I am considering buying a set of Tomei headers for my car (MY06 Spec C), but I have a quick question regarding the size of the primaries.

On the factory headers the primaries are 42.7mm, whereas on the Tomei headers they are 38mm, yet Tomei still claim they develop more power.

How is this and can anyone explain further?

 

hi,

think you need to do a bit of investigating. i was told that the 2.5 had equal length headers as standard anyway?

can anyone confirm this?

 

Spec C is a JDM only model mate and as such still runs the EJ20 engine, which uses equal length headers.

My question is relating to the design of the Tomei headers and the fact that the primaries are of a reduced diameter to OE headers and was wondering as to how this can be of an advantage as Tomei claim an approximate 15BHP increase when used with their own specific ECU, but I'm sure a remap would do just as fine as using their ECU anwyay.

When used with STD EDU
http://www.tomei-p.co.jp/inf/pdf/48.pdf

 

Anybody else know?

 

is it worth changing your headers as im sure all the jdm models come with stainless steel equal length manifolds as standard ??? i will know for definate on sunday when i pick mine up as i have changed mine for un equal length ones so i should have a scooby burble for a change

 

I know they come with equal length headers!!!!!

What I am asking is how can the Tomei headers claim to provide more power if the primaries are of a smaller diameter than the OE ones and how will this affect spool up?

I am considering buying them but would like to know if someone with a bit more knowledge and experience than me can elaborate on my question.

 

MrRa,
Save your money and stick with the standard headers! There are much better things to spend your money on mate!