golf ball head porting

[solvi]

is this dimplig porting vs polishing beter?

http://veicomer.com/servicos/citroen...ull-race-head/

dimpling efect is like the golf ball sulface!!!

it seeam a very hi tec head ....please opinions.

[axsaxoman]

the theory is that a smooth port will cause the gas to stick to the side --so slight imperfections will cause a turbulent layer at the surface of port and allow mian body of gas to flow past with less drag--aircraft use it "boundary layer technology" on wings sometimes
difference will be very small --but yes polishing ports sells head jobs --doesn,t make head flow any better --the shape and size does that

[solvi]

i agree the diference should be small and and not far from polishing!

but still a impresive machinery job , and its computer aided , so their all equal in all 4 inlets and outlets....

i will get a quote for this head job....maybe cheaper than handmade!

ist the first head i saw whith the type of work....i think they are all handmade!!


but maybe wrong...

[MartinObviously]

Like a Golf ball.

It'll be much better than a smooth port. smooth golf balls don't go very far

[axsaxoman]

the next major jump forward in making the jp4 head flow better is a job for someone on an engineering/motorsport degree course maybe.

get a head --cut it up and remove the ex ports +combustion chamber in one piece --basically half the combustion chamber +ex ports

take it to your 3d scanner -- then redesign it with much larger ports +suitably thick port walls
go to your 3d printer and make one
go to your local foundry = GET THEM CAST FROM YOUR PATTERN
then weld these units back into std head-.

you could even cast them with dimples !!
I have wasted quite a few heads trying to get ports -especially on the ex-side larger --just not enough wall thickness in castings to make size they should be --smooth or otherwise.
I certainly would have done it when we raced the 8v --but that was long before scanners +3d printers+CAD programs to make patterns ,
I did make a totally downdraft head by having inlets remade and entering head at a vey high angle down side of spark plugs -- it made a difference ,but no one wanted to pay the cost of doing it that 1294cc 8v made 171bhp @8700rpm
getting totally new head castings made--simple enough ,just you need to make a hundred at least to make them viable
best performing 1600 cc will be the honda --just have a look one and you will see why the j4or jp4 heads will never compete with them .--

[solvi]

not entering in casting....

the point is, if this dipling efect could benefict (3,8%) our tu5j4 or jp4 heads?


more than normal polished finishing?

i put a video makinkg the dimpling in a saxo head, in tranlate i can help!


https://youtu.be/iKbmrQIQOr0

and since this guys are local to me....maybe a option for head builder.

[axsaxoman]

seems quite possible it could give that sort of increase in head flow --but real question is how dif in BHP --that may not translate into a visible power increase
boeing --tried same sort of idea on 747 wings by fixing patterned tape on the first 1/3 of the wing --which is where all the lift is made --tests showed a 5% decrease in drag -- but you don,t see new aircraft using it --so must be some reason why not --could be it made ice sticking to leading edge harder to shift /--dont know --but never got as far as use in real world

[solvi]

ok if its a spheric object it will get big improvement....

if not spheric ...not big improvement but some...


not goint to sientific ill ask for the price on this head!

[solvi]

They ask arround 500€ to dimpling the the head plus 100€ for combustion chamber!

And 2000€ for a full race head ...not cheap but to consider!!

[axsaxoman]

Originally Posted by solvi

They ask arround 500€ to dimpling the the head plus 100€ for combustion chamber!

And 2000€ for a full race head ...not cheap but to consider!!

If that is including larger s/s one piece valves and uprated springs +caps its not that bad --but for just a porting job --expensive
"full race" you need a breakdown of exact spec to know if its a good price and is the dimpling done by CNC or hand ?

[solvi]

hi..

the dimpling is CNC made....

see de video...

yes it seeams a good head option for me, since they are local.