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 .................*NICK BRAMLEY'S 186CC ENGINE*.............

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nigel breeze
johnSbantam
John Colter
john bass
dansofield550
Trevor Amos
rexcaunt
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ....................*NICK'S ENGINE UPGRADE*............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeFri Dec 04, 2015 7:02 pm

Good Morning All!



A quick update on the 25HP/8250 rpm target!




1. Modify the clutch to 6 plates!    .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 RACING_6_PLATE_CLUTCH_DRUM_1





2. New upgraded cylinder to 25HP!
 .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 28_BHP_CYLINDER_VIEW_3



3. Upgraded carb to 34mm!   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 MIKUNI_ADAPTER_5



4. Reworked cylinder head to raise compression ratio to 13.85:1

  .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 28_BHP_BILLET_CYLINDER_HEAD


Nick reckons we have a good chance now!.................... Very Happy

Results will be the proof!

Have a Great Week End!

Rex
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Trevor Amos




Number of posts : 938
Registration date : 2010-08-13

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeFri Dec 04, 2015 8:54 pm

Very nice Rex should do the trick and make the `collective` opposition worry just a bit, especially with the very talented Nick in the saddle, is the 25hp at 8250rpm quoted crank or rear wheel power, the potential is there for 30hp, why stop at 25?


Cheers, Trevor
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john bass

john bass


Number of posts : 1748
Age : 94
Localisation : Bensberg, Germany
Registration date : 2006-12-06

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: 8250 rpm ........   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSat Dec 05, 2015 7:02 am

Is 8250 a misprint?

Very torquey motor otherwise!

Good luck,

John-Boy!?
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ............25HP-8250 RPM @ REAR WHEEL   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSat Dec 05, 2015 10:41 pm

Good Morning Trevor and John,

Yes it will create 25HP @8250 rpm rearwheel!................ Very Happy



.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 ENGINE_NEAR_READY_FOR_TESTING_1



Have a Fabulous Week-End!..........Rex
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Trevor Amos




Number of posts : 938
Registration date : 2010-08-13

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSat Dec 05, 2015 11:30 pm

Thanks for clearing that up Rex, so, 28+ at the crank, no one will catch that!
Is it a trick of the light or perhaps camera angle, but the crank-case mouth looks a little non BSA?

Trevor
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ..........*NON-BSA CRANKCASE MOUTH*............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSun Dec 06, 2015 7:15 am

Hi Trevor,

You are right!

It has an addition of JB Weld!.............Good Stuff!.......... Very Happy



.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 CRANKCASE_TRANSFER_MOD_2



.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 CRANKCASE_TRANSFER_MOD_5



.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 CRANKCASE_TRANSFER_MOD_4



.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 ENGINE_NEAR_READY_FOR_TESTING_2



Have a Great Night!..............Rex
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john bass

john bass


Number of posts : 1748
Age : 94
Localisation : Bensberg, Germany
Registration date : 2006-12-06

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Big Flywheels...   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon Dec 07, 2015 6:25 am

Big Flywheels??

OK OK! so I like them!

With torque and the right gearing should be difficult to catch....

Go for it...

Best of luck!

JayBee....
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nigel breeze

nigel breeze


Number of posts : 358
Registration date : 2007-12-23

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon Dec 07, 2015 8:51 pm

Sneaked another couple of transfers in then��
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ........*TRANSFERS*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeTue Dec 08, 2015 2:24 am



Hi Nigel,

Yes, the software said increase the transfer area a bit so we added two more!.


Very Happy Very Happy  Very Happy  Very Happy  Very Happy  Very Happy  



.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 CYLINDER_BASE_FINISH_MACHINE


All The Best!..........Rex
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ..................*PROGRESS*............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeWed Dec 16, 2015 7:11 pm

Hi All!

Great News!................... Very Happy

Debb's recovery is going Great and she can now move around the house without

fainting and being sick!

Anyway, the dyno motor is almost ready and calmly awaiting its new uprated

clutch!..................Very Happy

Nick had a stroke of luck and suddenly we had a BRAND NEW set of

crankcases appear off EBAY!............. Very Happy

These will be ideal for the race engine and we won't need to use any precious

JB Weld!..................Yippee!...........HAPPY DAYS FOR ALL!............ Very Happy


.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 BANTAM_NEW_CRANKCASES_FOR_60_MM_CENTRES

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 BANTAM_NEW_CRANKCASES_FOR_60_MM_CENTRES_1   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 BANTAM_NEW_CRANKCASES_FOR_60_MM_CENTRES_2

Wishing Everyone a Great Christmas and plenty of Workshop Activity for the

new race season!................ Very Happy

Cheers.........Rex,Debb & Steff
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Trevor Amos




Number of posts : 938
Registration date : 2010-08-13

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeThu Dec 17, 2015 4:24 am

Lucky and rare find that Rex, well done , just out a matter of historical interest what are the serial numbers stamped on the cases, be nice to know their traceable lineage? Good to see rapid progress at this early stage for next season, should be interesting!

Cheers, Trevor
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

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PostSubject: ..................*CRANKCASES*................   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeThu Dec 17, 2015 6:53 pm

Hi Trevor,

Apologies for the delay!

We were dynoing the two-stroke fuel injection project last night and finished at

12.15 this morning!  

Wonderful!!................ Very Happy

You are right! It is always good to be accurate with that historical link!.... Very Happy

I'll have a chat about the serial numbers etc. with Nick!

Meanwhile have a Fabulous Day!............ Very Happy

Cheers!.............Rex
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Jimmie




Number of posts : 166
Registration date : 2011-07-25

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeFri Dec 18, 2015 11:56 pm

Rex

What variety of JB are you using?

Jim
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

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PostSubject: ...............JB WELD*...............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSat Dec 19, 2015 2:41 am

Hi Jimmie,

We have used the standard type bought off Ebay......Part number JB8270P

We used it to get a seal for the base of the prototype 4 porter that's been

sitting waiting to be finished off and tested!

For the cylinder, we have used the high temperature version (broke through

the exhaust port casting), then if the power is there we can get a pattern

made to give us a good base surface on the new casting!

Ideal for standard cases!.................... Very Happy


The JB weld then will be redundant!...........Awesome!...... Very Happy

Good Luck with your efforts!.............. Very Happy


Cheers!...........Rex
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Jimmie




Number of posts : 166
Registration date : 2011-07-25

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSat Dec 19, 2015 5:18 am

Thanks Rex.

A Very Happy Christmas to you and Debb and also all posters and 'readers' of this forum.

Jim
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mjpowell

mjpowell


Number of posts : 1074
Localisation : Lincoln England
Registration date : 2006-12-09

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PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeThu Dec 24, 2015 4:54 am

Rex has many irons in many fires and many a Bantam project with him and Debb being so committed to the Bantam cause. I think Rex may of been pulling our legs of late with the JB Weld to Bantam cases (external) and blank crankcase casting being machined not to mention the casual remark of fuel injection for two strokes. Of course fuel injection and external changes to crankcase(175) are not allowed within the Rules of the Bantam class. I dare say Rex is building a Bantam World Land Speed Record attempt or something similar??

Mike
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dansofield550

dansofield550


Number of posts : 367
Localisation : gravesend kent
Registration date : 2011-10-23

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSat Jan 02, 2016 9:16 pm

The barrel looks good Rex, it's surprising how much metal there is in the crankcases' to accommodate the transfers , I thought I'd taken loads out on my first engine,bit the second one proved that wrong,there was tons left in there especially in the width, have you got a good batch of these done?
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ................*MIKE AND DAN*............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeSun Jan 03, 2016 6:58 am


Hi Mike and Dan!

Happy New Year to you both!.................... Very Happy

The latest photos show the next stage of Nick's engine for future projects!

We are just finishing the uprated clutch and Chalkie (Replay Scooters) has

kindly offered to run it on the dyno and get some base figures!

A lot of hours have gone into it already and it's a useful way to use time to

learn more of applying ideas that might give results.......positive or negative Very Happy

Nick has insisted it must fit in with the rules, (Rightly), and to that end what

you see here is only a prototype for evaluation! As a "trailer" not the full

movie!

We are both extremely keen to continue good solid development and forge a

path for the Bantam cause!.......... Very Happy

Good Luck with all your efforts!

Cheers!.............Rex and mending Debb
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: ....................*NICK'S NON BHR MOTOR*............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeTue Apr 12, 2016 5:26 am

Hi All!

As you may be aware Nick's new motor is only for Non BHR events!......... Very Happy

An interest topic to add is this one by Trevor on the latest pipe technology and how it could make worthwhile improvements!............. Very Happy

"Pipe Dreams

Rex has very generously allowed me to use some his 2016 186cc engine data and pipe drawing in the preparation of this article. The dimensions for exhaust duct outlet, centre section diameter, and tuned length remain unaltered.  

It is important to realise that you have to stay within certain percentage lengths for all elements of an exhaust system; starting at the cylinder port and on to the rear cone/tailpipe junction. You cannot make one part longer or shorter without losing power somewhere, or worse still, not making it in the first place. For instance, an overlong header delays the beginning of cylinder depression too late in the cycle, and too short a diffuser creates steep angles that have greater amplitude but of such brief duration that serves only to narrow the optimum power range. There is always a conflict between power range and peak power within the constrained scope of three speed gearboxes!
The dilemma we face is that there are a fixed set of lengths for the pipe, so in the case of the tuned length (t/l) the criteria for the calculated dimension are only met at around optimum torque rpm, and then only after a period of constant running that establishes the relevant time and temperature.
It is the depression at the cylinder/exhaust port interface which establishes the pressure differential with the crankcase that moves fresh mixture from the transfer ducts in to the cylinder. However, the point of maximum depression, in relation to BDC, changes with variations in rpm, thus temperature and pressure, as for instance during acceleration and gear changing. Whilst it is the returning pulse from the rear cone that re-cycles washed through mixture back into the cylinder via the exhaust port and effectively `plugs` it just prior to the port closing ; it is diffuser action that draws mixture into the cylinder during the  transfer phase. Nor is it just a matter of mixture drawn into the cylinder, but of mixture drawn through the cylinder. Some stays there, some exits and is returned and some is irretrievably lost, particularly at engine revs outside the optimum range! The pipe is an influence one way or another on all of these happenings.  
Notwithstanding the conditions in the cylinder at the point of exhaust port opening, it is blowdown time/area that determines the cylinder pressure at transfer opening. Blowdown, critically depends on four principle factors, exhaust timing, transfer timing, effective exhaust port area and exhaust flow co-efficient. Another apparent ambiguity is at play here also. At low rpm around the base of the power range rpm there will be more blowdown time/area than the engine needs, at high rpm there isn`t enough and blowdown may continue after the transfer ports open, they then become convenient, additional exhaust ports. So in one sense it can be argued that the exhaust gas determines how much time/area is needed to evacuate the cylinder effectively?

All of these complex, interrelated flow and pressure fluctuations are taking place inside the engine that is equipped with an exhaust pipe that has pre-determined, rigidly fixed dimensions, and that seems to be a direct conflict of intention.
The last 10 years or so has seen a burgeoning of worldwide understanding of the physics of wave action in exhaust pipes, which has been painstakingly arrived at by both countless hours of computer simulation and subsequent confirmation during dyno sessions and then track testing. If all three correlate pretty well then reliable parameters can be established. Linear dimensioning is now reasonably straight forward, but determining diameters is less clear cut, particularly so with low BMEP engines such as the larger 186cc Bantam. By definition, the amount of energy remaining after blowdown for the pipe to work with is comparatively modest and must be utilised to best effect, energy that can be utilised to work for us is a precious commodity in Bantam engines!
One thing is for certain, the old generic formulas dressed up in 2stroke tuning packages offering the last word in pipe design are, in the overwhelming number of instances, merely derivatives of Gordon Blair`s work of the70s and 80s that are now tending towards obsolescence!

Trevor"

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 PIPE_4_DRAWING_TREVOR_MODS_APRIL_2016


In this section we look at the pipe sketch that Rex posted on social media and has been used for successful, early season competition, the inset on the alternative pipe drawing is that same drawing.
The first dimension to consider is the tuned length, and that is shown to be 1064mm, we are also provided with values for exhaust port timing and the rpm. By inserting these into the formula for tuned length we can re-arrange the numbers to discover the speed of sound in mtrs/sec.

t/l =   speed of sound x exhaust timing x 88 / rpm    1064 =  S of S x 178 x 88 / 7845
Re-arranging for S of S  gives….. 533mtrs/sec

It is also useful to know the temperature value used in these calculations, and this can be found by re-arranging the equation for speed of sound.

533 = sq root…( YR(temp + 273)).  YR is a constant at 392.85, temp is in Kelvin, hence +273
Re-arranging for temp….533^2/392.85 = 723, minus 273 = 450*c

Working through the pipe from the piston face there is the 67mm length of the exhaust duct and the header pipe itself that begins at a diameter of 34mm then terminates at a diameter of 50.2mm producing an angle of 1.63*.
There is a finite quantity of wave energy available to be exploited, but by the time the exhaust gas has reached the first, larger diameter area it has expanded a lot, with the consequence that gas density and thermal energy density are much lower. The surface area of that cone is 37220 sq/mm and volume is 392cc. If we reduce that angle to 1.5*those numbers reduce to 36544sq/mm and volume of 381cc. The relationship between flow area and pipe wall temperatures means that the 1.5* header surface area has a smaller percentage of gas touching the wall and so the centre core remains hotter, maintains velocity and the rest of the pipe retains more energy with which to do good things. For any one that has seen those terrific thermal images of the pipe on the Bonneville Boy`s dyno tests will see confirmation of the centre core heat, whereby the mid-section is cool and the tailpipe entry glows with heat!
Header length, and that includes the ex. duct, should be in the range 30-33% of tuned length, so at around 348mm Rex`s pipe is on the money at 32.7% and straight into the ball game! The header serves ostensibly to time the beginning of diffuser action, as such we don`t want any nasty reflections travelling back towards the cylinder to mess things up and is the main reason for its shallow taper.
Reference was made earlier of the header volume, in itself is not an overly significant number but short circuited gas and some of the over scavenged mixture lurk in the header awaiting return to the cylinder, curtesy of the later plugging pulse, to augment the following compression process . With the smaller area of the 1.5* header the higher velocity will encourage combusted gas to evacuate the scene and the washed through fresh mixture will be a little cooler and thereby denser, and that is of benefit to a thermally stressed air cooled engine.

It is with the diffuser section that this alternative design is conceptually at variance with Rex`s pipe.
In an ideal world we would want the transfer flow to actually start at transfer port opening and come to a halt at transfer closing. The big problem with this is that the pressures at transfer duct entry in the crankcase and their exit into the cylinder are constantly in a state change, with one short exception. This occurs when the piston is stationary at BDC and where the transfer port area is also at its greatest! It is at this point in crank rotation that the diffuser should be able to draw the maximum amount of mixture into the cylinder for the longest period of time.  
What is important is the way that exhaust gas energy is converted into suction by diffuser action, and whilst doing so retaining some of that energy to create a later, positive return plugging pulse. For Bantam race pipes, it`s all about finding a balance. There is absolutely no benefit in having an aggressively angled diffuser that sucks a litre of fresh mixture into the header if the retuning pulse is so weak only half a litre is stuffed back in. Equally it is of no help when the returning plugging pulse not only pushes the washed through mixture but also a large amount of hot, spent gas back into the cylinder that dilutes and pre-heats the following combustion phase!

At this point it might be helpful to establish some aspects of what a diffuser actually is and what it does?
A diffuser is a gradually expanding passage in which gas flow speed decreases and pressure rises, with recovery of pressure from kinetic energy in a time dependent process. An efficient diffuser is one which converts the highest possible percentage of kinetic energy into pressure energy within the given length and expansion ratio of entry to exit. Gas expansion occurs in both the flow direction and out to the passage walls, here the velocity is almost zero and highest about its centre line core.
The diffuser on the Rex pipe has a two stages with a combined length of some 291.1mm, with the respective cone`s relationship of 2/3 and 1/3, this length represents 27.36% of the tuned length. From piston face to the end of the diffuser represents 60% of the tuned length. Almost every two stroke race engine in our current era, 2000+, uses an exhaust system in which the end of the diffuser is in the general proportion of 66% of t/l, accepting this then the diffuser is some 6% short of ideal, or almost 64mm, a significant number in exhaust pipe terms!
The alternative diffuser has 3 stages, with the steepest angle in the middle with equal angles either side, these were not necessarily desirable, but keeping the 106mm main diameter forces compromises. The general layout considers the wave activity throughout the power range right up to overrev. The first cone is longer, partly because because the transfer flow is delayed from initial port opening by flow reversal; but it also positions the start of the middle cone that makes the mid-top end power, however when referencing to bdc the cycle become asymmetric in nature. If we have the correct individual diffuser lengths, the effective part of the depression will always move with rpm from close to transfer opening, then centre on bdc at peak power and move towards transfer closing in the over rev area. The third short, shallow cone helps to get the long steep main cone leading to the belly section, again a compromise on maximum diameter. It makes no sense to have the steep angle right up to the belly and so cut its influence short, which can then only rely on the inertia of the transfer gas column to maintain flow at a point where case pressure is falling with a rising piston and cylinder pressure is increasing enough to oppose in-flow! If this should happen before transfer port closure scavenging efficiency is inevitably reduced.

The belly section almost maintains the Rex`s pipe diameter, it is never profitable to use big diameter pipes which have steep cones on engines with less than optimised transfer duct profiles. The outcome is that in-cylinder directional control of the high velocity scavenge streams is hugely compromised and large amounts of mixture short circuits out of the exhaust port.
Timing of the rear cone is performed by the belly length and as such has no impact on wave activity in that parallel sections won`t reflect pressure waves. The tiny taper out to 108mm diameter merely enables the rear cone to have a slightly steeper angle, up to 9.4* from a lowly 7.88*, accommodated in the same length.
By its very nature, an excessively long convergent cone will supress peak value and also has a heavily detrimental effect either side of the tuned length; the return pulse is of long duration but low in amplitude and incorrectly timed at low rpm and arrives far too late towards peak rpm. As such the plugging effect so essential in augmenting the combustion charge is heavily compromised. The steeper cone of the alternative pipe helps in this respect but is still shallow by contemporary standards. The highest I have used was 14*(28*inc) but that was on pipe we made for Steve`s RS, with ignition timing control and electronic carb mixture control, both keeping power up when pushing over rev to 13,500rpm where things start to drop off and power fades.
As the diameter of the tail pipe is determined largely by the amount of exhausted gas it has to handle, and a less than 8 bar bmep engine doesn`t produce too much; then the returning pressure wave from the rear cone can be enhanced a touch more with a smaller pipe/insert diameter. Care has to be taken here to prevent overheating from going too small and preventing full evacuation of the cylinder/pipe combination before the next cycle begins.

All of the forgoing is merely a rejigging of the original design, and in its self can be altered. But I have tried to give credence to this alternative design with cogent and I think, well-reasoned explanations.

Trevor"

Of course we are very keen to share and promote this knowledge so we all can learn lots more about the exciting Bantam Opportunity!

Have a Great Week!..................Rex




I
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Trevor Amos




Number of posts : 938
Registration date : 2010-08-13

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeTue Apr 12, 2016 6:21 am

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Alternative%20pipe%20dims_zps7ffmeznp

Thank you including this on your topic Rex,
 Here is a larger image of the pipe in question, again our gratitude is due to Rex for his kind co-operation in producing this article, I hope it will provide for some guidance for those looking for a better pipe, and the thinking behind a modern design!

Trevor
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nigel breeze

nigel breeze


Number of posts : 358
Registration date : 2007-12-23

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PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon May 16, 2016 7:17 am

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Img_2010

tinkering again... lol!
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rexcaunt




Number of posts : 79
Age : 77
Localisation : SUNNY BARWELL
Registration date : 2014-07-31

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PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon Feb 27, 2017 12:51 am

Hi All,

Good to hear of the awesome activity going on with Bantam Racing!

We will be at Mallory practice running more development products and pushing on to further our mission to build confidence with this Awesome Class! Very Happy

Thanks to all your continued support!

Have a Fabulous Week!

Cheers!.................Rex & Debb
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nigel breeze

nigel breeze


Number of posts : 358
Registration date : 2007-12-23

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon Feb 27, 2017 5:38 am

good luck Rex... im back to square one 175 cant handle 12500 rpm???
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nigel breeze

nigel breeze


Number of posts : 358
Registration date : 2007-12-23

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon Feb 27, 2017 5:49 am

having said that, im hoping my 125 can handle 30,000 rpm (potentially)
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john bass

john bass


Number of posts : 1748
Age : 94
Localisation : Bensberg, Germany
Registration date : 2006-12-06

.................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Empty
PostSubject: Dyno versus track testing...   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitimeMon Feb 27, 2017 9:12 pm

Way back in 1972 whilst trying to get Andy´s 250 Alpha special to work by track testing at Brands he gave me a chubby pipe with dimensions
similar you show and despiite playing around with gear ratios it just would NOT come on song. I spent two half-hour sessions changing the rear
sprocket and going out and making embarrassing  burp-burp-burp noises all the way round, several times  -- and getting in fast riders way --
to finally put the "old" (more slender) pipe back on and having a bit of fun revving up to 9 and a half thousand revs to annoy Dominatirs and Triumphs
and the like....

Thing was we wrote off that pipe where on the dyno we might have made it work and we might have made more revs -- who Knows??.

One thing seems positive now -- with the burbling around Brands the chubby pipe was Probably not getting warm enough to work properly ...??????

I know this bit of Rabbit is no Bl...dy use to anyone but it does point out that track development by Track testing is really only meant for AFTER
dyno work has been completed.

From quite a number of decades back Andy has been using dyno testing and  he now he the Alpha DKW Centurion Twin added to his 250 RE 5
stable  so I look forward  to seeing more of those two Historical bikes in the results....

Good luck to Rex and Nick at mallory....
cheers!
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PostSubject: Re: .................*NICK BRAMLEY'S 186CC ENGINE*.............   .................*NICK BRAMLEY'S  186CC ENGINE*............. - Page 4 Icon_minitime

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