Thanks for the suggestion I'll give them a shout.You'd probably find better answers over on Yellow Bullet. Good luck with it.
Boy this must be the most closely guarded industry secret of all time, I can't find a single piece of information on this anywhere. Calling whipple got me their support email and just no reply lol wtf
I can't say about the Whipples specifically. If the Whipples are like PSI screw blowers, which are similar to 71-series Roots blowers, you can't adjust the gear lash because the center-to-center distance is fixed.
The gear teeth are helical. Installing shims behind one gear or facing the back side of one gear will advance or retard one rotor in relation to the other. This is so the rotors interlock together properly and don't hit each other.
I'm not saying that it is beyond my capabilities, or yours, i chose to have Littlefield Blowers do my 71-series because I wanted it to be the best it could be and I didn't want to risk a first-timer's mistake on a complex and expensive setup that would destroy an expensive engine.
There is a service manual, from GMC, that describes how to set each clearance and what they should be. Maybe you could find just such a manual for your application.
I definitely would not just set it in the middle and let it rip.
As far as Whipple's customer service, if I am correct, clearancing your blower is more complex a procedure than a simple phone call or casual email can describe.
I’ve had good support from Whipple
did u email a general email box or someone specific?
I know they don't sell Whipples but I'm sure a few guys at VMP Performance can answer your question. See if you can get Joe on the phone.
So I recently found an interesting youtube video in which a guy does pretty much exactly this. I learned a good bit just from watching that video like how potentially measuring the rotor gap with a feeler gauge and adjusting via shims like you mentioned. I've actually already fully rebuilt a 2.9 before by just setting it in the center and didn't have any disaster but I also agree there is probably a more specific number I should be shooting for.
Unfortunately no idea what specification I should be aiming for since whipple hasn't responded to my support ticket in any form. A simple "you want .008 between the rotors" would be a pretty easy and doable reply, or actually any reply would have been cool.
Anyway I found a book on this I ordered off of amazon the other day hopefully I can find some more information here and apply it. There seems to be some "rules of thumb" out there for blowers, its not like whipple is the first and only person to ever build them, but who knows what sort of special coating or design they added.
But yeah, thanks for taking the time to add your thoughts! So far you are the first human who has been able to add to this conversation in the last week of searching on every social media/forum/internet platform I could find LOL
Oh here is the youtube video if anyone is curious.
I know they don't sell Whipples but I'm sure a few guys at VMP Performance can answer your question. See if you can get Joe on the phone.
Thank you
Please post the link to the book you found.
I will reply later with some more information from personal conversations with the guys and Mrs Littlefield at Littlefield Blowers. It's not as easy as just saying, Set it at .XXX clearance.
I haven't gotten the book yet but the guy in the video mentioned getting clearance info from SA book so I think this is it
https://www.amazon.com/gp/aw/d/1613251319?ref=ppx_pt2_mob_b_prod_image
That's an 'okay' book. There is a short section on Gene Mooningham setting up a 4-71. Basically, it's an overview of supercharging. I have yet to see a book with any real meat and potatoes.
Corky Bell's Supercharged! Design, Testing and Installation of Supercharger Systems has the most extensive calculations I've seen yet. Been trying to work through and proof out the formula.
https://www.amazon.com/Supercharged-Testing-Installation-Supercharger-Systems/dp/0837601681
I'm always looking for something that contains the next piece of the puzzle of the answer to the universe.
Try/Google Jon Bond performance. I once had a question on low vacuum bypass valve and called him directly. He was easy to reach/contact and he rebuilds these i believe and might just be the unicorn your looking for
Hard anodizing the case and rotors will help to tighten up the clearance. We constantly see .001" buildup on every surface, .002" on the diameter. You would need to compensate for this where applicable.
I'm curious to try https://www.line2linecoatings.com/, but I didn't want to experiment with my life's savings this go around. At least, Littlefield didn't even want to entertain the idea. I will discuss line2line coating with Brian Moreland of CP Pistons when I get to that stage of my rebuild.
can't you measure total clearance and then just set it at close to zero on the drive side and call it good? Put all of the slack on the back side.
the rotors on my TVS touch each other - just the coating, though, that's meant to wear to fit.