Anyone know how to compute CFM needed for 500 - 600 HP?

HighMileage · 09-26-2009, 04:58 PM

My throttle body is stock 48mm unit.

I want to upgrade to 52 or 58mm.

The 52mm has the attraction of not needed to pull manifold, redo all gaskets and fron of motor, and just a 20 min bolt on affair.

The 58 would need to pull manifold to bore openings to handle the 58mm opening.

More info for reference:

I have seen people making sick power (700+)with 3" blower inlet pipes.
A 3" inlet pipe has a surface area of 4560mm2
A 52mm throttle body has 4247mm2 (About 93% of a 3" pipe)
A 58mm throttle body has 5284mm2

TPIs rates the 52mm at 900CFM
58mm is 1000 - 1100 CFM

I believe the P1SC procharger head is rated to 1200 CFM

It seems the 52mm would be close to good enough, unless someone can confidently know how to bore the manifold with shop rags while on vehicle. The thought of a metal shaving going in the manifold seems dangerous....

REDC4CORVETTE · 09-30-2009, 07:40 AM

52 mm is way more than you will ever need.

USAsOnlyWay · 09-30-2009, 08:43 PM

Isn't that flow rated at 1.5"Hg if you are running a P1SC you will not be at 1.5"Hg... nowhere near it.

anesthes · 10-01-2009, 12:39 PM

Quote:

Originally Posted by USAsOnlyWay

Isn't that flow rated at 1.5"Hg if you are running a P1SC you will not be at 1.5"Hg... nowhere near it.

You don't want pressure drop either.

-- Joe

Mo_Bandy · 10-16-2009, 10:07 PM

If you are running your MAF I used to take the lbs per minute *14 to get CFM.... Then went on further to divide by 1.5 to get rough HP...

I agree if you aren't pulling any serious boost, go with the 52mm...

I opened up my manifold for a 58... NO take it off the car if you go with the 58mm you'll have metal EVERYWHERE!

Mo