Cause it dont go as good as it should. Head is good YT- small chamber, 192 bore crow 35802 cam, rollers, graphed elec dizzy etc
Is the manifold holding this thing back
pic lookin in at 5&6
Manifold dosent line up
Started by
Ferg
, Jun 01 2006 11:59 PM
12 replies to this topic
#1
Ferg
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Posted 01 June 2006 - 11:59 PM
Red 6 9 port with tripple xu-1 carbs, manifold is highly ported ( more than head ) so what is gonna happen, turbulance - pooling of fuel
Cause it dont go as good as it should. Head is good YT- small chamber, 192 bore crow 35802 cam, rollers, graphed elec dizzy etc
Is the manifold holding this thing back
pic lookin in at 5&6
Cause it dont go as good as it should. Head is good YT- small chamber, 192 bore crow 35802 cam, rollers, graphed elec dizzy etc
Is the manifold holding this thing back
pic lookin in at 5&6
#2
Ferg
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Posted 02 June 2006 - 12:10 AM
Plenty of comp in there to suck fuel
New guides, ulp seats, springs & retainers to suit cam......... wtf
New guides, ulp seats, springs & retainers to suit cam......... wtf
#3
rodomo
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Posted 02 June 2006 - 01:05 AM
All looks good to me for performance. What is the issue?
How does it run? is it bogging down? The overlap in your ports is not a huge issue.
How does it run? is it bogging down? The overlap in your ports is not a huge issue.
#4
Ferg
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Posted 02 June 2006 - 02:44 PM
Thanx Rodomo ive just been expecting more from this engine it did a 15.9 at heathcote in LJ and prolly knock .5 to 1 sec of that with a bit of practise
I think it cracked about 140HP on the dyno
was expecting it to be a bit quikka
I think it cracked about 140HP on the dyno
was expecting it to be a bit quikka
#5
Tiny
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Posted 02 June 2006 - 04:49 PM
Heya ferg!
You could take the manifold off and mark using the gasket the area that you see causing that lip! THen with a bit of careful die grinding you could blend the area in till you cant see your line anymore! Viola.. Port matched head to manifold!!
That'll be good for it... Maybe too if the manifold is too large you could be loosing your velocity.. One thing that people dont think about is that the air needs to flow in FAST ( thus creating some momentum!) and in a massive port the air flows slowly causing a HEAP of problems!
Do you have any other manifolds you could bolt on to try out before you port match the head to that manifold??
Cheers mate!
You could take the manifold off and mark using the gasket the area that you see causing that lip! THen with a bit of careful die grinding you could blend the area in till you cant see your line anymore! Viola.. Port matched head to manifold!!
That'll be good for it... Maybe too if the manifold is too large you could be loosing your velocity.. One thing that people dont think about is that the air needs to flow in FAST ( thus creating some momentum!) and in a massive port the air flows slowly causing a HEAP of problems!
Do you have any other manifolds you could bolt on to try out before you port match the head to that manifold??
Cheers mate!
#6
_Yella SLuR_
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Posted 02 June 2006 - 05:50 PM
Yup, do a port match. Was a good article in one of the Street Machine Mags on how to do this about 2 years ago. Only other thing is to get the carb's tuned so you are between 12:1 and 13:1 AFR. If it's running too rich, especially with those large valves, the fuel will just be putting the fire out.
Edited by Yella SLuR, 02 June 2006 - 05:50 PM.
#7
boomfunk
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Posted 02 June 2006 - 06:03 PM
im with tiny on this, big holes doent always make for big power....
#8
_Oldn64_
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Posted 02 June 2006 - 08:20 PM
One other thing ferg and something I fix on a mate car. whne port matching DONT. What I mean by that is make the head BIGGER than the manifold. what this does is when teh valve closes and the air gets bounced back of teh back of teh valve the wave returns the air up the intake. Now with what you have there you would end up slowing the air flow down. This is because teh air comming up the inlet hits the next charge and slows it down, not to mention that you will be creating huge tubulence in going in. By porting the head nigger than the intake the air will hit the intake and bounce back thus sort of canceling the effect. What this therefore does is create a air like tube for teh inlet charges to run through. At least port match it but the better solution if use teh characteristics of the air as a friend not an enermy.
Cheers
Cheers
#9
Ferg
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Posted 02 June 2006 - 10:47 PM
Thanx guys I reckon we will look for a standard manifold and if that dont work 
then off with the head
then off with the head
#10
_Sammy_
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Posted 05 June 2006 - 01:46 PM
back in the old days they used to polish ports for more power, less resistance to flow, all that stuff .... but these days it is actually better to have a slightly rougher inlet power rather than a polished one, as the bumps in it create turbulence and they keep the air/fuel mixture atomised better.
also i'd have to agree on the port matching, i'd be cleaning up the head so you can't see the port face through that hole .... looks like you will also have to trim the gasket to be a bit bigger aswell.
also i'd have to agree on the port matching, i'd be cleaning up the head so you can't see the port face through that hole .... looks like you will also have to trim the gasket to be a bit bigger aswell.
#11
Tiny
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Posted 05 June 2006 - 07:52 PM
Sammy: Spot on mate.. I always laugh when people tell me they paid to have their heads "Ported and polished!"
Cheers
Cheers
#12
Ferg
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Posted 05 June 2006 - 10:54 PM
Yeah good 1 Tiny thats what used to b in days gone by now there prolly polishin somthing else 
now there prolly polishin somthing else
#13
TerrA LX
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Posted 05 June 2006 - 11:06 PM
My experience is with V8's and match porting is usually done with the carb manifold slightly smaller than the head port as with HDT etc.
Is yella terra any help with the pic. If you purchased reciently i don't see why they would not recomend something.
Is yella terra any help with the pic. If you purchased reciently i don't see why they would not recomend something.
Edited by ALX76, 05 June 2006 - 11:07 PM.
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