# head porting for forced induction



## TBT-Syncro (Apr 28, 2001)

I keep reading that porting for a FI head is different then porting for a NA head. However, I never see any postings on what the difference actually is. My common sense on this would be that you open up the intake as much as possible. But do mild porting on the exhaust to keep the exit velocity high...
anyone got any input on this?
thanks in advance
Scott.


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## eiprich (Mar 4, 2003)

*Re: head porting for forced induction (TBT-PassatG60)*

We have found that the main reason for the difference in porting for NA vs. FI is to adjust the I/E ratio. To maximize gains, NA applications require different flow characteristics than FI and thus we port and flow the two applications differently and with a different I/E ratio. At least that is what our experience has taught us.
-Rich


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## 2kjettaguy (Dec 24, 2000)

*Re: head porting for forced induction (eiprich)*

I/E ?


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## TBT-Syncro (Apr 28, 2001)

*Re: head porting for forced induction (2kjettaguy)*

Intake / Exhaust


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## eiprich (Mar 4, 2003)

*Re: head porting for forced induction (2kjettaguy)*


_Quote, originally posted by *2kjettaguy* »_I/E ?

Yes, Intake to Exhaust ratio...basically it matters just how much air your intake ports flow in relation to your exhaust ports and this ratio is pretty important for overall benefits to be had. 
The optimum number (ratio) can only be found through testing on a flow bench and then on a dyno then back to the bench and then back...well you get the idea. This is one of the main reasons few (fewer than claim to anyway) make a really good head for the VR6, as it requires a tremendous amount of time and resources to be invested into the design of every head for every application, at least to get the best possible results.
-Rich


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## veedub11 (Mar 10, 2002)

*Re: head porting for forced induction (eiprich)*

Yea I used to know more about the subject. Allen (vw pickup) built my head and flow tested it due to his experences with his rabbit 2.0t. You may have seen it running 11s.


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## Holy Piston (Oct 24, 2003)

*Re: head porting for forced induction (veedub11)*

You want to port the exhaust,and clean up the bowls and smooth the intake but not polish the intake,and polish and hog out the exhaust ports.With FI the I/E ratio changes you are forcing in way more air and you have to let out way more air,so you want to get the exhaust flowing way better and I even unshroud the valves and open up small radius right after the bowl.


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## Slynus (Mar 19, 2002)

*Re: head porting for forced induction (Holy Piston)*

does that apply to the VR6 head as well?


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## eiprich (Mar 4, 2003)

*Re: head porting for forced induction (Holy Piston)*


_Quote, originally posted by *Holy Piston* »_You want to port the exhaust,and clean up the bowls and smooth the intake but not polish the intake,and polish and hog out the exhaust ports.With FI the I/E ratio changes you are forcing in way more air and you have to let out way more air,so you want to get the exhaust flowing way better and I even unshroud the valves and open up small radius right after the bowl. 

I do not mean to seem argumentative but that is exactly the opposite of what you want for a FI head. The objective is to get a lower I/E ratio for FI vs. NA. 
Some heads may require more exhaust side porting than others but using the VR6 or 16v as examples, they require much less work on the exhaust side than the intake side for FI.








-Rich


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## Holy Piston (Oct 24, 2003)

*Re: head porting for forced induction (eiprich)*

I would'nt argue with you anywayyou have built many more high hp motors than I so,I will not argue,but I am just re,iterating what I have read in 3 performance turbo books and various tech articles,that if you were to concentrate on one side of the head,they(the authors)recommend the exhaust side,due to the fact that the turbo is pushing more air into the intake side,so to help release that extra incoming cylinder charge,they recommend opening up the exhaust.(they)mention that the I/E ratio is factored for NA which has much less exhaust flow and since the turbo is making the intake flow well,it made sesne to me to open up the exhaust to help with more exhaust, so that is what I went with and since you are doing dam well with what you are doing with I might have to re-think my approach........I guess you can't believe everything you read







.........................


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## Capt.Dreadz (Jun 4, 2003)

*Re: head porting for forced induction (Holy Piston)*

Great thread fellas. Me and a friend are working on my head as we speak. He has a Super Flow SF-1020 at the shop so we can test and tune properly. Here's our slow progress. Down to the poslishing the bowls


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## Butcher (Jan 31, 2001)

*Re: head porting for forced induction (Holy Piston)*

Just so you all are on the right track, biggest restriction in any turbo system is not the ports but the turbo itself. Try measuring the exaust pressure before the turbo and you will find that most of the times it much more than the intake. I have measured many of Mercedes diesels and have seen as high as 3 bar but normally much less at 2 bar. Sure porting the ports will help but remember the turbo is the major restriction so the exhaust porting does help but not as much as you would think [I'm not talking about bowl work just ports].


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## Holy Piston (Oct 24, 2003)

*Re: head porting for forced induction (Butcher)*

What I meant by "bowls"was the area right under the valve.You still want to get the exhaust flow going so you can spool and you definitely want the least amount of backpressure after the turbo,guys will say a big exhaust hurts bottom end,but on a turbo it helps bottom end by getting quicker spool/torque.


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## eiprich (Mar 4, 2003)

*Re: head porting for forced induction (Holy Piston)*


_Quote, originally posted by *Holy Piston* »_What I meant by "bowls"was the area right under the valve.You still want to get the exhaust flow going so you can spool and you definitely want the least amount of backpressure after the turbo,guys will say a big exhaust hurts bottom end,but on a turbo it helps bottom end by getting quicker spool/torque.

I agree with you that doing some porting and shaping to the bowl area is good. 
BTW: In my previous posts here I should have been saying Turbo and not FI because this does not really apply to S/C heads. 
The reason you want to be careful when opening up the exhaust side of the head on an Turbo engine is to do with how the turbo's resistance is acted upon by the exhaust gas exiting the head. When you port too much on the exhaust side in relation to the intake side, you will almost always reduce the exhaust velocity and thus lower exhaust speed which is contrary to what you want on a turbo application.
-Rich


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## Capt.Dreadz (Jun 4, 2003)

*Re: head porting for forced induction (Butcher)*

I here you butcher. a friend told me the samething. But anything is better then stock i say. Every head we do, we take our sweet time and us our 1st cyl. as a template for the rest( _i.e bench flow 2,3, and 4 to match the flow of #1_ We inlarge the front part of the bowl very little and polished the snot out of each bowl. 20hrs alone on the bowl in the pic above.
He say's this ( is opinion, not saying he's right) 
Port the intake but dont polish
Lightly port the exaust and polish the snot outta it.
Im no head expert and the reasons why he say's this i dont understand but it kinda makes since.


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## TBT-Syncro (Apr 28, 2001)

*Re: head porting for forced induction (TBT-PassatG60)*

good info so far.....
and bump


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## Capt.Dreadz (Jun 4, 2003)

*Re: head porting for forced induction (TBT-PassatG60)*

I just picked 3 sets of these ( except they were Dremel brand)








here's some info from a site i had saved:::::::







V8 content but helpful for those DIY'ers)
*These basics can be done by any do-it-yourselfer, even those with no porting experience, using the Deluxe Porting Kit and the Gasket Removal Kit (part nos. 260001 and 260005) from the Standard Abrasives Motorsports Division, along with a die grinder and some common hand tools. 

There is a significant difference between basic head porting for a street-high-performance or weekend racer application and the very complex cylinder head work you see in a Pro Stock drag race motor or a NASCAR Winston Cup race engine. Doing full-on race heads requires the services of an experienced cylinder head professional, so Pro Stock, Winston Cup and similar heads are best left to experts. Basic head porting, however, is easy...so easy that even beginning hot rodders can do it well. 
Basic cylinder head porting will improve the performance of any production cylinder head by removing flaws that come through mass production. Basic porting does not attempt to correct any design or engineering deficiencies. Once your porting project turns to that, you're beyond the scope of basic porting techniques. 

Why is basic port work important to your engine's performance? It reduces the restriction in the engine's intake and exhaust tracts. Reduce that restriction and you let more air into the cylinders. If you have more air, you can add more fuel. The result is increased horsepower. 
Most of the work in a basic porting project is focused on reducing those restrictions which are caused by: 1) "steps" that may obstruct intake air flow as it transitions from the intake manifold to a smaller intake port entry in the head; 2) casting bumps, ridges or other marks, such as those you may find on port floors or roofs; 3) sharp edges, such as those you will find around the valve guide bosses at the top of the valve pockets; and 4) the point where the intake port floor curves down to the valve seat. 
Basic porting, while somewhat time consuming, is not hard work. It takes about 10-12 hours to do a set of average V8 heads. Some week nights and a weekend invested in your heads and your basic porting project will be complete. 
Time is money, so we are not going to tell you doing your own heads will save a lot; however, most professional cylinder head porting businesses will charge $400-$600 for what is sometimes known in the trade as a "street/strip" port/polish job. Your basic porting project, done with the Standard Abrasives Porting Kit, will allow you to spend that $400-$600 on some other performance enhancement you want. 
The project is made up of six sub-tasks: 
Intake port entry enlargement, surface finishing and port matching. 
Smooth the intake short side radii, valve guides and valve pockets. 
Smooth the exhaust short side radii, valve guides and bowls. 
Exhaust port and bowl polishing. 
Combustion chamber polishing. 
Intake manifold port matching. 
Five of these six tasks reduce restriction in the intake and exhaust tracts. The remaining step, polishing the combustion chambers, inhibits carbon build-up, decreasing an engine's tendency to detonate or "knock" under heavy load. 
After we touch on materials, tools and safety precautions, we are going to walk you through the specifics of a basic port job. As an example, we'll port a standard cast iron head as used on a 5.0-liter Chevrolet Small-Block V8; however, all basic porting techniques can be applied to the head or heads on any engine, regardless of its manufacturer, configuration or number of cylinders. 
To illustrate the improvement that comes with basic porting work, at the end of this web page, we'll post flow test results, both before and after porting, 
* 
The rest is here http://www.sa-motorsports.com/diyport.htm 
I just copied the inportant pieces
-dreadz


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## EvilVento2.oT (Dec 1, 2003)

*Re: head porting for forced induction (I Wuz BottlFedG60)*

it would seem to make sense not to mess with the i/e ratio clean any "burs" but that about it am i wrong?


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## Butcher (Jan 31, 2001)

*Re: head porting for forced induction (Holy Piston)*

What I have found on all VW heads I looked at are the valve seats to the combustion chamber are very shrouded. The valve can open a little and all it sees is the combustion chamber lip. I have removed that lip so when the valve starts to open there is nothing to obstruct it. The bowls as far as I understand is everything under the valve area and as far up as the valve guide area. 
I do agree that most anything is better than stock, but if we want to remove the restriction then the turbo must go, but no one seems to want to do that [I wonder why].


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## TURBOPHIL (Jan 31, 2002)

*Re: head porting for forced induction (Butcher)*

My assumption of porting turbo heads were to "hog" out the intake thus increasing cfm's , the more volume you can flow through the head the more power you will make, proper sizing of the turbo will be a must as you have to maximize the added cfm created from porting. On the exhaust side the main concern should be exhaust air velocity as this will help in spooling. Before I get flammed, I have never ported a head myself, however I have had heads ported on NA and turbocharged 8v. I noticed a slight difference upstairs in both motors, the turbocharged head was the one that got hogged out, the NA headwas ported with intake air velocity as the primary concern not cfms. 
Again this is my "backyard shadytree mechanic" opinion on porting heads.


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## '89gli (Sep 2, 1999)

*Re: head porting for forced induction (eiprich)*

Rich, what is your philosophy on larger intake and exhaust valves on a FI VR6 head?


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## TBT-Syncro (Apr 28, 2001)

*Re: head porting for forced induction ('89gli)*

the box in my trunk goes................................. bump.


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## goldwrench (May 28, 2003)

*Re: head porting for forced induction (I Wuz BottlFedG60)*

Hey did that kit come with prybar and circular saw?????
Tools of the trade you know......
Or was the meat cutting bandsaw, and butcher block optional?????


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## goldwrench (May 28, 2003)

*Re: head porting for forced induction (I Wuz BottlFedG60)*

Hey Home Depot has belt sanders on sale this week.
But one and they throw in a free tape measure.


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## vfarren (Sep 11, 2000)

*Re: head porting for forced induction (goldwrench)*

Lets try and keep this thread on target....or has it already gone to shyte? I thought we were starting to get some good info.........


_Modified by vfarren at 2:15 PM 12-8-2003_


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## goldwrench (May 28, 2003)

*Re: head porting for forced induction (vfarren)*

Well it looks like the info here has been coming from hardware/paints counter at Home Depot or Rona Home Building Centre....
Will the be a topic on using an air chisel to port and polish cylinder heads????
Or is the current technique of using 60 grit sand paper to clean a cylinder head as pictured in the post above accepted as standard now????


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## vfarren (Sep 11, 2000)

*Re: head porting for forced induction (goldwrench)*

Well I am not sure what you use, but yes, I have seen nice work done with flap wheels, sanding bits and some more agressive cutting stones/bits (not pictured). I suppose you think the only acceptable way to port a head is on a CNC machine? A bit out of the reach of the average DIY'er don't you think?


_Quote, originally posted by *goldwrench* »_Well it looks like the info here has been coming from hardware/paints counter at Home Depot or Rona Home Building Centre....
Will the be a topic on using an air chisel to port and polish cylinder heads????
Or is the current technique of using 60 grit sand paper to clean a cylinder head as pictured in the post above accepted as standard now????


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## Angular (Mar 12, 2002)

*Re: head porting for forced induction (goldwrench)*


_Quote, originally posted by *goldwrench* »_Hey did that kit come with prybar and circular saw?????
Tools of the trade you know......
Or was the meat cutting bandsaw, and butcher block optional?????

OK, wise guy. Show us what tools YOU use for porting aluminum heads.


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## Quiz (Sep 13, 2002)

http://www.theoldone.com/articles/b16a_head/
This may not be a VW but the person explaining this is probably the most qualified when it comes to porting or even intake/port/combustion/exhaust design.
Read and reread. 


_Modified by Quiz at 2:34 PM 12-8-2003_


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## Evolution Marine (Sep 18, 2003)

*Re: head porting for forced induction (Butcher)*

Butcher - Regarding the difference in exhaust pressure and intake pressure, when I built my turbo system for a 911 Porsche many years ago I installed an Aircraft Pressure Gage with two needles and hooked one up to the exhaust before the turbo and one up to the intake manifold, and I experienced approximately 2 lbs. more intake pressure than exhaust pressure. At the time I was running 17 lbs. of boost.







. Personally, I think the A/R of the turban is correct when there is more intake pressure than exhaust pressure, and that motor pulled hard to 7,800 RPMs. OH, BTW I ran the motor on Propane and injected Methanol under boost along with an Inter-cooler. - Bob


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## eiprich (Mar 4, 2003)

*Re: head porting for forced induction ('89gli)*


_Quote, originally posted by *'89gli* »_Rich, what is your philosophy on larger intake and exhaust valves on a FI VR6 head?

It really depends on which head we are discussing in specific. 
On 16v stock valves work fine for FI once the proper flow work and valve & seat cutting is done. 
On VR6 heads, along with proper flow work, installing and properly machining larger intake valves and seats are part of our formula and it is very good for FI when properly ported and flowed. Larger exh. valves are not installed for FI but work is done to the oem diameter valve and seat. 
8V also benefits more from larger intake and correct flow work than just installing all big valves. On some older 8v's we do change the exh. side setup more to downsize the stem from 8 to 7mm in order to reduce disturbance to the flow. 
It depends I guess would be my best answer but it isn't always best.
-Rich


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## goldwrench (May 28, 2003)

*Re: head porting for forced induction (vfarren)*

I was under the impression that the only way to properly modify a cylinder head is by using a flow bench to determine correct pressure and velocity...
Sorry don't have a pic....


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## vfarren (Sep 11, 2000)

*Re: head porting for forced induction (goldwrench)*

You are right if you are going to reshape the ports. But you can improve flow by smoothing out casting irregularities and doing some very basic and limited work on the bowls. Valve jobs are important too.


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## Hardcore VW (Oct 9, 2001)

*Re: head porting for forced induction (Evolution Marine)*

>>Personally, I think the A/R of the turban is correct when there is more intake pressure than exhaust pressure<<
I have read and heard more than once that's when you start really making big power is when you start getting thos numbers clower to one another.Lots of systems have 2x as much pressure in the exhaust.It's all a balancing act though like anything.


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## Capt.Dreadz (Jun 4, 2003)

*Re: head porting for forced induction (vfarren)*

I try and keep from replying to comments from people who never ported a head in their life. first, 60 grit barrel is the norm with any head porting. Wut you think you can remove material with a sand stone alone and still have a fairly smooth surface to polish? flap wheel works great in those hard to reach places. Im no head expert but ive seen real PRO's do it and they use course barrels then work their way down. The pic of the kit above CLEARLY states on the box that its ment for porting uses so i dont know know where Home depot came from.
It seems like any thread in this forum cant go past 25 post without someone picking on the stupidiest sh!t. There was some great info in here but some cant refrain themselves. Im sorry fella's but its getting old. Now back to the topic.
-Dreadz


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## goldwrench (May 28, 2003)

*Re: head porting for forced induction (I Wuz BottlFedG60)*

ugg, fire make hot.....hot rabbit taste better.... hot rabbit = no sore tummy


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## Tommy K (Feb 23, 2003)

*Re: head porting for forced induction (goldwrench)*

hey eip rich..... your eip turbo heads for a vr6. what kind of gains are achived. be specific http://****************.com/smile/emthup.gif


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## Butcher (Jan 31, 2001)

*Re: head porting for forced induction (Evolution Marine)*


_Quote, originally posted by *Evolution Marine* »_Butcher - Regarding the difference in exhaust pressure and intake pressure, when I built my turbo system for a 911 Porsche many years ago I installed an Aircraft Pressure Gage with two needles and hooked one up to the exhaust before the turbo and one up to the intake manifold, and I experienced approximately 2 lbs. more intake pressure than exhaust pressure. At the time I was running 17 lbs. of boost.







. Personally, I think the A/R of the turban is correct when there is more intake pressure than exhaust pressure, and that motor pulled hard to 7,800 RPMs. OH, BTW I ran the motor on Propane and injected Methanol under boost along with an Inter-cooler. - Bob

It must of been fast! but terrible without boost. I am not saying it cannot be done because of experiences like yours. Engines at that state of tune are most likely a race type motor and a real pain to drive in the street. I just think most individuals do not realized the amount of backpressure [before the turbo] the average street motor make and that was the point I was making. 
By the way how much power did that thing make?


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## KOOTER (Aug 13, 2003)

*Re: head porting for forced induction (Butcher)*

I like to use the aluminum specific die grinder bit(snap-on sells them).Then comes the 60 grit and working down to smaller grits.
On the exhaust side of the 2l heads(8v),I like to gasket match and work back to the seat(yea the front seat dip****







).I like to widen the bowls around the guides without creating a big shelf at the seat.
The intake is pretty similar to exhaust except I only remove material on the top of the port and around the valve guide also make sure you have a smooth radius on the bottom of the port.
Make sure you unshroud the valves in the combustion chamber.


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## FLACOMAN (May 6, 2002)

*Have you worked on any 1.8t heads?*

Doesn't look like there's much to be gained , but i'm sure i'm missing something..
TIA Jorge


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## Evolution Marine (Sep 18, 2003)

*Re: head porting for forced induction (Butcher)*

Butcher - The car was very drivable on the street and I never put the car on a dyno. This was probably 14 years ago, and the only measure of performance I have was when I would race stock Porsche Turbos I would put about 20 car lenghts on them by the time I was at 6,000 RPMs in third gear







and where I live you would run out of road if you went any longer so that was about as long as I could keep the hammer down. This car was so quick that at freeway speeds if you were approaching an off ramp that you were going to exit on and there was a space up about six cars you would just down shift and mash the throttle down and it would feel like you were literally being shot out of a cannon and boom you would be in that space six cars up before you knew it. It was a 2.7 liter motor and it used a .96 A/R tangential turban. I can not remember the compressor size. I also had to use a triple disc. clutch to hold the motor to the trans. I had to fabricate the entire intake and exhaust systems from scratch which took about 450 man hours. Any way it was a large project and a lot of fun.







- Bob


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## jwspin (Oct 17, 2002)

*Re: head porting for forced induction (Evolution Marine)*

i would like to learn about the propane you used to run your car, i havent found much on that!!!


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## Evolution Marine (Sep 18, 2003)

*Re: head porting for forced induction (jwspin)*

jwspin - The propane is about 100 octane and burns absolutely clean. When a motor that has been run on propane and is disassembled the pistons have no carbon on them and the oil does not get dirty from the carbon deposits going by the rings. It is normally less expensive than gasoline , however you use about 30% more if my memory serves me right. This is because there are about 30% less BTUs in a gallon of propane as compared to a gallon of gasoline. The installation of a propane system on a water cooled motor is Farly straight forward and all the parts are readily available from after market companies that specialize in propane conversions. Also, propane is an exempt fuel because it burns clean, however the equipment regulations regarding smog legal status still rear there ugly head. The only downside is your car smells like a Fork Lift but who cares when you feel like you have been shot out of a cannon when you smash the throttle down.







Hope this answeres some of your questions. - Bob


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## jwspin (Oct 17, 2002)

*Re: head porting for forced induction (Evolution Marine)*

sounds fun to me. maybe i will work on a propane motorcycle motor first, then ill "think" about one of my cars. do you have any links to any sites that have more info?
-jared


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## REPOMAN (May 3, 2001)

*Re: head porting for forced induction (TBT-PassatG60)*


_Quote, originally posted by *TBT-PassatG60* »_I keep reading that porting for a FI head is different then porting for a NA head. However, I never see any postings on what the difference actually is. My common sense on this would be that you open up the intake as much as possible. But do mild porting on the exhaust to keep the exit velocity high...
anyone got any input on this?
thanks in advance
Scott.

When designing or building a turbo engine you must not think of air being blown into the engine. you must think in terms of the compressor supplying higher density air. Flow is Flow and whether it is water, thin air or dense air, with different Reynolds Numbers, the rules are all the same. All of the things that interrupt flow are just as prevalent in a turbo engine as in a normally aspirated engine. The Port shape and combustion chamber are no different than it would be if the engine was normally aspirated. the transition in the bowl area from the port entrance. The shape of the port is probably the most critical factor in how much power a given engine can produce and more importantly where in the rpm band does the power start and peters out. Remember , the higher intake manifold pressure developed by a turbo leads to higher velocity flow into the combustion chamber. In my own experience I have found that getting the ports to flow at low valve lift seems to go hand in hand with a broad torque band and that translates into better drivability. Of course there are other factors that influence the width of the torque band of an engine but they are all tied to the breathing. The intake manifold for instance is very key as it is upstream from the ports of the cylinder head. Turbo charging, because of the huge benefit of the denser air can sometimes allow engines to get away with a lot. most manifold have literally sharp 90 degree corners in it but the engine makes (for most people) ample power. The bottom line is that every time the air has to change direction you need to gently convince it to do so, such that the amount of energy it looses through pumping losses is minimized. If you look at custome made intake manifolds you can see the smooth trumpet shapes that are used to get the air to enter the runners with the least amount of turbulence developed. the straight smooth runners to minimize the pumping losses. These are very typical characteristics of what you would see on any sophisticated normally aspirated engine. The difference in the normally aspirated engine might be in the runner length as it would be tuned for optimum performance at a different Rpm range.
As in the design of the Intake system the same things that are important to the normally aspirated engine are also important to the turbo. The headers don't have to be equal length but it helps if each of the pressure pulses going into the turbo impellers are equal. But here there is a difference from the normally aspirated engine which responds to a tuned length. The tuned length and proper collector actually help the flow of the normal engine by creating a negative pressure in the collector to help the next pulse flow out. The turbo has this hot housing and impeller stuck in the way so the equal pulses help but the pressure build prior to the Turbo negates any benefit derived from the a tuned length and collector. 



_Modified by REPOMAN at 7:47 PM 12-11-2003_


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## TBT-Syncro (Apr 28, 2001)

*Re: head porting for forced induction (REPOMAN)*

bump.


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## evilgti2000 (Apr 11, 2002)

*Re: head porting for forced induction (TBT-PassatG60)*

This a great tech thread and I hope everyone here keeps it going. It just seems that everyone has drifted alittle away from why you do head work in the first place, increase flow and minimize restriction wherever possible. But the fact of how the car will be used has kinda been skipped. All the time you hear of peoples cars with radical head work done to them (such as 16V's with already poor low speed torque) but 99% of the time the car never sees the strip. When in all actuality there probably doing more damage to low speed performance and driveability within their usable rpm range. In my opinion head work is in accordance to where and how the car will be driven. Is it really benefical to loss 20lbs of torque before 5K and gain 20hp above 6.9K in a street car? I definately don't think so. Every imagineable arrangement of head has already been done from 8V to 12V to 16V over the years. Most of this info can found from the posters on the 'tex and some from even the people of this thread. Head work is very application specific. And if I missed this somewhere in this thread I do apologize. I just thought I would add a little sub-topic to this post to see what all you head experts might have to say about the extreme ends of head work on street cars. And I do apologize for taking so long to get that question also http://****************.com/smile/emthup.gif


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