punishmentcycle

iTrader: (6)

Nice numbers bro.. What cam is that?

When i did the swap i used the 3.4/3.2 as mentioned. I had to clearance the manifold just under the drive side pulley and mill the oblong holes to get the belt on. Did the same for the front to get the shaft back to square. Im all around over driven lol.
Im doing a twin pump set up now so i can get the car on the dyno and see what the 122's got. Im seeing close to 20lbs of boost and running outta fuel fast. Its deff a kick in the pants when the 3-4 shift gets you sideways going 80+

Becker

iTrader: (4)

how fast are you spinning that 122? 20lb's that gnarly for sure haha.....IAT's?

rand49er

^^^ Yeah that.

bmylez

iTrader: (3)

punishment, I'd like to see how you stack up against a full exhaust, pulley'd V2. That's a nasty setup.

ryridesmotox

I can't remember, but what headwork do you have done on the 243s punishmentcycle? That's spinning that thing up good if you have ported heads, the extra flow would lower the boost pressure a bit

2007V

iTrader: (2)

I did the math on swapping heads or doing a cnc port and it just isn't going to drop the boost much or pick up much power from flow. The real driver is displacement. Going to a bigger CC and dropping compression to allow more timing may get you some but that is hard to estimate. You're better off with a cam then heads.

My cam is a Brian tooley stage 3 blower cam. 20psi is going to be huge power, just the ratio of mine to yours 35psi/25psi x 560 puts you at 780 rwhp. If my boost was 12 then it's 35/27 x 560 is 725.

Naf

iTrader: (1)

If you were to port the heads, you will see a gain, for your heads become more efficient and you will have less boost for more air is being pumped into the cylinders rather than squeezed. think mcdonalds straw vs normal...

Also if you raise the supercharger by 1/4-1/2" you will also see gains with lower boost pressures. an example is http://www.speedinc.com/d3-lsa-super...id-spacer.html

The air isnt being sqeezed between the bottom of the sc and the inner cooler inside the sc...

rand49er

This thread is getting scarier and scarier.

Sssnake

As usual NAF is on point. If that spacer is made from a phenolic then you get the added benefit of less heat transfer and lower IATs.

rand49er

Ad says both 7.5 and 7.6 hp gains, not that I'm splitting hairs, mind you. But, if that's coming from lower IATs, then whether you "squeeze" the air or "pump" the air, what's the difference?

There's only one thing limiting air into the cylinders on any particular setup, and to say one thing is gonna give you more hp without knowing what is truly limiting that setup is pure speculation. Does porting help? I might. But, if the cam design is the limiting issue, then it won't help.

Sssnake

There is one thing in common in all of the popular roots style blowers I've seen. To keep them under hoodlines they are extremely challenged vertically. This has negative effects on the charge flow. Take a look at this thread for an example.

http://www.silveradoss.com/forums/to...-radix-spacer/

A little more than 7.5 hp. Now in general I agree with your premise that there is no one size fits all solution for anything. In this case the only real negative I see is in a road racing scenario. Because you wouldn't have a thermal path from the blower back to the block if you beat on it long enough the blower could get hotter than the block. In this case the phenolic spacer is actually hurting you. However, the clever use of meth on the front end can eliminate that issue.

GFallen

Got my retune set up for April, for the guys that already went 1:1 rears, I'm thinking of doing a OD crank and a 2.8 up top. How does this set up sound to you? Thanks

2007V

iTrader: (2)

GFallen, that sounds like the ideal setup. I have similar but a 2.7 front instead of 2.8. But a 2.8 might be preferred.

I'll look through the calcs I did but it summed at that better heads dropped maybe a psi of boost and that costs 2k for just the heads. To really drop boost you need to stroke it. Sure you'll pick up some power from the blower being a little more efficient at lower boost but it wasn't worth the money for me. I was pretty surprised after I calculated it.

Becker

iTrader: (4)

2007v has definitley done his homework, seen his caculations first hand at least some. Im honestly thinking of doing the 1:1 rears as well.. Starting at 2.8" front.. Currently running 2.6" front on m122

punishmentcycle

iTrader: (6)

I was gonna make a spacer between the manifold halves but got restless having the car down.. I was also gonna do a spacer between the blower and upper manifold.. The problem with both on our v's is the hood,Specially with the 122 or tvs swaps. Im sure i can make em work by cutting the hood or going to a dome but i dont hack my car so no cutting holes in the hood and no free money for the domed hood.
For a stock ls6/2 the farthest id push it would be 1:1 od crank and a 3.0. Or od rears ,stock crank and 2.8.
All my experience with 6 rib amd smaller than 2.8 has been slip prone and i tried everything(but thats my own experience)

Sssnake

Yep, same thing here. I keep hoping the other hood option is going to materialize...

raven154

iTrader: (14)

Ok so the pulleys came in today and I got to work. I got the old pulleys off and went to install the pulley on the jackshaft and it made it about 3/4 of the way on and just locked up. I tried to pull it off with a 3 jaw and that was a bad idea. Ended up having the pulley pressed off but now it's unusable after the 3 jaw experience. I expected to see the shaft galled up but it looked fine. I cleaned it up with some 600 anyway and greased the shaft again and went after it a second time and it went on no problem at all. So I'm not sure if it was me or the pulley but now I have to wait on another pulley. FML

go4lucas

275s all around? do you have pics of this? I went with 255s in the front because i read it would rub like crazy

2007V

iTrader: (2)

I have 265's all around.

You can use some heat on the pullies to help as well.

Becker

iTrader: (4)

Raven that sux, any pics? what kind of puller was being used, cheap? I hate cheap pullers they get me throwing ****, usually the puller.

go4lucas, search team dynamic wheel threads. 275's are achievable with these due to their offset.