Here is a description and picture of how the whipple works (they have a patent on the design btw, which is why they tend to be more expensive than your generic roots supercharger). Also, like I said, there is a fundamental difference in the way they move/compress the air.

http://www.whipplesuperchargers.com/....asp?PageID=67

Here is a blown apart pic of a roots supercharger, you can also see that a twin screw moves the air back while the roots makes a 90* turn.

http://www.allenengine.com/header5.html

 

I always thought that the LSA was the determinate if boost was lost. The Zo6 cam has a 117.5 lsa. I have not seen any FI guys use below a 114. I am sure there are other factors that play in that too.

Stupidfast - I agree that for an ATI a big cam and stall is best. Why would the same not be good for a whipple or radix? Going back to the basics, don't you want to have more air flow. Hence the large cam. And a large stall to get these heavy trucks out of the hole? Of course there is a limit, but where?

 

I have recently learned that the LS6 cam bleeds off boost at the top of the RPM range.

For a boosted application I would go with the GT1 cam from Lingenfelter. I have heard from a very reliable sorce that this is the cam for a blower set up. This is what I plan too use also.

 

I have the 2002 LS6 cam and it doesn't seem to have increased the power much if any. If it bleeds boost off it doesn't show on the gauge. My Whipple makes instant full boost at the hit of the throttle and holds it until I let off. The only difference I noticed after the cam is that now I have to spin it to 6300 to run the same numbers as the stock cam ran at 5800.

 

A larger stall would not be good in a Radix or Whipple because you don't need it to get into the powerband that these blowers create. A larger cam would not be good in these blowers because of the powerband differences.
You need rpm in a NA motor for air flow. However, the point of a blower is not counting on the motor to draw air in. You are forcing it in.

 

stupidfast i have a rather large can in my 4.8 litter. It along with my radix makes great power. with the larger cami have noticed that it just help to spin everything faster and make nore power

 

Hey Blown, what kind of gains (hp and tq) do you think you will see over the stock cam with the GT1?

 

I had a 2600 stall in my blown 4x4. It was awsome, but I wanted a 3000. I could tell a huge difference in the stall over stock. I will be putting a 3000 stall in my truck now for the blower.

Just because these blowers make boost off idle, doesn't mean they make more power at 2000 rpms than they do at 5000 rpms. You still have the characteristics of the cam to play along. Even with the stock cam in mine, I could feel it come alive at about 2400-2600.

 

like flyer said, a larger stall with a whipple/radix isn't absolutely needed like it is with an ati but still makes a ton of diference. i can think of no set up that wouldn't benifit ALOT from a yank3000stall unless the slight loss in driviability is going to bother you.

also the comment about a larger cam not helping, larger than what? i am prety sure a stock cam is not the ideal cam for a whipple set up, yes it works well but there hasn't been enuff testing to show what is the best set up. i have a hard time seeing why a cam with 540(vs 500 or whatever stock is) lift wouldn't help a litttle.

that kind of sucks, i always thought that the 02ls6 cam would be a sure thing for a whipple/radix, mild cam with alot or lobe seperation. i wouldnt expect to see the boost drop because of it bleading off but rather drop off because more of the air is geting into the motor rather than backing up in the intake. even if there wasn't a hp increase as long as you made the same hp but just a little higher in the rpm's it seems like it would have helped your ET. the longer you can stay in 1st the better even to the point of staying well past your torque peek as long as springs and rods can take it.

this kind of relates to the conversation, when seting up you shift points you dont try and center your time in each gear around the torque curve, it doesn't work like that, you have to take the torque at a certain rpm and multipy it times the gear ratio of your current gear. to decide when to shift you have to look at what those numbers are before and after the shift, they should be close to the same. since your 2nd gear is alot less of a multiplier you end up shifting well after the torque curve starts to fall.

 

I had always thought that a higher stall might take a twin screw out of its powerband. Also, great info on LS6 cam w/sc.

THIS THREAD RULES