What is going to give more hp on a 05 JCW MCS

1. 16% S/C pulley
or
2. 3% lightened crank pulley

Would it be roughly the same?

Thanks
D-MAN

(yes I have done a search and couldn't find anything! )

 

#1. 16% S/C pulley

3% lightened crank pulley < nope!

 

Pulley without a doubt. (don't know the numbers though...)

 

The common rule of thumb was that a pulley , 15% would give ABOUT 15 lb torque and 15 hp over stock. These are a real generalization and everyones results will vary but at least you know what ball park you are playing in. You would most likely feel a more rapid throttle responce do to the lightened crank pully than any real horse power gain but there should be an aditional few hp to be gained there as well.

Randy
M7 Tuning

 

Would...

JCW pulley + 3% or 4% light weight crank pulley = approximately equivalent to a 15% pulley

or am I way off mark?

 

Wouldn't that combo roughly ne the same as a 19% ?

 

I dont agrre with your stateent re:crank pulley gains.

How wouldn't increasing the diameter of the crank have a similar gain as decreasing the diameter of the sc pulley...

End result is - you are still increasing the sc rpm...

 

Oh yeah - gotta be 2HP there at least...

 

They fooled you didn't they Rick.

Yes, you should see approx. the same SC speed increase with either pulley or crank. One drawback to the crank pulley is you will be spinning the a/c and alt faster also. Thus the same hp increae potential.

 

You must be assuming JCW pulley is 14-15%, but if as many have reported, it's only 11% then it should be about same as 15% pulley.

One thing to consider is the cost: replacing the JCW pulley vs. replacing crank pulley.
On the other hand, another factor, and negative for the crank pulley, is the loss of vibration dampening -- many have said it's not an issue, others feel uncomofortable giving it up 'cause potential damage wouldn't show up right away . . . but you can find a lot of info on crank pulleys with search

 

SC Pulley will give you probably 5 HP , crank pulley will give you 2-3. Lightened means nothing, the power comes from the fact that it spins the SC faster. With a JCW, putting a pulley on is a waste of money. Save up and get a head and a tune.

Many people say that the lack of harmonic dampening with a crank pulley can cause engine balance issues. After spending close to 30k on various mods and parts over the years on my car I wouldn't touch one of those with a 10 foot pole.

 

Please re read it again . I said the crank pulley will add a bit more hp, not as much as the SC pulley. It would not be similiar as the 15% is a much bigger change than the 3%.

Randy
M7 Tuning

 

This has be gone over at nauseum, there has never been any info. that has proven aftermarket crank pullies cause any problems. In fact I just talked with someone who has 90k with both a 16 and 2% pullies installed. Still with stock SC and pistons.

 

Gday

Can you help me then... I have a 3% larger crank pulley, and i was under the impression it'd perform like a 17% SC pulley...

What do i really have running?

Would there be any issue with running a 15% in conjunction with my 3%larger crank pulley? What would i then be running in theory?

What would the ideal set up include (pulley wise) in my case? Mods listed in sig...

Thanks

 

This crank pulley confusion must be an Aussie thing....

 

Piggy bank is full - head has been ordered and custom tune lined up....

I just want to get every last bit of hp out of the engine

I will try and get a dyno before and after each mod so I know if it was a waste of time or not!

 

So i'm really not getting that 20hp i thought i was getting?

 

Auscoops, I think it's more like your 3% crank pulley would be equal to a 3% sc pully. Like for instance, i have a 15% sc pulley on my car. I'm going to be installing a 2% crank pulley soon. That combination of sc pulley and crank pulley will be like installing a 17% sc pulley.

why not just install a 17% sc pulley instead? B/c the chances of a belt slipping off of a 15% sc pulley are less than having a 17%

(if you thought installing a 3% crank pulley gave you 20hp, you are going to sh*t yourself when you put on the 15% )

 

don't be so sure of that Jim

 

However much it has been gone over, there's no point, it doesn't make any power so it's a waste of money to begin with. It offers absolutely no performance benefit (We've tested them). The 05+ crank pulley is lighter, and accomplishes the same thing, without increasing the likelihood of it spinning off the crank and careening across the engine bay.

I happen to know at least 3 people who have gone through engines and spent thousands repairing damage caused by a crank pulley, so it can be argued both ways. What do you think they gained with a 2% pulley on top of a 15%, Considering the intake temps shoot up about 25-30 degrees with a 17%, and 40-50 with a 19%, do you really think you're actually accomplishing anything?

Tangent: Pistons and SC are fine? Nobody ever said anything about pistons or SC having issues if you use an aftermarket crank pulley. If your pistons have issues after putting a lightened crank on, uhh not sure what to tell you, the two have nothing to do with one another.

 

First off, the OP has a JCW, which already has a reduction pulley, so no, he's probably not going to notice that much of a difference (I barely noticed a pulley on my car and I had a stock MINI at the time, but the whole thinking a MINI with a pulley is fast thing is a whole different arguement )

Second off, if you use the right belt size, there's little chance of the belt slipping off. The risk in using a higher % reduction has to do with water pump cavitation at high RPM's, and IAT's going through the roof much past a 15% reduction. There's a reason JCW picked 11% instead of 19%.

What's more beneficial to running a car fast, hard, and long, another 1.5 psi of boost? Or intake temps that aren't pegged at 220 down the track's main straight?

 

Here is some actual proof . Keep in mind this thread is over 2 years old with over 3400 views. If there was a REAL issue more that two people would have heard about it

https://www.northamericanmotoring.co...t+crank+pulley

 

Yes, because a sample of 2500 driving miles is sufficient to test whether harmonic vibrations will shorten engine life over the life of the car (Not to mention there STILL isn't any proof that there's actually a point, a crank pulley that weighs 1.2 lbs less than stock isn't going to give you any power).

There were a handful of people on that list with over 10k miles driven. That's like saying not changing your oil is fine because you drove 26k miles and haven't had any problems. Yea, great, but what happens at 29k miles when you spin a bearing?

 

Call Jan and talk to him then. He's probably built up 50-60 cars that make 230+ wHP over the years. I guarantee you he didn't tell any of them to put a freakin crank pulley on their car.

Nobody in our little group that goes to the track uses that crap...

 

If you had bothered to read some of the posts rather than just scan the grid you would have seen many testimonials to much more than 2500 miles . These are all from the thread I referred to and some of the odometer readings are over 2 years old . I am sure they may have added a few miles more as well and would have posted if they had a problem. I have also included a very well thought out post by Alta with regards to this rumor .

I should have said above as well as my Batman comment, that we have had ZERO reports of any issues from around the world. Several thousand crank pulleys sold, so if there were an issue I SWEAR we would have seen it. I trust it enough to put it on my GP (haven't made time to do it, but will ASAP!)

I skimmed the MINI2 thread above. I am skeptical that the cars reported to have failed, can be directly linked to the crank pulley as RMW seems to have implied. (I like Jan so no poke there.) I would suspect other factors caused those failures. My point is again, there are thousands of ALTA versions and who knows how many other mfr's of similar design, that if this was an issue we ALL would have heard about it long ago.

Just my two cents.

Adam T. adam@altaminiperformance.com
[FONT=Arial][SIZE=2]
[/SIZE][/FONT]103,000 miles, still track and autox. Crank pulley on for 80,000. Original supercharger.

Steve

The 16+2 combo has been great so far for 12k

A 15%+2%, Lots of street mile, and lots of track miles. not a problem.

Chad
Detroit Tuned

Both the Alta -15% and +2% pulleys, 22K miles, no problems.

A blast from the past. I still have my 3% crank pulley. You and I have almost the same mods, but I do not put too many miles in mine, do not have to, but would like to. I am at 37K in a 2003 MCS. Crazy. Not problems at all with my inspired driving.

15% supercharger pulley Alta
2% crank pulley Alta

15500 miles
M7 16%
M7 2%

28,000 miles

.M7 16% and Alta 2% no problems at 7500 miles. Did the conversion at 2200 miles. Also have an Alta 0% crank pulley available for sale 300 miles on

Alta 15% SC Pulley 45,000 miles
Alta 0% Crank Pulley 25,00 miles
Moved up to:
Alta 2% Crank Pulley 10,000 Miles

Track and Street, no problems and no Alt. Pulley.
Alta 15% 9000 miles and Alta 2% 5500 miles no problems what so ever.

15% Alta supercharger pulley: about 20,000 miles, ZERO problems

2% Alta Crank Pulley: about 9000 miles, again, ZERO problems

Alta 2% crank (15,000 miles) with Madness 15% SC (70,000) . . . perfecto

Alta 15% SC pulley - 40,000 miles - no problems
Alta 4% crank pulley - 15,000 miles - no problems
Alta, 2% (with 15%) 4000 miles, ZD. (Zero Defects)

Alta 0% with 19% pulley. 4000 miles, no problems.

04 MCS
SC: Alta 15%
CP: Alta 2%
Milage: 9k
Problems: zero
M7 16%
M7 2% crank


I have had mine on for at least 10K with no problems 0% w 19%
Alta 15% pulley (56,000 miles) no problems - now 88,000 miles

m7 2% crank pulley (9,000 miles) no problems - now 32,000 miles