Cylinder head help

[1uk3m4n]

Hi guys, I’ve got a question I can’t find an answer for and hoping you can help. I’ve got two heads, 172 and a 182. On the 172 both inlet and exhaust ports have been machined, I would say it’s a standard job and not aftermarket. On the 182 only the inlets have been done, again I would say from factory. Does anyone know which one is best to use for power?
Thanks
Ash

 

[bloke]

I take it the 172 head is a phase 1 then?

 

[JamesBryan]

Ph2 172/182 pretty much identical

Ph1 172 larger ports.

 

[1uk3m4n]

Brilliant, thank you. Exhaust ports are huge compared to the 182 so It looks like i have a ph1 head.

 

[1uk3m4n]

Bloke - I don’t know. The engine was removed from a ph2 172 so assumed it was that. Comparing them side by side the only difference is the exhaust ports are massive and have been machined. Maybe I’ve got real lucky and it has a ph1 head on it.

 

[bloke]

pic of ports?

 

[1uk3m4n]

Yeah no problem. I’ll get them tomorrow.

 

[STEVE.M]

I’ve got two heads,
Ash

Found you an avatar.

 

[1uk3m4n]

Found you an avatar.
View attachment 1368460

Ha. Thanks Steve.

 

[1uk3m4n]

Pics here

 

[flebay]

Hi guys, I’ve got a question I can’t find an answer for and hoping you can help. I’ve got two heads, 172 and a 182. On the 172 both inlet and exhaust ports have been machined, I would say it’s a standard job and not aftermarket. On the 182 only the inlets have been done, again I would say from factory. Does anyone know which one is best to use for power?
Thanks
Ash

https://www.cliosport.net/threads/ph1-172-exhaust-ports.783654/

 

[1uk3m4n]

Thanks for that link! So is there any reason why people would go for the smaller ports? Surely bigger would be better, I’m up for being educated though.

 

[Jamie86]

Actually I was told the smaller port 182 head is the better option.. (by someone who did a lot of research into f4r design and building optimum engine)

I don't know enough to know why though.

 

[bozothenutter]

Actually I was told the smaller port 182 head is the better option.. (by someone who did a lot of research into f4r design and building optimum engine)

I don't know enough to know why though.

I'm guessing because the bigger the port, the lower the velocity will be....always a balancing act 'tween the two....

 

[1uk3m4n]

I'm guessing because the bigger the port, the lower the velocity will be....always a balancing act 'tween the two....

What a minefield! I’m putting a turbo on mine so currently looking in to which head will be better for that. There is just so much info out and lots of it conflicting. I’d love to own a dyno and do back to back tests to find out what is better.

 

[1uk3m4n]

The smaller ports must work, Renault got 180bhp from that and you can run a turbo up to 280bhp so it really can’t be that’s bad.
Thanks for the replies so far people

 

[bozothenutter]

for a turbo, the bigger ports might be better if running big boost, but i'm no expert on turbo's.
oh and don't match tho port to the exhaust manifold, there is supposed to be a step!

 

[1uk3m4n]

No I’m actually going to leave the ports well alone. I’ve grown up being told about smoothing ports to a mirror but I’ve seen M3’s with those weird lines in the ports and again if Renault have done that and achieved that BHP it must work. I’ve been reading so much this past week about it, even down to the dimples on a golf ball. Ha.