19% Alta pulley in feb according to an email from them yesterday. An improved air to air from alta is coming as well...

 

>>19% Alta pulley in feb according to an email from them yesterday. An improved air to air from alta is coming as well... :smile:

 

I've been making the P&D pulleys for over a year now, starting with the shrink fit 15%, a 10%, then 17% and 19%...several hundred so far. I machine them personally and use them on my own car. (The lathe is an Okuma L370, for you tool-heads)

Here is the most recent status:

1: P&D high strength steel hub, heat shrink fit. Originally supplied with an aluminum 15% pulley. Once the hub has been fitted, other pulley sizes can be re-fitted by a simple bolt-on, a much simpler procedure. So far, 15%, 17% and 19% aluminum pulleys have been made and will interchange on any P&D shrink-fit hub.

2: P&D taper fit hub from high strength steel with interchangeable pulleys; so far we have made 15%, 17%, 19% and 22%. Any P&D taper fit pulley will interchange at any point with a bolt-on procedure. These are self aligning and designed for ease of install; no heat, no chance of not getting it on the shaft right.

In my opinion, there is no other grip as tight as the shrink fit. Done properly, it is bullet proof and there are hundreds in use with no reported issues (with the obvious exception of Randy's reported case). On the other hand, there does exist the chance for an install problem, plus you do need a heat source.

The taper fit design is found in common industrial drive pulleys (Browning and Morse, for example). It is not found in such a petite application, however. Alta produced a 15% one for the Mini and it has worked perfectly.
P&D now has produced a taper fit as well and did a torque breakaway test: 160ft-lbs would produce slip, and that seems to be sufficient holding power. (Haven't yet tested the shrink fit hub for comparison).

 

>>Yeah MartyR, I agree! everybody gets something out of the deal Helix could post the results on the their WEB page. I'll be waiting and want to see those results. .......... norm

Norm,

I'm moving out your way (IIRC you're in/near Ellicott City...?) - will be in Catonsville by the end of January in my first house (!). By then things will have settled down enough to do the 19% but I don't know if I can manage the $$$ before then. I'd like to do it earlier, though, to get the dyno info out to the hungry masses. You up for a trip to Philly? heh heh heh

M

 

No Alta list prices quoted sorry. :???:

 

>>Ask someone who has done many pulley installs of both the bolt-on and interference fit design. Randy at webbmotorsports.com will provide great insight as well as the helix guys. It seems like the bolt on design is most used, at least at the Detroit Pulley party I believe that was all taht was used (I was only there one day).
>>
>>I had the 15% Alta done by Randy, it is a tremendous improvement. It is about the same as what is done on the JCW kit from what I have read. There have been some interesting threads on the 17% and 19%, questioning how that will affect the water pump cooling and the RPM capability of the supercharger itself?!?!? I am NO expert.
>>
>>If you can have the pulley changed at a 'pulley party', it is great fun, and well worth the $ to have it installed. Not to mention getting talked into additional modifications that you don't need, but absolutely want....
>>
>>Cheers

Randy talked you into "additional modifications"????
I thought it was just me who was gullible

 

>>Amen to that. I have the 19% pulley and know that RDR is working on a more effective air to air intercooler for around $500. If it's good, that sounds good to me!

I was leaning towards a 15% and software, but if a $500 intercooler becomes available, I may go with the 19% and intercooler. I hope it works out!

 

I'm definately getting the 19%, and when RDR has an affordable intercooler, I'll put that in next summer. I also hear that RDR/Helix is putting together an improved carbon fiber intake. Sign me up for the first one.