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Ported Head Or Not

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Bo0sTeD 4G63

15+ Year Contributor
469
78
Aug 31, 2008
Miami, Florida
im building a 4g63 motor and i sent the head to be build with all ferrea parts but the guy at the machine shop told me if i go with stage 3 i need sold lifters and i will also need to port the head is this true or does he just want to take my money is the porting and lifters really neccesary
 
You can for sure make 500 hp without porting a head that is a good combo of turbo size air fuel an skilled tuning, if you want your engine to hold 500 hp you need stronger engine internals such as a forged bottom end or u can use aluminum rods if you like. Stiff valve springs good valve guides and what not. Porting a head helps some but if your tight on money i wouldnt bother.
 
if your tight on money i wouldnt bother.

There's the KEY. If you're going to have your head ported, take it someplace and have it CNC'd. Spend the money properly and don't get someone's guess work port job done by hand.

You can make 500+ on an OEM ported head. Porting a head will only make this slightly easier to accomplish with the same turbocharger. You are going to net more gains in airflow with cams, a SMIM and properly worked intercooler piping, than you will with head porting. In all honesty, it should be the last on the list of anyone's to do list because, unless it'd CNC'd, it's mostly guess work anyway, and very easy to FUBAR.

Remember that air is a compressible fluid. You can make as much power as you want with an OEM head, you're just going to be squeezing the air down to a tiny orifice to do so. Compressing air makes heat, so the less restrictive you can make things, the better the car is going to perform for the given boost level (more airflow per rev). Work on your other mods before you consider doing this.

*edit* I would also only consider porting a head when you're pushing a GT40 or larger sized turbo. Anything smaller than this are going to get you negligible (street driven wise) power. If your car is going to be a dyno queen, then yes, port your head to squeeze every last drop of airflow you can out of your setup.
 
From what I understand, the 2G head is worth porting, the IG is not. There are certain places in the 1G exhaust port area that are almost wafer thin from the factory. Just removing a few thous from these areas and the head will not pass the 30 PSI pressure test, which all machinists should do before returning your head. I just went through a very exspensive and painful experience with a machinist with just that issue. I decided to stick with the 1G although he told me up front to do a 2G. The entry angle of the 2G intake port allows for better velocity at mid range rpm's than the 1G. Velocity is actually as important as flow. If the velocity is too low for the volume, the gasoline seperates from the A/F mixture and pools around on the sides and bottom of the intake port causing a poor burn.
That is why I am interested in designing an infinitely adjustable intake plenum. An improvement on the Cyclone variable velocity intake manifold. Anyway it depends on what you are building and why. I want my car to go faster, faster. So I want lots of low to mid rpm torque. If you are building an all out 1/4 mile dragster you will want the 1G head for top end flow. Remember if you get 650 cfm's out of your head you will need a turbo bigger than the EVO 3 16G or big 16G. Check the specs. You will need a TB with better than 63 mm orifice also. 75 mm would be nice, like a 'Stang intake. I must confess that my motor is waiting to go back in Bitchi1 (thats the name of my project car) so I cannot tell you how it runs yet. I had Manley racing 1 mm OS SS valves and Manley springs installed. I installed Blox 272 camshafts and used a MLS gasket. The block sports Eagle rods, Mahle pistons with 1.5 thousandths piston to sidewall clearance!!!
Sorry to get off topic. So thats what I thought. Use the Cyclone to kick in the short runners at spool up, say 3500 rpm and use the ported 1G head. Hopefully the intake will make up for the loss of velocity between 1000-3500 rpm.
 
If its ported too much you will have turbo lag. When porting you just reallly want to do minor changes for a turbo car. porting matching will help. I am narrowing the divider, port matching and taking out the valve guide humps for my exhaust side and I will see how that does on my car. For N/A small intake ports are good and good flowing exhaust with some back pressure but not a lot. After porting the head will need to be flow benched. It is best to port one section at a time as you flow bench each section to get them all the same.
 
You never ever need solid lifters either. Well, not never ever, but I don't think anyone under 1000hp are running them, even then I doubt it.

As you can see, there is a lot of "black art" in head porting. You are better off with bolt on parts like cams, intakes, exhaust, and turbo. Most people that are ready for a ported head already know where their engines are lacking when it comes to going faster.
 
From what I understand, the 2G head is worth porting, the IG is not. There are certain places in the 1G exhaust port area that are almost wafer thin from the factory. Just removing a few thous from these areas and the head will not pass the 30 PSI pressure test, which all machinists should do before returning your head. I just went through a very exspensive and painful experience with a machinist with just that issue. I decided to stick with the 1G although he told me up front to do a 2G. The entry angle of the 2G intake port allows for better velocity at mid range rpm's than the 1G. Velocity is actually as important as flow. If the velocity is too low for the volume, the gasoline seperates from the A/F mixture and pools around on the sides and bottom of the intake port causing a poor burn.
That is why I am interested in designing an infinitely adjustable intake plenum. An improvement on the Cyclone variable velocity intake manifold. Anyway it depends on what you are building and why. I want my car to go faster, faster. So I want lots of low to mid rpm torque. If you are building an all out 1/4 mile dragster you will want the 1G head for top end flow. Remember if you get 650 cfm's out of your head you will need a turbo bigger than the EVO 3 16G or big 16G. Check the specs. You will need a TB with better than 63 mm orifice also. 75 mm would be nice, like a 'Stang intake. I must confess that my motor is waiting to go back in Bitchi1 (thats the name of my project car) so I cannot tell you how it runs yet. I had Manley racing 1 mm OS SS valves and Manley springs installed. I installed Blox 272 camshafts and used a MLS gasket. The block sports Eagle rods, Mahle pistons with 1.5 thousandths piston to sidewall clearance!!!
Sorry to get off topic. So thats what I thought. Use the Cyclone to kick in the short runners at spool up, say 3500 rpm and use the ported 1G head. Hopefully the intake will make up for the loss of velocity between 1000-3500 rpm.

FWIW, the 2g head intake ports maintain higher velocity than the 1g ports. When ported correctly, the 2g orifice WILL OUTFLOW A 1G HEAD! However a 1g head ported properly vs a 2g head, the 1g will outflow the 2g up top.


taking out the valve guide humps for my exhaust side

YOU NEVER WANT TO TOUCH THE CEILING OF THE EXHAUST PORTS!
 
FWIW, the 2g head intake ports maintain higher velocity than the 1g ports. When ported correctly, the 2g orifice WILL OUTFLOW A 1G HEAD! However a 1g head ported properly vs a 2g head, the 1g will outflow the 2g up top.




YOU NEVER WANT TO TOUCH THE CEILING OF THE EXHAUST PORTS!

good thing I have 5 heads. why not? is it thin up top. I just mached another guys work. I asked about it a while back and no one claimed it was a bad idea they said it would be better to take them out. Here are some pictures of what I did. One head is just port match for a turbo car. The other one has no guide humps and the divider is thinned at the end, and it is port matched. I will flow bench this head with my friend when Im done.
 

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i have eagle rods and je pistons for the bottom end and for the head i did the complete ferrea kit valves guides 1mm over valves retainers locks etc.. but the machinst told me if i ever wanted to do more than 500hp i need to port i just want to make sure if i really need to port to go over 500hp or not because he is charging me alot of money but he also said if i decide to go with the hks stage 3 cams i need to port in order to use them basically my question is if i decide to get 700hp lets say will i have to port cause if im going to need to port then i might as well just do it now??? please help
 
You may mess up your head if you dont do the right porting on the head, send it to a machine shop is your best bet
 
There is no well defined line as to when you need to port or not. You can stuff as much boost as you want into a piss poor cylinder head and it will pretty much make whatever power you want. You'd better be running some badass engine internals and fuel though.

Many people run those cams without even having an upgraded intake or exhaust manifold, let alone head.

Let's say there was a magic number that required a ported head and you're hitting it. I still wouldn't let anyone but a DSM vendor touch my head. Also the fact that he advised solid lifters really makes me concerned about what they know about DSM's (http://www.dsmtuners.com/forums/bolt-tech/24598-solid-lash-adjusters-merged-9-8-lifters-valve.html). Someone who has not done R&D can easily make a worse flowing head.

http://www.dsmtuners.com/forums/bolt-tech/16920-1g-head-flow-numbers-intake-designs-long.html

There is some information on head porting. If you are shooting for that power level, if you don't know what you need, you probably don't need it yet. An engine making 500-700hp is going to need to be torn down more often then a stock one, so you could probably just run the head without porting and see if it really does keep you from your goals.
 
i will also need to port the head is this true or does he just want to take my money is the porting and lifters really neccesary
For a stock car or a near-stock setup, probably not.

However, if you want to make real power, porting is key. How else do you think Curt Brown's 1G ran a 10.33 on a 16G turbo with 264 cams?
 
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