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Old 10-11-2019, 08:12 AM   #1
HALFanINJUN
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Default Out of box port or ported?

So whats the real story with having a ported head or not ported for a turbo?

Is it as important as it is for N/A?

Can anyone give some real world experience with this?

Anyone here ever step up to a better flowing head and made more power ( if so how much more per pound of boost ) with out changing anything else?

I just had to buy a new head after finding out mine was cracked. It was a CNC 320cfm port. They only flow 270 new out of the box. So im not sure if its worth the money to get the head ported or just go with the stock port.

Would luv to hear what other experiences/opinions on this are..

Thanks...

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Old 10-11-2019, 08:17 AM   #2
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Default Re: Out of box port or ported?

Valve job will pick it up. Best money spent on the ootb head, imo.
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Old 10-11-2019, 09:03 AM   #3
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Default Re: Out of box port or ported?

yes i plan on getting a good valve job. But im wondering how important the extra cfms are for making the most power with a turbo...
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Old 10-11-2019, 09:13 AM   #4
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Default Re: Out of box port or ported?

Application specific and desired hp specific but everyone knows turbos are magical at making hp.

What cubic inch and intended hp goal?
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Old 10-11-2019, 09:14 AM   #5
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Default Re: Out of box port or ported?

Also at what rpm for peak hp?
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Old 10-11-2019, 11:52 AM   #6
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Default Re: Out of box port or ported?

Its a 4 cyl 198ci.

So far its made 620 rwhp at 35 psi

Drive train is turbo 400 with 9" 3.50 ratio ..

Im looking to make 750 rwhp .

As for peak rpm, that so far changes as i turn the boost up ..

At 35 psi its 6500 rpms where at 20 psi it dont go past 6000..

But im really just wanting to know if porting the head from 270 to 320 cfm is going to make enough extra power to justify the 650.00 .....

Thanks
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Old 10-11-2019, 12:20 PM   #7
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Your words “most power” lead to the natural answer. Yes a ported head will make more power at the same boost level or the same power at less boost. But, ported heads generally have slower air velocity. So if responsiveness and lower rpm operation are important, the unported will have a bit of an advantage. You just have to run additional boost
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Old 10-11-2019, 12:56 PM   #8
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Default Re: Out of box port or ported?

Quote:
Originally Posted by tempname View Post
Your words “most power” lead to the natural answer. Yes a ported head will make more power at the same boost level or the same power at less boost. But, ported heads generally have slower air velocity. So if responsiveness and lower rpm operation are important, the unported will have a bit of an advantage. You just have to run additional boost
Im glad you say this because i wanted to ask that question next.

But will the increased cfm be the same gains as N/A?

As the psi goes up is there a point where just like N/A , the head wont flow anymore , or will the power keep going up with increasing psi ?So in other words, is there going to be a ceiling eventually ? Im sure that heat will be a battling fact as psi goes up though .. And i do need the velocity . One of my biggest problems was power before boost. The out of box head has 215cc runners . My 320 head was 234cc. Not much difference in cc's but maybe it will be enough to pick up velocity and make a difference . Idk...
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Old 10-11-2019, 02:10 PM   #9
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Default Re: Out of box port or ported?

Here's the big picture. As boost goes up the actual CFM of air flowing into the engine doesn't change much. However, the increased density results in increased lb/hr of air entering the engine which means more O2 molecules.
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Old 10-11-2019, 03:27 PM   #10
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Default Re: Out of box port or ported?

I was hoping there would be someone that stepped up to a better head that could share there expereince with whether or not it was worth doing it ..

But thanks for all the replies so far..
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Old 10-11-2019, 04:24 PM   #11
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Default Re: Out of box port or ported?

Whoever moves the most mass flow wins, everything else being equal. As long as we are talking strictly EFI drag race, as long as there is adequate port airspeed to keep fuel atomized I'll take the big well designed CNC port everytime.
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Old 10-11-2019, 04:28 PM   #12
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Default Re: Out of box port or ported?

Anything different about a turbo head port job than we normally look for in a NA port job?
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Old 10-11-2019, 06:54 PM   #13
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Default Re: Out of box port or ported?

Quote:
Originally Posted by tempname View Post
Anything different about a turbo head port job than we normally look for in a NA port job?
In my opinion yes, often times porting is not as specific as it should be. Everyone seems to be possessed with intake port flow numbers but I would gladly trade some intake flow to gain some exhaust port flow. In most cases getting air/fuel into the cylinders is no problem but getting it out efficiently is more difficult with a lopsided port job. Cam design is more difficult as is hot side design. I think in many ways a turbo engine is almost the opposite of a NA engine. NA intake is #1 - Turbo exhaust is #1 Just my $0.02
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Old 10-11-2019, 08:25 PM   #14
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Default Re: Out of box port or ported?

Looks like ill just put the stock head on and see what it does.
I will be able to compare it to my old head and find out that way..

It will be interesting to find this out ..

Worst scenario ill just send the head to get done after i find out the truth on this...
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Old 10-11-2019, 09:16 PM   #15
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Default Re: Out of box port or ported?

Quote:
Originally Posted by HALFanINJUN View Post
Its a 4 cyl 198ci.

So far its made 620 rwhp at 35 psi

Drive train is turbo 400 with 9" 3.50 ratio ..

Im looking to make 750 rwhp .

As for peak rpm, that so far changes as i turn the boost up ..

At 35 psi its 6500 rpms where at 20 psi it dont go past 6000..

But im really just wanting to know if porting the head from 270 to 320 cfm is going to make enough extra power to justify the 650.00 .....

Thanks
Yes. Anything gained to a pressure ratio of 3 bar. After 3 bar heat begins to escalate and gains slow.
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