Dick,
Sounds good to me. A little story concerning Bob & Jim Brissette's Fuel
Roadster may help you decide.
In 1963 the roadster was running against Cobbs & Morris's 215.957 MPH
C/FR record. Paul Dearth was the driver running under the record on the
down run. They were pondering whether to try to return or not, when Jim
found one plug that was fouling. He replaced it with a hotter plug, put
40% nitro in it and returned at 229+ for a new record of 222.331 MPH.
Bob said they were doing everything that was not suppose to work,
according to the conventional wisdom of that day, which was 8:1
compression ratio, 25% nitro, & direct drive on the blower. They were
overdriving the blower, had 10.5:1 compression ratio, and came back with
40% nitro.
This record stood as the fastest high boy roadster for several years.
Bob also had a tank that was the fastest open wheel car for many years.
When I first knew Bob Brissette, in preparation for Bonneville, he would
purchase five 300 cu in Chrysler Windsor short blocks and proceeded to
use up one a day. He just bolted on his heads, put in the cam and
mounted his blower and went racing. He was brutal on equipment, but he
went fast, sometimes setting records, if the equipment survived. Bob's
last trip to the salt in competition was in 1963. He had gotten married
and I don't think that his wife approved of his obsession. I know his
mother was opposed to the sport, too. Jim got burned badly in the early
sixties at El Mirage. I don't believe either Bob or Jim drove after
that. Of course Jim has been in and out of top fuel drag racing as a
crew chief and consultant for many years. Both Bob and Jim were very
talented engine builders and they knew how to run nitro.
Tom, Redding CA - #216 D/CC
Dick J wrote:
>
> You got to the right answers alright. I just hope
> I'm understanding them. What I envision doing
> is having amotor that I can run gas on Saturday,
> then change jets and whatever that night, and run
> nitro-methane on Sunday. From what you and
> others have been saying, I gather I can do this
> with about a 8:1 CR if the motor is blown. I
> believe the little Dodge is 8:1 or 8.25:1. I
> think that with a good rebuild, good rods and
> forged pistons, this motor could be a candidate.
> Could I do this with 10:1 CR if the motor is
> unblown?
>
> Dick J
>
> --- "Thomas E. Bryant" <saltracer@awwwsome.com>
> wrote:
> > Dick,
> >
> > Sorry, I didn't reply to the main issue in your
> > question. I have not run
> > gasoline with nitrous as yet. I would imagine
> > that the same logic would
> > apply as with the fuels without nitrous. Alky
> > has a higher octane
> > allowing higher compression ratios, but I will
> > attest that Alky will
> > detonate at 12.5:1 when you hit the nitrous
> > switch. (Five pistons in
> > about two seconds) If your tuneup isn't right.
> >
> > Tom, Redding CA - #216 D/CC
> >
> > Dick J wrote:
> > >
> > > 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.
> > > .............................
> > >
> > >
> >
> __________________________________________________
> > > Do You Yahoo!?
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>
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