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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Wed Jul 30, 2014 4:54 pm Post subject: BLOWN MM |
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G'day all
My MM is supercharged at 15 PSI, Major brakes on front, 1000 rear end with 4.22:1 centre, alloys and all the other stuff required by VSB 14. Will post some pics when I learn how to.
Cheers Bob
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graham At rest
Joined: 06 Dec 2008 Posts: 744 Location: Wanguri NT
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Wed Jul 30, 2014 5:44 pm Post subject: BLOWN MM |
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Hi Graham
Standard MM claims 27.5 HP which is 20.5 Kw. When mine was set up on dyno it recorded 33.3 Kw. at 5000 rpm. I have had the motor up to 7000 RPM for a short bursts. However it goes a lot harder using a 4500 to 5000 limit due to the tremendous low down torque but mainly due to the fact that faster gear upchanges can be made at lower revs. The synchros at higher RPM are almost completely useless, requiring double declutching. This is painfully slow even with more than 2.5 Kg. removed from the flywheel.
Cheers Bob
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Wed Jul 30, 2014 7:22 pm Post subject: BLOWN MM |
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Hi all
My quoted figure of 33.3 KW. was rear wheel Kw. This equates to just over 40 flywheel HP. Bit better than Mr. Nuffield's 27.5.
Cheers Bob
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Wed Jul 30, 2014 7:45 pm Post subject: BLOWN MM |
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G'day again
My last post should have read 33.3 rear wheel Kw. which is a bit over 40 flywheel Kw. This equates to about 54 flywheel Hp. Not quite double Mr Nuffields 27.5.
Cheers Bob
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Kel 我能行
Joined: 31 Mar 2008 Posts: 463 Location: Hunter Valley
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Posted: Thu Jul 31, 2014 9:34 am Post subject: |
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Bob,
Would be nice to see some pictures and to hear a little more about the supercharger.
Kel
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Thu Jul 31, 2014 10:58 am Post subject: BLOWN MM |
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Hi Kel
Will post pics as soon as I learn how to. The blower is a roots pump made by Asian and is designated AMR 500 because it's displacement is 500 cc's per revolution. When driven at 1.936:1 times crank speed indicated boost is a bit over 15 PSI (a little over 1 bar) and results in 33.3 RW Kw @ 5000 RPM. I am doing a little experimenting at present and have reduced the drive ratio to 1.66:1 resulting in the boost dropping to 30.1 RW Kw. at 5000. This is not a proportionate drop and is what I am trying to understand. Even so 30.1 Kw. equates to 48.6 FW HP which is still pretty good.
Cheers Bob
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Kel 我能行
Joined: 31 Mar 2008 Posts: 463 Location: Hunter Valley
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Posted: Thu Jul 31, 2014 5:43 pm Post subject: |
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that's impressive !!!
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frosty moderator
Joined: 23 Dec 2003 Posts: 3833 Location: 4559 near a big pineapple, Qld
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brundahted 4th gear
Joined: 06 Sep 2012 Posts: 77 Location: Grenfell 2810
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Posted: Thu Jul 31, 2014 9:36 pm Post subject: |
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That's a very handsome beastie!!!!!
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Thu Jul 31, 2014 10:42 pm Post subject: BLOWN MM |
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Hi Guys
Thanks a million for the complements - sorta makes it all worthwile.
Cheers Bob
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graham At rest
Joined: 06 Dec 2008 Posts: 744 Location: Wanguri NT
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Fri Aug 01, 2014 3:46 pm Post subject: BLOWN MM |
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Hi Graham
Not as much sting as your rotary. Internals as you said not what Mr. Morris used. Crank is stock standard. I knew of a couple of Morris 8 engined specials racing in the GEAR or classic events that were blown at 12 to 14 PSI and circulated all day at 7500 RPM. One was using standard rods. The biggest killer is the excessive weight of overbored pistons. I modified a Morris 8 with 2 mm. O/S bore and the JP piston, rings and pin weighed in at 260 grams compared to 200 for a standard pot with rings and pin! My rods are Argo CNC machined and shot peened from 4340 HT alloy steel with 17 mm. fully floating pins instead of standard 15 mm. pins. Fitted with ARP 2000 series rod bolts - the all up weight of one of these rods with cap and bolts is 479 grams as against 486 for standard rod, cap, bolts and nuts. Pistons are forged from 2618 aluminium alloy. The all up weight of one of these 3 mm. O/S pistons with rings, pins and circlips is 211 grams - just 11 more than standard and 49 less than JP's at 2 mm. O/S. The rest is textbook - porting, O/S valves, cam reprofiled, good balance, lightened flywheel. With the bottom end and pots like this if I were to have it normally aspirated with 11/4" SU's and a suitable cam and springs I would not hesitate to rev it to 8000 plus. However the low down grunt the blower gives it is a waste of time going much over 5 to 6 thousand RPM.
Cheers Bob
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DON58VAN Full Licence
Joined: 25 Sep 2008 Posts: 863 Location: Sydney/Bowral
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Fri Aug 01, 2014 6:55 pm Post subject: BLOWN MM |
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Hi Guys
Thanks for the replies.
Cheers Bob
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Lukezaid Full Licence
Joined: 01 Feb 2010 Posts: 391 Location: Woolgoolga
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Posted: Fri Aug 01, 2014 7:37 pm Post subject: |
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Awesome
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graham At rest
Joined: 06 Dec 2008 Posts: 744 Location: Wanguri NT
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Sat Aug 02, 2014 2:20 pm Post subject: BLOWN MM |
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Forgot to include Tom Tom GPS for accurate speed indication.
Bob
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moridat Free Wheeling
Joined: 25 Feb 2006 Posts: 119 Location: JUNEE
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brundahted 4th gear
Joined: 06 Sep 2012 Posts: 77 Location: Grenfell 2810
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Posted: Sat Aug 02, 2014 7:48 pm Post subject: |
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Deadly!
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Bally At rest
Joined: 19 May 2011 Posts: 219 Location: ACT
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Posted: Sat Aug 02, 2014 8:12 pm Post subject: BLOWN MM |
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Hi Guys
Just to say thanks all for the interest and comments about my beast.
Cheers Bob
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