TunedElantra

There are two schools of thought regarding making big power on turbo setups especially on budget builds. They are the "the foundation of ANY big power setup is set of good flowing heads" and other guys have told me "don't bother porting the heads just let the boost do the work"



Bottomline: Are ported stock heads or even aftermarket ones worth the expense on a build or just forget about it and apply the money elsewhere and turn up the boost an extra 1 or 2 psi??? Or can you guys here provide me a middle ground solution between those two schools of thought??????

wheel_of_steel

A good port is good, but actually designing a good port is something best left to people with the following available to them:



-Knowledge of and experience with thermodynamics and thermofluids

-Knowledge of and experience with decent modelling and flow simulation software

-Decent manufacturing skills

-Buttloads of free time



Put it this way. Most companies that design kit cars, use engines from established auto manufacturers. Engine design is f*cking hard, and the last person to trust is some d00d with a dremel and a super low pricetag. 99 times out of 100, people have no idea what they are doing, and at best, you end up losing way more driveability than what you would expect for a meagre gain in horsepower. If any. The one thing that I do endorse, is cleaning up any casting marks, dirt, slag, and other imperfections in a factory head.





A factory head is not perfect once you start upping the boost, but it is far less worse than something that's been 'upgraded' by Homer Simpson.

faithofadragon

extrude hone is what i would do if i was gonna port a cylinder head, its a little on the expensive side, but the outcome is amazing



anyways back to OP's question



air restriction causes you to raise boost



raise boost increases heat



heat causes inefficiency



inefficiency causes lower hp number/increased wear/wasted fuel



so, if done right, a ported head will benefit you more than just a few HP, same power with less boost = good

Regit

300 + hp ,stock head ,ported and polished only ...for now...

i8acobra

Two identical motors, one P&P, one not... the P&P head motor will make more power. However, it's easier to make the second motor equal the first by turning up the boost a hair. Basically, if you're maxed out on boost, P&P the head. Otherwise, just turn it up.

MechaniX_034

Depends on what you want the engine to do, and what it wants to do. Changing the flow characteristics and flow balance characteristics does shift the torque around. At best, it'll give a bit more torque and if it goes badly, you can scrap the head from a bad port job. No point filling or fixing since the burr went too close to the water jackets. Probably also caused a split somewhere...



At the very worst, your port job doesn't agree with anything else and your tuner's going to be swearing up a storm trying to give you what you want.



SO. Are you looking to build a street motor, or a race motor?





Dead on. Most people think its about air, others think its about fluids. Both are wrong, and both are right. Port design has to do with a living, breathing nightmare: suspended fluid particles of varying size which tend to do strange things as they accelerate and decelerate after they are injected into the airstream at pressure. Temp fluctuations don't help. Then comes the seat and guide periphery, where things can go transsonic if the guy with the carbide burr didn't do the math or didn't do it right. Multiply by number of cylinders, and try to compensate for the pressure waves coming back as the valve closes. This BTW, is just the inlet side. Exhaust side, its a whole other can of worms.



Its enough to make me want to go grab a fresh slab.



Either way. Some motors, best leave them alone if you want any form of drivability.