What CR would be recommended for Nitro/Alky mix,
higher or lower than for gasoline?
--- "Thomas E. Bryant" <saltracer@awwwsome.com>
wrote:
> Dick,
>
> It really depends on what you want to do, I
> guess. I have always used
> the same motor in both classes. I just build
> for Gas Class and accept
> that it will be a little less effective on
> Fuel.
>
> We run about 12.5:1 compression, I have found
> that it gets real
> difficult to get much more than 13:1 in a 302
> cu in Chevrolet motor. We
> do well on Alky, better when adding nitrous,
> and have run 33% nitro with
> good success in the 1/4 and 1/2 mile drags. In
> 1967, we ran 190 MPH at
> El Mirage in D/FR, at that time we held the
> D/GR record at 173.74 MPH.
> That was as far as I could run the engine on
> nitro without major
> problems, it was detonating severely at the end
> of the run. My best time
> at Bonneville on nitro was 196, I could never
> make it live past the 1
> 1/2 mile with all cylinders running. It was
> surely a great ride while it
> lasted.
>
> I was running a basic gasoline setup, just
> changing nozzles and jet, the
> fuel pump was a Hilborn "0" which didn't
> deliver enough fuel for the
> longer runs. Everyone told me that running that
> percentage on 12.5:1
> compression ratio wouldn't work and basically
> they were right, but I got
> by with it on the short runs and had a ball.
> Kinsler tells me that I
> could run up to 20% nitro with the pump and
> nozzles I am using for Alky.
> They recommend going 16% larger richer on the
> bypass jet for each 10% of
> nitro. Some day I'm going to try it again. I
> have five gallons of nitro
> that I have been saving for a long time.
>
> Tom, Redding CA - #216 D/CC
>
>
>
>
> Dick J wrote:
> >
> > Tom,
> > I was just cruisin through your website again
> and
> > noticed that you made the notation that you
> run
> > both gas and fuel under a single photo, which
> got
> > me thinking. Do you run both gas and fuel in
> the
> > same motor? Can you do it all at one meet?
> Or is
> > it a complete changeover from one meet to
> > another? I have often wondered what the
> > differences between fuel and gas motors were.
> I
> > know that gas motors run common CRs in the
> 10:1 -
> > 12:1 area, and alcohol runs something like
> 15:1.
> > What if they are blown motors, CR must be a
> lot
> > lower. What about unblown nitro motor - what
> > kind of CR does that run? And last, what
> about a
> > blown nitro motor - what CR do they run?
> >
> > I guess what I'm asking is: can a single
> motor,
> > either blown or unblown, be built to run both
> > gasoline and nitro, or alcohol with just
> simple
> > changes like timing and jets?
> >
> > =====
> > .............................
> > ..........Dick J.............
> > ......(In East Texas)........
> > ..........# 729..............
> > ........Roadsters............
> > .Hemis and Flatheads Forever.
> > .............................
> >
> >
>
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=====
.............................
..........Dick J.............
......(In East Texas)........
..........# 729..............
........Roadsters............
.Hemis and Flatheads Forever.
.............................
__________________________________________________
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