A question about fuel?

ricematthews ricematthews at msn.com
Sat Aug 3 01:43:26 EDT 2002

In the States, our octane ratings are based on the R+M/2 method.  I don't
recall how this correlates to the RON values, but it is different.  Here in
Pennsylvania, premium fuel generally ranges from 92 to 94 octane (R+M/2)
with 93 the most common, while regular grades tend to be 86 or 87 (usually
For a while Sunoco stations were selling a high performance fuel at some of
their stations which I believe was 98, though I don't recall seeing that in
a while.

<alanthecelt at alanthecelt.screaming.net> wrote:
> Hi guys, after reading loads of mail forwards and
> backwards i thought id ask
> the question, what kind of ron fuel do you guys get
> in the states?
> see i just read a post where the lister mentioned 91
> ron, is that good for
> the states? see the reason i ask is the conversation
> regarding turbocharging
> an ng/nf engine, and it has always been said the
> compression is too high,
> Whilst from what i had read 10:1 is suitable for low
> boost applications, ie
> 5-6 psi, which i believe is easily acheivable with
> the 95/98 ron fuel we get
> here?
> So the question is am i speaking out of my butt? or
> is that the major factor
> in the states?

It's a small factor.  Up here in Colorado, we only get
91.  I heard that because were at altitude, it has the
same effect as 93 at sea level or something.  From my
experience, I have to say, that getting the turbo bits
in the car is the hard part, so you might as well do
the easy part too, and put the whole damn motor in.
You might be able to get 5-6 psi on high octane and a
little timing retard, but believe me, it will leave
something to be desired.  On my MC-2 motor that is in
reality running close to 9:1 CR because of the shaved
a couple of times head, nothing really happens until
10 psi. That's even with lot's of advance from the old
Haltech.  Don't get me wrong, it's still faster than
stock, but around 12+ psi it really gets fun.  If you
put and MC motor in, then you have all kinds of
options.  If you don't want to mess with the fuel
system, drop an MC in and run 9 psi.  Then you can go
from there when you feel like it, which shouldn't be long:)

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