Supercharged CBR250 build

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Thu Jan 26, 2012 5:51 pm

After a beer, I had a GOOD look 'round,,,it don't spin backwards,,its "upside down miss Pat", too easy,,too bad the frame will be in the way of the drive right side up though.
I may have been a tad optimistic with the revs the blowers can handle also,,it appears they max out @ 10,000, I might need an Aisin 400 ? and a pulley change too, that DEFINITELY won't fit :x
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

Dr Goggles
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Location: Right behind you Chief !

Re: Supercharged CBR250 build

Post by Dr Goggles » Thu Jan 26, 2012 8:08 pm

in light of the Mr Squiggle quote all I can say ( in a deep monotone) is ..." Hurry upppppppp"
...few understand what I'm trying to do , but they vastly outnumber those who understand why..

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Greg Watters
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Re: Supercharged CBR250 build

Post by Greg Watters » Thu Jan 26, 2012 8:11 pm

Ever crossed a v belt to reverse direction :wink:

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RGV
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Re: Supercharged CBR250 build

Post by RGV » Thu Jan 26, 2012 10:32 pm

Not sure if this is any good to ya Tiny. I couldnt get the video to play.

http://www.thefang.co.uk/eaton.htm

Last Minute Racing
DLRA #928

2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF

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JonB
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Re: Supercharged CBR250 build

Post by JonB » Fri Jan 27, 2012 9:13 am

Bummer

Are the inlet and outlet flanges the same bolt pattern?

Do you have to swap the whole housing around or does flipping the rotors and end plate relative to the housing get the charger right?


Cheers
Jon
DLRA#1115
Underhouse Engineering

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Fri Jan 27, 2012 12:21 pm

Flipping it over seems the easiest option (like everyone else does) the bolt pattern is very close, the boost side has 5 bolts, the carb side, 4, but 4 will work with the boost I plan on using.
That'll put the oil fill hole on the bottom (or is that the fill hole) and the writing on the side will suit the yanks, as it will be upside down .
One major hurdle to overcome looks like the reinforcing tubes for the shock mount on the frame will be in the way, and I'll need a new carb manifold to clear the same.
I'm about to embark on blower/plenum bolt N01 removal,,this little bastich took 4 hrs to get started, and 2 more to tighten it, after making several "special" 8mm open enders (weak as puss after removing most of the metal and thinning it down)
I need to cure that problem too.
Some things just HAD to be , while fussing around removing bits,,I noticed the rear tyre is looking a tad Burtish
I wonder if Grumm has any boot polish ?
I trolled 'round in lalaland regarding how many revs the blower will handle, opinions vary from 10.000 , to 16.ooo, and I had planned spinning it to about 12,000, so I guess it'll be up to me to find out for sure.
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

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Greg Watters
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Re: Supercharged CBR250 build

Post by Greg Watters » Fri Jan 27, 2012 12:57 pm

Tiny there is a guy near me putting a bigger version to yours on an Aprilia and he is planning just over 10K rpm out of it with a 1:1 drive , apparently thats std speed
on your smaller unit i would think a few extra rpm should be ok

Just how directional are those superchargers ?? are they twisted lobe type ?? or parrallel

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Fri Jan 27, 2012 4:41 pm

Greg Watters wrote: Just how directional are those superchargers ?? are they twisted lobe type ?? or parrallel
They use parrallel lobes Greg.
I'm not "reversing" it's direction, just inverting it, putting the driven lobe on the top, which will cure the suck it had when mounted with drive on the bottom(wrongly), and it'll actually blow.
Its from a 660cc Subaru Vivio, , pics of the original mounting position in the car(ette) are as hard to come by as winning the lotto, although I,d rather the latter, I found this,,,,,,,,,,
Image
!0 mnths too late, but that,s life.
There's a sheet load of work involved, as the ports are narrower on the bottom (previously, the top) so I have to reflange the plenum, which will be a good opportunity to cure the fiddly mounting bolt (it only took 1 hr to remove it )
Because the drive shaft will about 50mm higher than it's previous position, and the blower will also sit lower, the intake will be lower, resulting in it sitting at a slight angle, so the plenum flange will also have to kick up to elimate the angle, or the carb manifold will run into the top shock mount.
I'll need to make another of these too, and direct it over the shock mount, hopefully, it'll look better, work better, and be fitter friendly.
The blower will be under driven about 25%
the Max HP of the engine it @ 15,000, blower speed @ these revs will be 11,250, so long as it doesnt cavitate like a boat prop, it should be ok for the short bursts LSR involves
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

grumm441
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Re: Supercharged CBR250 build

Post by grumm441 » Fri Jan 27, 2012 6:05 pm

gennyshovel wrote: Some things just HAD to be , while fussing around removing bits,,I noticed the rear tyre is looking a tad Burtish
I wonder if Grumm has any boot polish ?
.
You're not supposed to ask those questions on the forum, 'cos now I have to have a real close look at your tyres
Speaking of tyres, I still haven't seen a rule change on tyres
Can't you just take the end plate off the blower and put it on the other way around

G
They make it
I make it work

dave leaney
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Re: Supercharged CBR250 build

Post by dave leaney » Fri Jan 27, 2012 8:08 pm

*
Last edited by 1 on dave leaney, edited 0 times in total.

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RGV
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Re: Supercharged CBR250 build

Post by RGV » Fri Jan 27, 2012 8:20 pm

grumm441 wrote: Speaking of tyres, I still haven't seen a rule change on tyres
Sorry to hijack the thread but what is the rule change?

Last Minute Racing
DLRA #928

2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF

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gennyshovel
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Re: Supercharged CBR250 build

Post by gennyshovel » Fri Jan 27, 2012 8:27 pm

grumm441 wrote:Can't you just take the end plate off the blower and put it on the other way around

G
Yeah,,no worries,,I'll just hacksaw a piece out of the frame for the drive shaft, and a matching hole in the tank :wink
A new tyre is "on da list"
:
dave leaney wrote:G'day Tiny, here's a potential fix. Timing belts are available with teeth on both sides of the belt. You would need to make a new idler bracket assembly and mount a toothed idler pulley below the crank pulley. The idea is that the crank and blower pulleys operate on the opposing side of the belt to each other so as to reverse the direction of rotation. Everything else stays the same. Not the most elegant of solutions but would be simple and quick enough to make.
Cheers, Dave.
Thanks for thinking of me Dave (I hope ya weren't gigglin'?)
I'll do it properly mate, as tempted as a quick fix and racing seems , its not me
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

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Greg Watters
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Re: Supercharged CBR250 build

Post by Greg Watters » Sat Jan 28, 2012 8:48 am

G
i spend quite a while trying to find the rule change form , buggered if i could find it on the site , and been flat out so just organised a big pile of disposable tires .

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RGV
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Re: Supercharged CBR250 build

Post by RGV » Sat Jan 28, 2012 10:01 am

Greg Watters wrote:G
i spend quite a while trying to find the rule change form , buggered if i could find it on the site , and been flat out so just organised a big pile of disposable tires .
Page 75 & 76 of the downloadable 2012 rule book has it I think

Last Minute Racing
DLRA #928

2010 MPS/G 250 118 MPH
2011 Washed Out
2012 Washed Out
2013 MPS/G 250 131 MPH (RECORD)
2014 MPS/G 250 140 MPH (RECORD)
2015 MPS/F 250 DNF
2016 MPS/F 250 114 MPH (RECORD)
2017 MPS/F 250 DNF

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gennyshovel
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Location: Broken Hill

Let the rebuild begin

Post by gennyshovel » Sat Jan 28, 2012 1:34 pm

I started by cutting 40mm from the engine side of the intake.

Image

There needs to be some more trimming from the shocky tower, & No1 & 4 intake tubes need a cut,twist,reshape to line up again.
Image

The plemum flange needs to be inverted, angled, the plenum massaged into a new shape to conform to the blower outlet, now it's upside down.
But it's gonna fit :D
Image
Image

There is still a glimmer of hope it can be ready, so I'd better nom this week :wink:
Tiny DLRA# 484
Postiebike Racing , created & funded by TwoBob Engineering

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