would larger diameter headers help sohc honda engines run cooler?...

[isa1023]

jdm d15b
eg8 sedan (ferio)
cone-type filter
freeflow muffler
NO PLAN to enlarge midpipe diameter, remove cat and go full-exhaust

*****

I was thinking of replacing the stock 421 headers with aftermarket ones (nodalos and the like)....

Question:
Since sohc ang engine, makaktuong ba kung upgrade na ko to those 'race-type' (as they say) headers (421 din)?
Would that make the engine run cooler?
Would those larger pipes rob off low rpm torque?

*Provided I won't upsize midpipe and catback
*Aim is just basic IHE mod, no plan to drag race
*Taken from the idea that dohcs run cooler coz of the separate exhaust-dedicated camshafts.

Thanks

[ghosthunter]

With exhaust pipes including the headers, you have to balance the way the exhaust gasses flow through them. Too small, the gasses create backpressure. Too large, the gasses lose velocity in the tube and will require extra work from the engine to push them out. This is why there is a typical recommended size for these pipes.

[meledson]

Most new catalytic converters are not that restrictive. I would recommend that this should not be removed. Also, as you said, you will not upgrade your mid pipes.

You can wrap your headers in order to help the hot gasses escape the engine faster (less cooling) and keep the engine bay a little bit cooler.

[isa1023]

Thanks for the replies.

Yung sports muff with removal silencer ng Nodalos kaya (ala Tanabe Tuner) eh mas restrictive pag nakakabit yung silencer? O free flow parin ang effect?

Kasi im thinking twice of installing those nodalos headers to tandem with my existing freeflow kasi masyado na maingay eh,.. hindi na maappreciate ang driving music tuloy.

If I go back to the chambered stock muffs naman, eh di parang useless narin yung IHE setup diba?

[ghosthunter]

Yung sports muff with removal silencer ng Nodalos kaya (ala Tanabe Tuner) eh mas restrictive pag nakakabit yung silencer? O free flow parin ang effect?

Kasi im thinking twice of installing those nodalos headers to tandem with my existing freeflow kasi masyado na maingay eh,.. hindi na maappreciate ang driving music tuloy.

If I go back to the chambered stock muffs naman, eh di parang useless narin yung IHE setup diba?

I suggest having a custom muffler made to something similar to what I have done on both my cars. Quiet yet free-flow.

Here is a cut away view of what it looks:



If you still have your stock muffler, you can use that as a template for the size of the muffler body. If not, just let them measure and make something as big as would fit in the muffler cavity under the rear bumper.

Piping size would depend on your engine. Since you have a 1.5L engine, a maximum pipe diameter of 2 inches is recommended.

The big pipe gives it the freeflow while the big chamber of the muffler makes it quiet at low to medium range RPMs. Even high RPMs isn't that noisy as compared to those "racing" or "performance" exhaust mufflers.

My muffler was made from full stainless with fiberglass packing. I remember it was P8K at FREMUFF.

[isa1023]

I suggest having a custom muffler made to something similar to what I have done on both my cars. Quiet yet free-flow.

If you still have your stock muffler, you can use that as a template for the size of the muffler body. If not, just let them measure and make something as big as would fit in the muffler cavity under the rear bumper.

Piping size would depend on your engine. Since you have a 1.5L engine, a maximum pipe diameter of 2 inches is recommended.

The big pipe gives it the freeflow while the big chamber of the muffler makes it quiet at low to medium range RPMs. Even high RPMs isn't that noisy as compared to those "racing" or "performance" exhaust mufflers.

My muffler was made from full stainless with fiberglass packing. I remember it was P8K at FREMUFF.

Thanks a lot gh. Will definitely take that into consideration.