Standard Manifold Porting with pictures and explaination

stuarty1

stuarty1

Member +
standerd manis are strong prob stronger than most after market ones get it ported u also need to port runner two mate it has a restriction i couple manis if u stuck
 
pilgrim_fgau

pilgrim_fgau

Member +
starletburkie said:
id defo go with an aftermarket like zisco or wepr. make a big diference over standard ported or not
Click to expand...

Wouldn't agree with that tbh... if a mani is ported, to having a similar runner diameter as an aftermarket mani, air flow will be almost exactly the same, if there is a difference, it wouldn't be £150 worth of a difference, would rather keep the £150 to go towards other mods, like an ecu or actuator + fcd where you will find a nice increase in performance
 
dark_knight

dark_knight

Member +
stock exhaust, restriction on 3rd runner

i've read about and heard of this for longer than i can remember. would someone care to shed some light on the specifics about there being a restriction in the 3rd (& in some cases 2nd) runner on the stock exhaust mani. the talk of it reducing performance without technical data to back it up is all i've ever got, is there someone who has done gas flow (cfm) tests to prove this theory..? :teach:
 
dark_knight

dark_knight

Member +
the lump i believe, is affiliated to the bolt that holds it onto the block, correct..? how much smaller is the port in comparison to the others..?
 
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lukep

Member +
the restiriction is where the bolt comes through the cast but toyota decided to block the tread in, resulting in the lump of cast and restrition its a huge restiction and does really hinder flow in both 2nd and 3rd runner(ok for standard boost but still a restriction). I compleatly removed mine so it exposed the tread on both ports, the bolt does not come out into the runner though which is the same as the JAM manifold, ( know because I have compaired them both) you can port the standard mani by quite a bit, toyota have gone over kill on the cast :S prob to stop it from cracking. mines been ported for close to two years now and hasnt cracked with a lot of the runners removed. and ive ran a hybid on it at 1bar
 
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djdiller

Member +
I am thinking of Porting mine now after readinr wat lukep has jus said........iv had my doubts before about doin it but
ye know wat??? out of all the aftermarket mani's an standard stainless ones, the standard gt ones never crack imo.

Cheers lukep

Diller
 
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gtizz i

Fresh Recruit
Thanks guys standard ported mani it is i guess and like pilgrim_fgau said i'll rather spend £150 on something else i've got the actuator all i need now is a FCD and a standard mani then am done. Thanks guys for the reply's
 
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starletburkie

Member +
pilgrim_fgau said:
Wouldn't agree with that tbh... if a mani is ported, to having a similar runner diameter as an aftermarket mani, air flow will be almost exactly the same, if there is a difference, it wouldn't be £150 worth of a difference, would rather keep the £150 to go towards other mods, like an ecu or actuator + fcd where you will find a nice increase in performance
Click to expand...

but thats the problem! ya cant port all the runners trough to make them all bigger. if your on a budget id go with the ported but otherwise aftermarket atw, made a way bigger diference all round compared to my well ported one
 
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Nickzorz

Member +
Out of curiosity. Is the oem manifold (before you port it) the same size as the ports on the block? (dont know the correct term) If so then wouldnt porting all the runners to a bigger size be pretty pointless?
 
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lukep

Member +
Yes you can port all the runners to make them bigger by quite a bit, Toyota went overkill on the standard mani, prob to eliminate any chance of cracking but I've ported the shit out of my mani and nearly 2 years on its still going as strong as ever even running 1bar on a rev 3 Gt spec hybrid.
 
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lukep

Member +
No the exhaust runners should be bigger than the ports to reduce back pulsing, this is where the gases hit the face of the head insead of making it's way back to the valve.
 
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