346whp @ 0 pounds of boost
03-17-2011, 11:45 AM
#202
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My build was done on a small budget. In fact, if you look at the money spent on my longblock you would realize it's almost nothing. It consists of the following ONLY:
JE Pistons
Eagle Rods
Revup Oil Pump
ARP Mains / Head Bolts
JWT Cams / springs
Like the above poster said, keep it simple.
My goal for the future for a further developed race engine would be to remove the 2nd ring and go to a much smaller piston, with a longer rod, and spin it to 9000rpm for exactly 30hrs at which point I would rebuild, and feel like I have a real motorsport engine
The UR pulley was on the car when I got it, and is the only under driven pulley that I know if. It hasn't caused any failures to date so I am taking my chances. Knowing what I know now I would use a stock pulley instead of anything else. if not the UR. The ATI would be nice if it was a smaller diameter, but all of the ones I have installed actually spin all of the accessories faster. Error.
JE Pistons
Eagle Rods
Revup Oil Pump
ARP Mains / Head Bolts
JWT Cams / springs
Like the above poster said, keep it simple.
My goal for the future for a further developed race engine would be to remove the 2nd ring and go to a much smaller piston, with a longer rod, and spin it to 9000rpm for exactly 30hrs at which point I would rebuild, and feel like I have a real motorsport engine
The UR pulley was on the car when I got it, and is the only under driven pulley that I know if. It hasn't caused any failures to date so I am taking my chances. Knowing what I know now I would use a stock pulley instead of anything else. if not the UR. The ATI would be nice if it was a smaller diameter, but all of the ones I have installed actually spin all of the accessories faster. Error.
"Features a 6 7/8 inch outer diameter, with aluminum shell, and steel insert where it mates to the crank. Retains a/c, power steering, and alternator. Belts not included. Air Conditioning is 32% underdriven, Power Steering and Alternator are 15% overdriven."
Having used both the UR and the ATI on my built motor, I much prefer how the engine feels with the ATI. Was zero balanced out of the box (the UR wasn't....close, but not quite), and the UR made the clutch extremely grabby (OS Single disk). Swapping to the ATI made the clutch exponentially easier to drive in day to day traffic, and even with the stereo setup I have in the car (and a/c is retained on mine too), I've not had a single issue. Downside is the price of course
Last edited by Z1 Performance; 03-17-2011 at 11:48 AM.
03-17-2011, 12:18 PM
#203
The ATI street pulley is the most underdriven crank pulley out there. From the measurements I did:
"Features a 6 7/8 inch outer diameter, with aluminum shell, and steel insert where it mates to the crank. Retains a/c, power steering, and alternator. Belts not included. Air Conditioning is 32% underdriven, Power Steering and Alternator are 15% overdriven."
"Features a 6 7/8 inch outer diameter, with aluminum shell, and steel insert where it mates to the crank. Retains a/c, power steering, and alternator. Belts not included. Air Conditioning is 32% underdriven, Power Steering and Alternator are 15% overdriven."
http://www.atiracing.com/products/da.../damnissan.htm
03-17-2011, 04:45 PM
#205
03-17-2011, 07:06 PM
#206
First, remember that the purpose of the damper is not to balance the rotating assembly. It is not a "balancer" (as though a 60 deg split throw could be balanced on the crank end alone). It is a damper, designed to dampen the torsional vibrations induced from the periodic application of torque about the crank centerline every time a piston is fired down its bore.
Now, in the case of Adam's build (and any other decent build) the crank has been "balanced" with regard to the rotating and reciprocating mass of the con rod, piston, and pins; so that the interia of these components traveling through the stroke is balanced (cancelled) by the inertia of the accelerating mass of the crank counterweights . Thus, the engine can be seen as "balanced" such that with a constant & even application of torque, and ignoring friction, the entire assembly would spin smoothly (without "wobble").
The issue is that there is not a constant application of torque. Force is applied to the crank in periods defined by the number of pistons and firing order. These periodic applications of torque about the crank centerline are also not perfectly equal amongst all the pistons, as variations in cylinder filling, friction, temperature, etc.. will induce some pistons to fire down the bore with different amounts of force. Also, the split crank design of a V6 cannot cancel out all the inertial loads imposed about the crankshaft by the reciprocating assembly, as the third order harmonic is not balanced (a straight crank design such as an inline or boxer 6 solves this issue).
So, while the crank may be balanced, there is an application of uneven force applied in defined but unbalanced intervals (a harmonic) acting on the crankshaft. These variations in force cause a twisting of the crank about the centerline (torsion). The crank has a big hunk of mass on one end to "absorb" some of this torsional energy. It is the flywheel. Dual-mass flywheels are designed to absorb these vibrations (torsional unloading) while not transmitting them through to the clutch (and consequently, the transmission input shaft). The other end of the crank does not have a huge hunk of mass on it. As such, the torsional vibrations of the crank tend to increase the further away from the flywheel the crank extends. Thus, this end of the crank features a harmonic DAMPER (not balancer. You cannot "balance" a harmonic anymore than the shocks on your car "balance" road vibrations). This is designed to help unload the torsional energy from the front of the crank through the use of a specific mass bonded to an elastomer material (some OEM's employ a viscous type damper, and there are several SAE papers to show they are more effective across a broader range of vibrations).
Therefore, the superior ability of the ATI damper to dampen these torsional vibrations reduces the amount of stored torsional energy in the crankshaft unloading to the flywheel, and because Adam uses a single-piece flywheel (without the extra damping capability of the OEM dual-mass unit), this can offer a direct benefit to clutch feel and engagement.
Will
Last edited by Resolute; 03-17-2011 at 07:14 PM. Reason: cleaned it up a bit
03-17-2011, 10:25 PM
#209
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I hope Adam doesn't mind me answering a question directed at him, but I'd like to discuss this a bit.
First, remember that the purpose of the damper is not to balance the rotating assembly. It is not a "balancer" (as though a 60 deg split throw could be balanced on the crank end alone). It is a damper, designed to dampen the torsional vibrations induced from the periodic application of torque about the crank centerline every time a piston is fired down its bore.
Now, in the case of Adam's build (and any other decent build) the crank has been "balanced" with regard to the rotating and reciprocating mass of the con rod, piston, and pins; so that the interia of these components traveling through the stroke is balanced (cancelled) by the inertia of the accelerating mass of the crank counterweights . Thus, the engine can be seen as "balanced" such that with a constant & even application of torque, and ignoring friction, the entire assembly would spin smoothly (without "wobble").
The issue is that there is not a constant application of torque. Force is applied to the crank in periods defined by the number of pistons and firing order. These periodic applications of torque about the crank centerline are also not perfectly equal amongst all the pistons, as variations in cylinder filling, friction, temperature, etc.. will induce some pistons to fire down the bore with different amounts of force. Also, the split crank design of a V6 cannot cancel out all the inertial loads imposed about the crankshaft by the reciprocating assembly, as the third order harmonic is not balanced (a straight crank design such as an inline or boxer 6 solves this issue).
So, while the crank may be balanced, there is an application of uneven force applied in defined but unbalanced intervals (a harmonic) acting on the crankshaft. These variations in force cause a twisting of the crank about the centerline (torsion). The crank has a big hunk of mass on one end to "absorb" some of this torsional energy. It is the flywheel. Dual-mass flywheels are designed to absorb these vibrations (torsional unloading) while not transmitting them through to the clutch (and consequently, the transmission input shaft). The other end of the crank does not have a huge hunk of mass on it. As such, the torsional vibrations of the crank tend to increase the further away from the flywheel the crank extends. Thus, this end of the crank features a harmonic DAMPER (not balancer. You cannot "balance" a harmonic anymore than the shocks on your car "balance" road vibrations). This is designed to help unload the torsional energy from the front of the crank through the use of a specific mass bonded to an elastomer material (some OEM's employ a viscous type damper, and there are several SAE papers to show they are more effective across a broader range of vibrations).
Therefore, the superior ability of the ATI damper to dampen these torsional vibrations reduces the amount of stored torsional energy in the crankshaft unloading to the flywheel, and because Adam uses a single-piece flywheel (without the extra damping capability of the OEM dual-mass unit), this can offer a direct benefit to clutch feel and engagement.
Will
First, remember that the purpose of the damper is not to balance the rotating assembly. It is not a "balancer" (as though a 60 deg split throw could be balanced on the crank end alone). It is a damper, designed to dampen the torsional vibrations induced from the periodic application of torque about the crank centerline every time a piston is fired down its bore.
Now, in the case of Adam's build (and any other decent build) the crank has been "balanced" with regard to the rotating and reciprocating mass of the con rod, piston, and pins; so that the interia of these components traveling through the stroke is balanced (cancelled) by the inertia of the accelerating mass of the crank counterweights . Thus, the engine can be seen as "balanced" such that with a constant & even application of torque, and ignoring friction, the entire assembly would spin smoothly (without "wobble").
The issue is that there is not a constant application of torque. Force is applied to the crank in periods defined by the number of pistons and firing order. These periodic applications of torque about the crank centerline are also not perfectly equal amongst all the pistons, as variations in cylinder filling, friction, temperature, etc.. will induce some pistons to fire down the bore with different amounts of force. Also, the split crank design of a V6 cannot cancel out all the inertial loads imposed about the crankshaft by the reciprocating assembly, as the third order harmonic is not balanced (a straight crank design such as an inline or boxer 6 solves this issue).
So, while the crank may be balanced, there is an application of uneven force applied in defined but unbalanced intervals (a harmonic) acting on the crankshaft. These variations in force cause a twisting of the crank about the centerline (torsion). The crank has a big hunk of mass on one end to "absorb" some of this torsional energy. It is the flywheel. Dual-mass flywheels are designed to absorb these vibrations (torsional unloading) while not transmitting them through to the clutch (and consequently, the transmission input shaft). The other end of the crank does not have a huge hunk of mass on it. As such, the torsional vibrations of the crank tend to increase the further away from the flywheel the crank extends. Thus, this end of the crank features a harmonic DAMPER (not balancer. You cannot "balance" a harmonic anymore than the shocks on your car "balance" road vibrations). This is designed to help unload the torsional energy from the front of the crank through the use of a specific mass bonded to an elastomer material (some OEM's employ a viscous type damper, and there are several SAE papers to show they are more effective across a broader range of vibrations).
Therefore, the superior ability of the ATI damper to dampen these torsional vibrations reduces the amount of stored torsional energy in the crankshaft unloading to the flywheel, and because Adam uses a single-piece flywheel (without the extra damping capability of the OEM dual-mass unit), this can offer a direct benefit to clutch feel and engagement.
Will
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Chinky4U (01-31-2018)
03-18-2011, 05:00 AM
#211
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And just to expand a bit on what Will wrote, it's not something unique to my setup. If you were to take any of the aftermarket single mass flywheels, and combine it with a lightweight crank pulley, you would find a similar characteristic in clutch engagement. When I was forced to decide what to do about a new crank pulley, I didn't want to use a stock pulley because I've seen those come apart at high rpm and with age. If memory serves, the Fluidampr was backordered at the time, and had just been changed to use an aluminum center section, which I wanted to avoid. The ATI uses a steel center hub section, so no concerns with long term wear against the crank.
FWIW we did take the time to balance the UR one as well (we also balanced my clutch too prior to install, you may be able to see this in the original pics posted in my build thread). I've also noticed that with the ATI, I've never once had to tighten the belts since it went on in summer 2008. That's pretty good, considering the mileage now on it, and the rpm's I turn.
In the case of your Chevy, on many of them at least, the crank pulley is actually used as a balancer, and the application of a proper aftermarket pulley should be even more beneficial
FWIW we did take the time to balance the UR one as well (we also balanced my clutch too prior to install, you may be able to see this in the original pics posted in my build thread). I've also noticed that with the ATI, I've never once had to tighten the belts since it went on in summer 2008. That's pretty good, considering the mileage now on it, and the rpm's I turn.
In the case of your Chevy, on many of them at least, the crank pulley is actually used as a balancer, and the application of a proper aftermarket pulley should be even more beneficial
03-18-2011, 06:26 AM
#214
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i have heard nothing but good things about the ati pulleys
03-18-2011, 06:53 AM
#217
^^^ so ATI street damper > Fluidampr 
but on the flip side... and if i'm interpreting this correctly, this is why i thought the Fluidampr was the better choice. broader rage of dampening vibration. i think of the crank ends like a (wobbling) hotdog, don't know why, lol!
and
i never really liked the hard bend on the inlet to the plenum, that's pretty sweet integration!
why didn't Nissan do this from the get go!? LOL!
Zquicksilver
but on the flip side... and if i'm interpreting this correctly, this is why i thought the Fluidampr was the better choice. broader rage of dampening vibration. i think of the crank ends like a (wobbling) hotdog, don't know why, lol!
As such, the torsional vibrations of the crank tend to increase the further away from the flywheel the crank extends. Thus, this end of the crank features a harmonic DAMPER (not balancer. You cannot "balance" a harmonic anymore than the shocks on your car "balance" road vibrations). This is designed to help unload the torsional energy from the front of the crank through the use of a specific mass bonded to an elastomer material (some OEM's employ a viscous type damper, and there are several SAE papers to show they are more effective across a broader range of vibrations).
and
i never really liked the hard bend on the inlet to the plenum, that's pretty sweet integration!
why didn't Nissan do this from the get go!? LOL!
Zquicksilver
Last edited by Zquicksilver; 03-18-2011 at 07:03 AM.
03-18-2011, 10:23 AM
#220
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you can contact ATI for the exact amount of under/overdriving Sasha, I forget the %'s of under/overdriving- it might be in my thread too
edit - found it
https://my350z.com/forum/5859855-post567.html
edit - found it
https://my350z.com/forum/5859855-post567.html
Last edited by Z1 Performance; 03-18-2011 at 10:26 AM.