sammundo
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| posted on 12/12/20 at 02:23 PM |
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exhaust port size
hi folks. Quick question. I have a standard 1300 crossflow going in my locost with 30mm exhaust ports. I have the standard manifold but i have found a
4-2-1 with 34mm ports for pretty cheap. Will it work well without porting the head? Or should i stick with the original.
cheers
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Deckman001
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| posted on 12/12/20 at 02:34 PM |
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Hi ya, the slightly larger exhaust shouldn't affect your 1300 xflow, it lets the exhaust escape quicker that normal so if you have a big valve
head, it'll be even better. I have a larger than normal exhaust on my 1600, it allows the gases to escape better.
Jason
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gremlin1234
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| posted on 12/12/20 at 04:45 PM |
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mismatched pipes can/will cause turbulence, think of the exhaust as a tuned musical instrument.
but just go for it, gives you an excuse to 'port' the head later too
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steve m
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| posted on 12/12/20 at 05:48 PM |
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I would fettle the head to match the headers, its an easy but time consuming job,
You will also need the larger exhaust gaskets
But in reality a 1300 xflow, even in a locost/lightweight car will be like driving a Nissan Micra
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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Shooter63
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| posted on 12/12/20 at 07:49 PM |
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Just to go against the grain here, don't match the port to the manifold, mismatch is a good thing as long as the manifold is bigger, what it
does is help stop the pulse going back into the chamber and pushing the new inlet charge out.
Shooter
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snapper
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| posted on 13/12/20 at 08:01 AM |
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quote:
Originally posted by Shooter63
Just to go against the grain here, don't match the port to the manifold, mismatch is a good thing as long as the manifold is bigger, what it
does is help stop the pulse going back into the chamber and pushing the new inlet charge out.
Shooter
Shooter is sort of right but the professional way is to use anti reversion stubs which are short tubes welded on to the manifold plate that are port
matched then a much larger primary pipe welded over that.
In reality only any good for a drag racer.
You 4 branch manifold will be better than the cast original by a long chalk and work well on a 1600 if you ever swap it out.
Fit it and enjoy
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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jelly head
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| posted on 13/12/20 at 08:27 AM |
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Smooth flow on the exhaust side is not quite as importand as such as don't forget you have a piston pushing the exhaust gasses out, depends if
you're after every HP in which case you'd be doing the head anyway.
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sammundo
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| posted on 13/12/20 at 05:48 PM |
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thanks for the replys guys. I think i'll go for it. I am liking the simplicity of the xflow so maybe a 1600 will come in down the line.
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steve m
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| posted on 13/12/20 at 06:56 PM |
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You wont regret going up to 1600, its 7/8" taller,
and then you may progress to a 1700 (1696)
Thats was probably spelt wrong, or had some grammer, that the "grammer police have to have a moan at
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coyoteboy
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| posted on 15/12/20 at 12:41 PM |
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It's 2mm on the radius, you won't see any difference without back to back dyno runs. If it had been 5mm I'd be much more worried,
but I've still seen OEM manifolds worse.
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