Why all engine heads have relatively low exhaust port exit, compared to intake.

[ELS]

is there a particular reason why even F1 engine heads have the exhaust port much sharper than the intake?
I'd think you'd want as straight of a flow path as possible for both intake and exhaust, or is that not such a good thing?

[rebelrouser]

No complete answer to your question but all max effort Mopar big block aftermarket heads raise both the intake and exhaust ports. I know because I have had to build several sets of headers for my race car because of it.

[Tom68]

I'm not sure that they do, not port c/l anyways.

It's about packaging and gains, no point making an engine that fits nothing with a high exhsust port that can only pick up power a few percent.
Gotta get the air in to make power, getting it out is easy.

[allencr267]

Less head heat, Ford flat heads liked the long way around.

[digger]

Exhaust runners are always longer than inlets so would be too hard to package with a very high port

[GerryP]

[hoffman900]

is there a particular reason why even F1 engine heads have the exhaust port much sharper than the intake?
I'd think you'd want as straight of a flow path as possible for both intake and exhaust, or is that not such a good thing?

You do want as straight flow path as possible for horsepower, but aero and CoG dictates packaging on a F1 car. On Superbike engines, the radiator, CoG and front wheel dictate it.

[ELS]

is there a particular reason why even F1 engine heads have the exhaust port much sharper than the intake?
I'd think you'd want as straight of a flow path as possible for both intake and exhaust, or is that not such a good thing?

You do want as straight flow path as possible for horsepower, but aero and CoG dictates packaging on a F1 car. On Superbike engines, the radiator, CoG and front wheel dictate it.

do you know any engines that didnt have anything in the way and thus had a really high exhaust port?

[BCjohnny]

The better non-cross flow heads favour placing the inlet ports higher than the exhausts for known and packaging reasons

Lots of production crossflow heads however don't have a 'sharper' exhaust port than intake, SBC being the more obvious one

Biasing intake angle, thus usually flow, always takes precedence where possible, especially in more optimised designs, but every head has to exist in the real world reality of packaging etc ....... and actually having to have a valve

None more so than OE that has many more limitations, not least cost ...... so as with most things it ends up being the best compromise relative to objectives

[NXBOY]

Why is one Jewel lower then the other? To fit all parts in the chassis.

[Tom68]

100_0591.JPG

[ELS]

100_0591.JPG

what's the point of posting those pictures? I was talking about the exhaust port exit, not the exhaust header, and not at all about where it exits in the car. and both those engines have the exhaust port exit nearly 90 degrees off the piston axis

Less head heat, Ford flat heads liked the long way around.

but wouldn't a more curved exhaust port increase the heating of the head? unless you could in possible decreased velocity due to restrictions.
only thing I can think of is maybe the exhaust valve seat, it being heated more because of the exhaust flowing directly at it, as opposed to a more curved exhaust port.

It's about packaging and gains, no point making an engine that fits nothing with a high exhsust port that can only pick up power a few percent.

yeah but aren't formula 1 cars all about picking up a few percent of power? I doubt raising the exhaust port a few cm would make it impossible to get relatively good aero as opposed to a lower exhaust port.

Lots of production crossflow heads however don't have a 'sharper' exhaust port than intake, SBC being the more obvious one

yeah I should've said most racing engine heads, I've yet to see any engine head with a high exhaust port...

[modok]

I think of three main reasons.
-intake flow is more critical for power
-heat is more of a problem, short height of approach lets the guide be closer to the valve head, shorter port means less port surface area to absorb heat.
-the lighter/hotter gas will actually follow sharper bends vs intake, (Reynolds number and other things I don't fully understand)

[Tom68]

100_0591.JPG

what's the point of posting those pictures? I was talking about the exhaust port exit, not the exhaust header, and not at all about where it exits in the car. and both those engines have the exhaust port exit nearly 90 degrees off the piston axis

Less head heat, Ford flat heads liked the long way around.

but wouldn't a more curved exhaust port increase the heating of the head? unless you could in possible decreased velocity due to restrictions.
only thing I can think of is maybe the exhaust valve seat, it being heated more because of the exhaust flowing directly at it, as opposed to a more curved exhaust port.

It's about packaging and gains, no point making an engine that fits nothing with a high exhsust port that can only pick up power a few percent.

yeah but aren't formula 1 cars all about picking up a few percent of power? I doubt raising the exhaust port a few cm would make it impossible to get relatively good aero as opposed to a lower exhaust port.

Lots of production crossflow heads however don't have a 'sharper' exhaust port than intake, SBC being the more obvious one

yeah I should've said most racing engine heads, I've yet to see any engine head with a high exhaust port...

EEZ up dude, this is the internet, not China, report our posts as off topic for deletion, You've been given sound reasons but apparently you know better, so you tell us.

[allencr267]

The intake gets separated, un-vapor/atom -ized from inertia in turns.
The exhaust, who cares, except valves have enough heat trouble so, get it away/out ASAP.