PDA

View Full Version : Designing Custom Expansion Chamber



coffee
04-03-2009, 10:12 PM
Guys,
Does anyone have any literature on designing an expansion chamber. That gives angles of the inital opening and angle of the closing how to calculate the volume etc how to work out the max dia and optimum velocity?

Noassmblyrqired
04-05-2009, 08:57 AM
Variables are too complex for hand calculations, this is mostly done with software. Not sure what the "hot" software is these days.

My Jollymoto Corsa system came with little spaces and venturis to tweak the system...it was pretty cool.

coffee
04-05-2009, 11:03 PM
have you used a cosa pipe, I am currently looking into buying one, just not 100% sure if it would be good enough for a very high rpm range like 15-16,000ish?
If you have one would love to hear what is done to your bike and your opinion of the exhaust system. Good or bad

FUERA.....1
04-06-2009, 03:58 AM
Mate... seriously, your dreaming about getting 16,000rpm and maintaining it as a reliable road engine. Mabey once your engine pulls that kind of rpm, then by all means tell us about it, you make laugh bud

And a jolly pipe if anything it would be the most suitable to achive higher revs as it has more of a racing characteristic behind the design

coffee
04-06-2009, 06:26 AM
Thanks

PJ ENGINEERING
04-06-2009, 01:14 PM
Photos from my visit to the Jolly Moto factory

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-1.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-2.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-3.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-4.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-5.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-6.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-7.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-8.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-9.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-10.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-11.JPG

http://www.apriliachat.co.uk/IMAGES/EBAY/JOLLY-MOTO-12.JPG

coffee
04-06-2009, 10:02 PM
Do you think they will do custom pipes like what i am suggesting?
Surely they have expertice and software etc to design from scratch. Might be interesting to enquire.

FUERA.....1
04-07-2009, 01:34 AM
Do you think they will do custom pipes like what i am suggesting?
Surely they have expertice and software etc to design from scratch. Might be interesting to enquire.

Could try, its something like $1500au to get a new jolly pipe here is aus, so a custom one would prolly cost a fortune

coffee
04-07-2009, 08:01 AM
Well I am expecting that but can't hurt to ask. I expect they may not even deal directly with me and only with dealers?
I have asked for a price here from two companyies a few weeks ago and neither got me a price yet for a corsa. They really are not helpful here in Sydney regarding this bike.

Rca119
04-07-2009, 08:11 AM
Gordon Jennings<------ 2-stroke guru.....look him up. Here is a primer http://www.bridgestonemotorcycle.com/documents/do_you_really6.pdf

coffee
04-07-2009, 04:51 PM
Rca,
That is great mate. Much appreciated, not sure why the UK forum isn't so forth coming and helpful. Will email him as well as Jolly and see what they both say

FUERA.....1
04-08-2009, 12:47 AM
Well I am expecting that but can't hurt to ask. I expect they may not even deal directly with me and only with dealers?
I have asked for a price here from two companyies a few weeks ago and neither got me a price yet for a corsa. They really are not helpful here in Sydney regarding this bike.

I thought the importer of jolly pipes was located in sydney?

William the Third
04-08-2009, 02:03 AM
Exhaust calculator 2 (http://fpp.hamradio.si/roost/software/index.html). It defaults to commas "," and not decimals "." so if you get some strange numbers (like negitive numbers), make sure all commas are decimals.

coffee
04-08-2009, 02:55 AM
Fuera,
You maybe correct? I was going to email the manufacturer directly.

Old Geezer
04-10-2009, 10:27 AM
Rca,
That is great mate. Much appreciated, not sure why the UK forum isn't so forth coming and helpful. Will email him as well as Jolly and see what they both say

No offence mate, but 'unhelpfulness' is due to the fact that you are nuts. Pointless silly Qs by the dozen, this is the most developed engine in the history of motor sport I should think, what on earth do you expect to achieve?

random0082
04-10-2009, 01:54 PM
Good luck contacting Jennings and getting him to design and / or build a custom spannie for your 16,000 rpm RS125, LOL! Might as well contact Einstein and Sir Isaac Newton while you're at it, get them to help with the maths and physics.

Maybe Brunel could help you fabricate it too? and then you could ring up some alchemists, they could turn water to gold and plate it for you


:happy:

The_Reaper
04-12-2009, 03:21 PM
Good luck contacting Jennings and getting him to design and / or build a custom spannie for your 16,000 rpm RS125, LOL! Might as well contact Einstein and Sir Isaac Newton while you're at it, get them to help with the maths and physics.

Maybe Brunel could help you fabricate it too? and then you could ring up some alchemists, they could turn water to gold and plate it for you


:happy:

sounds like a plan (: if you want to organise it i'll give you 5 towards your budget XD

coffee, i have some two stroke tuning books from when my dad was racing that has some stuff about designing spanny chambers, but 16k? good luck dude. i'll try and post any information and pics that may help if you really want to make a pipe for your rs, but aimt a little lower down the foodchain dude (:

Zak

coffee
04-14-2009, 07:34 PM
Zak,
That would be helpful and expect for others as well. Much appreciated!

The_Reaper
04-15-2009, 05:45 AM
coffee, if you give me your exhaust port size, target rpm for powerband if not 16k, exhaust open period in degrees, and weather you want a wide spread powerband (less power) or a peaky powerband (more power), and i will do the calculations as soon as possible.

Zak

coffee
04-15-2009, 05:45 PM
Reaper,
Much appreciated. I will come back to you with that and hold you to it.

Old Geezer
04-16-2009, 01:54 AM
What you might well find is that one of the pipe makers uses the same software, and their design will be very close. Simply cut and shut the downpipe might be the cheap way of achieving the custom pipe of your dreams.

The_Reaper
04-16-2009, 03:09 AM
old geezer i dont actually use software :D which makes me a very cool 16 year old :D

Old Geezer
04-16-2009, 04:49 AM
You make do with a small hand axe and a sledgehammer I assume. And if it doesn't work the 1st time, use a bigger hammer?

The_Reaper
04-16-2009, 04:53 AM
haha no :D i go straight onto the bigger one :p:
no i've learnt a lot of my two stroke knowledge from my dad, as he used to race yamaha lc's back in the day and now owns a motorcycle repair shop :D

i also have a small collection of two stroke tuning books that cover this topic of making exhausts for a specific use.

Luckily i'm not like the average "hoodie on a hairdryer" and i do have some mechanical knowledge :)

Zak

The_Reaper
04-16-2009, 04:55 AM
i'm not saying that this exhaust for a 16k powerband is possible, i am just interested in what dimensions and sizes i reach from my calculations. the making part is up to whoever wants to use it.

Old Geezer
04-16-2009, 11:55 AM
I never thought you were the average hoodie on a hairdryer.... glad you have a sense of humour! I like to fiddle with my 2 strokes (fnar fnar), currently don't have enough, I am taking steps to rectify that, by getting one myself, as well as 2 new ones for my twins. We will briefly have 5 RSs of various types if all goes to plan.

The_Reaper
04-17-2009, 05:05 AM
I never thought you were the average hoodie on a hairdryer.... glad you have a sense of humour! I like to fiddle with my 2 strokes (fnar fnar), currently don't have enough, I am taking steps to rectify that, by getting one myself, as well as 2 new ones for my twins. We will briefly have 5 RSs of various types if all goes to plan.

five rs's?!?! that would be pretty cool :D i've currently stopped fiddling with my sr untill i get my tuono 125 on the road, as i need the little scoot to get to and from 6th form and work :D it's going to need a new piston shortly though but i can squeeze one more month out of it :)

i know you didnt think that i was a hoodie with a hairdryer lol :p: i have a very good sense of humour, as you can tell by my response to the sledge hammer :D