New 370z (13.5 @ 105 mph) combined times - Page 3 - MY350Z.COM Forums



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Old 11-29-2008, 01:23 PM   #41
trebien
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Quote:
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Too be honest, if I had a 370z, I would be putting 17's on that car.
Over 14" brakes? You sure about that?

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Also, the equation for rotational inertia is I = m * r^2, where m = mass, and r = radius. Even if the mass is less than the outgoing wheel, the larger radius of the newer wheel governs the behavior of this equation due to the fact its squared.
Yes, but remember that r = RADIUS... so we're talking about the difference between those 2 variables being 81 (9 squared) and 90.25 (9.5 squared), about 11%. And of course, we need to consider where along the radius is the mass concentrated, but then we get really technical.

In this case, I'll take the 6 pounds lighter weight with the marginally larger diameter... just for the unsprung weight suspension benefits.
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Old 11-29-2008, 04:11 PM   #42
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Originally Posted by trebien View Post
Over 14" brakes? You sure about that?



Yes, but remember that r = RADIUS... so we're talking about the difference between those 2 variables being 81 (9 squared) and 90.25 (9.5 squared), about 11%. And of course, we need to consider where along the radius is the mass concentrated, but then we get really technical.

In this case, I'll take the 6 pounds lighter weight with the marginally larger diameter... just for the unsprung weight suspension benefits.
After reading your remark on the brakes, I completely forgot about the upgraded brakes on this car. In that case, I'll have to settle for 18's. Sorry that I overlooked that.

I believe that even though 11% might not seem like a lot, it is still noticeable.

Let's assume that the weight of the old 18" wheels is 25 lbs. This equals a mass of 11.34 kg. Lets say the newer, 6 lb lighter 19" wheel has a mass of 8.61826 kg.

Converting the radii to meters, the 9" radius now equals 0.2286 m. The 9.5" radius now equals 0.2413 m.

Substituting these values into I = m*r^2, we get these values:

18" wheels = 0.592605 kg*m^2
19" wheels = 0.501804 kg*m^2

The rotational inertias between these 2 wheels differs by about 15%. So, although you were right about the differences in radii being only 11%, after inserting these into the equation, there is now a 15% difference with the actual masses.

Another relationship, T = I * alpha, where T = torque, I = rotational inertia and alpha = angular acceleration, can be used to find the required torque to spin these wheels. We will hold alpha to be the same between the two, or constant, because we will assume that we would like to have the wheels spin at the same rate. The rotational inertia of the 19" wheel is 15% larger, so theoretically, that means that the engine needs to gain 15% more torque to spin the larger wheel at the same angular acceleration of the smaller, 18" wheel. You will definitely feel this.
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Old 11-29-2008, 04:58 PM   #43
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Well you guys are also overlooking tire sidewall height (stiffness etc) which is a big factor in the handling department... remember its not a 1/4 car... its all about the balance...
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Old 11-29-2008, 05:51 PM   #44
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the Nismo 370z will probably be 50k with the same 330hp.

The 370z does not entice me to trade-in my 07HR for one like I thought it would. Test pipes, cat-back, and tune and I could wipe the floor for the 370z.
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Old 11-29-2008, 06:19 PM   #45
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I wouldn't trade the HRs for one either but don't fool yourself this car is stock..
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Old 11-29-2008, 07:21 PM   #46
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Quote:
Originally Posted by trebien View Post
Over 14" brakes? You sure about that?



Yes, but remember that r = RADIUS... so we're talking about the difference between those 2 variables being 81 (9 squared) and 90.25 (9.5 squared), about 11%. And of course, we need to consider where along the radius is the mass concentrated, but then we get really technical.

In this case, I'll take the 6 pounds lighter weight with the marginally larger diameter... just for the unsprung weight suspension benefits.
I'm betting they subtracted the 6lbs off the heaviest older wheel, the rear 19x10 weighing in at a colossal 29.5lbs. The smaller front 18x9 weighed in at 21.25lbs. 6lbs off the heavier wheel is still heavy.

TK
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Old 11-29-2008, 07:50 PM   #47
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Quote:
Originally Posted by pistols07Z View Post
the Nismo 370z will probably be 50k with the same 330hp.

The 370z does not entice me to trade-in my 07HR for one like I thought it would. Test pipes, cat-back, and tune and I could wipe the floor for the 370z.
Just as BobDigi stated, the test are from a stock 370Z. Apples to apples comparision, give the 370 the same mods and you will get owned.
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Old 11-30-2008, 12:31 AM   #48
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Quote:
Originally Posted by 03Tour6Spd View Post
Well you guys are also overlooking tire sidewall height (stiffness etc) which is a big factor in the handling department... remember its not a 1/4 car... its all about the balance...
The RE050A's have a good sidewall stiffness. Hence, their superior response over many other tires out there.

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Originally Posted by Arnold K. View Post
Hmm, what tires are the 19s wrapped with? Also, doesn't increasing wheel size still have an affect on acceleration?
RE050A's.

Assuming you're comparing a car with 3 different options for rim sizes, the tire diameter is the same. Increasing the rim diameter doesn't necessarily mean you're increasing the whole wheel's (tire's) diameter. If you did, you would be messing with the gearing of the car.

.

Last edited by skaterbasist; 11-30-2008 at 12:35 AM.
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Old 11-30-2008, 04:50 AM   #49
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Just as BobDigi stated, the test are from a stock 370Z. Apples to apples comparision, give the 370 the same mods and you will get owned.
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Old 11-30-2008, 05:36 AM   #50
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I hope 18inch buddy club QF's fit over the big brakes.
those wheels are 16lbs fo 18x10's.
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Old 11-30-2008, 06:29 AM   #51
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Quote:
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Just as BobDigi stated, the test are from a stock 370Z. Apples to apples comparision, give the 370 the same mods and you will get owned.
Reality = Mod for Mod will be drivers race.

We are not talking about a big difference here fellas.
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Old 11-30-2008, 07:39 AM   #52
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i take .3 off a mags times anyway....

Ex.- 2003 sentra ser specv, rated at a 15.8 c&d and a 15.5 M.T., I ran a 15.1 stock, and then a 14.9 with some bfgs tkw's. Then got it to 14.1 bolted and tuned.

07 Z- 13.8s i think, i ran 13.6 stock with a clutch that wont feather...
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Old 11-30-2008, 07:47 AM   #53
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Quote:
Originally Posted by skaterbasist View Post
The RE050A's have a good sidewall stiffness. Hence, their superior response over many other tires out there.



RE050A's.

Assuming you're comparing a car with 3 different options for rim sizes, the tire diameter is the same. Increasing the rim diameter doesn't necessarily mean you're increasing the whole wheel's (tire's) diameter. If you did, you would be messing with the gearing of the car.

.
Yeah, I just saw it in the C&D review. I looked up the specs of the tire, and yeeouch are they heavy - 31lbs for the rear, 30lbs for the front. The larger brakes must also be holding the car's acceleration back, as well.
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Old 11-30-2008, 08:29 AM   #54
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This is sounding like a drag race forum... if you guyz bought the 350z to just go in a straight line... you are mistaken.
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Old 11-30-2008, 08:59 AM   #55
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This is sounding like a drag race forum... if you guyz bought the 350z to just go in a straight line... you are mistaken.
My thoughts exactly.

Let's just look at it like this. The 370z can hit 13.3 in 1/4. I think that is stellar. The new Z can also hit 13.7 in the 1/4. We have a good range of what this car can do.

Overall, I'm very excited about the performance of this car, both in a straight line and in the corners.
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Old 11-30-2008, 06:36 PM   #56
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Quote:
Originally Posted by Arnold K. View Post
Yeah, I just saw it in the C&D review. I looked up the specs of the tire, and yeeouch are they heavy - 31lbs for the rear, 30lbs for the front. The larger brakes must also be holding the car's acceleration back, as well.
The tire weight is pretty average when you put them in perspective with other performance tires in that size. The Akebono BBK's that they carry are VERY heavy though. Some aftermarket 2-piece rotors would definitely help.

Quote:
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This is sounding like a drag race forum... if you guyz bought the 350z to just go in a straight line... you are mistaken.
We already know its handling is going to be superior to the 350Z in every way. How much faster in sheer acceleration itself is going to compare to the 07-08 350Z isn't that clear so far, though obviously its still going to be significantly faster in the straights. A head to head comparison would be great.
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Old 11-30-2008, 10:38 PM   #57
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One thing people are over looking is that at least in the case of the C&D article the times listed are estimated. As in they didn't actually time the car, they guessed.
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Old 11-30-2008, 10:46 PM   #58
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if the heavier G37 coupe can run 13.7 stock automatic at the track, this new 370z will definitely be a quicker vehicle. The same brakes as teh G37 w/ Sport Package will definitely make everyone start hunting for new high offset rims. good thing plenty of wheel companies are staying on top of the game
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Old 12-01-2008, 05:22 AM   #59
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pathetic LOL
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Old 12-01-2008, 06:26 AM   #60
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If Veetec, Bateman and others can take the current HR 350Z to low 13s bone stock there is no reason why this won't be a high 12 second car bone stock. Considering the tires are better (thus the skidpad results) it might do even better than I am thinking (12.8~12.9)...

For those who can't drive it's going to be a mid 13 second car but for those who can this thing is going to be a rocket.
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