phelpsa
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| posted on 21/3/10 at 11:41 PM |
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Top work by Exhausts By Design
Just a quick plug. Took the Locost up to them last saturday along with a silencer and basically said 'erm, this joined to that please'. A
week later this is what was waiting for us:
It was a pretty mean task as its all pretty tight clearance wise! £520 all inc. Almost a shame to use it and get it dirty!
http://web.ukonline.co.uk/grahamf/index.htm
Adam
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mookaloid
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| posted on 22/3/10 at 12:04 AM |
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neat 
"That thing you're thinking - it wont be that."
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dan__wright
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| posted on 22/3/10 at 08:03 AM |
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graham made my manifold too, piece of art even if i do say so myself 
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indykid
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| posted on 22/3/10 at 09:31 AM |
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looks great but shouldn't (ports 4 and 1) and (ports 2 and 3) be siamesed in a 4-2-1?
the wave pulses will surely be out of phase so you won't get any scavenging.....or does this give you 2 lesser bands of scavenging?
tom
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Mark Allanson
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| posted on 22/3/10 at 09:40 AM |
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quote:
Originally posted by indykid
looks great but shouldn't (ports 4 and 1) and (ports 2 and 3) be siamesed in a 4-2-1?
the wave pulses will surely be out of phase so you won't get any scavenging.....or does this give you 2 lesser bands of scavenging?
tom
As far as I am aware, a 4:2:1 is good for torque at low end revs, and a 4:1 is good for power at higher revs. As Adam is using a starter motor from a
Pinto, the 4:1 may be more appropriate
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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Richard Quinn
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| posted on 22/3/10 at 10:08 AM |
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quote:
Originally posted by Mark Allanson
quote:
Originally posted by indykid
looks great but shouldn't (ports 4 and 1) and (ports 2 and 3) be siamesed in a 4-2-1?
the wave pulses will surely be out of phase so you won't get any scavenging.....or does this give you 2 lesser bands of scavenging?
tom
As far as I am aware, a 4:2:1 is good for torque at low end revs, and a 4:1 is good for power at higher revs. As Adam is using a starter motor from a
Pinto, the 4:1 may be more appropriate
Looks like a 4:2:1 from the photo
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franky
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| posted on 22/3/10 at 11:03 AM |
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On a bike engine 4-2-1 will give the best power all over, Due to the extra rev's it doesn't quite work out the same as car exhaust
theory.... how many aftermarket performance superbike exhausts do you see that are 4-1?
None, all 4-2-1
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iank
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| posted on 22/3/10 at 11:55 AM |
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Yes, but you can't just choose random cylinders to pair up in the 4:2 sections (as far as I'm aware) which is indykid's concern.
[Edited on 22/3/10 by iank]
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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Richard Quinn
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| posted on 22/3/10 at 12:23 PM |
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quote:
Originally posted by franky
None, all 4-2-1
Not on my BEC! 
(Ok, so it's not strictly a superbike)
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eddie99
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| posted on 22/3/10 at 12:35 PM |
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The picture also looks like a 4-2-1 to me
http://www.elitemotorsporteng.co.uk/
Twitter: @Elitemotoreng
Facebook: http://www.facebook.com/pages/Elite-Motorsport-Engineering/153409081394323
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NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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smart51
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| posted on 22/3/10 at 12:55 PM |
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His question is not "is that a 4 into 2 into 1" but "haven't you joined the wrong pairs of cylinders together?"
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phelpsa
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| posted on 22/3/10 at 12:58 PM |
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I have no idea on exhaust design... could someone in the know advise?
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scootz
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| posted on 22/3/10 at 12:59 PM |
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quote:
Originally posted by iank
Yes, but you can't just choose random cylinders to pair up in the 4:2 sections (as far as I'm aware) which is indykid's concern.
Yep, think we're all agreed it's a 4-2-1 system (was there ever any debate?), but the question surrounds the appropriateness of the choice
of twinned cylinders for the '2' bit!
It's Evolution Baby!
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matt_gsxr
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| posted on 22/3/10 at 01:02 PM |
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Very nice and shinny.
Interestingly Graham also made my exhaust and paired them 1 with 4, and 2 with 3.
Mine is basically the same engine (water cooled rather than air cooled). It looks to me like you have longer primaries and secondaries than I have
but it could be an illusion.
It would be interesting to see the design documentation, given the name of his company I assume there is some ;-)
I don't have power figures on my engine so don't know whether mine is right or not, but it seems to go alright.
Matt
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dan__wright
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| posted on 22/3/10 at 01:17 PM |
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just had a look at mine and he did 1+4, 2+3
FREE THE ROADSTER ONE…!!
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wicket
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| posted on 22/3/10 at 04:26 PM |
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Mines a modified Ford part & is 1+4, 2+3
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Hellfire
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| posted on 22/3/10 at 06:40 PM |
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The firing order of the GSXR 1100 is 1-2-4-3 which would suggest 1&4 should be paired and 2&3 should be paired.
Phil
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indykid
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| posted on 22/3/10 at 11:18 PM |
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huzzah, we got there in the end.
as has been noted by some people, my concern is that 1 and 2 are siamesed, as are 3 and 4.
the theory behind 4-2-1 is driven by the echo of the pressure wave scavencing the other cylinder. if you think of it like a clock, 12 scavenges 6 and
vice versa, both 2 cycles away from each other
that manifold has 1 scavenging 2, (3 oclock scavenging 6 o clock) but 2 can't scavenege 1 at the same rpm because it's got to get back to
2's exhaust valves being open....which is 3 cycles away, not 1.
i hope they can either prove their theory or sort it out for you. seems like an expensive manifold to not be tuned
tom
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phelpsa
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| posted on 23/3/10 at 02:54 PM |
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quote:
Originally posted by indykid
huzzah, we got there in the end.
as has been noted by some people, my concern is that 1 and 2 are siamesed, as are 3 and 4.
the theory behind 4-2-1 is driven by the echo of the pressure wave scavencing the other cylinder. if you think of it like a clock, 12 scavenges 6 and
vice versa, both 2 cycles away from each other
that manifold has 1 scavenging 2, (3 oclock scavenging 6 o clock) but 2 can't scavenege 1 at the same rpm because it's got to get back to
2's exhaust valves being open....which is 3 cycles away, not 1.
i hope they can either prove their theory or sort it out for you. seems like an expensive manifold to not be tuned
tom
I've been having a think... surely this would mean the scavenging effect would just happen at a higher rpm so the engine has gone through more
cycles before the pulse returns to the exhaust valve? The longer primaries/secondaries brings it down the rev range a bit by increasing the time taken
for the pulse to return, so you end up with that extra torque somewhere above where a normal 4-2-1 would put it but below where a 4-1 would (on the
same size primaries). I'll get in contact with graham to confirm my theory though.
EDIT: thinking about it it would give a better spread of torque as a small amount of scavenging would occur at two points in the rev range.
I've just remembered that the standard exhaust on the bike is a 4-2-1 in this setup, which is probably why graham did it like that.
[Edited on 23-3-10 by phelpsa]
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matt_gsxr
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| posted on 23/3/10 at 06:27 PM |
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Just been googling.
It looks like Yoshimura (who are recognised as being pretty good on this stuff), connect 1-3 and 2-4.
Obviously a bit of a black art.
Are you going to ask Graham why he connected them like he did? He can be a bit gruff!
also like this one (bandit, but same engine as gsxr1100 oil cooled).
Once more proving that I don't understand exhaust design!
Matt
p.s. I like the wheels (Pug rallye perhaps?)
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indykid
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| posted on 29/3/10 at 11:11 PM |
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quote:
Originally posted by matt_gsxr
Just been googling.
It looks like Yoshimura (who are recognised as being pretty good on this stuff), connect 1-3 and 2-4.
looks like 4-1 to me.
did you ever get an answer on this adam?
tom
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