overlay of exhaust ports ph 1 vs ph 2

[marinemackay2003]

So messing about with the head today

i have a ph 2 head and was comparing gaskets from a ph 1 and ph2

i already knew ph 1 ports were bigger

^ ph 2 head with ph 1 gasket

there is quite a size difference

so the question

does any one know if its possible to convert the ph 2 port to ph 1 size?

or am i going to hit a water way ect

as i think the smaller exhaust ports will be a restriction on a boosted engine

 

[NorthloopCup]

Yes you can open them out to ph1 size mate. In fact you can go significantly larger than ph1 if you want but it's a bit pointless. It's all in the shape of the ports not how big they are mate. What hp are you looking for? Original ph2 head flows fine in boosted applications anyway (up to a point though obviously)

 

[marinemackay2003]

thanks may have a go at them over December then

yeah the port shape is not the best but they seem to flow fairly well as standard as you say to a point

i am not really aiming for a figure any where over 300 will be more than enough

just trying to make it make it as best i can with out spending any more money

 

[NorthloopCup]

thanks may have a go at them over December then

yeah the port shape is not the best but they seem to flow fairly well as standard as you say to a point

i am not really aiming for a figure any where over 300 will be more than enough

just trying to make it make it as best i can with out spending any more money

At 300 you'll be fine mate. It would probably only knock a couple of psi off the boost level as well if you opened them out. Have you got experience of porting cylinder heads? If you haven't mate I'd leave it personally or take it to someone that has.

 

[marinemackay2003]

yeah should be more than ok, there are a fair few running well over that on normal ports

i have a little bit of experience, and fairly good understanding of whats required

but tbh im going to give it a go anyway as have a month off work and nothing to do

 

[NorthloopCup]

Yeah fair enough mate, nothing ventured nothing gained! Finish off the ports with 60-80 grit for your final finish though.

 

[marinemackay2003]

100% agree dont try, dont learn

will try to get them mirror finish tbh

 

[NorthloopCup]

100% agree dont try, dont learn

will try to get them mirror finish tbh

mirror finish is not what you need mate. Trust me.

 

[marinemackay2003]

it will end up more like this with 60-80 grit (one on right )

this is from my old inlets

why avoid mirror smooth out of interest?

 

[Dan519]

mirror finish is not what you need mate. Trust me.

on an exhaust port? textured finish just gives carbon something to stick to easier so you get a build up faster

 

[NorthloopCup]

on an exhaust port? textured finish just gives carbon something to stick to easier so you get a build up faster

You'll get carbon build up on a mirror finished port as well mate in the same way as on an 80 grit finished exhaust port. I've seen and done enough.

 

[NorthloopCup]

it will end up more like this with 60-80 grit (one on right )

this is from my old inlets

why avoid mirror smooth out of interest?

Yeah looks alright to me mate. The guy who taught me told me not to bother. He's a well respected tuner in ford circles as well, so I trust his opinion.

 

[marinemackay2003]

will just do it the same as that then

will pop up photos when i am done, thanks for the advise

 

[NorthloopCup]

No worries mate. Yeah look forward to seeing your progress.

 

[Chip-mk1]

197 head is also on the smaller ports (but way bigger inlets), and mine did over 300bhp without them being touched.

 

[marinemackay2003]

just trying to make things better as i go along really chip

hopefully i will be able to get it right so running slightly less boost ect

and on 421 cams too so will see how it goes

and like i said its a free mod so cant be a bad thing to have a go at

 

[Chip-mk1]

Id be careful of cam timing with 421 for boost, could end up with a lot more overlap than you want.

On a turbo big ports can mean more lag, but less of an issue with a supercharger, will just cost you a bit of torque at lower rpm if you go too big.

 

[Dan519]

You'll get carbon build up on a mirror finished port as well mate in the same way as on an 80 grit finished exhaust port. I've seen and done enough.

Sorry but you're wrong about this, yes you'll get some carbon whatever you do, but the less you give it to stick to the better

 

[NorthloopCup]

Sorry but you're wrong about this, yes you'll get some carbon whatever you do, but the less you give it to stick to the better

Well we will just have to agree to disagree then mate.

 

[Chip-mk1]

On the inlet you want to avoid mirror finishes because of fuel condensing, on the exhaust though there isnt any real harm in a smooth finish. If you think about it the inside of the exhaust manifold is next place it goes and thats smooth anyway.

 

[NorthloopCup]

On the inlet you want to avoid mirror finishes because of fuel condensing, on the exhaust though there isnt any real harm in a smooth finish. If you think about it the inside of the exhaust manifold is next place it goes and thats smooth anyway.

I've always done the exhaust ports with an 80 grit finish Chip, which leaves them nice and smooth as I'm sure your aware. I just don't see any point in mirror polishing the exhaust ports. For the amount of effort you have to put in to get that finish, the gains in performance aren't warranted. All imo of course. I'm going off how I was taught.

 

[Chip-mk1]

I've always done the exhaust ports with an 80 grit finish Chip, which leaves them nice and smooth as I'm sure your aware. I just don't see any point in mirror polishing the exhaust ports. For the amount of effort you have to put in to get that finish, the gains in performance aren't warranted. All imo of course. I'm going off how I was taught.

Once you are on a smooth finish anyway, a mirror polish or not really doesnt make any difference IME, so I totally agree with you that its just time wasted for at best a very shortlived gain and in reality more likely no gain at all.

I dont think its worth doing, I just dont think it will do any harm either.

 

[NorthloopCup]

Once you are on a smooth finish anyway, a mirror polish or not really doesnt make any difference IME, so I totally agree with you that its just time wasted for at best a very shortlived gain and in reality more likely no gain at all.

I dont think its worth doing, I just dont think it will do any harm either.

My sentiments exactly.

 

[1uk3m4n]

When you see performance cars from the factory they are not mirror finish

For example bmw m3 head the ports on that are very smooth but not a mirror finish. Im sure if getting a mirror finish help improve bhp/torque/flow or anything like that then bmw would have done it from the factory

 

[marinemackay2003]

Ref -Id be careful of cam timing with 421 for boost, could end up with a lot more overlap than you want.


yeah you are probably correct chip

however this one made 341hp with 421 s and is a similar spec to what i am doing, so does not seem too bad for it

although dont know if it was on standard timing

http://www.cliosport.net/forum/show...percharged-Clio-)-0-9-bar-boost-7900rpm-limit