Head porting and polishing on a K04???

[RobH]

So read Steve's thread and didnt want to take it off topic, hes hoping for +50hp with the head polishing.

Is this worth it on a k04? Obviously the gains wont be as much as the turbo flows less air but 20-30hp id be happy with similar to WMI without the hassle of filling up.

Will it work well with a standard stage 2+ map or will it need a custom map to take advantage?

Cost?

Cheers Rob

[Tfsi_Mike]

Sub'd 

[berg]

enter alex, pdt, statller steve, nick 

[RobH]

enter alex, pdt, statller steve, nick 

Yep or Kieth@APR or maybe someone from LOBA, they will probably be able to offer this aswell.

[Tfsi_Mike]

Or Harold in the shed down the garden with his Dremel 

[rich83]

If you think that you can port a head and instantly gain 50bhp, i think you might be wrong. 

I think steves 50bhp increase will be made up of cumulative mods and the fact it probably wasnt running full beans before hand.

[RobH]

If you think that you can port a head and instantly gain 50bhp, i think you might be wrong. 

Never said that it would gain 50hp and thats why im asking if its worth it

The fact that Alex is running a hybrid k04 and said he would send his head off straight away had me thinking.

Steve hasnt touched the valves either.

[Poverty]

Words from my engine builder, Race developments

"Head work is absolutely critical on boosted apps. Traditionally its gets overlooked because its easier to turn the boost up a bit more than think about things! Lets say you can add 20bhp to a normally aspirated engine from headwork. If you chuck 2 bar boost on then not counting some extra losses you are looking at a 60bhp gain. Boost magnifies improvements and problems.

There is also more to the head if done right. You might have an engine that starts to wake up at 3500rpm. Now the head porting guy decides there is a flaw in the exhaust port that he can fix, the flow velocity profile is then optimised. What was a lazy port now comes to life at an earlier rpm which shows up in earlier spool.

Cylinder heads are like a womans head. There is lipstick, then there is makeup, then there is plastic surgery! One basic mistake is to assume the OEM got the head right in the first place."

[sub39h]

"One basic mistake is to assume the OEM got the head right in the first place."

there has to be a trade off though, right? why would OEM compromise on it otherwise?

[RobH]

All im thinking is, if its under or around £1k to do the head and gains are around 25hp then thats better than WMI for me and at a similar price and gains without the hassle of filling up.

So lets hope VW didnt get the head right in the first place and theres room for improvement which APR seem to think there is and who am i to argue with them

[Poverty]

"One basic mistake is to assume the OEM got the head right in the first place."

there has to be a trade off though, right? why would OEM compromise on it otherwise?

Cost, these are mass produced cars,

Genuine hyper/Supercars, whole different subject

Oh and another big reason, Emissions!!!!

[DaveB@Vagbremtechnic]

Also...

The very thin air attached to the ports themselves is boundary layer, flow sits on top of the boundary layer and on occasion can be turbulent. Not always a bad thing.

Some race engines (NA) used to use a sliding plate throttle which had no butterfly and therefore no restriction.

Wasn't always best.

Shiny and smooth isn't always best there more too it than that

[sub39h]

"One basic mistake is to assume the OEM got the head right in the first place."

there has to be a trade off though, right? why would OEM compromise on it otherwise?

Cost, these are mass produced cars,

Genuine hyper/Supercars, whole different subject

Oh and another big reason, Emissions!!!!

exactly, this is a mass produced engine designed to go into millions of units worldwide - so the extra expenditure is easily offset by the units sold

and surely having a freer flowing exhaust with reduced turbo lag would reduce your emissions? not only would you be able to leave the car in a higher gear to accelerate, you are also putting less load on the engine. this is demonstrable by fitting a larger DP. of course, aftermarket DPs have sports cats (or no cats!) and hence emissions go up, but your fuel economy improves so the amount of fuel being burned does go down

[Hedge]

Shiny and smooth isn't always best there more too it than that

I would tend to agree. Bit of a dark art.

[Poverty]

"One basic mistake is to assume the OEM got the head right in the first place."

there has to be a trade off though, right? why would OEM compromise on it otherwise?

Cost, these are mass produced cars,

Genuine hyper/Supercars, whole different subject

Oh and another big reason, Emissions!!!!

exactly, this is a mass produced engine designed to go into millions of units worldwide - so the extra expenditure is easily offset by the units sold

and surely having a freer flowing exhaust with reduced turbo lag would reduce your emissions? not only would you be able to leave the car in a higher gear to accelerate, you are also putting less load on the engine. this is demonstrable by fitting a larger DP. of course, aftermarket DPs have sports cats (or no cats!) and hence emissions go up, but your fuel economy improves so the amount of fuel being burned does go down

No they dont think like that. Making a super efficient cylinder head costs alot more money. Believe it or not VAG are massive believers in cost management, its the only way to make profit these days. Why would they need to supply our cars with super duper wonder cylinder heads on road cars which will make the power thats require on a cheap easy to manufactur and develop cylinder head? If VAG want their cars to leave the factory with more power, they can just alter the ECU for a start anyway. Thats the easy and cheap way.

Low emissions are achieved generally by a lean and hot burning engine. A free flowing head for example, which has been designed by someone who knows what they are doing and understand cylinder head design for the primary objective of increasing power will remove the inbuilt emissions controls. One example being the intake tumble flaps. They restrict flow, but increase low RPM and cold running emissions, which allows the manufacturers to hit EU targets and make tax cheaper for consumers.