03 Cobra Lower Pulley help

[UrHookUp]

My question, Which is best to use? I have option to use 2# or 4# lower. Here is a list of what I have:

Heavy Duty CNC Machined Aluminum Relocation Bracket
CNC machined billet aluminum aux. idler pulley
(3) 100mm Idler Pullies
(1)90mm Idler Pulley

Kit Includes

- LFP QC Upper Pulley Kit
- LFP QC Upper Auxiliary Idler Package
- LFP QC Lower Crank Pulley Kit
- Your Choice of a 2#,4#,6#,or 8# Pulley Ring
- 14mm Hex Head Tool
- Allen Bolt Hardware
- Proper Sized Alternator Pulley

I'm already at 15-17psi

What do you all think? which lower should I go with?

 

[thomas91169]

whats your upper pulley size?

id do a 4lb lower, and port that summabitch to be able to flow that much air that you are requesting.

 

[Uncle Meat]

I'm assuming this is on the stock Eaton? Are you ported? 16PSI is about the max as far as power/heat production are concerned.

U.M.

 

[UrHookUp]

oops, forgot to add that info. hehe
I have a 2.8 Upper
And a Stage IV Ported Eaton right now. But putting on a KB 2.6L after I get back from SEMA & the PRI Show in Dec.

 

[Tommy98016]

with a 2.8 upper I would go w/a 2lb lower, the 4lb is a little to much.

 

[UrHookUp]

k. that's what info I'm getting.

 

[Uncle Meat]

1st choice would be a 2.93 upper and 4lb lower because this is supposedly the "optimum" combo for a Stage IV ported Eaton (Max of 16.2PSI) and minimal belt slip with the 2.93 vs the 2.80.

U.M.

 

[grey03cobravert]

i had ported eaton with 2.75 upper 9.0 lower 6 lbs i had 20 psi dropped to 17 during the pull , i had 490 rwhp and 576 rwtq. but i took off the 9.0 lower and but stock lower back on , i was throwing belts due to the cheap moto blue brand i had. iam sure other name brand did not have this problem. iam going kb 2.6 in a few months , when my cars out of the body shop. with a 3.0 and i 9.0 pulley set up i had 17 psi dropped to 15psi only had 470 rwhp and tq was 511. with 576 tq at 3500 it blows the right right off. in 3 gears.

 

[UrHookUp]

Well, Since posting this. Things changed. I not have a KB 2.6L & a whipple 1140a. Just need to decide which one to use. I'm topping it off at 650 rwhp. don't have a use for any more. Just need to figure the pulley option for that.

 

[Uncle Meat]

Huh? You have two twin screws? Give me whichever one you don't use.

U.M.