2007 VQHR Dyno Results!
#76
02-08-2007, 03:14 PM
Originally Posted by AlterZgo
Practically EVERY car mfg does this so that their cars generate the best 0-60 times.
I think Lexus's gearing makes more sense than what Infiniti chose for the G35. The 6 speed G35 hits 69 mph in 2nd and 98 mph in 3rd vs. 60 mph and 90 mph for the Lexus. Thus, it appears if the G was geared shorter, its 0-60 times would be as quick as, if not quicker, than the IS350's times.
On the top end, the G35 has a relatively short 6th gear which causes the car to rev at 2400 rpm at 60 mph when the IS350 is only turning 1950 RPM at 60 mph. This relatively short 6th gear gives the G worse gas mileage for not useful advantage in acceleration. Since the G already hits top speed in 5th gear, you would think Infiniti would have spec'd a tall 6th gear for good freeway crusing gas mileage.
I think Lexus's gearing makes more sense than what Infiniti chose for the G35. The 6 speed G35 hits 69 mph in 2nd and 98 mph in 3rd vs. 60 mph and 90 mph for the Lexus. Thus, it appears if the G was geared shorter, its 0-60 times would be as quick as, if not quicker, than the IS350's times.
On the top end, the G35 has a relatively short 6th gear which causes the car to rev at 2400 rpm at 60 mph when the IS350 is only turning 1950 RPM at 60 mph. This relatively short 6th gear gives the G worse gas mileage for not useful advantage in acceleration. Since the G already hits top speed in 5th gear, you would think Infiniti would have spec'd a tall 6th gear for good freeway crusing gas mileage.
#77
02-08-2007, 03:19 PM
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#78
02-08-2007, 03:40 PM
I don't blame you or anyone for getting this all mixed up. It is one of the biggest common misconception in the community. Hopefully I can better explain it as follows ...
Indeed that is exactly what I said below,
Further more, it is understood that chassis dyno figures have inherent drivetrain loss in everyday speak. When Joe Schmoe says he puts down 250hp at the wheel, let it be DynoJet or what not, it is understood that 250 implies drivetrain loss associated.
It doesn't. Not automagically at least. Again this is where the Transmission Correction Factor (TCF) is suppose to come in for the DynaPack software. Take at a look at the screen shot Tony posted above. You'll notice it is at "1.0" or no correction. If the transmission loss is believe to be 15%, the operator would input "1.15" and the net result would have been multiplied by 1.15 and thus accounting for the 15% believed to be loss by the transmission. That in it's very essence is in fact the flywheel figure, or what the engine pumps out.
There are several manual procedures in determining a particular vehicle's TCF on the dyno, but an estimate at best. It also leaves too much shady fudge factor at stake, so most operators choose to not deal with it and simply leaving it at "1.0". By doing that, all readings will still be the flywheel figure with NO transmission loss noted.
And that my friend is the FLYWHEEL figure (minus the drivetrain loss of course) you have just described.
can you say transmission loss? 
Originally Posted by ttrank
If it were "flywheel hp" it would not include the transmisson loss.
Originally Posted by THX723
The "Flywheel" designation for power and torque by the Dynapack software is technically correct. For that matter, the numbers you get from DynoJet, Dynodynamics, or whichever dyno are also technically "Flywheel" figures minus the drivetrain loss (aka transmission loss).
Originally Posted by ttrank
But how would this reading be able to compensate for the transmission, driveline and axle loss?
There are several manual procedures in determining a particular vehicle's TCF on the dyno, but an estimate at best. It also leaves too much shady fudge factor at stake, so most operators choose to not deal with it and simply leaving it at "1.0". By doing that, all readings will still be the flywheel figure with NO transmission loss noted.
Originally Posted by ttrank
From what I understand, the number is a wheel or hub hp reading but it is calculated based on the final drive ratio of the gear you are in. So it is not flywheel hp.
Originally Posted by ttrank
If it were, it should be higher.
#79
02-09-2007, 01:56 PM
Originally Posted by THX723
I don't blame you or anyone for getting this all mixed up. It is one of the biggest common misconception in the community. Hopefully I can better explain it as follows ...
Indeed that is exactly what I said below,Further more, it is understood that chassis dyno figures have inherent drivetrain loss in everyday speak. When Joe Schmoe says he puts down 250hp at the wheel, let it be DynoJet or what not, it is understood that 250 implies drivetrain loss associated.
It doesn't. Not automagically at least. Again this is where the Transmission Correction Factor (TCF) is suppose to come in for the DynaPack software. Take at a look at the screen shot Tony posted above. You'll notice it is at "1.0" or no correction. If the transmission loss is believe to be 15%, the operator would input "1.15" and the net result would have been multiplied by 1.15 and thus accounting for the 15% believed to be loss by the transmission. That in it's very essence is in fact the flywheel figure, or what the engine pumps out.
There are several manual procedures in determining a particular vehicle's TCF on the dyno, but an estimate at best. It also leaves too much shady fudge factor at stake, so most operators choose to not deal with it and simply leaving it at "1.0". By doing that, all readings will still be the flywheel figure with NO transmission loss noted.
And that my friend is the FLYWHEEL figure (minus the drivetrain loss of course) you have just described.
can you say transmission loss?
Indeed that is exactly what I said below,Further more, it is understood that chassis dyno figures have inherent drivetrain loss in everyday speak. When Joe Schmoe says he puts down 250hp at the wheel, let it be DynoJet or what not, it is understood that 250 implies drivetrain loss associated.
It doesn't. Not automagically at least. Again this is where the Transmission Correction Factor (TCF) is suppose to come in for the DynaPack software. Take at a look at the screen shot Tony posted above. You'll notice it is at "1.0" or no correction. If the transmission loss is believe to be 15%, the operator would input "1.15" and the net result would have been multiplied by 1.15 and thus accounting for the 15% believed to be loss by the transmission. That in it's very essence is in fact the flywheel figure, or what the engine pumps out.
There are several manual procedures in determining a particular vehicle's TCF on the dyno, but an estimate at best. It also leaves too much shady fudge factor at stake, so most operators choose to not deal with it and simply leaving it at "1.0". By doing that, all readings will still be the flywheel figure with NO transmission loss noted.
And that my friend is the FLYWHEEL figure (minus the drivetrain loss of course) you have just described.
can you say transmission loss?
LOL, that was one very detailed reply.
Thanks for the clarification.
#81
02-11-2007, 08:50 AM
#83
02-11-2007, 05:23 PM
No, if your motor makes peak horsepower at 6700, you should shift at Redline (7500) so you will be in your powerband for the next gear. If you shift at 6700rpm, your rpms will drop too much and you will be out of your peak powerband for next gear. You can test this at the track if you have an 07 G35 and see what I mean, you will be much slower if you shift before redline.
#84
02-12-2007, 01:17 AM
#86
02-12-2007, 01:37 PM
Torque is not a measure of power, instead it is horsepower. Look no further than the horsepower chart when determining optimal shift points, where the interest is to swept the most area underneath the horsepower curve. Quickly looking at the HR power curve says shifting @ 7500 rpm is the most optimal point (assuming 1500 rpm drop at each up shift).
Last edited by THX723; 02-12-2007 at 01:59 PM.
#88
02-12-2007, 01:51 PM
Originally Posted by 03FXer
So it looks like the 05/06 6speeds are putting done more HP than the 07 autos? I guess I should got the 07 6speed , but the auto is so nice in traffic.
, but the auto is so nice in traffic.
#89
02-12-2007, 01:59 PM
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Interesting that the HP drops off so much after 6700 rpms. Especially with another 800 rpms until redline. Sure, I would expect it to drop some, but that's pretty steep. Seems it runs out of breathing up top... surprising, now that we have both intake and exhaust valve adjustable timing (one infinite, one binary).
I wonder how much of that is negated "at speed" due to the ram effect of the intake.
Hydrazine - just for kicks, you should do a run with a leaf blower pointed at each intake.
Seriously.
I wonder how much of that is negated "at speed" due to the ram effect of the intake.
Hydrazine - just for kicks, you should do a run with a leaf blower pointed at each intake.
Seriously.
#90
02-12-2007, 02:06 PM