Drivetrain Replace lower pulley, Anyone done it?
Well my tools came in from Classic MINI today (they're SO awesome, have I mentioned that before? 
)
I'll have time to do the changeover this weekend, however I may have trouble getting accurate dyno runs because the roads here are still very salty and tires are cold (even snow tires lose grip eventually, lol)
I have about 20 dyno runs with the current setup on the car, so even if I can't get accurate dyno data this weekend, I'll be able to do reasonable comparisons later when the roads (oops, I mean closed test circuit) are in better, cleaner conditions.
At the very least I'll flip on my ole' Audio Engineer cap and give stethoscope feedback on valvetrain and accessory acoustics, as well as drivability changes.
Cheers for now,
Ryan
P.S. Pilo: I think there'd be an interest on a lighter damper for both the MC and MCS. The MC still should run a damper, due to higher C/R and cast bottom end, and a lighter damper may entice less-than-hardcore MCS owners not willing to go "*****-to-the-wall" with the ALTA solid pulley. From my chat with DCX, the stock MCS damper is tuned outside the engines normal operation, so keep that in mind when designing a lightweight one.
)I'll have time to do the changeover this weekend, however I may have trouble getting accurate dyno runs because the roads here are still very salty and tires are cold (even snow tires lose grip eventually, lol)
I have about 20 dyno runs with the current setup on the car, so even if I can't get accurate dyno data this weekend, I'll be able to do reasonable comparisons later when the roads (oops, I mean closed test circuit) are in better, cleaner conditions.
At the very least I'll flip on my ole' Audio Engineer cap and give stethoscope feedback on valvetrain and accessory acoustics, as well as drivability changes.
Cheers for now,
Ryan
P.S. Pilo: I think there'd be an interest on a lighter damper for both the MC and MCS. The MC still should run a damper, due to higher C/R and cast bottom end, and a lighter damper may entice less-than-hardcore MCS owners not willing to go "*****-to-the-wall" with the ALTA solid pulley. From my chat with DCX, the stock MCS damper is tuned outside the engines normal operation, so keep that in mind when designing a lightweight one.
...well, my car blew up...
No, I'm joking....no really! Seriously, I'm joking! Alright forget it, I'll explain!
*First off, the install was easy - easier than doing a s/c pulley! AGOKART has the pics, as his camera doesn't suck like mine
so we'll have to wait until he actually gets 'em over to my Inbox.
*Second, the car starts quicker. Not literally, but when it revs up to get to idle, it's quicker. That was the first thing I noticed.
*The car idles smoother than stock. Don't ask how, but there's less perceived NVH, it's like buttah.
*Driving: Clutch engagement in 1st seems to induce some gear noise (at least that's what it sounds like to these ears), anyone with a light flywheel have a simlar experience? It's much easier to do a burnout, so I'd deduce less power is being lost in overcoming rotational inertia - damnit, no I haven't been able to do any dyno pulls since the install - like I said, salty roads yield innacurate measurements, and I know Andy doesn't want innacurate There seems to be a bit more high-load/.WOT NVH - not exactly comforting, but not scary either. Then again, my car has always vibrated under WOT (quirk of my vehicle, err, yea)
So that's it for now - 2nd gear is now pointless on anything but clean pavement, lol. Now I need to start running R-compounds daily. I'm not sure how El Diabolito can possibly use his 281wHP, I'm having trouble with my paltry 191wHP!
Until next update,
Motor-On,
Ryan
No, I'm joking....no really! Seriously, I'm joking! Alright forget it, I'll explain!
*First off, the install was easy - easier than doing a s/c pulley! AGOKART has the pics, as his camera doesn't suck like mine
so we'll have to wait until he actually gets 'em over to my Inbox.*Second, the car starts quicker. Not literally, but when it revs up to get to idle, it's quicker. That was the first thing I noticed.
*The car idles smoother than stock. Don't ask how, but there's less perceived NVH, it's like buttah.
*Driving: Clutch engagement in 1st seems to induce some gear noise (at least that's what it sounds like to these ears), anyone with a light flywheel have a simlar experience? It's much easier to do a burnout, so I'd deduce less power is being lost in overcoming rotational inertia - damnit, no I haven't been able to do any dyno pulls since the install - like I said, salty roads yield innacurate measurements, and I know Andy doesn't want innacurate
There seems to be a bit more high-load/.WOT NVH - not exactly comforting, but not scary either. Then again, my car has always vibrated under WOT (quirk of my vehicle, err, yea)So that's it for now - 2nd gear is now pointless on anything but clean pavement, lol. Now I need to start running R-compounds daily. I'm not sure how El Diabolito can possibly use his 281wHP, I'm having trouble with my paltry 191wHP!
Until next update,
Motor-On,
Ryan
Originally Posted by Ryephile
So that's it for now - 2nd gear is now pointless on anything but clean pavement, lol. Now I need to start running R-compounds daily. I'm not sure how El Diabolito can possibly use his 281wHP, I'm having trouble with my paltry 191wHP!
Banned
Joined: Aug 2004
Posts: 864
Likes: 0
From: So Cal
Originally Posted by Ryephile
...So that's it for now - 2nd gear is now pointless on anything but clean pavement, lol. Now I need to start running R-compounds daily. I'm not sure how El Diabolito can possibly use his 281wHP, I'm having trouble with my paltry 191wHP!
Until next update,
Motor-On,
Ryan
Until next update,
Motor-On,
Ryan
Do you have LSD? that helps a bunch.
6th Gear
Joined: Jan 2003
Posts: 1,882
Likes: 0
From: Wyckoff, NJ
We will have available very soon a 4lb Vibration Dampener that will act as the OEM does to reduce harmonics, while increaseing the boost to the SC at the same time as it will be an overdrive pulley!
I will have the first unit next week.
I will have the first unit next week.
6th Gear
Joined: Oct 2002
Posts: 3,652
Likes: 6
From: Lansdale, PA
Originally Posted by MiniPilo
We will have available very soon a 4lb Vibration Dampener that will act as the OEM does to reduce harmonics, while increaseing the boost to the SC at the same time as it will be an overdrive pulley!
I will have the first unit next week.
I will have the first unit next week.
Originally Posted by El Diablito Rojo-N20Mini
well, you learn how to peddle the car... that's how Do you have LSD? that helps a bunch.
Do you have LSD? that helps a bunch.
5th Gear
Joined: Oct 2004
Posts: 855
Likes: 1
Originally Posted by MiniPilo
We will have available very soon a 4lb Vibration Dampener that will act as the OEM does to reduce harmonics, while increaseing the boost to the SC at the same time as it will be an overdrive pulley!
I will have the first unit next week.
I will have the first unit next week.
2nd Gear
Joined: Sep 2004
Posts: 144
Likes: 0
From: Albuquerque, NM
MiniPilo,
Please feel free to leak some more info, like... What will the diameter change be? Is the dampener any lighter than stock?
However, first thought in my head was the fact that everything else spun by the belt, not just the SC pulley, will be turning faster.
-Barry
Please feel free to leak some more info, like... What will the diameter change be? Is the dampener any lighter than stock?
However, first thought in my head was the fact that everything else spun by the belt, not just the SC pulley, will be turning faster.
-Barry
Originally Posted by MiniPilo
We will have available very soon a 4lb Vibration Dampener that will act as the OEM does to reduce harmonics, while increasing the boost to the SC at the same time as it will be an overdrive pulley!
I will have the first unit next week.
I will have the first unit next week.
Neutral
Joined: Nov 2004
Posts: 7
Likes: 0
Harmonic Balancer?
If the original Mini crank pulley had a harmonic balancer ( AKA: harmonic damper) built into it, replacing it with the Alta could compromise the life of the crankshaft. The practice of replacing the crank pulley with an underdrive and/or lightweight aftermarket unit is popular with the Japanese import crowd. The most popular is Unorthodox Racing.
The purpose of the damper is to absorb torsional vibrations, which are created by the explosions in the combustion chamber. When the fuel/air mixture ignites its like someone smacked the rod journals with a hammer. The crankshaft actually rings. The stock pulley is made up of three parts, one part is fastened to the crank (the hub), a rubber ring is bonded to the hub and to the outer ring (inertia ring).
The reason why the stock unit is so heavy is because the inertia ring ( along with the rubber isolator) needs mass to absorb the vibrations.
Any dope with a machine shop can make an underdrive and/or lightweight pulley. The real question is, how much damage is being caused by this unchecked vibration force and how much has it shorted the life of the crankshaft. If you lease your car or are not keeping for more than a few years its not your problem, let the next guy worry about it.
Bottom line: Hundreds of engineers working for all the top manufactures put in many many hours to design, build and install these dampers. They must be there for a good reason. Oh yeah, open up a Summit or Jegs catalog they claim to make more power by absorbing more vibration then a stock factory unit.
The purpose of the damper is to absorb torsional vibrations, which are created by the explosions in the combustion chamber. When the fuel/air mixture ignites its like someone smacked the rod journals with a hammer. The crankshaft actually rings. The stock pulley is made up of three parts, one part is fastened to the crank (the hub), a rubber ring is bonded to the hub and to the outer ring (inertia ring).
The reason why the stock unit is so heavy is because the inertia ring ( along with the rubber isolator) needs mass to absorb the vibrations.
Any dope with a machine shop can make an underdrive and/or lightweight pulley. The real question is, how much damage is being caused by this unchecked vibration force and how much has it shorted the life of the crankshaft. If you lease your car or are not keeping for more than a few years its not your problem, let the next guy worry about it.
Bottom line: Hundreds of engineers working for all the top manufactures put in many many hours to design, build and install these dampers. They must be there for a good reason. Oh yeah, open up a Summit or Jegs catalog they claim to make more power by absorbing more vibration then a stock factory unit.
Originally Posted by Ryephile
Jeff Perrin and I talked about the crank pulley on the phone for quite a while yesterday.
My utmost concerns are essentially thrashing the engine with harmonics and power pulses it otherwise wouldn't see with a high-inertia rotating assembly and a harmonic damper. Of course Jeff couldn't refute that removing the damper would not transmit some increased vibration to surrounding components (bearings, cam chain, accessory belt), the specific design of the engine (i.e. well balanced assembly with firing pulses ever 180 degrees and a very short, strong crank) tends to lead itself to having minimal inherent resonances. This I can understand.
The other aspect is damping the "power pulses", where each compression slows the crank, and each combustion speeds up the crank. Reducing your rotational inertia makes the crank speed vary greater over the combustion cycle. What you end up getting is a crank speed that can resemble a sine wave (though that's just for illustrative purposes). The lighter the rotating inertia, the bigger amplitude the speed variance. This would be relatively fine if there were nothing else connected to the crankshaft, however the valvetrain, the accessories, and the clutch, are. Engines that don't make a ton of power (read: us) don't have enough power in the combustion to vary the speeds that much. Basically, long story short [too late], is there is a practical limit to how much inertia you want to remove from the crank assembly. If you have a lightweight crank pulley, there's probably no need (or desire) to get a lightweight flywheel. You want mass somewhere. If your rotating mass is too light, you end up jerking the chain of the valvetrain, as well as yanking on the accessory belt more, and stressing them more.
Getting rid of some mass in the crank assembly isn't a bad thing. Getting rid of too much can lead to stressing your timing chain and accessory belt and engine bearings to the point of failure. The inherent balance of the rotating assembly is critical too, and according to Jeff, Tritec has done a great job with that. According to Jeff, the MINI, specifically, doesn't benefit much from a harmonic damper, and that removing it will have only a minimal impact on longetivity. Jeff also said that certain engine configurations (like V-8's and I-6's) have very bad resonances in their crankshafts and need a harmonic damper, and engines that tend to have more compact cranks (like the MINI, WRX, EVO) don't really benefit from a harmonic damper.
All that said, I still want to rig up a sensor that graphs the speed of the camshaft, seeing that varying waveform based on power pulses, with and without the added mass and harmonic damper. Anyone have a solution to do that?
My utmost concerns are essentially thrashing the engine with harmonics and power pulses it otherwise wouldn't see with a high-inertia rotating assembly and a harmonic damper. Of course Jeff couldn't refute that removing the damper would not transmit some increased vibration to surrounding components (bearings, cam chain, accessory belt), the specific design of the engine (i.e. well balanced assembly with firing pulses ever 180 degrees and a very short, strong crank) tends to lead itself to having minimal inherent resonances. This I can understand.
The other aspect is damping the "power pulses", where each compression slows the crank, and each combustion speeds up the crank. Reducing your rotational inertia makes the crank speed vary greater over the combustion cycle. What you end up getting is a crank speed that can resemble a sine wave (though that's just for illustrative purposes). The lighter the rotating inertia, the bigger amplitude the speed variance. This would be relatively fine if there were nothing else connected to the crankshaft, however the valvetrain, the accessories, and the clutch, are. Engines that don't make a ton of power (read: us) don't have enough power in the combustion to vary the speeds that much. Basically, long story short [too late], is there is a practical limit to how much inertia you want to remove from the crank assembly. If you have a lightweight crank pulley, there's probably no need (or desire) to get a lightweight flywheel. You want mass somewhere. If your rotating mass is too light, you end up jerking the chain of the valvetrain, as well as yanking on the accessory belt more, and stressing them more.
Getting rid of some mass in the crank assembly isn't a bad thing. Getting rid of too much can lead to stressing your timing chain and accessory belt and engine bearings to the point of failure. The inherent balance of the rotating assembly is critical too, and according to Jeff, Tritec has done a great job with that. According to Jeff, the MINI, specifically, doesn't benefit much from a harmonic damper, and that removing it will have only a minimal impact on longetivity. Jeff also said that certain engine configurations (like V-8's and I-6's) have very bad resonances in their crankshafts and need a harmonic damper, and engines that tend to have more compact cranks (like the MINI, WRX, EVO) don't really benefit from a harmonic damper.
All that said, I still want to rig up a sensor that graphs the speed of the camshaft, seeing that varying waveform based on power pulses, with and without the added mass and harmonic damper. Anyone have a solution to do that?
6th Gear
Joined: Jan 2003
Posts: 1,882
Likes: 0
From: Wyckoff, NJ
Originally Posted by muy_mini
MiniPilo,
Please feel free to leak some more info, like... What will the diameter change be? Is the dampener any lighter than stock?
However, first thought in my head was the fact that everything else spun by the belt, not just the SC pulley, will be turning faster.
-Barry
Please feel free to leak some more info, like... What will the diameter change be? Is the dampener any lighter than stock?
However, first thought in my head was the fact that everything else spun by the belt, not just the SC pulley, will be turning faster.
-Barry
The Diamater change will go from 5.45" to 5.80"
Because of this I will be testing with both a 19% and a 15% to see what the boost levels will be.
The other accessories will be spinning faster as well, including the AC, and the Alternator.
Let me know if there are any other questions.
Ok, after a week, I can give more driving feedback.
I've had to change my daily driving technique a bit. I'm sure this would be similar to someone that put in a light flywheel. I have to either drop the clutch at idle and just putz off the line, or rev it up to about 2k and slip the clutch a bit. This is contrast to my previous method of slight clutch slip at about 1500 rpm; doing that now yields a prefer-to-avoid resonance.
Fuel economy has changed...for the better. My economy is usually rather steady with my boooring street-level commute. The last two full tanks with the light crank pulley have yielded about a 1.0 MPG improvement. Less inertia to overcome at stop lights may account for this.
Dyno runs: these have turned out to be a pain - I messed up my control runs with the latest vehicle setup prior to installing the pulley by not running on the exact same stretch of road, so posting graphs will no doubt only confuse most people. If you've ever seen a dyno of a car going down anything less than perfectly smooth road, lol, it's somewhere between useful yet incomparable in a literal sense, and amusing. Long story short - there seems to be noticeable torque improvement across most the RPM band, accounting for error. Nobody hold onto their socks, this isn't an item you get for big dyno figures; the diamond in the rough is the transition from idle to WOT, especially at lower engine speeds, that is most usable for around-town driving.
Well, I hope that helps. well...ok ok I'll post the graphs, lol.
The Orange and Red runs are with the ALTA crank pulley. They represent a clean, smooth, flat road and thus the nice flat torque curve the MCS has. The green and blue runs show the YUKKIE un-smooth road I did my control runs on, you can literally see the peaks and valleys in the road surface!
Cheers,
Ryan
I've had to change my daily driving technique a bit. I'm sure this would be similar to someone that put in a light flywheel. I have to either drop the clutch at idle and just putz off the line, or rev it up to about 2k and slip the clutch a bit. This is contrast to my previous method of slight clutch slip at about 1500 rpm; doing that now yields a prefer-to-avoid resonance.
Fuel economy has changed...for the better. My economy is usually rather steady with my boooring street-level commute. The last two full tanks with the light crank pulley have yielded about a 1.0 MPG improvement. Less inertia to overcome at stop lights may account for this.
Dyno runs: these have turned out to be a pain - I messed up my control runs with the latest vehicle setup prior to installing the pulley by not running on the exact same stretch of road, so posting graphs will no doubt only confuse most people. If you've ever seen a dyno of a car going down anything less than perfectly smooth road, lol, it's somewhere between useful yet incomparable in a literal sense, and amusing. Long story short - there seems to be noticeable torque improvement across most the RPM band, accounting for error. Nobody hold onto their socks, this isn't an item you get for big dyno figures; the diamond in the rough is the transition from idle to WOT, especially at lower engine speeds, that is most usable for around-town driving.
Well, I hope that helps. well...ok ok I'll post the graphs, lol.
The Orange and Red runs are with the ALTA crank pulley. They represent a clean, smooth, flat road and thus the nice flat torque curve the MCS has. The green and blue runs show the YUKKIE un-smooth road I did my control runs on, you can literally see the peaks and valleys in the road surface!
Cheers,
Ryan
6th Gear
Joined: Apr 2003
Posts: 3,957
Likes: 2
From: a canyon, south Bay Area
Thanks Ryan for the follow-up. I suppose launching at 2k is not that big of a deal, and the improved gas mileage is certainly a nice plus...
So tell me, while the plots are not as revealing as you would have liked, if you had to do it all over again, from a performance and driveability stand-point, would ya? Thanks again.
So tell me, while the plots are not as revealing as you would have liked, if you had to do it all over again, from a performance and driveability stand-point, would ya? Thanks again.
I'll put it in the form of a comparison...
I drove a friends' bone-stock MCS the other day. I went to go downshift, tapping the throttle pedal like I normally do on my car to rev-match....except the engine didn't change revs!
I forgot you had to STAB the throttle to get the engine to rev up to downshift nicely. That said - I can't wait to get a lightwieght flywheel in my car 
So yea, from a performance and drivability - yes, definite thumbs up. Long-term reliability will take longer to determine [hopefully!]
I drove a friends' bone-stock MCS the other day. I went to go downshift, tapping the throttle pedal like I normally do on my car to rev-match....except the engine didn't change revs!
I forgot you had to STAB the throttle to get the engine to rev up to downshift nicely. That said - I can't wait to get a lightwieght flywheel in my car So yea, from a performance and drivability - yes, definite thumbs up.
Long-term reliability will take longer to determine [hopefully!]
6th Gear
Joined: Apr 2003
Posts: 3,957
Likes: 2
From: a canyon, south Bay Area
From your research, "hopefully" seems to be quite plausible . From what you say, it does sound worthwhile. Are you running with any stiffer engine bushes, such as the PowerFlext poly ones? Just trying to see what other factors might be contributing to or confounding that 1,500 resonance...
. From what you say, it does sound worthwhile. Are you running with any stiffer engine bushes, such as the PowerFlext poly ones? Just trying to see what other factors might be contributing to or confounding that 1,500 resonance...
I have not had to alter my start-ups from a stop at all with my pulley. I'm surprised that you feel you have too and that you feel that much difference with torgue at the low rpm.
Otherwise, I still love my Alta crank pulley and feel it's a very good add-on mod.
Otherwise, I still love my Alta crank pulley and feel it's a very good add-on mod.