Porting IDI heads - please quantify

[rabbitman]

Yeah I've heard the incoming air should tumble rather than flow smooth and for some reason that lets more in. But remember though, you'll have a turbo pushing the air in.

As for mixing the air fuel mixture, that happens inside the swirl chamber where the air is really spinning so no worries there . But if a rough intake allows more air in then there's that much more to be packed into and spun around in the swirl chamber.

A flow bench would be nice.........

[theman53]

1.6 head, but theory is the same. He said it would make more power than a head that flowed more. Here is what the ports looked like for reference.




You can see where the gaskets matched up and it is still smaller than that on the exhaust side. You can also see what is about a 220 grit finish or better if you can pick it out in the crappy pic.
Just trying to encourage you.

[AudiVWguy]

According to NASCAR people, 120 intake and polished exhaust (to keep the carbon down). Tests show 120 grit flows better than polished. Think of the boundary layer created on racing swim suits.   my .02 cents

[Aki-76]

big gate does not necessarily mean big power,bigger valve and nearly constant channel already provides better results

http://s434.photobucket.com/albums/qq68/Aki-76/asiakas%20osia%20ja%20muuta/?action=view&current=tsivirtauslappu.jpg

this case is 41mm intake and 35mm exhaust..
http://s434.photobucket.com/albums/qq68/Aki-76/moottorin%20osia/?action=view&current=03042010812.jpg

port is also very shine

http://s434.photobucket.com/albums/qq68/Aki-76/moottorin%20osia/?action=view&current=07102009606.jpg

next week we see results in dyno.i hope break 200kw   

[Smokey Eddy]

Aki-76 posted on one of my topics! I'm honoured!

theman, WOW that went from 72.6 to 90.5 ?!?! that's a huge increase to me.
and that's with a slightly less than polished finish eh?
Okay so i'll mirror the exhaust ports and matte the intake.

And from Aki's photos i'll cut the valve guide al the way down (mine stick out a lot) and smooth the cuts up. I'll also widen the port just below the valve seat.

[Smokey Eddy]

I've always wondered if rifling ports would help eliminate the boundary layer, or at least thin it out 

that would be really interesting to see if you could do it somehow? some sort of hone?

Look at the surface of a golf ball.  It is not smooth for a reason.  The dimples actually make it go farther than a smooth ball would.  I saw it once on mythbusters.

AH YOUR RIGHT!! Where they took that Ford Taurus and put clay all over it and dimpled it, and did better numbers then without the 1500lbs of clay? I stand corrected. Ed leave some golf ball dimples in the intake

will do Jer

[theman53]

Aki-76 posted on one of my topics! I'm honoured!

theman, WOW that went from 72.6 to 90.5 ?!?! that's a huge increase to me.
and that's with a slightly less than polished finish eh?
Okay so i'll mirror the exhaust ports and matte the intake.

Yeah I just wanted to have AKI's name next to mine in a post as well:D

I can go get another pic if you want but the intake is smooth. I say 220 grit finish, but I don't have any way of proving that. My buddy has an RA gauge deal you drag across the surface to tell you what the surface actually is, but that tool doesn't leave his shop. The finish on the intake side you cannot feel any abrading marks. It feels and pretty much looks just like the exhuast side real smooth. Could be a finish from AVFN scotch brite on a mandrel. That is supposed to give a finish somewhere between 240 and 320.

Let me know if you need a pic I am leaving to go to the farm soon.

[rallydiesel]

Aki, where did you get your valves from? Are they solid stainless steel? Did you need larger valve seats?

[Aki-76]

I used very strong special cromy alloy steel in seats,because valve seats is only 1mm wide.seats is also very much bigger than orginal 36mm = > 42mm (intake).
If i calculate correct that engine produce 120-130hp without any boost or turbo.Whit turbo mayby slightly more 

Valves are stainless steel and longer than orginal ( 2.2-2.5mm )...

that number ( 90.5) is prosent,no flow..correct flow is 115 cfm/10" = 200hp na gasoline engine !

[Smokey Eddy]

dear god Aki...
i keep typing a sentence and deleting it.
I am so stoked to see the results
im really hoping the head doesn't warp/lift.

[Alcaid]

I used very strong special cromy alloy steel in seats,because valve seats is only 1mm wide.seats is also very much bigger than orginal 36mm = > 42mm (intake).
If i calculate correct that engine produce 120-130hp without any boost or turbo.Whit turbo mayby slightly more 

Valves are stainless steel and longer than orginal ( 2.2-2.5mm )...

that number ( 90.5) is prosent,no flow..correct flow is 115 cfm/10" = 200hp na gasoline engine !

Why did you use longer valves than stock? Running solid lifters?

Any dyno results that you could add to this old thread?