Hello Guys.

I have a MK1 Citi Golf fitted with a 1.8T motor.
I used to run stock boost of around 0.7bar hassle free. By that I mean I could accelerate with no hesitation or missing.

I have now added the 1s water injection system on to the motor. My query is that now it sometimes "misses" around 0.7 bar and above. It maxes out at about 0.9bar boost which I can only get to in 4th and 5th gears as my turbo is on it's way out and can't spool fast enough to get to the higher boost settings.

The car has been tuned twice now for the water injection but I am still getting these misses every now and again, not pinging but missing. It feels like their is no spark or maybe not enough fuel or maybe not enough water or maybe too much water ? ...just a guess. Some times she works beutifully but I also don't think my intake temp has come down very much as below 0.7 bar I can't feel any differance in power which I thought I might.

Any ideas on the probs ?

What size jet are you using?

And who did the chip?

Yeah, sounds as your jet is too big for the boost your running.

The 1s system sprays a fixed amount of water so if the jet is too big the car will miss.

Where is your jet positioned, that is another factor that may be working against you?

Thanks for the quick responses.

Currently using the 0.6 jet I think.

The kit comes with tree and it's the middle one. Pretty sure it's 0.6.

The inlet is mounted about 4 inches infront of the throttle body, I recon it should have been just at the exit of the intercooler which would have given me about 1 and a half feet more to mix with I would have thought that it meant more cooling and better mixing the longer it was ?

The engine managment is a Domingoes F200 unit.

John, what size fuel injectors do you have?

The 0.6 mm jet flows 225 cc/m - to have a Water : Fuel ratio of 15% (you don't want to go higher than 15%) you need 375 cc/m fuel injectors.

I'm not sure on the size of the injectors other than the fact that they will be able to apparently cope with a K-04 turbo as when I built it the idea was to have a std K-03 turbo on and later install a larger turbo K-04 or STi rollerbearing turbo.

I have a manual fuel mixture setting in the car that I can use to increase the fueling, do you think I should richen it or lean it out maybe ?

mmm, don't know the Domingoes F200. I worry if its not happy with the water injection.

I know Gandalf's car also was very spark plug dependant. When at Phakisa is was very unhappy with the water, and that was sorted by using the original spec plugs. Any comments Istari?

@John - if you have the standard 1.8T injectors (Bosch 0-280-150-447), they only flow at 240.7 cc/m. If you can have a look what the Bosch part number is on the injectors, I can look up the flow rate and do the sums.

I would speak to 20VT about what to do with the mixture.

@Mayor - the plugs were too cold and didn't work well with water.

Your plug gaps are too big.

With water it is more difficult to jump the gap.

Make them smaller

Problem solved

I am currently running 0.6 plug gaps.

Would that not be a little too small going to like 0.5 or 0.4 ?

@John - RS6KING is the water injection fundi in SA! I am sure he is right. I know it is a pain but I would try 0.5 and see how it goes. If you still have the problem try 0.4.

BTW Have you found the Bosch part number of you injectors? What duty cycle are you running?

I will adjust the gaps as soon as the sun comes up tomorrow : )

Not doubting what RS6King was saying at all, just letting him know what they currently are incase he thought that I was running 1.1 or 0.8 or something fairly large ish.

Also will try look at what type of info Ican find on my injectors. I have know idea of what make they are or duty cycle but will hopefully be able to tell you some info on Monday.

Thanks for all your support so far...He he... You'll probably be pleased to know that unlike all the other guys with modded cars my engine cover doesn't say VW 1.8T but rather Audi 5v : ) .
The motor in my car has more audi parts than V-dub as it was originally a natrually aspirated 1.8 (96kw) version from an A4.

Thats the hard way - wouldnt it have been easier to just find an already turbo'ed motor?

Tell us more about this project of yours!

@Mayor my motor started out life a 97 model 1.8 20v Normally Aspirated from an Audi A4.

Converted the pistons to the Audi A3 1.8T spec ones to handle the turbo and then got bolted it all together using a Damingoes F200 Engine managment system.

Was initially running the std head (AGR)but then moved across to a turbo head (AUM) which is the one that supposedly the one with VVT.

Now at 0.7 bar I am making 130kw and 250 n.m. but for reasons unknown in 4th & 5th now with water injection it climbs straight up to 0.9bar and is much more livley.

I have finally adjusted the plug gaps this morning to 0.5 and on this new setting so far I had no missing at all but that was only on a 10k run. Poor C32 didn't know what hit him : )

Running a 63mm exhaust system with a 3inch down pipe.

found out that my injector codes are as follow 464 inother words same as a previous post but last 3 letters are 464.

Using a FMIC and stock K-03 turbo which I think is slowly dying, I think I killed it by Running at Duratec as one of my boost pipes blew a 2 inch hole in it after increasing the boost with race fuel and I didn''t know it. Still ran a 196km/h but foot was flat for most of the way round so I new something was not right.

Hey.

Wow, sounds like an awesome project - you should be an Audi club member, with so many Audi bits in your VAG

It does sound like an awesome project - a nicely tuned 1.8T in a light body such as a Golf I

OK, it looks like the Bosch 0-280-150-464 injector flows at 249.1 cc/m. Now if we assume you are running a duty cycle of 95%, you are flowing 249.1 x 4 * 0.95 = 946.6 cc/m of fuel. From what I have read Aquamist recommends the you run between 10% and 15% of water to fuel but you cam use as much as 25% in aggressive applications. The 0.6 mm jet flows 230 cc/m i.e. 24.3% water to fuel. If you use the smallest one in the kit, the 0.5mm jet (185 cc/m) you will have 19.5% w:f ratio. If you are still having problems after decreasing the plug gap, I would recommend that you try the 0.5mm jet. BTW the 0.4 mm jet (150cc/m - not included in the kit) will give 15.8% w:f ratio.

RSKING, do you agree?

Hey guys,
Gandalf your fuel injector calculations are right in theory concerning duty cycles etc. But it is impossible to tell what the injector is flowing merely by checking the part number on some list. Fuel flow on a injector is relative to fuel pressure and changes from application to application. If you check your list you might see that it may refer to a fuel flow @ a certain pressure.
Chat again.

George

John,
How big is your intercooler and what diameter are your intake pipes. Sounds like something is wrong if you can only see .9bar on that little turbo. Have you tried to measure boost pressure at the turbo to see what kind of pressure drop you are achieving across the system.
Your project sounds awesome though. I really like Frankenstein like conversion.

That sounds like quite a bit of power for a little Golf. Must be good fun!

Hope to see you at one of the future get togethers.

@smoothboost . I am currently running quite a large intercooler although I am pretty sure it's rather inefficient. I think it measures in at 50*5*30 or somewhere around their.

My piping is 50mm aluminium all they way round.Then onto TT/S3 (newspec 2 yeasr ago) internal DV.

My little turbo used to be able to boost higher and resond very quickly with the current setup, just since Duratek that things started to pack up. I used to be able to boost about 0.7 from say 2000rpm till about 5700ish befor it started dropping in boost and can if need be reved to 7000rpm but that's at about 0.4 by then.

Now she will only boost to 0.4 till about 3000 rpm and their after will climb up to 0.7 . Thats only in 1st,2nd and thrid gear though. For some reason in 4th and 5th it can run to 0.9 bar .That is after adjusting it on the actuator. Can definately get more out of the turbo still but I'm pretty sure it on it's way out and am only just getting the water injection working.So far no misses : ) . Almost feels as though I have a massive turbo and am waiting for it to spool up, just never gives that extra power though : )

After fixing the pipe at Duratec I found that we had adjusted the boost all the way up to 1.2bar and that was on pump 93 octane,needless to say we rapidly stopped boosting,went home,topped up with race fuel and then proceeded to scare myself by spinning in third gear. @.7 I can only spin in 1st. And now with the turbo almost dead not even that.


If I had to replcae the turbo what would you guys recommend. K-03 , K-3Sport , K-04 or WRX STi Rollerbearing ? Bear in mind that my car is a daily driver so driveability is crutial as well as economy but obviously that's largley down to your right foot.Maybe even get mine referbed ?

The cheap (and far far easier and less stressfull) way is to just replace with a K03S. Otherwise - a GT28!

@Smooth, I realise that is pretty theoretical but with these things I guess the best place to start is with theory and then to adjust it in practice, if needed.

@John, your turbo problem puzzles me somewhat! Why do you think the turbo is gone, is it making a noise, is there smoke etc? I would make sure that everything else is fine before I rip out the turbo. Are you sure you don't have a boost leak somewhere (including vacuum pipes)? A boost leak would also cause the car to spool up slower. Also check your TBV (diverter valve), it can also be leaking. Is there anything else that you changed after Duratek (Gerotek?)?

If it is the turbo, you will need to find out what the various new turbos cost and what it would cost to fix the old one. The best (and most expensive) option would be to go for a double roller bearing Garrett GT (GT25RS or GT28RS) but there is some work involved making it work on your current EM and water and oil feeds.

I heard on a thread the other day some saying that the GR28RS has oil feed probs on these type of motors ?

Basically if I went new all of the Tubos mentioned befor cost around R10 000 ,and to recon mine would be about R4500,quite a chunk of change sine I originally bought my turbo second hand for R1500.

I have only seen smoke twice on the same journey once and never again, I know what to look for as the first turbo I had lasted about 3 days and then died so this one was swapped out for it. That one also rattled, this one has no rattles that I can here. Ok well I mean it's a golf 1 everything rattles, but I don't think any of the rattles are comming from the turbo.


On the dyno my power seems to have remained the same @131kw on the wheels but the torque has gone from 272nm to 250nm.

I have had my car on 2 different dynos both of which did a tune up for me and both sets of people supposedly looked for probs but came back moaning about the turbo. Both said they think that the impeller has melted on the out side but need to take off the turbo to check. Both recon though that I would need another turbo handy to bolt on if it is the turbo, prob is that if it is not the turbo then I have 2 turbo's and no solution.

Would my injectors be able to handle a K-04 ? Do you guys know of anyone trying to flog one sencond hand ?

Would the GT28RS have the same sort of pool up speed because it's roller bearing and what sort of RPM range would it start to spool at.

Currently I think mine starts to spool at about 1500-1600 and the K-04 at a guess about 2000ish.

Is it possible for you to just remove the downpipe so you can have a look at the exhaust wheel? I would imagine that space might be a bit tight in the Golf 1 engine bay

Garrett makes 9 variants of just the GT25 rated from 220 hp to 420 hp. You would need to speak to somebody who knows these turbos well and understand the effects of altitude on turbo applications. The double roller bearing GT turbo spools up much faster than a normal turbo, so you would be able to get a turbo which is bigger than the K03 that spools up equally as fast - it all really depends on what you want! I doubt that your injectors would cope with a slightly bigger Garrett.

The only problem with the Garrett centre housing is that the oil and water feeds have different fittings to the KKK. It is not a big problem - Geoff Mortimer is currently sorting that out for me on my new turbo in the S2.