Porting and Polishing question

[SpeedySub]

I have been doing a bit of reading on NASIOC about porting and polishing. Im not worried about porting the heads as that has been done at the factory. What I was interested in is opening up the inlet of the turbo, throttle body.

https://forums.nasioc.com/forums/showthread.php?t=729711&page=24

 

What I am wanting to know is there any real gain to doing this. What I mean by this is it going to be a noticeable difference like earlier/better spool.

I can see that opening up the turbo and TB inlets should flow better but not sure of any downsides.

 

I wouldnt mind port matching the exhaust manifold at a later date, as that's one area I know can help.

[A_J_T]

It helps you sleep at night 

[pedro]

Modest performance gain for maximum warm feelings...

[SpeedySub]

1 minute ago, A_J_T said:

It helps you sleep at night 

Im not a fan of port but I do enjoy a polish at night/morning/afternoon

[pedro]

Also read somewhere that matching exhaust gaskets to ports can be counter productive for reliability of gasket..

[A_J_T]

But actual, i once did a bit of research on this myself. porting and polishing was a Lad way of obtaining a couple extra hp on the old NA stuff. You could go to town on heads, intake mani, just anything that stuff flows through and reap real world gains. Dad always loves telling me how he spent weeks polishing the guts of his old Corolla and then dialing in the twin throat carbs to the point it was a weapon... what a Lad! cough cough.. and im sure thats still the case with high performance engines where all bottlenecks are taken into consideration. However, on boosted platforms such as a simple EJ with a VF porting and polishing intake manifolds and heads can be counter productive. to the point that the rough surface inside some housings and intake plenums can help keep air flow consistent? idk. regardless forcing air through somewhere is entirely different than pulling it through. 

 

That being said i have ported my baby P20 exhaust housing, wastegate hole and matched it to the up-pipe... just for the warm feelings basically. I dont believe it helps alot, and if it does we are talking less power difference between a humid muddy day and a fresh winters day. I think alot of this kind of thing is common sense stuff, go to town on making things tidy and port matching etc. but dont try get mirror finishes on a 65mm TB when you're running 2.5inch intercooler pipe..  idk bad example but eh rant over. 

[SpeedySub]

The polish bit is not really what I was wanting to do as read that it only really helps in the combustion chamber and exhaust ports. Slightly rough is better for intake ports.

It was just cleaning up and opening up the TB and turbo inlets I was thinking of.

[boon]

On 29/03/2017 at 3:40 PM, SpeedySub said:

The polish bit is not really what I was wanting to do as read that it only really helps in the combustion chamber and exhaust ports. Slightly rough is better for intake ports.

It was just cleaning up and opening up the TB and turbo inlets I was thinking of.

 

I dare say it will do exactly nothing. In the performance realm that 99% of relatively-stock turbocharged cars operate in, all of that stuff does three-fifths of F*** all.

[SpeedySub]

May give this a miss then, looks like I may be putting the VF8 back in sooner than I thought so won't have time to do it any way.

[newsuba]

port and polishing was old school work back in a time when n/a ruled and car motors were produced with much wider tolerances than today.

[SpeedySub]

32 minutes ago, newsuba said:

port and polishing was old school work back in a time when n/a ruled and car motors were produced with much wider tolerances than today.

Haha that must be coz I am old School.

Most of the stuff I learned on and worked on was mostly N/A and carb'd cars.

[boon]

54 minutes ago, SpeedySub said:

Haha that must be coz I am old School.

Most of the stuff I learned on and worked on was mostly N/A and carb'd cars.

 

As a massive oversimplification; on a stock-ish car you're basically limited by the smallest part of the system, which is going to be the turbine housing volute every single time.

[SpeedySub]

Good to know, makes sense. But what about having the edge into the turbo inlet as more of a knife edge to minimise turbulence? From what I read it doesn't give more power but does help with response. But whether it's really noticeable I'm not sure.