CNC headporting for 20v head.

[prj]

It says it makes alot of power. or is that false?

A stock head can make a lot of power too. If you understood anything about tuning internal combustion engines, you would understand what I am getting at.

But it seems you don't, so the discussion is pointless.

[MrVain]

A stock head cant make that kind of power. And who knows, does the pic show the finnished "jens" head or mabe just something else?!
I know a thing or two about the I5... But im not trying to be a smart @#%. Please tell me whats not so good with this jobb? Besides its proven to work and all ports are exactley the sama

[willg54]

not everyone claims to be an expert...share the knowledge and you might also learn!

[prj]

A stock head cant make that kind of power.

It can.
Saying it can't, is like saying that an engine with 2.2 liters displacement can't make power, and forced induction is useless.

[campbellWS]

good to know someone that gives good head jobs

[JP]

Get the Run DMC on, I see a challenge brewing...

RWD19T did a fantastic head job on my RS2, can't rave enough about it.

Thankyou, ironically you got the cheapest option too

Which part of the intake port you prefer filling by welding? Raising the port floor from port opening to short side turn or filling the roof at the valve guide, long turn and bowl? Long higher arc to the valve or lower straight shot?

You don't need to weld the intakes. They infact are a very good design and need lots of small tweaks for big gains. Unfortunately one of the most important tweaks has not been done on their pictures and the cnc'ing looks like it hasn't been able to reach all parts correctly. Meaning the engine has to rev higher to get enough airspeed before it starts making power.

http://www.veloxmotor.com/index.asp?...article_id=380

Somewhere down the page, ... if you find another head which flowes better than that one, money back :-)

Unfortunately with forced induction engines flow is not the be all end all. I can do you teo cylinderheads with the same flow figures. Both produce the same peak power figures.

But one head will be nothing nothing bang all hell breaks loose and once peak power has been achieved dies of quickly. Whilst the other head has a more progressive power delivery and once peak power has been achieved carries on pulling.

Likewise there is no point cnc'ing a head for max peak flow as the average person will not run enough cam lift to benefit. As the more a head flows at high lift the less it flows at low lift. Much like small vs big turbo you can't have best of both worlds.

[prj]

I will also make my point - a power figure says nothing about the quality of the head.
For all you know they boosted it with 8 bar. On a NA engine it would tell a lot more, but not on a FI engine.

Best way to measure gains electronically is really a MAP vs MAF vs RPM log and try to keep MAP as close as possible (obviously rise will be a bit slower on a better flowing head).
That way you can see, how much cylinder filling you gained at every RPM and for a given boost level.

Based on such measurements on Ross' car, JP (RWD19T) is very good at what he does.
Another head with great data and results was Tomas' PK-Motorsport head, that had a fortune spent on it though.

So, what I am saying is, saying "use this head, because someone made xxx hp on it" is not convincing for me, because it says nothing about the head in question on a forced induction engine. I like my numbers, not hearsay.

[Mcstiff]

A stock head cant make that kind of power. And who knows, does the pic show the finnished "jens" head or mabe just something else?!
I know a thing or two about the I5... But im not trying to be a smart @#%. Please tell me whats not so good with this jobb? Besides its proven to work and all ports are exactley the sama

612 WHP at ~1299km above sea level (Salt Lake City) with a stock head & stock pistons.

http://www.youtube.com/watch?v=9kQJS71ZRdc

[MrVain]

612 WHP at ~1299km above sea level (Salt Lake City) with a stock head & stock pistons.

http://www.youtube.com/watch?v=9kQJS71ZRdc

This is also a stock head:

http://www.youtube.com/watch?v=3DUgt9M_neE&list=UUeA3wP-5orwVoc-stdnX9tA&index=3&feature=plcp

With 7A cams. Original valvesprings and valves. And pistons.

I dont know whats been done on Jens head on the original but from seing the car "live" I must say that everything under the hood is very nice, and alot of thought have been put in a car of that size to make those type of quarter miles.

The car was a beast on every race he went do, and very fast spool between every shift. With that kind of power!

But youre right, thats no guarantee this head has a good flow

[MrVain]

Just looked and one of his videos from 2008, he had 943hp @ 2,4 bar of pressure

You can see the vids here:

http://eklundracing.se/videos.html

[vcosmin]

Just looked and one of his videos from 2008, he had 943hp @ 2,4 bar of pressure

You can see the vids here:
http://eklundracing.se/videos.html

Also he had 1.2 backpressure @ 2.4 boost pressure !

[prj]

Horsepower also depends on RPM. Just saying.
Not to mention fuel octane, compression ratio etc.

Really, this is very off topic now. We know that car was pretty fast, it still does not tell anything about the head or how it will work on your car, like I said.

[porkkis]

I would not publish the pictures of my masterpiece. So you guys who judge the cnc head based on 2 pics on internet may think again if the pics are of the real deal or not.

And for the flow question... The speed of sound is the theoretical limit and I bet no one of you has calculated when it will be achieved on stock head on different pressures and temps.

I'd say Eklund's engine must be pretty good in any possible point of view and copying it can't be a very bad idea.

[goodall]

http://www.cncheads.co.uk/vw_1800_16v.html

This an example of what is on offer in the uk, admittedly the link is to a 1.8 16v vw head but its of the same basic design

[JP]

I would not publish the pictures of my masterpiece. So you guys who judge the cnc head based on 2 pics on internet may think again if the pics are of the real deal or not.

And for the flow question... The speed of sound is the theoretical limit and I bet no one of you has calculated when it will be achieved on stock head on different pressures and temps.

I'd say Eklund's engine must be pretty good in any possible point of view and copying it can't be a very bad idea.

That's how I port my heads. Sonic choke occurs at 209fps @ 10" pressure drop. Work out max cam lift and work out what you're desired engine speed is for the chosen application. From there shape accordingly to balance airspeed as evenly as possible across the full cross section of the port.
One of the reasons I use a digital manometer for R&D work. Ironically the optimum airspeed and shape does not give the best flow figures although there is some correlation.

http://www.cncheads.co.uk/vw_1800_16v.html

This an example of what is on offer in the uk, admittedly the link is to a 1.8 16v vw head but its of the same basic design

Saw them at the motorsport show and the average Joe can do better with a flapper wheel. At least the head shown on the first page is 90-95% of the way there.


Edit* Also their flow figs are poop. Had a G60 big valve head on the bench and they claim 120cfm @ 10" the thing struggled to make anything past 95cfm. And the exhaust well that was all over the place.