Z1 Motorsport Driveshaft B4 / After Dyno G35
05-18-2012, 08:59 PM
#92
i just realized it is only for the manual...anyone know when the auto is coming out? and no offense to the car being boosted but for most people we want to see a before and after NA and as soon as they have an auto driveshaft ill get it and have that posted
05-21-2012, 01:10 AM
#94
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I just bought this. Not sure how long shipping will take, but if I'm lucky I will have this installed within 2 weeks. I can't PROMISE a before/after dyno, but I am going to give a shout to Hill's Garage and a maybe another shop a bit more local (Northern VA), and see what their prices are like.
STAPLES: Looks like you are semi-close to me, and have been to Hill's. Any idea what their baseline dyno prices are like, sans tuning? I would love to be able to give the community an accurate before/after, but seeing as how i just dropped close to $500 for the DS, might not be in the budget
STAPLES: Looks like you are semi-close to me, and have been to Hill's. Any idea what their baseline dyno prices are like, sans tuning? I would love to be able to give the community an accurate before/after, but seeing as how i just dropped close to $500 for the DS, might not be in the budget
05-23-2012, 12:34 PM
#95
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I can't comment on the strength of the aluminum shaft vs the steel one and the vibration increase from using a longer 1 pc. shaft, keep the info coming guys who know more about it than I do. I'm learning a lot.
The increase in power at the wheels is from less rotational mass that has to be spun by the engine's power. How much power does it take to spin a straw between your thumb and index finger? Now what about a rod of steel the same size, how much power would it take? Same principle. If every part of the drive train were half the weight it is now, engine output would be the exact same but how much of that power output would make it to the wheels would increase dramatically. Reducing the difference in the dyno number between engine HP and wheel HP for every pound of rotating mass saved.
The increase in power at the wheels is from less rotational mass that has to be spun by the engine's power. How much power does it take to spin a straw between your thumb and index finger? Now what about a rod of steel the same size, how much power would it take? Same principle. If every part of the drive train were half the weight it is now, engine output would be the exact same but how much of that power output would make it to the wheels would increase dramatically. Reducing the difference in the dyno number between engine HP and wheel HP for every pound of rotating mass saved.
Although this should correctly translate to better performance, that's not the same thing as more power. Apart from a potential reduction in friction losses, this change should (theoretically) simply move the HP/Torque curve to the left - equating to equal power achieved at the wheels sooner along the RPM scale.
This is how I would expect to see the benefit appear in a dyno test. Just my 0.02....
05-23-2012, 02:11 PM
#96
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Been traveling and just now catching up on this thread. Having read BB's reply (and others) it seems like we may be confusing power with inertia. I believe the various posters are exactly correct when they compare the lighter driveshaft with a lighter flywheel or any other lightened drivetrain components; basically there is less mass to accelerate, therefore everything accelerates more quickly.
Although this should correctly translate to better performance, that's not the same thing as more power. Apart from a potential reduction in friction losses, this change should (theoretically) simply move the HP/Torque curve to the left - equating to equal power achieved at the wheels sooner along the RPM scale.
This is how I would expect to see the benefit appear in a dyno test. Just my 0.02....
Although this should correctly translate to better performance, that's not the same thing as more power. Apart from a potential reduction in friction losses, this change should (theoretically) simply move the HP/Torque curve to the left - equating to equal power achieved at the wheels sooner along the RPM scale.
This is how I would expect to see the benefit appear in a dyno test. Just my 0.02....
05-23-2012, 06:41 PM
#97
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Hi, want to chime in my opinions on this.
The dyno charts certainly look very interesting - impressive gains
but, from some quick calculations I did on this thread https://www.myg37.com/forums/modding...-analysis.html, I concluded that the reduced inertia from the lighter drive shaft won't have much effect on straight line acceleration.
My model assumes the car sits on the ground, and accelerates the entire mass of the car in a straight line. This has a different dynamic behavior to a car sitting stationary on the dyno and turning a big drum. Assuming the dyno chart is legit, I have a few guesses as to why there is such a noticeable improvement:
I'd be very surprised (but curious to get a scientific explanation) if the drive shaft gave noticeable improvements to actual driving in straight line (perhaps some 1/4 mile times).
I personally would not go for this upgrade, unless I'm convinced otherwise. However, like I said before, reducing the mass or inertia from any part of your car will improve acceleration - the only question is is it cost-effective to do so.
The dyno charts certainly look very interesting - impressive gains
but, from some quick calculations I did on this thread https://www.myg37.com/forums/modding...-analysis.html, I concluded that the reduced inertia from the lighter drive shaft won't have much effect on straight line acceleration.
My model assumes the car sits on the ground, and accelerates the entire mass of the car in a straight line. This has a different dynamic behavior to a car sitting stationary on the dyno and turning a big drum. Assuming the dyno chart is legit, I have a few guesses as to why there is such a noticeable improvement:
- Car sitting on dyno may have similar behavior as a car spinning its wheels in the air while sitting on jacks. One of my earlier models assumed the latter case and showed that even a measly lightened pulley upgrade can have a measurable effect in improving how quickly the wheel gets spun up (Basically this confirmed the observations from the ppl who noticed engine revved up more quickly in neutral when they replaced pulley). However, don't be fooled - a lighter pulley has very little effect when the car is on the ground accelerating in a line.
So,- ASSUMING that a car on the dyno is similar to a car spinning wheels in the air, but with a load applied;
- AND, that many (less sophisticated) dynos get their numbers by measuring the angular acceleration of the drum;
- THEN, it is conceivable that the drive shaft can post impressive gains.
- perhaps the gains are due to the inherent inaccuracies of dyno, as someone else pointed out. +/- 10whp or whatever. Perhaps there were more favorable conditions like air temperature, humidity, etc
I'd be very surprised (but curious to get a scientific explanation) if the drive shaft gave noticeable improvements to actual driving in straight line (perhaps some 1/4 mile times).
I personally would not go for this upgrade, unless I'm convinced otherwise. However, like I said before, reducing the mass or inertia from any part of your car will improve acceleration - the only question is is it cost-effective to do so.
Last edited by harbin9er; 05-24-2012 at 05:27 AM. Reason: added "...noticed engine revved up more quickly in neutral"
05-23-2012, 07:00 PM
#98
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...I'd be very surprised (but curious to get a scientific explanation) if the drive shaft gave noticeable improvements to actual driving in straight line (perhaps some 1/4 mile times).
I personally would not go for this upgrade, unless I'm convinced otherwise. However, like I said before, reducing the mass or inertia from any part of your car will improve acceleration - the only question is is it cost-effective to do so.
I personally would not go for this upgrade, unless I'm convinced otherwise. However, like I said before, reducing the mass or inertia from any part of your car will improve acceleration - the only question is is it cost-effective to do so.
self: Show the Hill's Garage guys this thread. Maybe they would 'sponsor' the dyno time in the interest of science and promotion.
Coop
05-23-2012, 09:23 PM
#99
Hi, want to chime in my opinions on this.
The dyno charts certainly look very interesting - impressive gains
but, from some quick calculations I did on this thread https://www.myg37.com/forums/modding...-analysis.html, I concluded that the reduced inertia from the lighter drive shaft won't have much effect on straight line acceleration.
My model assumes the car sits on the ground, and accelerates the entire mass of the car in a straight line. This has a different dynamic behavior to a car sitting stationary on the dyno and turning a big drum. Assuming the dyno chart is legit, I have a few guesses as to why there is such a noticeable improvement:
I'd be very surprised (but curious to get a scientific explanation) if the drive shaft gave noticeable improvements to actual driving in straight line (perhaps some 1/4 mile times).
I personally would not go for this upgrade, unless I'm convinced otherwise. However, like I said before, reducing the mass or inertia from any part of your car will improve acceleration - the only question is is it cost-effective to do so.
The dyno charts certainly look very interesting - impressive gains
but, from some quick calculations I did on this thread https://www.myg37.com/forums/modding...-analysis.html, I concluded that the reduced inertia from the lighter drive shaft won't have much effect on straight line acceleration.
My model assumes the car sits on the ground, and accelerates the entire mass of the car in a straight line. This has a different dynamic behavior to a car sitting stationary on the dyno and turning a big drum. Assuming the dyno chart is legit, I have a few guesses as to why there is such a noticeable improvement:
- Car sitting on dyno may have similar behavior as a car spinning its wheels in the air while sitting on jacks. One of my earlier models assumed the latter case and showed that even a measly lightened pulley upgrade can have a measurable effect in improving how quickly the wheel gets spun up (Basically this confirmed the observations from the ppl who noticed engine revved up more quickly when they replaced pulley). However, don't be fooled - a lighter pulley has very little effect when the car is on the ground accelerating in a line.
So,- ASSUMING that a car on the dyno is similar to a car spinning wheels in the air, but with a load applied;
- AND, that many (less sophisticated) dynos get their numbers by measuring the angular acceleration of the drum;
- THEN, it is conceivable that the drive shaft can post impressive gains.
- perhaps the gains are due to the inherent inaccuracies of dyno, as someone else pointed out. +/- 10whp or whatever. Perhaps there were more favorable conditions like air temperature, humidity, etc
I'd be very surprised (but curious to get a scientific explanation) if the drive shaft gave noticeable improvements to actual driving in straight line (perhaps some 1/4 mile times).
I personally would not go for this upgrade, unless I'm convinced otherwise. However, like I said before, reducing the mass or inertia from any part of your car will improve acceleration - the only question is is it cost-effective to do so.
$430 isn't much when you compare it to a lot of other mods out there. This is also one of the easiest things you could install on your car. If you can install an exhaust, you can do this.
05-23-2012, 11:59 PM
#100
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I will contact Hill's...Not sure if I am going to be able to get a before/after, though. I am planning to install the driveshaft this weekend when I am out at my house and have access to my lift. So we'll see what's what.
Packaging
DS
Close-Up
Packaging
DS
Close-Up
05-24-2012, 12:23 AM
#102
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The packaging would be the least of my concerns. It was secure and it made it here just fine. I would be much more worried about the weight savings not having a noticeable effect
But I'm okay with being a guinea pig!
05-28-2012, 09:37 AM
#105
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Out of curiousity, is this the same Z1 Auto that is spoken about here: Z1 Auto in NY - Page 8 - MY350Z.COM Forums