CLOSED: NST TRD/ Magnuson 4.0 supercharger lightweight billet crank pulley | crank dampner

So quick question......in my case, we all know I have the 2.825. If doing this pulley gets me 2.7 flow of boost and no belt change or pulley wrap mod. How much doesn’t it increase you guys with the 2.3’a, 4’s, 5’s???

 

Will do!

Wait, I'm not sure I understand the question? How much DOES or DOESN'T increase us with the smaller pulleys?

 

(Supercharger crank / supercharger pulley) X max RPM = rotor speed.

So a 2.7 pulley with stock crank is
13,241.
Now say this pulley works out and we are .100 over stock it would be
(6.6/2.7)x5500 which comes out to
13,444 rpms.

Now in reality, with a stock SC crank pulley, the difference from a 2.85 to a 2.7 is 12,554 vs 13,241.

This is getting confusing so I am gonna make a table with calculations, but it is going to compare assuming we get a 6.6 crank pulley.

 

I guess I asked it wrong.....so if I remember correctly, I thought someone said I’d get the best out of this cuz I’m still at a 2.8. So....if your running a way smaller pulley doesn’t get you the reverse affect? Like your basically putting on a bigger top pulley?

 

The larger crank makes the supercharger’s RPMs higher (aka more boost, technically speaking more airflow).
It’s on average about 200 rpms more, on top of what ever pulley you are running.

Edit: fixed my graph. Messed up the 2.7 pulley entry

 

The supercharger crank pulley is not a 6.5 or 6.6 it is actually 6.81".

 

Interesting you say that because it’s only carb certified for a 6.5” crank pulley through TRD and Magnuson. I won’t tell anyone if you don’t

 

I think I remember reading that on the actual carb certification paperwork. Interesting ly enough it actually is bigger then what they state.

 

They must measure it somewhere else? Not sure where the extra .31” came from. Where did you pull the 6.81” measurement from? I always wondered how you are supposed to measure a pulley, I tried on my 3.0 and 2.8 and I never could figure out where to measure from to get those numbers.

 

You know what. I just thought the same thing. It is possible they are meseauring it at the ribs and not the OD of the entire pulley itself.

 

That must be it. Makes sense I guess. Either way that graph gives you a good estimate of what to expect. For every .1” of the crank pulley its like going down .05” on the supercharger pulley.

 

I have the pulley with me. I'll use a different method of measuring it at the ribs because they definitely step down in height after the wall. I'll update XPO, I'm glad we talked about this some more actually.

 

And centrifugal forces holding oil against walls.

 

I am also waiting on cost. Money is tight for the foreseeable future.

 

@Murphinator I am sooo proud of you!!!
You get it!

 

Not quite enough for me.

 

Don't do it Athlaos... don't.... don't type it.... damn it.... can't.... resist.... bragging....... Nooooo!!!

By my calculations it would give me the equivalent of a 1.84 pulley. Might not be noticeable but I can't go bigger now. Never, never go bigger!

Although I've been thinking about Snakebite all day. No joke.

 

Superman ain't got nothin' on you.

 

A question I have is there measurable gains to be had by mirror polishing the entire s/c airway? That sand casting has to impede flow demands. I have some ideas how to do it in a day for cheap. I might (will) do it.

 

What did snakebite cost? Too lazy to look.