Versus_Creations

iTrader: (1)

I have my own opinions and my own reason's for choice.

After reading this topic i thought i would ask everyones else's opinion

https://passionford.com/forum/viewtopic.php?t=109182

Whats better for porting, polishing, bigger valves, etc...

Is there any difference? Or is it just whats prefered?



Please leave a reason for your choice.

Rick

makes naff all difference. Much more important is the condition of the head, and quality of porting.

M K

iTrader: (9)

as above
surely they can can both be ported / polished as well as one another as they are basically the same,,

but i dont think you could flow or polish 1 better than the other

Ginge !

but what about the thickness of the water channels


oh and whats the difference in the valves too ?????, im seriously stumped on that one jano

chiz

i was under the impresion that the mfi has bigger valves??? av got an mfi head runnin with a carb on my escort. obviously theres differences inlet side with the injectors and manifolds bein different.

stumped

Oranoco

I know the EFi head has the notches on the inlet for the injectors but beyond that I'm stumped. That was the only real difference I noticed when I put a new head on the 2i. Didn't pay any attention to the valves though TBH

Wouldn't have though there was that much in it. Saying that a few years ago the EFi lean burn head was considered an arse to tweek. So there must be differences there

pauldudley

hi ya jano I was told by a man in burtons that the mfi head gave 10bhp more power when they tested it.The duratec flows better tha the cossy 16v.

Ginge !

now thats interesting !!!!

was both heads of the same capacity or not ???

as burtons know there stuff and all that but how many different heads did they test and was it on the same engine ect or different cars

did they swop em back over and see if it was still the same too

pauldudley

well as far as I know there put early head It mite have been xr3 carb "is there any differance?" one on A s2 and it on rollers and 10bhp more and I think there both standard

JesseT

EFI inlet valve in the left and standard 1.6 MFI valve in the right.

essexrsturbo

looks like the mfi valve is a lot more gas flowed, judging by that pic... but i new that anyway, which is why i built my efi head with turbo valves

Ginge !

yeah but after a certain lift they just flow the same air, infact the efi ones have a better flow design going by that, looks less turbulant, but then my stage 3 head had bigger valves to flow more air,

are they any bigger in diamiter ???

Bread

on my xr2i big valve head valves are 43.5mm inlet 38.5mm exhaust, an its all ported had valve throats shaved n stuff
ive got an old erst head stuck in the ocrner here and thats got some nasty looking bends in the inlet where mines all smooth

essexrsturbo

a betta flow design? have a look at a gas flowed valve and see if it looks anythink like that

Ginge !

think if ya look into it abit more ya will see what i mean

theres only son far a valve needs to be open before theres no more air that can flow !!!

the shape of the valve being like that will flow moew when opeing it but will make the air sweep, not hit and turn

theres alot to head porting that im looking into and i do thank jano for mentioning the difference between the valves as thats a good thing hes discovered

now im sure if ya gonna re cut the valves ya would fit larger ones but then im sure jano aint gonna give too much away

Versus_Creations

iTrader: (1)

any more input from anyone ?

pauldudley

i say y bother with a std 8v, 16v is better, I can understand if you a highly modded head and your on a tight budget but ?why?

Rossco

Iam with Paul on this one, 16 valve heads all the way

essexrsturbo

16v heads are alot better as they can flow more air ect.. so im with ya on that 2!

Ginge !

cause not everyone wants to use just one engine, may aswell say why not slap a vtec engine in it, sounds better and revs the tits real nice, no need to fook about with turbos


then theres the others who swear by bike engines, there smaller, cheeper and more fun, why bother with 16v heads

then theres the thought of why not stick a v8 engine in it, cheaper than a crack head whore dying for a fix and hits peak torque lower in the rev range



think its all due to one thing


thats the engine spec ya wanna go !!!!!!, if ya want a xetec engine fit one, if ya want a CVH fit one, if ya want a hampster in ya engine bay fit one, if we all used the " fit a ==== engine" then we would all have the same power outputs


oh and different engines respond differently too


hope that helps

pauldudley

yeah maybe!!!

Versus_Creations

iTrader: (1)

anything to add anyone?

Ginge !

yeah ive just converted a mfi head to efi and after precision measuring ect ive actually made it better than a efio head as the efi fuel pattern hits a wall rather than flutes in the head

i could be talking bollocks but i will know for sure if its worked

LEE-RS

dave baker at puma racing says efi are best

http://www.pumaracing.co.uk/cvh.htm

lee