How much of a HP boost can I expect from doing a port and polish?

Translation: Is it worth having a car down for a month or so?

 

nope... red did this and barely gained anything... tibs come with a 3 angle valve job from the factory... the head flows pretty well its the **** feeding the head that doesnt flow 2 well

 

If you do a search you will find PLENTY of Info which was covered about Port and Poilished jobs.
Myself and Red have done a Port and Polished to our Tiburons with very little gains.If im not mistaken Red gained about 4whp by this mod with a 3 angle valve job.
Personally i wouldnt recommend this as the gains are VERY LITTLE and not worth wasting the money into this project.
I gained about 8-10WHP when i did a radius cut valve job and Port and Polished the cylinder Head.The radius cut seemed to make more power as opposed to a 3 angle valve job.
Over at the OLD FXtreme forum i posted up Dyno results of before and after when i had this done about 3 YEARS AGO!!!
So IF YOU decide to do this mod MAKE SURE you get a RADIUS CUT done to your valves along with a Port and Polished JOB!
Hope this helps!!!!! smile.gif

 

Some other things that work well with the head on most cars, I'm not sure bout tibs, match port the intake manifold to the head and polish the runners on the intake manifold. For the ppl who have already done the other mods can you tell me if you polished the combustion chamber and ported and polished the exhaust side along with the intake side or just intake side.

 

You shouldn't polish the intake manifold...
air coming in needs to atomize within the combustion chamber, this is best done by running it over the rough (unpolished) surface of the intake manifold.

 

There's 2 opposing schools of thought on that.

One says that the last 4"-6" intake manifold should stay rough for air turbulence to promote air/fuel mixture.
In general, it has more to do with Throttle body injection engines and carbureted engines, not Port injection engines.

The other says that smooth intake manifold walls promote better air flow, increasing hp.

In our specific application(beta's and Alpha's), with the fuel injectors less than 3" away from the intake valves, and the fuel injecotors aimed RIGHT AT the intake valves, the better air flow (smooth intake manifold walls) is better than rough.

Rough intake manifold walls will not help air/fuel mixture since the air/fuel don't meet until well after the IM is over and the air is in the actual port itself. At which point turbulence is created by dividing the airflow into 2 ports, and forcing the air around the valves and into the combustion chambers.

It's a valid theory, when applied to the proper technology/engine style.

[ January 18, 2003, 10:05 PM: Message edited by: Random ]

 

Hey Alex..I have my stock head off of my 1997 Tiburon FX that i am needing to sell. If interested email me at cysco00@aol.com.

Cisco C.