Hello from the UK

[BenR]

I'm sorry, that is where we will have to disagree.
The 4age story is one where the designers (who in terms of qualifications) are probably light years ahead of you or me, but got the whole mod considerably wrong the whole way along.

First they design an engine that geometrically is good, resembles the BDA in its geometry. However, the bigport is just plain crap, i have no idea what they were thinking, port sizing capable of feeding your average yank v8 but stiffled with tiny valves. Chamber is quite good, but factory machining made it so horrible and det sensitive that CR had to be kept so low. They make TVIS to try and cure some of the initial design flaws, but it just doesnt work.

Then they make the smallport, the best 4age around. A port shape that is actually decent, the 16v chamber which has an acceptable level of quench.

Then come the 20v's.........in std trim they come with wilder cams and ITB's and more complex management, so its no wonder they hit 100bhp/ltr. But it isnt because they are better designed. The ITB;s they run are poor, the port designs are horrible and generate poor flow quality, the chambers have no quench at all, and without quench your fighting a battle against end gasses, auto ignition, stupid amounts of ignition timing and a piston crown design that just doesnt benefit anything in anyway.

If quench wasnt important, then all of us top tuners dont spend all our time trying to increase it and use it effectively.

Modelling and engine takes me more than a day, i have to design and input every factor. This is more than your geometry and bearing clearances and friction factors, but weighs of every component, cam profile per 0.5degree, top end geometry data and valve train assebly data, then i have to port and flow a head and add that data, input every part of the ports dimentions/geometry/volumes/seat configurations etc etc. Induction methods, exhaust parameters, fueling and ignition factors...the list is endless and takes a fair amount of time to input all the correct data. And at the end of that, the results are only aids, most of the time about 5% accurate, but either way, you still have to build the engine and will net the same result if you modelled it or not. Not many customers have the budget to design and redesign and engine.

Dont bother with megasquirt, if you want a cheap and good ecu, run a VEMS unit or an omex. I personally arent one for over complicating ECU's, i find it a waste of time.......good tuning makes up for any fancy systems people are running. Most of my ITB setups run tps vs rpm with the MAP used for baro correction, running MAP on ITB's is over complicating and you dont gain anything.

A good foam filter has the capacity and filtration quality which is fine for tarmac use, i would only bother considering paper if the user was not going to look after the filter and was competing in very dusty conditions.

With your carbon airbox are you talking of just surrounding the ITB entries? If so, MAP values wont be affected unless the throttle is placed upsteam, if the plenham is before the butterflies then you will still recive map variations at idle with any decent cams. But on many ecu's you can just run tps vs rpm at low range and swap to MAP for load at higher rpm once the value settles.

Oh, and just to bring the point home....20v's are rubbish. In an attempt to increase valve area they destroy burn conditions, and you cant add too much quench or you just shroud the valves, making all that area pointless in the first place. And the ports are just plain bad........although the audi 20v ports are worse.