Gas flowed cylinder heads

[SonicHedgeHog]

Are they worthwhile on a modern engine? What sort of Bhp gain would you get on a standard 4 cylinder petrol engine and what sort of cost would be reasonable?

Thanks from my iPhone.

[davepoth]

Always worth doing, although it depends on the engine. Some will come better flowed from the factory than others. HP gain will again be variable, and will depend on what other mods you have done.

[MDT]

A gassed flowed head would not make “much” difference to a car unless it was joined with say

- Different Cam’s
- Different exhaust manifolds
- Increased Compression Ratio
- Larger valves
- Re-mapped
- Etc

As for its likely improvement on a modern engine, I would suggest that the above may well see an healthy improvement if the engine in question was built and set up for economy in mind. IF however you were looking to have gains from gas flowing on its own on say a Honda S2000 head I think you might be disappointed.

Cost would depend massively on how long it took and if you were sticking with standard Valves and Cam’s etc.

What car/engine you talking of?

[SonicHedgeHog]

Thanks guys. Engine is a 1.6 Ford zetec. Don't want to change the character of the engine as I like it the way it is, so just looking for refinements really. Tbh I am just tickled pink with the car at the moment so am exploring all the tinkering options. The Mountune kit seems to change the character too much so I thought a gas flowed head end a new air filter might do the trick.

[Crafty_]

Don't waste money on a small engine in what is a fairly big car (compared to escorts of the past).

Switch to a bigger engine first.

[DanGPR]

Crafty_ said:

Don't waste money on a small engine in what is a fairly big car (compared to escorts of the past).

Switch to a bigger engine first.

This.

No=one likes hearing it , but if you really like the focus, save for an ST170,you'll be thankful you did in the long run.

[300bhp/ton]

SonicHedgeHog said:

Thanks guys. Engine is a 1.6 Ford zetec. Don't want to change the character of the engine as I like it the way it is, so just looking for refinements really. Tbh I am just tickled pink with the car at the moment so am exploring all the tinkering options. The Mountune kit seems to change the character too much so I thought a gas flowed head end a new air filter might do the trick.

You won't get more power without changing the character.

HP = torque x rpm / 5252

So more HP normally means moving the torque curve to the right on a dyno graph. More revs and potentially less HP in lower rpms.


EDIT: as others say, if you want more power, start with a powerful car.

Edited by 300bhp/ton on Sunday 16th January 18:04

[SonicHedgeHog]

Thanks again. It doesn't actually need more power. I'm just trying to think of things that might be fun. The engine has only done 400 miles so changing it would be a bit silly anyway. I think I might have to try the Mountune car myself rather than just go on others opinions. Gas flowed head with all the Mountune goodies would probably give an normally aspirated 100+bhp per tonne which would be great fun and super responsive. Thanks again for the info.

[Slade Alive]

It's only worth flowing the head if you can shift the required volume of air through it to optimise its potential.

Such would require induction and exhaust modifications to accomodate the cfm (cubic feet per minute) achieved once flowed.

[300bhp/ton]

SonicHedgeHog said:

Thanks again. It doesn't actually need more power. I'm just trying to think of things that might be fun. The engine has only done 400 miles so changing it would be a bit silly anyway. I think I might have to try the Mountune car myself rather than just go on others opinions. Gas flowed head with all the Mountune goodies would probably give an normally aspirated 100+bhp per tonne which would be great fun and super responsive. Thanks again for the info.

Is it a new car? Only 400 miles on the engine or is this some kind of kit car?

[Rubin215]

If you want a faster car, buy a faster car; it's always cheaper in the end!

[nonuts]

Rubin215 said:

If you want a faster car, buy a faster car; it's always cheaper in the end!

This, and normally better not just cheaper.

[SonicHedgeHog]

300bhp/ton said:

SonicHedgeHog said:

Thanks again. It doesn't actually need more power. I'm just trying to think of things that might be fun. The engine has only done 400 miles so changing it would be a bit silly anyway. I think I might have to try the Mountune car myself rather than just go on others opinions. Gas flowed head with all the Mountune goodies would probably give an normally aspirated 100+bhp per tonne which would be great fun and super responsive. Thanks again for the info.

Is it a new car? Only 400 miles on the engine or is this some kind of kit car?

It is a new car. If I wanted more power I would have bought a Focus RS. Wanted small, NA and fun and that it was I've got. Just enjoying exploring all the options with the new car and tweeking the engine is one of them.