Re: 505 N9TE -> N9TEA

Jim Lill (jpl@vectorbd.com)
Tue, 2 Jun 1998 16:43:17 +0000 (UTC)

Many thanks to David for pointing out my mistake. As I has said, the 3.6
seemed a little low. I'll have to go back to the Boost vs. Effective CR
and other charts and nomographs I used and make sure I didn't make another
error that results in the 173 vs. 180 difference.

On Tue, 2 Jun 1998 davidtowle@lycosmail.com wrote:

> 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.
>
>