Compression Ratios
  • Register
  • Help
Results 1 to 15 of 15
  1. #1
    Fellow Frogger! PUG309's Avatar
    Join Date
    Feb 2001
    Location
    Sydney, Australia
    Posts
    231

    Default Compression Ratios

    I was looking at this site ...

    http://www.fefcholden.org.au/techinf...e/norman5.html

    and there is a sentence talking about Methanol that says ...

    "This will operate satisfactorily on compression ratios as high as 20:1,although it is generally recognized that no increase in power takes place by exceeding 16:1"

    Is it really "generally recognised" that there is no increase of power exceeding 16:1???

    Advertisement
    Daniel Djuracic

    Ex UK spec 89 309
    206 XT 1.6 16V (Diablo Red)with Peugeot Lion in back windows

  2. #2
    Budding Architect ???? pugrambo's Avatar
    Join Date
    Jul 2000
    Location
    Parkes - N.S.W - Australia - Earth
    Posts
    12,256

    Default

    i would hazard a guess that at those sorts of CR's you will start getting a deiseling effect in that the compression will ignite the charge long before it's needed and start to push then piston back from whence it came
    3 x '78 604 SL

    1 x '98 306 GTi6

    1 x secret project

    1 x '98 406 STDT troop carrier and i don't care if it stinks, i don't sniff it's arse Death by wank tank

    1 x '99 406SV 5spd wagon, time to burn more fuel

    1 x 1994 605 SV3.0


    WTD long range fuel tank for 605

  3. #3
    Fellow Frogger! PUG309's Avatar
    Join Date
    Feb 2001
    Location
    Sydney, Australia
    Posts
    231

    Default

    The way its worded though makes it seem that Methanol doesnt self detonate till at least 20:1 compression...

    On next page on website there is this...

    "So effective is methanol in reducing temperatures that it is quite common under humid conditions, to see a supercharged car come in after a hard race, with the entire supercharger and manifold encased in ice"

    Im gusseing that if this is really the case then this Supercharger is setup in a drawthrough arrangment using a carby???

    Is this guy talking outta his arse?
    Last edited by PUG309; 21st March 2005 at 11:16 PM.
    Daniel Djuracic

    Ex UK spec 89 309
    206 XT 1.6 16V (Diablo Red)with Peugeot Lion in back windows

  4. #4
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,446

    Default

    Quote Originally Posted by PUG309
    I was looking at this site ...

    http://www.fefcholden.org.au/techinf...e/norman5.html

    and there is a sentence talking about Methanol that says ...

    "This will operate satisfactorily on compression ratios as high as 20:1,although it is generally recognized that no increase in power takes place by exceeding 16:1"

    Is it really "generally recognised" that there is no increase of power exceeding 16:1???

    I thought around 15:1 was the limit too. Then again, if it's on the web..............

    '92 205 Mi16
    '90 Mi16x4

  5. #5
    1000+ Posts PeterT's Avatar
    Join Date
    Jul 2000
    Location
    Castle Hill, Sydney
    Posts
    7,446

    Default

    Read the whole 10 Chapters. It's a great read! 1969 Vintage!

    '92 205 Mi16
    '90 Mi16x4

  6. #6
    Gone Fishin' Ray Bell's Avatar
    Join Date
    Jun 2001
    Location
    Burpengary and Murrumburrah, Qld and NSW
    Posts
    9,223

    Default

    Problem is you don't know who it is you're quoting and questioning here...

    The guy was a fairly reasonable engine head in his day, and though some later developments have taken place in engines, the basic stuff remains the same.

    Let's just look at his credentials:

    1. Racing driver and race car tuner of note, competed in races as far apart as Narrogin in WA and Southport in Queensland.

    2. When he competed in the 1954 Australian Grand Prix, he towed a trailer from Adelaide to Southport with drums of his own brew of fuel. He raced his car in the sports car race with a decompression plate in between the head and block, then took that out for the main race and ran the event with a nice bit of compressive help from a GMC 2/71 supercharger. He finished fourth in the 153-mile race, bolted the decompression plate back in and towed a much lighter trailer home.

    3. Having bought a blown up 1930s 6-cylinder Maserati Grand Prix car, he rebuilt the block, replaced the rods and pistons with parts unavailable in Australia, cast brand new cylinder heads in bronze, fitted a second supercharger to give it a bit more grunt and went motor racing.

    4. His first self-built racer was created out of scraps from his many post WW2 war-surplus buying sprees. A Dodge Weapons Carrier Chassis, two Ford V8 engines in series (joined by the simple expedient of having a sprocket on the front of one crank and the rear of the other... and a double-row chain wrapped around the two sprockets), fuel pumps wired into the brake light circuit so they pumped water over the brake drums when the brakes were applied and twelve stub exhausts. It was at one time leading the Australian Grand Prix at Narrogin in WA, later it fared well in the Singapore Grand Prix in the hands of Sid Anderson.

    5. Recognising the value of a backbone chassis, he created a car that used a Holden front suspension bolted to a block of iron that took the place of the timing cover on a Ford Zephyr straight six. At the back of the block he bolted a length of 7" steel tube, with flanges that bolted to the block at one end and the Tempo Matador gearbox (or transaxle) at the other. The rear suspension hung off the gearbox, it was independent all round. The supercharger drove by a chain from the flywheel end of the engine, the driver sat on a seat suspended to the right of it all (pedals on brackets off the engine sideplate etc) and a huge fuel tank was on the left. When presented for scrutineering it was questioned whether or not the whole thing might fall apart over the bumps of the new Port Wakefield circuit. He immediately organised a truck to be reversed up to the car so the tray overhung the driver's cockpit. He put a jack on the steel tube and jacked up the back of the truck.

    6. During the war he built his own design of gas producers. These were very neat, and as he built them he used them too. His honeymoon was to the Gold Coast during those times, with a stop on the way to chip the all-important charcoal for fuel from tree trunks burned in a bushfire.

    7. He also made his own superchargers, that's why the book you've quoted existed. His son Michael still makes them at Noosaville. He got into the supercharger business when a faulty one was for sale at a hock shop near his workshop in Adelaide.

    8. After years of heating his tins of baked beans on the exhaust manifold of his racing cars during the early events of the day, his Zephyr convertible had a more sophisticated method. Heater lines went through the walls of a box in the engine bay, this creating an oven that warmed his food as he drove the family to the popular picnics and race meetings.

    9. Faced with the need to get dozens of trucks from the auctions at Darwin to Adelaide after the war, he took to the scrub and cut out bamboo poles. These were lashed and bolted together to make A-bars to go from one truck to the next, and with six trucks in tow he made several trips to get the job done. Each trip was done non-stop. When a hill hove into view that required more power than the lead truck could muster, he stopped, put the last truck into gear, turned on the ignition and laced the accelerator to the floor.

    10. He built his own observatory in his back yard. Tons of concrete were poured to make a totally stable floor, while the lenses were created by grinding the glass himself. This was arranged with a bunch of servos and other bits sourced from the war surplus gear. Some trial and error was required, but after many days and nights of leaving the grinding gear to do its job he had accurate lenses and mirrors through which he could look at the stars.

    11. Spiders were kept out of the observatory by having a ring of steel around the base and another one less than a spider's length away, one being charged with 240 volts.

    So you see, this guy was no ordinary backyarder without a background on which he based his knowledge... though there were moments.

    12. His wife, famous author Nancy Cato (All the Rivers Run etc...) was concerned for his health. So she insisted that the Maserati engine reconstruction take place inside the family home. He removed the kitchen window to crane the engine in and set up his assembly on the French polished dining table they'd been given as a wedding present. "How could I complain?" she reflected 45 years later. "I'd already burned it with the iron..."

    13. Stuck in a bog in western NSW, travelling back from Bathurst after heavy rains, he waited to see if someone would help him out. The only vehicle in hours was a T-model Ford and that went straight past, the owner sucking on a pipe that was turned upside down. So he cut wires out of the fence and fetched one of the bigger examples of the beef cattle beyond the fence. Wired up so that the cow was harnessed to the car, it still didn't budge, so he got more wire and hooked it around the cow's horns, then ran them back to the ignition system. He got out of the bog.

    You see... you're quoting no mere man... you're quoting a legend...

  7. #7
    1000+ Posts Poo-Go's Avatar
    Join Date
    Sep 2003
    Location
    Canberra
    Posts
    1,420

    Default

    Great post, Ray!
    Care factor = -273.15șC

  8. #8
    Gone Fishin' Ray Bell's Avatar
    Join Date
    Jun 2001
    Location
    Burpengary and Murrumburrah, Qld and NSW
    Posts
    9,223

    Default

    Thanks... I just felt a need to put things into perspective...

  9. #9
    Fellow Frogger! PUG309's Avatar
    Join Date
    Feb 2001
    Location
    Sydney, Australia
    Posts
    231

    Default

    Guy does sound like a legend. Seems to have been a pioneer in many areas of motorsport

    Still I dont see how Ice can develop just because the fuel is Methanol. Im not trying to say that he was wrong, just trying to get my head around the idea that ice can form on a Supercharger for no apparent reason other than the Methanol is absorbing the heat...
    Daniel Djuracic

    Ex UK spec 89 309
    206 XT 1.6 16V (Diablo Red)with Peugeot Lion in back windows

  10. #10
    Fellow Frogger!
    Join Date
    Feb 2002
    Location
    Tamworth NSW
    Posts
    496

    Icon7

    Ray,

    Firstly, just adding my appreciation for a snapshot of the life and achievements of Eldred Norman. Australian pioneers are often ignored or unrecognised for their achievements in a particular field and surely E Norman is one of these people. Thank you for your contribution.

    We are fortunate that Eldred Norman's son Mike has retained and loaned out a copy of his father's technical notes. Much of the theory he espoused in regard to the combustion process, supercharging, ignition timing etc I was learning back in the mid '60's at the RAAF technical school in Wagga.

    In regard to Pug309's statement that you still did not understand the process by which ice could form around the supercharger casing etc, I would add the following:

    One of the key pre-conditions mentioned in the Norman article was the existence of the right amount of humidity - that is, the presence of water vapour within the atmosphere. Ice cannot form without water.

    Secondly, the cooling process which was occurring with Methanol was due to a process known as the Latent Heat of Evaporation. That is, being a fuel, as it evaporated, the Methanol absorbed heat from its surroundings, causing a rapid drop in temperature. You can demonstrate the same effect by putting a small quantity of fuel (petrol) onto the cup of your hand on a warm day, and note the cold sensation produced as the fuel evaporates.

    Other similar residual effects (ice formation) can be seen on a hot day when you are running your car's airconditioning system. If you look at (and feel) the return pipe from the evaporator and TX valve back to the condenser, it will be very cold, and may even have ice around it. On engines running a LPG system, the gas regulator will be heated by the cars cooling system, to prevent it icing up as the gas expands and converts from its liquid state to that of a gas, prior to entering the engine induction system.

    Carburettor icing is a deadly process, especially on aircraft engines. As pilots of carburetted engine aircraft, we utilise a chart known as the Carburettor Icing Probability Chart, which interacts the atmospheres Dew Point, Humidity and Temperature to predict ice formation within the carburettor.

    This chart further considers the engine operating conditions at the time (eg cruise power, descent power etc), and therefore shows what type of icing may occur. Aircraft engines have a pilot operated Carburettor Heat Control to enable the pilot to prevent this insidious type of icing from occurring, or, if ice is present, to melt it before the engine stops completely. There are many case histories showing that the ice went undetected, the engine stopped, and the aircraft made a forced landing, or crashed.

    I have also experienced carburettor icing on a car engine, especially with the twin throat, down draft Weber, as fitted to some Renault models (Renault Virage etc). On more than one occasion, the engine rapidly lost power, then stopped. Within a few minutes the ice had melted, and the engine would be back to normal, as if nothing had gone wrong. A quick removal of the air horn would show the ice accumulation around the venturi and throttle valve.

    Some piston engined aircraft were fitted with Water Methanol injection systems, such as the Curtis Wright R3350 (ie the engine displacement was 3350 cubic inches, producing 3,700 HP). The water methanol injected during combustion (at take-off power only) cooled the combustion chambers of the cylinders (all 18 of them), allowing the mixture ratio to automatically adjust from a rich ratio of 10.5:1, to a best power ratio of 12:1. The cooling process prevented detonation due to excessive cylinder temperatures, and the mixture adjustment enabled the engines to produce another 400 HP each.

    The engines were supercharged (as per the Norman article), but we were using 115 / 145 Octane fuel, at manifold pressures at take-off power of 59 inches. To relate this to Norman's tech article, this is equivalent to 29.7 lbs of boost!

    Cheers,
    Kim.

  11. #11
    Gone Fishin' Ray Bell's Avatar
    Join Date
    Jun 2001
    Location
    Burpengary and Murrumburrah, Qld and NSW
    Posts
    9,223

    Default

    I can certainly testify to what happens when the LPG converter (or heat exchanger) doesn't get a flow of warm water through it!

    Long lines to the converter with water not loaded down with antifreeze in a Canberra winter teaches you these things...

    And you get a clear picture of that icing up that occurs, too.

  12. #12
    1000+ Posts robmac's Avatar
    Join Date
    Nov 2004
    Location
    Melbourne / Caulfield
    Posts
    19,041

    Default Well Worth Reading !

    Quote Originally Posted by Ray Bell
    Problem is you don't know who it is you're quoting and questioning here...

    ........ edited..........

    You see... you're quoting no mere man... you're quoting a legend...


    This would have to be one of the most straightforward and well written introductions to supercharging I have ever read.

    The only item his is/was proven incorrect on is " turbochargers are never likely to be used much because of their complexity" But his reasons for favouring surperchargers are still equally valid.


    Look forward to some more history on the man

  13. #13
    Gone Fishin' Ray Bell's Avatar
    Join Date
    Jun 2001
    Location
    Burpengary and Murrumburrah, Qld and NSW
    Posts
    9,223

    Default

    Like the way he removed the stumps from the old orchard when he was clearing the yard?

    How he compacted the soil around the fenceposts at the Collingrove Hillclimb?

    Perhaps the story about young Bill and his musical talents... allied, of course, with getting the first sporting camshaft grind ever made for a Holden engine?

  14. #14
    Fellow Frogger! PUG309's Avatar
    Join Date
    Feb 2001
    Location
    Sydney, Australia
    Posts
    231

    Default

    Thanks for the fantastic reply Kim, i would have thought the compression from the supercharger would have created enough heat to counter that effect but obviously not.

    So how did he remove the old stumps Ray???
    Daniel Djuracic

    Ex UK spec 89 309
    206 XT 1.6 16V (Diablo Red)with Peugeot Lion in back windows

  15. #15
    Gone Fishin' Ray Bell's Avatar
    Join Date
    Jun 2001
    Location
    Burpengary and Murrumburrah, Qld and NSW
    Posts
    9,223

    Default

    Explosives... remember he bought a lot of war surplus gear...

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •