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I was thinking of fitting a GTI inlet manifold onto a 1.4 16V. I no that the engines are 99% exactly the same but just wanted to confirm whether the inlet manifold will be a direct fit and how much bigger the diameters are compared to a 1.4 manifold. Are there any other complications that i should be aware of?

Also is it possible to fit the GTI fuel injectors and rail onto my car as the more air would require more fuel right?

I think someone tried to fit a GTI Throttle body onto the 16V 1.4 .... it didnt work!

Electronically the systems are ever so slightly different...

IMHO the GTI inlet manifold is pretty poo... If I were going to be spending that much time and effort doing this sort of work.... I would get myself a set of bike throttle bodies, make a nice short aluminimum manifold and then get a custom engine management system to run it... Would give you far better power gains than trying to get the GTI inlet to work!

I was not planning on fitting the GTI throttle body as i no it wont work with my car, i was just thinking of puttin the GTI inlet manifold on and reattaching my old throttle body that i have got. I can get a GTI inlet manifold for £70 and i dont think fabricating a manifold would come that cheap. Do you know if the inlet manifold is a direct fit? There shunt be any problems with the ecu as the inlet manifold has no connections or wires going into or out to the ecu.

There would be no performance gains whatsoever by using a GTI manifold with your standard throttle body...The throttle body would be the limiting factor..

The whole idea of engine tuning is to get more air through the engine... so...cold induction feed> decent flow airfilter>good sized throttle bodies> properly designed and flowed manifold> flowed and ported head>bigger valves> properly designed exhaust headers and pipe...

Simply increasing the size of the intake manifold wont help...

IMHO.. you WOULD see impressive power gains if you use bike throttle bodies as I said above..

You could get some for around £60... plus about £120 for a manifold... then about £300-£600 for a decent engine managmenet system and rolling road setup...

can you use any type of bike carb?

1der wrote:can you use any type of bike carb?

You need bike throttle bodies, not carbs!

Throttle bodies have injectors on them, carbs have float chambers, needles etc.... Big difference!

Within reason yes you can use any.... Something off a 600 sports/super bike would be ideal.... You could go slightly larger...

This is normal practice for those guys building kit cars... they fit bike Tbs to Zetecs, Pintos etc... so fitting them to the GTI engine is nothing new...

This company are the Rolls Royce of manifold creation..... http://www.boggbros.co.uk/fabrication.html

dont know why i said carbs. Must have been half asleep

might be a silly question but how many tb can you run?4?

Yes... you need one bike TB for each cylinder.... so 4...

Since there would be more air entering the engine does it mean that bigger fuel injectors are needed? I was thinkin of puttin in GTi fuel injectors in my 1.4 16V but sum1 told me that they will not work properly as the car needs to be put on a rolling road and tuned to make sure that the correct amount of fuel is being injected, is this true?

To get more power from the engine you need to burn more fuel AND air...

So if you put on bike Tbs you may need larger injectors... you would have to get it on a rolling road and see if the standard injectors provided enough flow... the engine management would decide on the flow..

I suspect larger injectors would be required, exactly what size would have to be calculated, or worked out through trial an error I suspect.

I would start off with the standard injectors and get the engine running on the bike throttle bodies and then consider doing other engine mods at that time like increasing the compresson or adding a different cam... Then get it on a rolling road and get your engine management setup properly to cope with any changes you have made..


Having said all that above... if you are unsure of exactly what you are doing, I suggest it might not be a good idea to go messing with it! (although that never stopped me in the past