Big port 20v heads

[Andrew@A.L.D]

Other than the AEB head what other engine codes have the big post head?

I just think i might need it if i'm going 2.1/2.2

 

[S3 Paul]

Large Port head you mean?

 

[Andrew@A.L.D]

Me and my fat fingers

Yes thats what i mean

 

[Welly]

AGU has the big port head as well.

 

[666markyboy]

AJQ too i beleive

 

[S3 Paul]

Well there was a table posted up on here about which engine had what... search and yee shall find

 

[ian52]

AJL too.

 

[mat20vt]

my ajq didnt have large port

 

[Dani_B19]

I cant decide wether togo large port or not. How would it affect power band etc?

 

[S3 Paul]

I think i know somebody with a couple of AGU heads
when i thought i was going to do this with mine,
Ive decided i will just get a fully sorted head when the time comes

 

[sam80quattro]

adr from a4, passats etc also has the big port head on it

 

[Andrew@A.L.D]

The problem is i have a APY head that has the secondary air injector that bolts to it

I might remove it but people say that it may not pass a MOT?

 

[<tuffty/>]

eh?? most people bin that especially as you are going BT and 2.1... think that will be the least of your problems getting it through an MOT tbh...

Decent stage 3 map and a suitable CAT will get you through I would have thought

<tuffty/>

 

[Broken Byzan]

going large port will move the power band up the rev range and probably reduce low down torque . IIRC there is no increase to be had till post 400 BHP.


My understanding is this....
The large ports can affect air speed by slowing down the air going into the ports and cylinders. Imagine putting your finger over the end of a hose pipe, squeeze the end and the speed increases, but the amount of water is limited, let it go and the water will flow more but the speed will lower . To keep the water speed the same the water needs to be pushed harder to make use of it.

 

[<tuffty/>]

What is it you are trying to achieve with your build? Powerful daily driver or insane weekend rocket?

If you think you might need a large port head due to the displacement of your engine build I am not sure you are getting the right advice or are going about your build the right way...

Going much more than 400bhp on a 1.8t is big money and moves into the realms of race car like drivability imo...

<tuffty/>

 

[Dani_B19]

No, when i do mine paul i want an everyday driver.
Think andy's wanting a insane crotch rocket .

 

[Andrew@A.L.D]

Just weighing up my options really

400bhp would be nice

The only reason i'm going 2.1 is because my crank has been badly damaged and bore has been too so what the hell i might as well seeing i need new pistons and crank

I just want it to be a nice drive with lots of torque and power?

 

[Andrew@A.L.D]

eh?? most people bin that especially as you are going BT and 2.1... think that will be the least of your problems getting it through an MOT tbh...

Decent stage 3 map and a suitable CAT will get you through I would have thought

<tuffty/>

I'll bin that then as its one of my fault codes that keeps coming up ( incorrect flow )

 

[<tuffty/>]

Just weighing up my options really

400bhp would be nice

The only reason i'm going 2.1 is because my crank has been badly damaged and bore has been too so what the hell i might as well seeing i need new pistons and crank

I just want it to be a nice drive with lots of torque and power?

Can see your point and if you have the budget then go for it. I did debate on going stroker before getting a bigger turbo but the expense seemed a little too much bang for buck wise... I know someone with a stroked Leon running a GT2871 and he has spent loads and done loads on his and produces around 370bhp as a result (bit more now with the water/meth kit he has) but I essentially produce more with more or less bolting a GT30 on...

Bill reckons the GT28 is a little short of flow for a 2ltr anyway which is one of the reasons he suggested I go for the GT30 as I was going down that route... tbh I doubt I will do that now as I won't benefit that much from it and have better things to spend my money on.

If I was doing it again, I would have gone 1.9 ish (82.5mm or 83mm overbore) and rebuild the head with supertech valve gear. That would be more than enough to give me the reliability, drivability and power that I was after. Bill manages 600bhp on a similar base although granted he does have a large port head

You say 400bhp would be nice but I don't see why you are going to the effort of building the engine you are if you are not after big numbers. The TDi crank route is the most difficult and complicated one and one that you will struggle to get decent advice about I suspect.

If you really want to go down the stroker route, get a TFSi crank based kit... its tried and tested, fits in a 1.8t and you will have less hassle with getting bits, advice and it working.

Use the spare cash to sort the head out, small port will be fine especially if using as a daily driver. If you want to chase numbers then you are looking at large port head, supertech valve gear (as the power band will move and you need to up the rev limit to make any use out of it) large throttle body (75/80mm) and SEM inlet (or equiv) and then even with a GT30 you may only be making 50 bhp more than me?

Do you have the chassis and brakes sorted on your car yet? What is your budget?

<tuffty/>

 

[Andrew@A.L.D]

I'm just going to rebuild the engine first and then go from there

Fitting the TDI crank will not be a problem as i know about the machine work and what needs to be done and when you work in a CNC machine shop then its not a problem

My spec i plan to do it 2.1 using the TDI crank, stroker rods and pistons with 83mm bore, ALT 2.0 head gasket, valves and valve springs, ported head.

Turbo will come at a later date as the chassis and brakes will be sorted after the build

 

[<tuffty/>]

Fair enough mate... don't forget to write it up in some kind of build thread sounds like an interesting project.

<tuffty/>

 

[Andrew@A.L.D]

I will

The reason i'm asking about all this is that i'm new to the 20v engine