Drivetrain TRUE Light Weight Vibration Damper Replacement Crank Pulley
#51
Originally Posted by jlm
i don't think it is at all clear why (if at all) a belt with a 19% pulley is short-lived on the track. here are some factors:
the stock pulley is 2.6" dia, 15% is 2.2 dia, the 19% is 2.0 dia so the diameter, and pretty much the wrap, for the 19% is about 10% less for the 19% compared to the 15%
with the larger crank pulley, the belt is travelling about 5% faster, so...
with the 15% pulley you have 10% more wrap, but 5% more belt speed compared to the 19%.
theory #1 is that it is the tightness of the radius around the pulley that will eventually stress the belt to failure, but I'm not sure the 10% dia. difference between 15 and 19 is significant.
theory #2 is that a faster travelling belt will wear out faster than a slower one.
the stock pulley is 2.6" dia, 15% is 2.2 dia, the 19% is 2.0 dia so the diameter, and pretty much the wrap, for the 19% is about 10% less for the 19% compared to the 15%
with the larger crank pulley, the belt is travelling about 5% faster, so...
with the 15% pulley you have 10% more wrap, but 5% more belt speed compared to the 19%.
theory #1 is that it is the tightness of the radius around the pulley that will eventually stress the belt to failure, but I'm not sure the 10% dia. difference between 15 and 19 is significant.
theory #2 is that a faster travelling belt will wear out faster than a slower one.
#52
Originally Posted by MiniPilo
The 15% to the 19% is 2 things, first is a less drastic bend around the pulley, and second, it's more surface area on the pulley. The first, I'm not 100% sure how much it affects the belt. I'm not sure is an issue of speed as much as it is an issue of slipage. I thnk that is the largest cause for belt failure. Any chance that you can reduce slipage, it will conserve belt length. I agree that the belt will more faster, and cause the alternator to turn faster, but the amount of HP drawn from the Alternator Vs. the Supercharger is almost nothing, for 1, it is not doing anything other then spinning against a small magnetic force, and 2, it has a much larger surface area to the belt for very little, if no chance of slipage. Let me know if this helps you
I cant really follow what you're saying. Would you mind editing this post so its understandable? Thanks.
#54
Originally Posted by macncheese
Dan,
I cant really follow what you're saying. Would you mind editing this post so its understandable? Thanks.
I cant really follow what you're saying. Would you mind editing this post so its understandable? Thanks.
JLM Stated 2 things.
First that the Radius has an effect to the belt life
Second that the speed has an effect.
What I was trying to state that both of those are factors in belt length, but the largest factor to a failure of a belt is slipage. That has the largest effect on the belt, first being friction of the belt slipping against the pulley, second being heat.
With a larger diamater pulley, both the crank and the SC Pulley (not stating there is any slipage on the stock crank pulley) there will be more contact area of the belt and the SC pulley. This enlarged contact area will help the belt drive the supercharger, with a less chance for slipage.
Lets say that on average a belt with no slipage can last 15K miles. If it runs 5% faster, that means that it will traverse the pulleys 5% more in that same ammount of time, so you may only get 14250 on the same belt. Again that is with no slipage. Now, if you bring slipage into the mix, as seen with the heat generated on a track event, you can go though a belt in a very short time. Say 1-2 track events as shown by the failures that we have seen. If by increasing the contact patch of the SC pulley, you can either severly reduce the chance for slipage, or eliminate it, then you can go many more events with out a failure.
Again, this is all theory right now, but it seems to make sense to me. Let me know if this clears it up for you.
#56
#57
Originally Posted by MiniPilo
I don't believe that they have released an oversized pulley.
#58
Originally Posted by 62Lincoln
Here's the thread with their info: https://www.northamericanmotoring.co...ad.php?t=39154
#60
#61
2% advantage?
Hi Dan,
here in germany we do a lot of high rev and high speed driving on our autobahn (with no speed restriction ). Most of us using 56,5mm pully, 15% reduction, a 19% reduction is (I guess) to much considering our driving caracteristics.
Are you able to produce a 2% or 3% bigger crank pully instead of your 5% increase?
Best regards,
Mick
here in germany we do a lot of high rev and high speed driving on our autobahn (with no speed restriction ). Most of us using 56,5mm pully, 15% reduction, a 19% reduction is (I guess) to much considering our driving caracteristics.
Are you able to produce a 2% or 3% bigger crank pully instead of your 5% increase?
Best regards,
Mick
#62
Originally Posted by MadMick
Hi Dan,
here in germany we do a lot of high rev and high speed driving on our autobahn (with no speed restriction ). Most of us using 56,5mm pully, 15% reduction, a 19% reduction is (I guess) to much considering our driving caracteristics.
Are you able to produce a 2% or 3% bigger crank pully instead of your 5% increase?
Best regards,
Mick
here in germany we do a lot of high rev and high speed driving on our autobahn (with no speed restriction ). Most of us using 56,5mm pully, 15% reduction, a 19% reduction is (I guess) to much considering our driving caracteristics.
Are you able to produce a 2% or 3% bigger crank pully instead of your 5% increase?
Best regards,
Mick
#63
Originally Posted by MiniPilo
I only plan to test this unit in comparison to diffrent setup's of Supercharger pulleys. There would be a bit more HP gained most likely on a solid pulley, but I do feel that having an effective vibration damper with a gain in HP is a better solution for most people then the little bit more they may gain with the solid pulley.
#66
#67
Dampers
Originally Posted by jlm
It appears that the problem of crankshaft torsional vibration may be quite important for very high performance applications such as drag racing. Perhaps one can extend the logic to modified Minis that are taken to the track? How about fairly aggressive street driving? Would you also comment on the use/availability of a fluid damping system in a Mini that is pulling 200+ whp?
Thanks,
#68
Originally Posted by RECOOP
Many thanks for the reference. I'll try to track down the SAE paper from 1979, unless you can post it .
It appears that the problem of crankshaft torsional vibration may be quite important for very high performance applications such as drag racing. Perhaps one can extend the logic to modified Minis that are taken to the track? How about fairly aggressive street driving? Would you also comment on the use/availability of a fluid damping system in a Mini that is pulling 200+ whp?
Thanks,
It appears that the problem of crankshaft torsional vibration may be quite important for very high performance applications such as drag racing. Perhaps one can extend the logic to modified Minis that are taken to the track? How about fairly aggressive street driving? Would you also comment on the use/availability of a fluid damping system in a Mini that is pulling 200+ whp?
Thanks,
We believe that Dampening is very important to a higher performing mini's engine.
#69
Lightweight Damper
Are you going to offer this damper in only 1 oversize? I am interested in a unit that will bring me from a 15% to a 19% overdrive of the supercharger. The reason I'm talking in percentages is that I want to use it with a software program designed for a 19% overdrive of the supercharger. I think that most tuners work to tune their software to a certain pulley as that is a popular upgrade. I don't have a booste gauge so I don't have a way to gauge any differences in boost,but I do know what percentage of overdrive to specify.
I guess that it's the long way of saying that I would be interested in a oversize that brings me to the same supercharger speed as a 19% pulley while keeping the 15% pulley. I think that a lighter weight, oversize damper is the soundest solution to get to 19% without the belt durability problems that some people have experienced.
I guess that it's the long way of saying that I would be interested in a oversize that brings me to the same supercharger speed as a 19% pulley while keeping the 15% pulley. I think that a lighter weight, oversize damper is the soundest solution to get to 19% without the belt durability problems that some people have experienced.
#70
Originally Posted by dcummings
Are you going to offer this damper in only 1 oversize? I am interested in a unit that will bring me from a 15% to a 19% overdrive of the supercharger. The reason I'm talking in percentages is that I want to use it with a software program designed for a 19% overdrive of the supercharger. I think that most tuners work to tune their software to a certain pulley as that is a popular upgrade. I don't have a booste gauge so I don't have a way to gauge any differences in boost,but I do know what percentage of overdrive to specify.
I guess that it's the long way of saying that I would be interested in a oversize that brings me to the same supercharger speed as a 19% pulley while keeping the 15% pulley. I think that a lighter weight, oversize damper is the soundest solution to get to 19% without the belt durability problems that some people have experienced.
I guess that it's the long way of saying that I would be interested in a oversize that brings me to the same supercharger speed as a 19% pulley while keeping the 15% pulley. I think that a lighter weight, oversize damper is the soundest solution to get to 19% without the belt durability problems that some people have experienced.
i've done a few calculations using these numbers:
stock crank: 5.46"
oversize crank: 5.76"
stock pulley: 2.59"
15% pulley: 2.2"
19% pulley: 2.1"
adding to a stock supercharger pulley set up is like a 5% reduction:
5.46(2.59)/5.76=2.46" so 2.46/2.59=0.95
adding this crank pulley to a 15% set up will make it the same a 19%:
5.76/2.2=2.62 and 5.46/2.1=2.60
adding to 19% set up:
5.76/2.1=2.74
2.74(7000rpm)=19180 superchrger rpm @ 7000rpm
and
5.46(2.1)/5.76=1.99 so 1.99/2.59=0.77, which is like a 23% reduction!
eek
stock crank: 5.46"
oversize crank: 5.76"
stock pulley: 2.59"
15% pulley: 2.2"
19% pulley: 2.1"
adding to a stock supercharger pulley set up is like a 5% reduction:
5.46(2.59)/5.76=2.46" so 2.46/2.59=0.95
adding this crank pulley to a 15% set up will make it the same a 19%:
5.76/2.2=2.62 and 5.46/2.1=2.60
adding to 19% set up:
5.76/2.1=2.74
2.74(7000rpm)=19180 superchrger rpm @ 7000rpm
and
5.46(2.1)/5.76=1.99 so 1.99/2.59=0.77, which is like a 23% reduction!
eek
#71
#72
#73
Just an update. We are just about ready for production. Having to make one change to the Pulley, and it will be set.
Just a side note on Harmonics and Harmonic Dampers. The harmonic damper does not aid in the balancing of the Crank Shaft. I've see it stated that the Crank shaft is Balanced to a tolerance of Grams. This does not apply towards the use of a Harmonic Damper. The Harmonic Damper's Function is to Dampen the Vibrations Created by the Pulse of the Combustion Cycle.
Just a side note on Harmonics and Harmonic Dampers. The harmonic damper does not aid in the balancing of the Crank Shaft. I've see it stated that the Crank shaft is Balanced to a tolerance of Grams. This does not apply towards the use of a Harmonic Damper. The Harmonic Damper's Function is to Dampen the Vibrations Created by the Pulse of the Combustion Cycle.