TonyB,
Brings up another good point about belt wear. This is a problem with the 19% guys and the larger crank pulley with the 17% pulley will definitely save some belts.

GClemons,
The 3% isn't a part we plan on making.....yet. We are going to do the 2% for sure, but the 3% will be dictated by the end customer. If you are interested in one, we can calk you up as the first one interested. You say you wanted the 3% because the JCW 14.X pulley. I belive the JCW pulley is much closer to 15% than 14%. I have had a couple people measure them and i remember calculating them to be 14.8%. I belive it may actually be 15%, and that there may have been some varience in the way it was measured. I could be wrong.

namwob,
We have discussed the Harmonic Balancer thing a few times and how it doens't really matter. Yes the stock one is a big hunk of rubber, and ours is solid. But the SC/accessory belts will dampen much of the vaibrations that could cause problems. Key word to that sentence is COULD cause problems. These vibrations that COULD cause problems have shown virtually zero negative effects on this engine and many others. The whole vibration dampener is sort of a thing of past.

Remember the 3% pulley is up to the NAM crowd if they want it to happen. IF there are any interests at all let us know and we will make it happen.

 

I left you a PM on this. I am interested in the 3%, so I guess that makes me #1. Sounds like it could be a nice complement to the JCW.

 

The 3% is a go! We will be making a limited number of 3% pulleys with the next batch. We will be taking names for people interested in them. These will clear the belts and pulleys just fine, they will be constructed the same as the existing parts, and anodized a dark grey color.

This is in an attempt to find out what size pulley the NAM community will purchase. If in the end both proove to be desired, then so be it, we will make both. This of course will lead us to the people wanting a 4% bigger pulley! We may just have to make some of all of them!

 

Any other side effects to using a 2% or 3% reduction crank pulley? Alternator effects, if any? I'm guessing water pump speed will be increased slightly. Any other effects, besides boost increase of course? I'm trying to think of any downsides but there don't seem to be any.

Sounds like a 3% might be interesting for a JCW like mine. I may be in too.

How's the installation on these suckers?

 

It would seem that a 4% pulley would be a goood option for people like me looking to go from 15% to 19% without having belt worries. If you do a 4% count me in.

 

OK... If you already have the Alta 15% SC pulley installed, I assume the primary benefit to using the 2-3% crank pulley versus changing to a 17% SC pulley on the existing Alta spindle would be 1.) the decreased weight of the new crank pulley and 2.) replacing the crank pulley is easier than changing SC pulley sizes on the Alta spindle(?)

D.

 

I already have the Alta 15% installed. I want to go the 19% / GIAC / Injector route. I think that ending up with a 19% effective reduction with the larger crank pulley is more effective from the point of better pulley engagement on the 15% pulley vs. the 19%. I'm concerned with belt slipage / durability. As I already have the Slip on pulley the dificulty of swaping either pulley isn't an issue.
In a nutshell. I want to ge to a 19% speed increase without losing any more contact area on the pulley or making the belt have to go around any tighter of a radius. A larger crank pulley will acomplish this for my application. The cost of the either pulley is in the same ballpark but the larger crank pulley should give better long term durability. The reduction in weight is a bonus that I feel more than makes up for the price difference alone.
17% or 18% doesnt work for me as I want to use an existing software program designed for a 19% reduction.

 

Harmonic damper, or vibration dampers are needed on cars.
All cars have them if they were not needed they wouldn’t be there.
Please see this brief write up from Dinan.

http://dinancars.com/whitepapersFile.asp?ID=5

By the way I do like Alta products, I have an Alta 15% pulley and Alta CAI.

 

This topic has been discussed to death. This thread is not about the pros and cons of the harmonic dampener. It is about a vendor trying to get feedback from potential customers. If you don’t believe in, or don’t wish to use this product, that of course is your choice and you can show the vendor this by not buying it, or post your thoughts in the appropriate thread.

I do mean this in the kindest way. :smile:

Dave

 

Has anyone with a overdrive crank pulley (any brand) dyno'd the results yet?

Spinning the accessories (AC, Alternator, Water Pump) faster will result in more parasitic drag - will it be significant?

Will there be a measureable loss of longevity in the accessories?

What about possible cavitation issues with the water pump spinning faster?

 

SCA,
The only side effect of increasing the crank pulley size is the alternator will be spinning faster. But only by 2-4%, which isn't much. The water pump will spin the same if you did a 15%+2% crank pulley, or a 17% pulley. The best way to think about it is, "What RPM is the SC going to be spinning at a given crank RPM".

Installation is pretty simple, just need the $50 mini tools.

GoodOLDan,
You are correct, the benifits are the lighter rotational weight, and the ease of replacing it.

dccummings,
You are hitting on one of the main benifits, belt slippage, or wear. This is a known issue with the 19% pulley, and the 3-4% crank pulley with the 15% SC pulley is a great option in keeping the belt life high, and from keeping it from slipping.

matma92ser,
D1JL can offer some insight to that. He has done some of our testing and found that with a 2% CP 15% SCP it gives the same boost as a 17% SCP. I belive he has done some dyno runs with them and seen some pretty good gains. I will leave that to him to post any results, since it was their hard work.

As for the parasitic losses, the alternator is the only thing that will be spinning faster if you compare the 2%CP/15%SCP, to a 17%SCP. The water pump is attached to the SC and the RPM of the SC is the same (comparing at 17%) so the risk of cavitaion and drag won't be any different.

The alternator pulley may be something we make but it will be down the road. The problem is the installation, it is somewhat time consuming, and the gains may not be that different.

The AC doens't matter unless it is turned on. The idler pulley around the AC pump has very little mass, and will not effect HP much if any. If the pump is on, it will but when your racing around your AC should be off.

 

Jeff, any experience with the '05 JCW ecu programming that would suggest that moving to a '19% solution' might actually take better advantage of the rich a/f curves of the program?

 

No, but one of our local dealers is a GIAC tuner and will be doing some tuning soon. Also Unichip has a plug and play piggyback ECU that seems to be working very well for people. This might be an option also, just not sure if they have done a car with a 19% pulley.

But using the stock ECU on a 19% pulley may be a risk. The ONLY way to verify this is safe is using a wide band O2 sensor, and checking the AFRs under boost. I would assume there is plenty of fuel there to make it safe, but if the ECU 1)adds too much fuel and causes misfires, that would be bad.
2)doesn't add enough fuel and cause a lean condition, that would be bad also.
The other concern is the charge air temps with the 19% pulley. This is where our Larger TMIC comes into play and also adds a large saftey margin to the higher boost and higher charge temps.

 

Jeff,
Will you have an example and/or sample to look at for the Tech day at Rasmussen this Sunday? Has Unichip done any programs for the 17% pulley? How about a How-To demo for the Tech day? See you Sunday.
Dan

 

Unichip hasn't built a program just yet, but I have one here I have built for a 19% - SpiderX is using it.

I have a 2% on my car right now, and am evaluating it.

Randy

 

Randy,
I am glad to see you got it installed, please let us know your findings, i would love to hear how it makes your car feel with the lightened flywheel feel. Also what do you think about the size? 2%,3%,4%????? The other thing i would like to know is what you think about the install of the alternator pulley and if it is for the average installer.

sanddan,
Aaaaahhhh, i think someone at Rasmussen forgot to call us????

 

Jeff,

Check out the PDX Mini club web site. This is a joint BMW/MINI tech session, with both BMW and MINI race cars ion display. Hope to see you there.
Dan

 

The alternator pulley can be installed on the car by the average auto mechanic with the correct tools. These tools include a chain wrench, 3/8 drive air impact wrench, 22mm or 7/8 ball type 3/8 drive impact socket, and 6 in. extension. Oh, and an extra pair of hands.

Dave

 

Well sure if it is a little bigger you will get more boost… if that is what you are after that is one thing… but it is also not of little concern if you have any kind of built in dampening in the stock crank pulley.

They make them heavy and put the rubber in them for good reason. You can fail your crankshaft and lose your entire motor if the harmonics are off at all… so while they may be making great claims, there is plenty of risk.

Does anyone have any thoughts or comment on that? Any failures or high stress tests?

 

Take some time reading this thread:

http://www.northamericanmotoring.co...ead.php?t=35290

It covers more or less all the issues.

 

someone like me is quite worried... i intend to keep this car.. and i already got a 15%

pilo racing's own crank pulley is said to have vib dampener... but its a bit heavier than the alta unit...

 

Dead thread.... rather, it doesn't open. :-)

 

right now i running the alta 19% and the unorthodoxracing light weight crank pulley.

and right now at 6000 rpms my check engine light goes on... dont be scared all this means is that im boosting over 18 PSI... the factory sensor only goes up to 18 so any higher it will turn on the check engine light because it doesnt know whats going on... and i have to turn on and off the car 3 times to make it go away.. my guess is that if at 6000 im boosting past 18 PSI i should be very close to 18.5+ at red line... which i never take my car to...

what im trying to get to is.. that by simply slowerin the wieght of the crank pulley you will boost more because of less rotatory mass.. so a 2% larger pullay my actualy work like a 3%...

i would think with the 2% larger pulley and the 17% reduction pullay the car should boost just about 18PSI or more and thats very high... if you are an everyday driver like me and does rev up is cool but if you are rev happy... your car might take some damage...

my set up runs sweet but i only take it pass 5000 rpms once in a blue moon... but let me tell you it the SC screams like hell when i do and well my car just goes forward kinda fast...

one thing the 2% larger pulley will do is more torque at lower rpms ... more took good thing!!

good job ALTA... this are just might thoughts....

Carlos

 

I'm a little nervous with respect to those who maintain that the harmonic balancer doesn’t matter at all on our engine… that’s what "they" said on the Miata’s until motors started grenading constantly when people had the aftermarket pulley’s on them.

My race engine building book says not to remove them; it says in the book that overriding/removing the harmonic balancer will result in engine failure “just as surely as repeatedly going 2000 rpm’s past the redline”

 

Oops! Try this link: https://www.northamericanmotoring.co...t=tritec+crank