[Diy_efi] sequential injection timing

[William Shurvinton]

Ok.....Can't get at a full range torque figures until I get back to the
office on monday but I think it runs about 1.2lbft/CI up to 1.4.

Looking at the width. One of the more highly tuned GM 4-pots (vauxhall XE)
in a lotus 7 type car does 85% of torque from 3500-9000RPM. It is very fast
although not the best 1/4 horse at only 10.9   , but that's more down to
aerodynamics than anything else.

What is a good number for an NA V8 then?
----- Original Message -----
From: Chris Conlon <synchris at speakeasy.org>

>
> [Typical exhaustive disclaimer to prevent pointless bickering:
> The following applies to normally aspirated engines in the
> same class (SI vs CI, 2 stroke vs. 4 stroke, port fuel induction
> vs. direct injection, etc) and running the same fuel. The results
> apply to boosted engines as well, as long as you correct for inlet
> air density (and Ve variations due to speed of sound) between
> different engines.]

<SNIP>
> Specific torque (torque divided by displacement) is a much more useful
> number when comparing engines with power bands in different rpm ranges.
<SNIP>
> There's one other number you might want (oops, so much for that
> single number to use when arguing!), and that's some indication of
> how wide your torque band is. > An ok way to measure torque band is to
find the rpm range over
> which the engine makes at least some decent percentage (say 85%)
> of max torque, expressed as a ratio of high rpm over low rpm. If
> you can get this ratio (at 85%) up to 2:1 (say 3000 to 6000 rpm)
> I'd say you're doing pretty well (at least for a street car type
> of setup).
>
>
>    Chris C.



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