Re: 505 N9TE -> N9TEA

davidtowle@lycosmail.com
Tue, 2 Jun 1998 12:02:03 -0400 (EDT)

Jim- your calculation below is incomplete, you're only estimating the difference that a compression ratio change alone (like taking off a head, shaving it down, and putting it back on with no other changes) would make. In a turbo the compression gets increased by injecting more air and gas into the fixed combustion chamber volume, so you have not only higher efficiency from the CR but also more air and fuel.

Using your numbers, I would estimate the total power increase as follows:

(Increase in avail fuel&air)*(Incr in eff)*(Original hp)

(13/11.5)*(1.02)*150=173hp, much closer

---- you wrote:

> The 1.5 difference in CR would be about a 2% increase in HP.
>
> So for the same "type of HP", the N9TEA would have 3.6 HP more.
>
> That seems a little low for the effort of the N9TEA changes though.

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