Exhaust tuned length

[Knowledge]

I didn't ask the question to learn the secrets of the exhaust designers, and I do appreciate that the way that an exhaust works is greatly affected by the design of it's cones and volumes, but tuned length is so closely related to peak power that I hoped that by knowing the tuned lengths of a series of exhausts, it might help people decide which exhausts were unsuitable for their tune.

Being able to dismiss a number of exhausts from your possible choices is time well spent.

[tony]

On this forum there are one or two people who really know their stuff. Adam is one such person. But he feels "why should i bother" when he reads stupid comments on a thread. Its a shame as those people might learn something if they are interested. And now the genuine people such as Martin Knowledge who asks genuine questions dont get the answer.

I tried to get Adam to post up the factors of exhaust design.. or at least how he does it, today.. but no go..
So... i'll tell a bit..

For proper pipe design...CC,stroke,comp, Ex port area inlet, ex port area outlet, radius, top radius, lower radius, ex exit angle.. ex port length, duration, blow down period, trans duration and boost duration,trans main back angle, trans 2nd back angle.. trans area and up angle, 2nd trans area and up angle, trans radius', boost up angle and area. Inlet timing (if applicable). Squish angle and velocity. ex temp req, Aimed rpm peak, Over rev req?, Torque start rpm and finish rpm.
This is only the start of 'proper' exhaust design..
So... yes.. you can get an 'idea' by measuring the length of a pipe.. but its only an idea. There are so many factors involved its easier to say "how long is a piece of string".

[cezeta]

can you expand on the stupid comments tony, all i can see is my tin snip and rivets comment which was obviously a joke in contrast of the reality of making these things and apart from that everything was constructive from everybody.

the thread wasn't aimed at you or adspeed, you offered to contribute. it appeared to be a general open for all debate that created some curiosity into the relationship with tuned lengths and barrel tuning.

many of the answers are in the tuning books but its interesting to chew the fat over these things.

adspeeds exhausts have been received well from what i can see, if he doesn't want to debate the pros and cons with them with his potential punters then that's ok, most dealers/tuners ect are quite cynical about these forums and i imagine they become sensitive when their products are under constant scrutiny.

others use the opportunity for a running advert.

but to the rest of us its just a hobby that's not taken that seriously. in the overall scheme of life us middle aged has-beens don't really score on the worlds relevance stakes so why everyone keeps getting precious and sulky i don't know.

lighten up and enjoy

[coaster]

So... yes.. you can get an 'idea' by measuring the length of a pipe.. but its only an idea. There are so many factors involved its easier to say "how long is a piece of string".

I don't think Martin is questioning that Tony, I think he is just trying to determine the tuned lenths of proprietory off the shelf systems so that he can select one which best matches his state of tune.

I've just finished reading my first 2 stroke tunning book (Bells) and my head is still hurting

[tony]

Coaster.. sure mate... I know martin pretty well and I agree with his question.. it would be nice to know what these designers had in mind.. tbh I think a lot of off shelf pipes are based on Bell's prinicples and thats fine as long as we understand how basic the info is in that book. Lets throw another few spanners in.. how about the dreaded primary comp.. wall thickness.. and most of all material!Bell doesnt touch on hardly any of these factors or the above in his book.. I've made pipes to Bell's theory.. I realised that the port areas and blow downs i was using made the pipe no good whatsoever and I had to lengthen them.

Nick.. I'm not sure thats how your comments were taken 'as a joke' hence I guess why we didnt get Adam's in-depth post. Shame really cos he knows a hell of a lot more than us and he has been succesful at it too with more to come I reckon.

[cezeta]

Tony, adspeed is not stupid or a baby that needs anyone to speak on his behalf. He knew that my comment was a joke, he may have thought it was at his expence implying his pipes were made with tin snips and rivets but thats not the case. pipes in general are easy to make not addspeeds in particilar......which of course is an inversion of reality and with a smiley.....the international code for humour with expression

and like he needs my aproval any way

http://www.youtube.com/watch?v=DTwaX2AAAlQ

[drunkmunkey6969]

Ads, out of interest, have you any idea what the total volume of your race pipe measures?

[Supereibar]

[cezeta]

Out of this subject I post here to say that I am quite tired and saddened of observing irrelevant, nearly personal connotations from one onto another amongs those who I consider friends of mine. I would politely ask this to stop.

Kind regards to all,

Jaime

no way....its too much fun. there was no bad intention on my part amigo and i would bet a pair of tin snips that addspeed just got the wrong end of the stick and if he read what i said again then he would realise that i was defending exhaust designers from having their exhausts copied in czech republic without permission not being derogatory about his pipe.

but you know me......i see a warped humour in these things

anyway....i just bought a motorbike so im off to grow a mullet.

[Supereibar]