blower set back

got a question about the amount of set back is needed
current set back 2.5" got room for aprox. 3" more
this is a pro mod
540 kb 600 olds
dart 360 heads ported nicely
bds intake match ported to heads
kobelco k9 w/mods 45lbs boost @8400 29.4 o/d
couple cyl. 1&4 running hotter than 2&3 back four cyl are fine.
changed front nozzles (larger on the hotter ones) around to balance the cyls that are hot. got them reasonable close.(roughly 75 degrees hotter on big end)of track
thought it would help by moving the blower back some more. just trying for some toughts on this
would this move the current hotter cyls more to the center of engine or possably balance the hotter cyls toward the rear
and would it make a little more power when all the cyl are more evenly by moving the blower back
just listening for a while and would like a more professional thought on this
thanks
dale

 

dale im sure moving the blower will change the temps but couldnt you go up a couple of numbers on the front two nozzles to bring the temps down even closer get mike c. to chime in on this buy moving the blower might just move the problem around changing the other holes just my thoughts

 

i have tryed enlarging the hot cyls. - (now) #1 =84 nozzle - #4 =68nozzle
the back cyls. are as little as #45 =nozzle . just seams a long way apart (IN NUMBER SIZE) from front to back (# 45- #84)
just thought by moving blower back .the heat would be more center and then start over with the nozzles
may be chasing my tail?
thanks jim
dale
thomaston ga

 

check my post of basically same question in this section 0n 12-31 09. Heading is set back blower vs gating intake. This will answer your question

 

couldnt find a post with that date

 

http://www.insidetopalcohol.com/showthread.php?t=28652

 

well thats pretty easy to understand so is the best place to put the blower opening is in the center of the manifold and how long of a snout do you need and how do you figure the size of the nozzles for the intake setting the blower seems the easiest to do but the nozzle sizes i would be lost

sorry dale its your thread but i would like to have more for this beater i got also

 

set-back blower

Guys, is there any reason to use set-back if not running a helix?(as in standard 14-71 style?) Just wondering. thanks, Les

 

MY thinking is that you figure out your totalport nozzle area before you do the set back. Once you move the blower back take that total nozzle area and divide by 8 for a starting point and put the same size in each port. Start the motor up to check egt and plugs at idle. If all looks ok then run it up to 5000 rpm and check egt and plugs again. I would think that would work. What do you think?

The topfuel guys set them back and they don't use helix rotors

 

I relate the setback to a front discharge blower vs the high helix (although the high helix may require a little more setback)

 

This is the way I do it also.

 

When we started back in the 90's the nozzles where very diferent when the high helix came out , the retro helped a little and the plates even more... last year we ran a new high helix and we instaled it at the maximun 15inch setback. nozzles where with 3-5 thousands from each other. If you dont have access to a dyno just make a couple of 330' and half tracks before letting all hang out .

 

Another option would be to take off the BDS and put on an Indy manifold. They make one that will make your port nozzles pretty equal but without a setback blower.