GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: lemski on 23 December 2010, 17:14
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Can I use the k-jet fuel system or not. Might have been covered but am on ma phone and can't see search function.
Cheers liam
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LOL just had a funny thought, Kjet throttel bodies ........... if you made an airbox to the flappy meter and made the injectors kit you chould use k jet and ITB's
it'd be diffrent probaly for a reason.
if you on about supplying fuel to the carbs you need to remove the injection pump and use the lift pump on its own
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I had a thought like that but wanted to run twin k-jet with to tbs. Then realized there's a vac or breather pipe were I wanted the left side tb so thought against it. So undercar pump gets removed and then get the parts I would usually need for the bike carbs. Mates go the stuff on his mk2 he wrote off.
Cheers danny
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its possible, you would be better off starting with itb's as thats prettymuch what carbs end up as once youve taken all the gubbins out of them. for k-jet to work ALL the air that goes into the engine must first go through the metering head which is where the plan falls down as thats where the restriction is (see below).... you would still need a custom manifold between head and carbs/bodies, and you would need some sort of plenum feeding the bodies and fed from the metering head.
when i was running k-jet on my 2litre 8v we spent a lot of time on the dyno (perk of the weekend job ;) ) and eventually dicovered that the flap in the metering head was fully open at around 4500 rpms, (nicely ported head, hot cam etc) anyting over that it was causing a huge restriction, that engine is now running an ec1 from tdf power engineering and makes 152hp in the same mechanical spec that made a maximum of 139hp on k-jet (and to get it to do that took ages, was sh!te at anything but full throttle, and was very fuel/weather sensitive) in short a standard engine running k-jet with one of everything present and working is best left alone and at all other times the big problem with k-jet is, er, the k-jet.
to get port throttle breathing cheaply but at a cost of ultimate all condition accuracy carbs will be fine as long as you can get them set up properly, but bear in mind you will still be stuck with the same old ignition system where you can advance it at all times or retard it at all times but not fine tune any one point in the load/rev range. and predictably enough throttle bodies with a properly calibrated ecu controlling both fuel and spark are the top option, far better driveability and fuel economy, plus a decent ecu and loom, while seeming costly initially are a great investment for a tinkerer, if you go for carbs and then decide its not enough and want a little boost they will be exactly no use whatsover in a road car and heavily compromised in a fair weather track car too, a quality ecu can run prettymuch any setup you like, plus you can efi without thebodies to save cash at first and give everything a good shakedown.
didnt notice if yours is 8 or 16v, if its a valver then bodies, yep, cool. 8valve, forget it. they will be sat pointing the wrong way, shrouded by the bulkhead and breathing hot air from around the exaust manifold unless you make a plenum which is surprisingly hard to do without subtantial loss in breathing efficiency..... and back to square one. thats before you consider the manifold from bodies to head, ports 2 and 3 exit the head very close together and due to the lack of room you cant get a long enouigh runner to make them flow the little bit of hot air that seeps past the bulkhead at all well.
if it IS a valver though ive got a lovely set of bodies with injectors and rail for sale..... ;)
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above was a good read and enlightened me to more mk2 info..
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That's was a good read and indeed it is a valver. How much we talkin for the bodies and injectors you have for sale?
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going itb isn't cheep.
most ecu's are about £500
the wideband lambdas about £150
manifold £150
ITB's £50 - 500
rolling road time £300-500
cost about £1150 at least by the time you finish
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Wide spread lambda?
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your conventiona lambdais called a narrowband, its desinged to see an afr of 14.7:1 there range of afrs is about 14 - 15.
a wideband lambda can accuratly determine AFR's from around 10:1 throuogh to 19:1 they are very usefull for ueing and AFR corection ( the ecu uses a 2nd map that st0ores target AFR's ) it then uses the lambda to to trim the fueling to get the afr's spot on
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lambda that sits in the cat? which being an 87 engine it doesnt have surely would mean there isnt a labda. and the lambda ratio is going to be 14.7 to 1 on k-jet but way out when throttle bodies are introduced until properly set up. when i replied to this i was half asleep, now ive just thought back to theory at college.
would it be better then to either get my k-jet set up properly or bike carbs for that little bit extra in the gears. i mean my mates 1.3 on bike carbs (polo gt engine in a golf) felt quicker than a 1.6 driver and picked up quite well.
i can get all the stuff for the bike carbs for pretty much nothing. just need something to puch my valver abit quicker at the top end of the gears when it starts slowing down.
cheers liam
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right av just researched into the carbs again. so far i have made a list of:
bike carbs
manifold
facet fuel pump
fuel regulator
is there anything i have missed off?
cheers liam
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right av just researched into the carbs again. so far i have made a list of:
bike carbs
manifold
facet fuel pump
fuel regulator
is there anything i have missed off?
cheers liam
My 2 pence worth, Carbs are a backward step.
But yes that is all that you will need.
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Yeh but its an experiment. Always go back to k-jet if its not good enough.
Liam
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Yeh but its an experiment. Always go back to k-jet if its not good enough.
Liam
The trouble is and I guessing your's is a 8v in which case unless you run a crossflow head they are sitting right above a hot exhaust.
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No its a 16valve. I know about the probs with the xvalve having exhaust under the inlet heating the inlet up. Rubbish design really.
Liam
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Here is a vid of my mates setup. I cant remember what bike the carbs are off but the fuel pump was off a bike too delivering about 5psi to the carbs. it still needs setting up properly. the car was a 1.3 and he brought a valver complete for engine and other bits.
he is having an exhaust made after crimbo :grin:
http://www.youtube.com/watch?v=4eMvINzCMe0
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No its a 16valve. I know about the probs with the xvalve having exhaust under the inlet heating the inlet up. Rubbish design really.
Liam
Good luck with it. :smiley:
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Here is a vid of my mates setup. I cant remember what bike the carbs are off but the fuel pump was off a bike too delivering about 5psi to the carbs. it still needs setting up properly. the car was a 1.3 and he brought a valver complete for engine and other bits.
he is having an exhaust made after crimbo :grin:
http://www.youtube.com/watch?v=4eMvINzCMe0
good videoto see how they are put on to the valver cheers for the info
liam
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Yeh but its an experiment.
If you're going to experiment with something then experiment with something you can measure and manage - bike throttlebodies instead of carbs - you've got to get the stub manifold made up anyway, so do it properly.
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it is getting done properly, i have thought of some propblems that could occure like the sensors near the airbox on the k-jet, can i leave them unplugged or what. i've seen a full thread on club gti but that wasnt really much help.
liam
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there is no actual experiment to be done..
have met a LOT of 16v 's that are running bike carbs a couple of them have had real poke. the rest of them were all suffering various degress of lameness and din't run that well.
DH's 2.0 8v handed a bike carbed 16v it's it arse after thoroghly spanking it. looking at the engine bay it all looked lik there was potential 200 there till you heard it running up close and smelt it. AFR's were all wrong as obviously hadn't botherd to set the carbs up with the rght jets or anything once it ran that was enough i think.
end result naff all power
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DH's 2.0 8v handed a bike carbed 16v it's it arse after thoroghly spanking it.
Hahahah - forgot about that at one of the VAG Action Days. :grin:
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When it comes to setting up, there is a bloke in Barnetby called dennis vessey he is a carb god! Also he is pretty damn good with the k-jet
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Cheers caister banetby int that far from me. And it'll be set up. I'll get it running sweet and then take it to rasp to get fine tuned on the rr.
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Sorry dude, should have explained better. He isn't just some random bloke. Back in the day he was the man for Webber carbs, he has a few old boys working for him and will get anything running spot on. He has a full RR to set up on and wont let it off it until he is fully happy with it.
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Fairplay. I'll pm u closer to the time to get the details or I'll only loose em.
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he has a few old boys working for him and will get anything running spot on.
Between 2-4k revs with a flat spot around 5000RPM and then for 500 revs from 6000RPM, when it's 18-20degrees C and the car's running on 97RON petrol. :grin:
And that is why people use throttlebodies.
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And yet am still going to get it all set up deside if I like it or not and then run it as if everyoe strayed away from b/c and did everything the same the world would be a boring place to be honest
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Yes, I'm sure throttlebodies would be very dull.... :grin:
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if you really must go down the carb route, which it looks like you are, then at the very least pay some attention to the ignition system, the one you have now is very limited in its adjustability- this may sound like a minor thing but it really really isnt, firstly any ignition system has less time to soak (charge) the coil as rpm rises and therefore spark energy drops, hence the twin coil systems found on a huge number of modern family wagons, plus if you actually succeed in getting a meaningfull increase in airflow at high rpm/full throttle (the hard bit) and get the right amount of fuel in (the easy bit if you arent bothered about part throttle accuracy too) and get it properly atomised (harder than it sounds) you will need LESS spark advance for a given engine speed- this is because the denser air/fuel charge will alow the flame front to propogate more quickly, the only way to achieve this with a dizzy twisting setup is to retard the spark under all circumstances which will cost economy and driveability, similarly when you get to your desired cruising speed and let off to say 20-30% throttle the amount of air introduced to the engine is reduced enormously and so the spark advnce should be increased to suit, hard to explain but trust me.
as for the 14.7:1 ratio? yes, that is the stoichiometric ratio and the one aimed for by a narrowband lambda, however just whacking a lambda in will get you no closer to achieving your desired ratio without an ecu capable of reading the information it provides and making adjustments based on them. Also stoich/lambda 1 ratio is fine for things like mid-high rpm cruise and light load, or ticking over when warm but under hard acceleration a richer mixture is what you want so a k-jet system that works properly won't just maintain a constant lambda ratio, and isnt supposed to either, its far more complicted than that. it may sound like i hate k-jet but i dont at all, its what gave us the all important little 'i' on the back of our cars and in its day was fitted to some very exotic, expensive, and high performance cars, its just that the day in question was 20 years ago..... also it was a BIG step forwards from carbs and the first one towards the great systems on offer today. Even bikes are almost all running port throttles now, progress you see ;)
the megajolt system http://www.autosportlabs.net/MegaJolt_Lite_Jr._-_A_DIY_Programmable_EDIS_Ignition_Controller_-_Users_Welcome! is probably the cheapest setup and uses ford edis parts (escort/mondeo/ka/fiesta etc) so it is very easy to source parts too, properly installed and set up it is capable of giving a healthy and accurately timed spark under any of the conditions your engine will encounter. the shape of a fully trimmed advance curve when drawn on a graph is nigh on impossible to achieve by mechanical/vacuum means and the cost of the dyno time to get close would far outweigh the cost of something more capable in the first place.
A.G Bell has written various books on engine tuning such as this one (the one i have and has served me very well) http://www.amazon.co.uk/Four-stroke-Performance-Tuning-Graham-Bell/dp/1859604358 if you get a copy read it from cover to cover once, then possibly again, then research every detail of what you want to do by going through the relevant parts and actually working it out. the earlier editions were written at a time when the golf 8v/16v were considered current but before a properly mappable ignition or injection system was readily available to home tuners on a budget so one of the later editions would perhaps be a good idea as well as. oh, and shop around, the link i showed was just first one that came up when i searched- you should get one for peanuts on ebay.
you said you had your carbs already but the bodies i mentioned are up for 150, the injectors are peco type but i may-hopefully- have the connectors for them to go on a suitable loom too. they taper from 50mm diameter at the in end down to 43mm at the out end and are in very very good clean condition. the only thing that needs doing to them is the holes for the secondary ecu operated throttle shaft need plugging or welding- not a hard job if you know what you're doing. plus the obvious like as suitable manifold/trumpets etc to suit
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Late entry for the most informative post in 2010. :afro:
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LOL! thanks! i have learnt an awfull lot over the years but sadly its cost me a few cars and engines so im only too happy to advise where i can, unfortunately i know maybe 3% of what the guy who has been teaching me recently does (matt @ tour-de-force power engineering) which as it turns out is plenty enough to make a 2litre 8v go very nicely, if not actually hugely quickly..... but 165lb/ft, 152bhp and a trio of 14.9sec passes at the pod are pretty damn good for home brew, especially as one of my earlier efforts was a 2litre pinto (capri four pot roughly equivalent in age/type to the vw motor) which had a mental big valved head, wild cam, expensive mechanical distributor, nice manifold, blah blah blah and it drove like a pig stuck in another pig, really, it was awfull, less power/torque everywhere, about 9 to the gallon, pain to start, total guff. It doesnt have to be expensive to get a usefull gain from a road engine without compromising reliability, and to be honest they are all much of a muchness in that the same principals apply- find the restriction, remove it without weakening anything, calibrate to suit. obviously a true race engine will cost true race money and as power rises the usefull life of the engine will get shorter but it isnt a problem as long as you play it safe, 140-150 hp out of a 2litre 8v is pretty tame when you consider the 16v equivalent is doing that as standard, likewise 180 or more out of a valver is commonplace for some makers too, as you aproach the magical 100bhp/litre the long term durability will fall if you use it constantly but really that wont happen on the road will it? much more than that and some form of supercharging will be more cost effective unless you are in a race class that wont allow it... and so on.
while i'm in the mood the best way to make an engine last is to ALWAYS warm it up before you drive it hard (twin chokes make this sooooo easy too), keep the filters clean, do preventative checks and maintenance rather than spoiling things and being hit with a big bill and crucially use good oil and dont let it get dirty- a good engine is like a good woman, cleanliness is next to godliness but proper lubrication will save a lot of red faced swearing!
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I don't disagree with ne of the information giver, and I do know about the spark. As I have already said though, if it doesn't work how I want it to work then I will just put the k-jet back on and start with a new idea. And I never said I was puttin a lamba senser put in. To be honest if it can still beat a civic type r with bike carbs on then al be happy with it.
Liam
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if you are definitely happy with a full throttle blaster then carbs + dizzy should be setuppable, obviously you will be setting to give best available performance over the last 2-3 krpm at full throttle and will probably have to make compromises elsewhere, as long as the engine is safe at the times when not optimised (rich is safer than lean, retarded spark is safer than advanced) there shouldnt be a problem as long as nothing is too far out.
the autosport labs link i posted has a few interesting threads on the subject of vacuum lines from port throttles - a few people have done experiments as joining 4 pipes to one dizzy can give funny pulses etc so they have devised a few ways around this, most of which involve a little plenum, worth a look anyway. likewise the books go into great detail on the effects of advanced/retarded cam timing which if you are lucky can be used to move the peak torque a little towards where you want it, or if things get tricky can be used to make the engine breathe less heavily at a point where detonation has become a problem, plus of course it goes into huge mind-bending detail on carbs themselves, how they work, the importance of gas velocities etc so that would still be a sound investment.
hope some of this is usefull, and happy tinkering- you should be able to drill type R's into the floor as they are er ghey (small torque plus big revs = hollow power imo)
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Yeh ep3 typre rs. Never bothered wotha slower new one.and I'll have a look through that cheers for the info and such
Liam