Ok guys, I'm talking about a typical efficient (ie smallish 35R turbo) with trims similar to the AMS standard 35R with .63 hotside etc.

I know that making up a nice four inch intake would be optimal, but here in Cali, I'm stuck running the stock airbox with custom 3 inch aluminum piping to the stock MAF. This keeps the emmisions police happy.

With that said, is there any real advantage to running a compressor cover that has a 4 inch inlet as opposed to one with a three inch inlet. Even with the 4 inch inlet, there is an immediate neck-down with a 4 to 3 inch silicone coupler. Why not just use a three inch cover to begin with?

How much power could that actually cost me? Could I increase spool up time? Is there really that much of a difference? Could using a straight 3" inlet cover cause other problems like surge, or should it help in that regard.

Just curious...

 

Does someone make a 3" surge ported cover?

 

You can cut down an S-cover to acheive a 3" inlet, which I would not imagine makes a big difference. The next option would be to run the E-cover cut for the 35R wheel, which I think would effect, to some degree, the power potential of the turbo. Most use the E-cover with the 35R due to space limitations such as when using on a BMW M3.

 

smog... just get a twin scroll 35r. oh wait... that doesn't solve your problem hahahaa