For a nitrous engine, would you want small chambers in the head with dished pistons, or would you want larger chambers with flat top pistons? IE: -10 piston with a 47CC head or -2 piston with a 56cc head?

Say you want to keep the compression around 12:1 would you want a deep dished piston and small head chamber?

 

The ideal piston to use for good flame travel is a flat top. It wouldn't be a good idea to bring down the chamber volume from 56 to 47, that's requires milling 0.07" from the head. Production heads don't have thick decks so you'll be left with a week head which will not work well with nitrous. Even on aftermarket heads with thick decks, milling that much will hurt the head flow capability.

 

Are you talking a max effort nitrous motor or just adding some nitrous for an extra kick? In the latter case, it pretty much doesn't matter. If it's a max effort nitrous motor, there is a lot to consider - too many variables to really generalize. But the biggest area of concern is not how to make the power - it's how to keep the thing together.

Rich

 

Lets say a 396, with AFR 215's and a 250 shot. What piston and chamber size would be ideal. I want all I can get on the bottle.

 

Doesn't matter - any combination that gets you the desired CR will, for all practical purposes, give you the same result.

Rich

 

One problem with deep dish on the pistons is the thinner piston crown. For a big shot of nitrous, you want a strong crown. Flat tops will provide that strength easier than a deep dish.

 

Amen to sturdy pistons! You don't want to see this:



However, there are pistons designed for forced induction/nitrous with a dish. JE, for example, has a whole series of them as do the other big piston manufacturers. I will venture the opinion that the power difference between a properly designed flat top, dish piston, or a small dome in your application will be very small. A percent or two at most.

Rich