From what I understand and read about the Lightened Crank Pulley " That reduction is effectively the same as removing 100 pounds of weight from your vehicle."

And If you have a 15% pulley on you MINI now, you can add our (Alta) 2% over driven crank pulley and make you 15% pulley act like a 17% pulley.

Is there anyone here who has combined the Lightened Crank Pulley and the Over drive pulley along with a 15% Supercharger Pulley? And what were the gains?

 

I have both and am very pleased with the car's performance. I particularly like the fact that the combination used the stock drive belt, aligned properly and was taken up by the idler pulley just fine. I recommend the combination.

 

Did you install them after installing the 15% or at the same time? Have you dyno'd your car?

 

i have a 15% and 0% light weight crank pulley. i noticed right away that the car started fasted, reved up faster, and the butt dyno told me the car really liked the light weight pulley. the car pulled a lot stronger. and i have had it on my car for a while now with no problems, some of it on a track. next will a 3% crank.:smile:

give me a call if you have any other questions.
chad

 

Installed both at the same time. No dyno data.

 

I do get a vibration around 3,000 rpm .... , otherwise 15 + 2% works fine

Not sure if that is the only culprit or not .... Anyone else ???

 

I have a 15% + 3% and no problems and no vibration. The car has been on th etrack with this setup in 100+ heat with no problems.

 

Take a look at this tech article by Steve Dinan, it gives you some ideas to consider: http://dinancars.com/whitepapersFile.asp?ID=5

 

I could be feeling something else? I also had PSS9s go on about the same time ...

Could those have some vibration under hard throttle ?

 

Gentelmen, my understanding of doing a lot of research in regards to the MINI motor was that the crank pulley was designed to keep the motor in its harmonic range. If you change the crank pulley my understanding is that you will be getting a lot of vibration from the motor as well as taking it out of its harmonic range thus allowing the motor to possibly have problems later on. I dont know if this was fully discussed in the Dinan article but in talking to them in terms of why they never tested a crank pulley they said that the harmonic vibration is more important than loosing some weight to the actual crank. Let me know if I am way off here though guys. Thanks

 

I am installing a 17% Helix pulley with Alta's 2% crank, and 380cc injectors on our race car with JCW kit. I have just made a puller for the JCW pulley and we are taking the car to VIR this weekend. I do not have time to do software now, but I think GIAC 19% is in order. I will post back with how the car does.

 

Are you using "harmonic" as a synonym to "resonant." Resonance can be positive or destructive.....see Tacoma Narrows bridge. However resonant frequecies are harnessed in the case of low frequence loudspeakers to gain more efficiency. All this harmonic stuff is missing some components. At what frequency are the harmonics and are those frequencies at that "Q," and that amplitude destructive to the parts of the Mini engine. A blanket statement does not move me......are transducers being used to "data log" said frequencies etc.......I'm not saying that the problem does or does not exist but the developers clearly have not taken any of this into account or they would have posted a defense by now....or they simply don't care......but what do I know?

 

Spider,
I am sorry I did not define what the heck I am talking about. But here is a simple explaination. A "harmonic" is when multiple sound waves, generated by multiple sources, all overlap at a common frequency in the sound wave, and you get a "harmonic", that causes distortion. Basically, a sound wave has two amplitudes, a positive, and a negative. When you overlap or generate two sound waves at the same time, they each have a different frequency (likely), a different amplitude. But, if it happens that the two hit the same frequency point at the same time, you get a additive situation, that instead of the two sound waves co-existing, they duplicate, and the sound explodes. If a motor, which generates lots of vibrations, gets to a point where the vibrations don't balance out (hence, the need for a "balancing shaft" on reciprocating motors), they get a harmonic, and can literally tear themselves apart. Does that helpin my earlier statement?

 

I have not read any posts yet about lightweight crank cars exploding due to harmonics, has anyone else? Actual practice usually is a better indicator than general Popular Science reading/surmising. Quite a few folks are running them. What say they?

 

The Cooper (not S) does not have a harmonic damper.

 

i am personally not a fan of the crank pulleys... they slow everything else down like A/C which is important to me... and the lack of a proper harmonic balancer scares me... i have seen motors come apart as a result of a bad ballancer or lack their of... i have also seen a motor come apart because my buddy didn't listen to me and took the balance shafts out of his car to make more power...it made more power... for a while...

Also, now i don't think anyone has blown up a MINI motor yet because of a crank pulley... these things may take time... i am just worried about the longevity of the motor. i don't care about 10k miles from now i am worried about 40K miles from now... thats what i try to think of when i am designing a product... i am not interested if it only makes power for a while and then causes damage...

to me the crank pulleys extra however many horsepower (2-8hp or whatever it is) is not worth the pottential engine failure that may occur... i would just go with a lightend flywheel... that will really help your car out! I have had lightend flywheels in all of my cars (as light as 7lbs in some cars) driveability is perfect! I love them... they are a great thing that people always forget about...


okay im done just my $.02

 

Now it is my turn to be more clear.... I fully understand the concepts of sounds waves etc....what I am saying is without absolute knowledge of the frquency,"Q", duration and amplitude....you don't have much.....it is also likely that all those parameters change with engine rpm...then fatigue testing needs to be done to find what if any, the effects are of the engine being subjected to the criteria.

 

until someone runs a crank pulley for 100,000 miles, we wont have any conclusive reports on the relation between power and longevity

 

So from opinions expressed............Lightened Crank Pulley.....NO and Over drive pulley....OK.

 

Funny, that same thing was said about the SC pulley reductions, especially the 19% wasn't it? Bottom line though will be that even after 100,000 miles some folks would not consider it conclusive testing, nor that it is a "safe" mod. Depends on one's perspective. With any mod comes the potential for premature failure. Moreover, if a multi-mod car does fail at a given mileage, who is to say that it was the result of any specific component change, or if it would have failed without any modding at all.

I would suggest that any power increase from stock and originally designed longevity are inversely proportional. So, the more fun you want, the sooner you get to rebuild/replace. If one dances, one has to pay.

 

replacing a SC is considerably cheaper than a engine

 

i wont lie that i am one that's on the fence abut the crank pulley, but since i intend to keep my car for awhile....... i'd love to see more longevity about it..

there's more and more documentation about the supercharger pullies than the crank pulley at this stage of tuning... while i knw what you are saying, especially when the 19% pulley first came out, BUT, isn't there someone here who posted that a 15% pulley you aint pusing too far beyond the stock supercharger's capability? isn't JCW using a 14.8 pulley as well?

the reason i got the 15 is because jcw is running similar size pulley, so i assume it was safe, yet there has NOT been any significant long term tests about the loss of the dampener to the longevity of the engine.... i'd love to hear when minipilo comes out with their dampened pulley... because that'd offer the best of both worlds...

im not slamming m7 nor alta for making their's without a dampener... just some of us are not as risk taking as others (and i find it amazing im saying this!)

 

I hear what you're saying. And you know there's gonna be a difference of opinion on this one for quite a while given there may soon be two different designs on the market. Personally I can't see the harmonic being a real critical design issue on these engines. But that's just my engineering/design edumacated opinion. So, don't hold me monetarily responsible for it. Bottom line is that each has to weigh the risk with the benefit.

 

Are we talking about under or overdrive crank pullies? I thought they were underdrive. Check out Steve Dinan's comments on the Dinan Website. Also check out Randy Webb's FAQ on the Webb motorsports website regarding SC pullies that are greater than 15% reduction.

 

Randy just posted that he is going to post some "findings" on the crank pulley soon.