Power loss question

[Hemi345]

How much power can I expect to lose by going back with stock heads on my supercharged build from my cnc ported big valve heads? I have cnc ported heads on there now with 2.055IN and 1.60EX, that I may have to sell unfortunetly, How much would I need to turn the boost up to make up for the loss since I have all forged internals?

[Darell]

How much power can I expect to lose by going back with stock heads on my supercharged build from my cnc ported big valve heads? I have cnc ported heads on there now with 2.055IN and 1.60EX, that I may have to sell unfortunetly, How much would I need to turn the boost up to make up for the loss since I have all forged internals?

Putting on stock heads will increase your boost on it's own and may require more timing to be pulled / better fuel. (boost = airflow restriction)

[Hemi345]

Hmmmm I dont like the word restriction

[Darell]

Hmmmm I dont like the word restriction

For example: When I switched engines/heads I was making much more power at 3.5 psi than the stock engine/heads was at 9 psi. You won't be to this extreme though keeping your same engine displacement, but I would expect your boost to be a few #'s higher after the stock heads are put back on.

[sldhemi]

Hmmmm I dont like the word restriction

boost is technically restriction, its the pressure of air in the intake manifold... you can make the same hp, it'll just take a little more boost to do it...

on the other hand, the benefit of running smaller valves is that you can get away with less seat pressure on the valve springs. so you wont have to go balls out with the springs

[Hemi345]

stock 5.7 springs ok? or should at minimum upgrade to 6.1s?

[sldhemi]

i wouldnt use 5.7 springs... not sure about the 6.1 springs because i dont know any of the info on them... this is another part that will be determined by how much boost you plan to run

[coley 1334]

how much u gonna sell ur BV heads for?

[Hemi345]

They are listed in the for sale section I sent you a PM as well, Im not sure how much boost I will eventually run But its safe to say for now its gonna be 6-8PSI Nobody makes a smaller pulley for the blower Its gonna have to be custom made.

[sldhemi]

They are listed in the for sale section I sent you a PM as well, Im not sure how much boost I will eventually run But its safe to say for now its gonna be 6-8PSI Nobody makes a smaller pulley for the blower Its gonna have to be custom made.

if your going with a forged bottom end i would go with more boost... around 12-14lbs... a machine shop can cut you a pulley, it wouldnt be that hard to get a hold of one...

whats the size of the stock valves? 2.00 and 1.55?

[Hemi345]

if your going with a forged bottom end i would go with more boost... around 12-14lbs... a machine shop can cut you a pulley, it wouldnt be that hard to get a hold of one...

whats the size of the stock valves? 2.00 and 1.55?

Not sure I already have the engine built Its forged I have been waiting to put the rest together. I would like to go 12-14 PSI wonder what size pulley it would take for that beings the one now is 4"

[418BEE]

What size engine and blower??

[Hemi345]

What size engine and blower??

5.7 engine and paxton 1200

[418BEE]

Well I'd imagine you could compensate cylinder head loss with more psi.
any idea what rpm the blower is rated for?

[Hemi345]

PN Description Max RPM Max PSI Max CFM Max HP Price
1016119 NOVI-1200 / Straight 52000 22 1150 775 $2011.95

[418BEE]

paxton should be able to set you up with a pulley.. or not?