golf ball head porting

10th April 2016, 22:09

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.

11th April 2016, 08:47

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

12th April 2016, 18:38

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...

12th April 2016, 21:47

Like a Golf ball.

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

14th April 2016, 08:37

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 .--

15th April 2016, 22:13

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.

18th April 2016, 08:34

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

18th April 2016, 20:34

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!

26th April 2016, 16:25

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!!

27th April 2016, 12:28

Quote:

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 ?

24th July 2016, 17:22

hi..

the dimpling is CNC made....

see de video...

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