentum you can carry from getting slightly more speed out of each gear, coupled with the powerband effect mentioned earlier, ensures that the car will never be "slower" than if I shifted earlier. I enjoy the run with a stock redline car, where I have a couple hundred rpms to pull after they shift. It's visually very hard to understand, why i'm still going after they let off to shift, even if the actual speed difference isn't much.
10-10-2011, 06:28 PM
#14
I no has the bottle but, my car way raps out long before 8K rpms, in any gear.
10-10-2011, 07:27 PM
#15
Just please do us all a favor & try to remember the sound the engine makes when revving this high.......just before the explosion, so you can tell us what the sound of $$$$ in the trash sounded like.
I no has the bottle but, my car way raps out long before 8K rpms, in any gear.
I no has the bottle but, my car way raps out long before 8K rpms, in any gear.
Want me to show you vids of it passing 8500?
10-10-2011, 07:32 PM
#16
Just please do us all a favor & try to remember the sound the engine makes when revving this high.......just before the explosion, so you can tell us what the sound of $$$$ in the trash sounded like.
I no has the bottle but, my car way raps out long before 8K rpms, in any gear.
I no has the bottle but, my car way raps out long before 8K rpms, in any gear.
Want me to show you vids of it passing 8500?
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