Say on a 2 litre, 4 cylinder engine you had a plenum with a narrowest diameter of 56mm on the entry - and it couldn't be opened out any more...

At what power would it 'cap' at?

 

Slightly off topic but what is happening with your Escort Will? I haven't seen any updates for a while.

 

alot more than you think

 

You can only come up with an absolute figure if its before the turbo really, after the turbo its going to depend on the turbo itself.

 

It's going to be a bit of a restriction at 500bhp, you'd be better off with a 60mm one. You'd be seeing gas velocities in excess of 500ft/sec with the 56, and ideally you want to keep it 350 ish. It depends on so many things. Ultimately yes, you could do it, if you had a turbo big enough to push it through.

 

A 56mm throttle will give no relative restriction at 500bhp on a turbocharged 2.0litre engine. (I say relative as every component has some restriction, just that going larger than 56mm won't give a power increase)

Max power potential of a 56mm throttle is arguable but I have run engines in excess of 650bhp using one.

 

Ultimately you shouldn't need a TB larger than the outlet of your compressor

 

Well it's the Focus WRC Plenum that i'm using which i know is designed for balls out torque and not big bhp - the ID of the entry is 56mm prior to the split runners and i'm using 45mm Titan Roller Barrel ITBs to join it to the head...

I'd like to think it'd do 500bhp