GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: frybert on 25 May 2009, 22:26
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right... what is the difference between a k-jet 8v head and a digi 8v head, thinking about doing a mk3 2.0l 8v bottom end conversion on my gti 8v on k-jet. and i was goin to get another mk2 gti head and have it gas flowed, to save messing around with the one thats on the car. also could i use a inlet manifold off a digi aswell. cheers scott.
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Not 100% sure on the inlet info but the PB runs slightly bigger inlet valves (40mm instead of 38mm).
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Injector holes are different.
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If you're wanting to do headwork - pick up a crossflow head to go with the 2.0l bottom.
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How easy are the crossflow heads to find and how much would you expect to pay for one? Also with the inlet on the opposit side can you use the standard inlet manifold or do you have to switch to carbs?
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I dont think K-jet is going to be easy to convert to use with a crossflow head somehow. Assuming you did want to go that route you would be much better off getting a complete AQY or APK engine including the inlet although as I say, I dont recon K-jet is gonna be easy and the conversions far better suited to a digi setup or going onto throttle bodies with a standalone management (carbs might look funky, work etc etc but they are so last millenium lol). I managed to find a head on its own for £25 last year but it needs rebuilding and the only other heads I have seen on ebay have been ported ones so not cheep and should I ever get enough money together to buy a 2l bottom end Ill be going for the complete crossflow engine.
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k-jet/digi injector inserts can be swapped over, apart from that i dont think there is much difference on the later k-jet heads. I'd go for a hydro tappet one though, dont have to mess with shimming then. its said the later k-jet heads have a better cam in, but personally cant say for sure either way.
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you can fit k jet to practicaly anything, you fit the right injector seats shove the injectors in and pipe the throttel body to the meatering head, its about as easy as it gets. the only issue on some engines is finding somewhere to put the wur. hell if fitted k jet to a 20v and that was piece of piss to do. ( i still hate k jet tho )
digifant II on crossflows is crap it just dose not work very well at all. your stuck with same ignition map for the counterflow thats allready burnt into the prossesor and nothing can be done about that. you MUST run bigger injectors than the PB as it should make more power than they can support. also the crossflow breathes quite a bit better so needs much more fuel up top so need a custom chipnot just a std one tweeked for g60 injectors.
TC ran into this problem, his engine is running a chip that was origanly desinged to run rich up top on a heavy breathing counterflow and it still ran out of fueling up top, it then got presented with a 4 bar fpr with that it's getting about right fueling up top but there is a to much where the torque should be and masses to much on cold start. hence why digi 2 is destined for the bin
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thanks for the advise people, might go down the 16v route and just change the whole thing. not sure yet, just getting ideas and prices, lots of people have said that im silly doing all that work to an 8v, still looking for a k-jet head though but cant seem to find any :sad:
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you can fit k jet to practicaly anything, you fit the right injector seats shove the injectors in and pipe the throttel body to the meatering head, its about as easy as it gets. the only issue on some engines is finding somewhere to put the wur. hell if fitted k jet to a 20v and that was piece of piss to do. ( i still hate k jet tho )
digifant II on crossflows is crap it just dose not work very well at all. your stuck with same ignition map for the counterflow thats allready burnt into the prossesor and nothing can be done about that. you MUST run bigger injectors than the PB as it should make more power than they can support. also the crossflow breathes quite a bit better so needs much more fuel up top so need a custom chipnot just a std one tweeked for g60 injectors.
TC ran into this problem, his engine is running a chip that was origanly desinged to run rich up top on a heavy breathing counterflow and it still ran out of fueling up top, it then got presented with a 4 bar fpr with that it's getting about right fueling up top but there is a to much where the torque should be and masses to much on cold start. hence why digi 2 is destined for the bin
Sweet, always good to know, I thought there may be issues with running the crossflow manifold and clearance but if that lots all correct, I take back all I said about k-jet and digi :P.
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digifant 1 is managable , digifant 3 is better megasquirt 2 is optimal. ms2 with itb's ftw