FNR Stealth Project Ep 10 - Porting Exhaust Manifolds

While the engine is apart, we examine the exhaust manifolds and discover ways to increase flow and reduce cylinder-to-cylinder flow variation via porting.
Support us on Patreon! / farnorthracing
Visit our site! farnorthracing.com

[@steve87uk]

That bit of steel sitting inside the manifold is unbelievable..

[@samhicks97]

Hoping to port my stock cast manifolds for a bit of an "Umph" thanks for the vid.

[@skylarscales9922]

Love that grinder

[@BoostedPastime]

Outstanding video I am currently doing this on a 4-2-1 Header on my SOHC Honda D series.

[@hondatrix]

You left 1 thing out, when you make the manifold flange larger than the port, it turns into an anti reversion step...helps especially at higher rpm..

[@reborn9110]

Awesome tips

[@shawnsebikesandstuff15]

Great video , after seeing it I've been paying attention to all the intake manifold pieces and gaskets they don't match up for crap either a good Porter could probably make another 20 horsepower Plus out of this engine .

[@sethharper9653]

really nice vid

[@jerrychinn]

Great video! What is that blue material you used around the ports? I think you said "Dicom"

[@FNR]

Dykem. It’s a machinist marking dye.

[@MrUltraworld]

Pretty unusual that a cast manifold would be used for one side and a tubular manifold welded up in an interesting way with the sheet metal right in the way of air flow on the other side.

[@skippy2987]

Got a question re port matching. Have you ever measured (or got one of those endoscope cameras) to see if there's actually a step between the head & manifold when you've got it bolted to the head? I can see the compressed gasket being very thin and making only the tiniest of gaps. Also, if they match when cold, how much does the manifold move when it's hot? Is there much of a case for deliberately making the outer manifold ports wider to cope with expansion and still not have a reversion step?

[@FNR]

I'll be port-matching the heads to the gasket, so there shouldn't be much of a step, and the general idea is to err a touch on the big side on the exhaust side so if the match isn't perfect, the flow passage necks up rather than down. The expansion question is a good one, but I wouldn't expect stuff to move that much.

[@hamishmcmanus2027]

Any problems only porting the exhaust manifolds and or extractors?

[@warrantyvoid100]

Thanks for the video, what kind of scriber is that?

[@FNR]

Thanks!
I don't remember where I got it, but it is similar to this one: www.amazon.com/exec/obidos/ASIN/B00004T7S1/thedsmautocropag

[@KollynJ]

When you do this do you also have to upgrade the intake?

[@FNR]

No. But it sure helps support future upgrades on the intake side, if you are planning them.

[@KollynJ]

@@FNR if not is it kinda debatable whether it’s worth the effort? I have a matrix 1zz motor. The revised plastic intake may have more flow but I’d assume it’s the same

[@FNR]

@@KollynJ anything that helps flow on the exhaust side of a turbo motor will pay dividends - even if the intake is itself restrictive.

[@KollynJ]

@@FNR good to know. Mines just a 1zz on a matrix. I happened across a couple porting videos and sparked my interest since the part it already out. My manifold is warped and I want to machine or sand it flat but it has raised rings around the manifold ports which would get eliminated. Are these needed? Or would it be better to take it down to flat

[@oiudsaf]

Vw do the same