AGU Head

[ibizacupra]

Hi All, sorry to hijack this thread a bit but i thought it was better than starting a new one,
anyway can anybody confirm weather an ADR code head is defo large port as i've picked one up cheap and may build it up for the ibiza.

I did have a search and found a thread from 06 in which Bill says that ADR is a large port but in the mk3 ibiza section at the mo there is a list of small port codes and ADR is in that list to

Can any of you shed any light on this?

Tasha

ADR is largeport 100%
my ibiza runs one

its off non turbo 20v cars
AEB is turbo cars.. AGU also

 

[tashacupra]

Thanks Bill thats just the answer i was looking for, as you say 20v non turbo, think the one i have is from a passat or A4, cam belt had gone so every valve was bent/snaped but the head seems ok but i'll have it crack tested etc, then if its ok built up with supertech throughout including new guides.

Thanks again, Tasha

 

[Backdraft]

Dont forget to get it ported first as they are quite bad in/out flow.

 

[ibizacupra]

Dont forget to get it ported first as they are quite bad in/out flow.

What?

you talking AEB head? ADR, AGU?
flows s h i t loads more than a smallport..

bad for flow my ar$e

 

[tashacupra]

Dont forget to get it ported first as they are quite bad in/out flow.

What?

you talking AEB head? ADR, AGU?
flows s h i t loads more than a smallport..

bad for flow my ar$e

, the reason i was thinking of useing the large port head is so it would save me the cost of porting my standard small port AYP head, which as i understand in full ported form will only flow slightly more than a standard large port so therefore making it not very cost effective, am i correct in thinking this?

There is no way with the size turbo i will be running i would need a fully ported large port head, as i have no chance of maxing its flow capacity as far as i can see, the most i was going to do before building it up was knife edge the inlet ports and take some of the casting marks out and just genrally buff everything up a bit as my partner can do all this for free at work.

 

[ibizacupra]

side by side smallport to largeport its night and day difference in port runners, diameters, all in favour of largeport

I can only assume whoever typed the backdraft comment got it round their neck, as its 100% the opposite.. Smallport.. yea port it, largeport, clean it up at most for 99% of applications.

ported to hell smallport = stock largeport

 

[tashacupra]

Your on tha ball tonight Bill, very helpfull i may give you a shout over the next few weeks regarding all the supertech stuff as i have not sourced any of it yet, but i'll have to see how funds develope.

 

[h17och]

although a smallport ported may flow the same as a largeport, the smallport ported would be a nicer drive

iirc, knife edge aint a good idea...

 

[tashacupra]

iirc, knife edge aint a good idea...

Any more info on that hooch?

 

[h17och]

im talking inlet side

it creates turbulance by knife edging. also will drive crap as you 1st go WOT

 

[Indy]

Hey Hooch, remember seeing my engine being put together at JP's? He's done a fantastic job. I've got Cat Cams on mine and the my engine runs fine but I dont think my cams are knife edged.

Bill's doing the mapping on the 28/29th of March cant wait to see if the car will fall apart with all that power or remain intact

 

[ibizacupra]

although a smallport ported may flow the same as a largeport, the smallport ported would be a nicer drive

iirc, knife edge aint a good idea...

sorry hooch, but thats plain cr4p info

knife edge?
lmao

 

[ibizacupra]

im talking inlet side

it creates turbulance by knife edging. also will drive crap as you 1st go WOT

bollox

does no such thing..

if you have experienced such a thing, it was mapping not anything to do with knife edging the runners to the valves.....

 

[tashacupra]

So Bill in you opinion knife edging is a good thing then?

I must admit i have seen some pictures of a cnc cut head and due to the machining methods used they end up with a natural knife edge and i have not seen anybody say to much bad about them, and i've also seen hand ported ones done to both 16v and 20v all knife edged.

 

[ibizacupra]

So Bill in you opinion knife edging is a good thing then?

I must admit i have seen some pictures of a cnc cut head and due to the machining methods used they end up with a natural knife edge and i have not seen anybody say to much bad about them, and i've also seen hand ported ones done to both 16v and 20v all knife edged.

its not a bad thing, and its what you see on ported heads.
the crok of wot problems etc is just that...... a crok, and unreleated to physical head more setup and mapping to cause that.

my largeport head which is ported lightly is flowing well, very wel in fact, on stock valve sizes currently, producing 500bhp from 1.3bar of boost.. so far. no stumbling, never has it had this.

 

[h17och]

bill my info is from fl ow bench results.

 

[ibizacupra]

Sorry.. but the wot issue you describe and a head port is complete tosh hooch.

JP knows his heads for sure, but there is no such side effects as you badly describe in your post.

You are obviously quoting JP, but I think you have got this one round ya neck fella

every ported head I have ever used and run has had no such issue..

Not saying a small radius on the edges is'nt better for flow etc, but I would like to see actual facts on the degree of difference it makes.. flow bench is not an engine, its a guide to flow.

 

[Ibiza sport man]

I agree with Bill. Never had problem with knife edge ports, it's the normal way to do it. If you had rough running afterwards it was due to something else.

I must say the bigport head as standard has some pretty poor matching of the inlet throat to the back of the valve seat. Must be a 3 mm difference in diameter presented to the airflow as sharp step. It's like they've overbored it just behind the seat land. You can't improve it much and still retain a 3 angle seat.

 

[JNL]

Just a little food for thought in order to help clarify Hooch's comment:-

Traditionally 99% of multivalve intake ports that you see have knife edged port divisions. The theory is the thinner the partition the easier that air passes over it.

The reality of it is air will pass over a knife edge like a radiused one but as it does it tumbles and rolls of the edge. The resultant effect means that the incoming air passing over it has to first overcome the turbulance around the area of the port division before entering the combustion chamber.

In a real life situation this means that you have a slower throttle response in respect to a port division that is nicely radiused.

For those that don't understand the science behind it, it's around you everyday of the year in the form of an airplane wing. Get the radius correct and you can get air to stick to the surface instead of lift away and get turbulance. It's called the coander effect. Anyone that dissagrees please show me an airplane wing with a knife edged leading edge.

As for porting small port vs standard large port. A ported small port gives better throttle response and a flatter less spikey power curve to that of a large port head due to improved port velocities. The result is a much more enjoyable road car. One of the reasons why VAG introduced the small port head for their 225hp road going cars instead of fitting a largeport head as found on the earlier 150hp models.

A correctly ported small port head will comfortably support 500hp on a GT3071R with 0.82 backhousing as proven by Andy with his 10.2 sec white MK1 golf. Compared to a standard big port head that runs out of puff at 450-460hp on the same turbo and boost settings.

 

[JNL]

I must say the bigport head as standard has some pretty poor matching of the inlet throat to the back of the valve seat. Must be a 3 mm difference in diameter presented to the airflow as sharp step. It's like they've overbored it just behind the seat land. You can't improve it much and still retain a 3 angle seat.

The throat of the seat is the flow restriction within the port and it sets the desired port airspeed in relation to the bore size of the engine. By opening up the throat you will slow the port velocity sacrificing low lift gain in favour of high lift gains. As the cams for the 1.8t's are all considered low lift (less than 440thou) it is pointless to unnecessarily open the throats up as the restriction favours driveability.