Schneider N/A Cam or P90 Turbo Cam

[jkelly]

Hey guys,

 

I'm curious what my best option here would be regarding cam selection for a NA motor that will be eventually upgraded to a turbo.

 

Current motor specs:

Block: N42 from a NA L28

Pistons: Flat tops at 0.50mm oversize

Head: Rebuilt N42 with a Schneider Cam (260 exhaust, 260 intake, 36 degrees of valve overlap, and 300ZX springs)

 

Options:

I have a freshly rebuilt P90 head with a 'B' grind original cam ready to go.

P90 cam specs: 240 deg intake, 248 deg exhaust, 26 degrees of valve overlap

 

Now my question is would I be better off changing the P90 'B' cam out for the Schneider cam given the amount of extra valve overlap the Schneider has? What are the pros and cons from a performance perspective? I'd like to put the P90 on the N42 block and run that either way at about 8.6:1 CR and run it naturally aspirated while tuning my megasquirt and be one step closer to a turbo.

 

Other engine build option suggestions are certainly welcome.

 

Thanks and Happy Thanksgiving!

Edited November 22, 2018 by jkelly

[HuD 91gt]

They say a true divided turbo/manifold is ok with cams with overlap. To what extent, I don’t know. I’ve wondered this myself.

[bradyzq]

If I understand correctly, you have the complete N42 engine in your car now, and a fully assembled P90 head on the side. I would tune the existing setup on megasquirt. At least that way if your turbo plans change or are delayed, you will still be driving something that is meant to be together, not a transitional setup. 

 

When you go turbo, you can swap the whole P90 head on at that time.