scootz
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| posted on 23/11/08 at 05:29 PM |
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V8 Exhaust
Hypothetically speaking... does anyone have any idea about how a V8 engine would run if each of the 8 exhaust ports was fitted with a short link-pipe
(2-3 inches) and an aftermarket (Micron, etc.) bike can?
My engine is a 4200cc and 420bhp, so each can is dealing with 525cc and 52.5bhp... not a lot, so no great concerns about longevity of the
silencers.
Just wondering how well it would breathe really.
Only reason I'm asking is that I can do this myself and it will cost / weigh a damn sight less than a bespoke 4-1 system.
Appreciate it's not an 'everyday question' but would welcome any comments!
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blakep82
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| posted on 23/11/08 at 05:31 PM |
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8 exhausts?! 
or did i get the wrong end of that?
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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cloudy
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| posted on 23/11/08 at 05:36 PM |
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For a start you loose all scavenging, you'll experience a sizeable drop in power...
Plus the cost of all those cans!
James
www.warnercars.com
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speedyxjs
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| posted on 23/11/08 at 05:56 PM |
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scootz - Thats not the jag engine you were trying to sell a while back is it?
How long can i resist the temptation to drop a V8 in?
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scootz
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| posted on 23/11/08 at 06:34 PM |
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Blake... yes  (hypothetically speaking)
Cloudy... tell me more about the loss of power theory - this is the stuff I'd like to know about. Noticed a lot of drag cars had short straight
pipes directly from the exhaust-ports. PS - Cost of cans is not a problem... I have a supply!
SpeedyXJS... nope - that sold a while back 
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cloudy
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| posted on 23/11/08 at 06:35 PM |
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Exhausts are normally designed so the low pressure area behind the previous cylinders expulsion is used to help draw the exhaust of another cylinder
out....
www.warnercars.com
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scootz
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| posted on 23/11/08 at 06:36 PM |
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Ah... so basically a non-starter then!
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C10CoryM
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| posted on 23/11/08 at 06:45 PM |
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Most drag cars are boosted which do not require the same level of care when it comes to scavenging. They also make 600 to 6000+hp so other factors
are often more important.
Where exactly would you fit 8 mufflers on a locost?
"Our watchword evermore shall be: The Maple Leaf Forever!"
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scootz
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| posted on 23/11/08 at 06:47 PM |
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I've plenty of room Cory... I'm not building a 7-type.
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blakep82
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| posted on 23/11/08 at 06:48 PM |
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you're building 'a thing'
i like how people only see 7's being built lol
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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scootz
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| posted on 23/11/08 at 06:55 PM |
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Indeed... t'was once a Spyder kit - has now mutated into a thing!
Bugger... so, I'm going to have to fork out loads of dosh for 2 custom manifolds!
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C10CoryM
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| posted on 23/11/08 at 07:20 PM |
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Well you are on a locost forum after all.
For your manifolds you may be able to do what I've done. Buy a cheap, commonly available header kit like this
http://www.speedwaymotors.com/SMALL-BLOCK-CHEVY-HEADER-KIT,3843.html
And then make or get flange made up to bolt to your heads. $170 or so and a lot of your own time should get you some nice headers.
Cheers.
"Our watchword evermore shall be: The Maple Leaf Forever!"
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scootz
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| posted on 23/11/08 at 07:30 PM |
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Cheers Cory!
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02GF74
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| posted on 23/11/08 at 07:54 PM |
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^^^ wot they say.
on drag engines, thosethings are running at such high pressures and high rpm that scavenging does not matter, hence the short and individual pipes.
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scootz
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| posted on 24/11/08 at 10:43 AM |
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Does the compression ratio come into it... the engine I'm using is pretty high at 12.5:1
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NS Dev
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| posted on 24/11/08 at 12:19 PM |
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no, you really need the scavenging effect on a non forced induction engine
You could stick a supercharger on it and run the 8 cans though!
[Edited on 24/11/08 by NS Dev]
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
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scootz
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| posted on 24/11/08 at 01:03 PM |
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Okay dokay... hint taken - 2 manifolds it is!
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