Author Topic: K03 or K04?  (Read 15748 times)

Offline breadman

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K03 or K04?
« on: September 01, 2008, 08:51:58 pm »
I know everyone and there dog fits the K03 onto the G40 engine when converting to a turbo, but is it really the best option?
I've spoken to Pete (Yoof) about this and he is very impressed with his (he has every right to be, its a bloody awsome car). However, I don't think its all down to the fact that he is using a K03. He uses a bit of the funny gas which helps, plus slicks and a nice lightweight shell with subframe/wishbone suspension and he's half decent at rowing it too!
Pete has said how the turbo spools up nice and early which is great for torque and midrange grunt. However, if you look at the compressor map for a K03 it really is way beyond its best much above 10psi. I was thinking of trying the K04 - 015 as its a direct fit in place of the K03 so the Rothe manifold can still be utilised. I know it wouldn't hardly be the ultimate upgrade but it might be slightly better, or not?
Anyone care to discuss or shall I just be a sheep and follow the crowd?
Cheers,
Richard.

Offline PeteG40

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Re: K03 or K04?
« Reply #1 on: September 01, 2008, 10:20:35 pm »
or what about a k03s?

Offline breadman

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Re: Re: K03 or K04?
« Reply #2 on: September 01, 2008, 10:39:46 pm »
There's been a lot of discussion about these on an American VAG website. One of the blokes on there eventually contacted the manufacturers and apparently there was never officially a K03s available. None were ever marked as such. IIRC it was something to do with the manufacturer fitting a fractionally larger or modified turbine housing and it being fitted to certain models. However it was never officially an upgraded or bigger turbo and isn't any improvement power wise over an ordinary K03. However, a lot of pub talk has made them almost legendary. Apparantly!

The K04-015 is a direct replacement and fits the later Passat's. Apparently 220+bhp is possible just with mapping, whereas the K03 limits it to about 200bhp or so. So the K04 can't be a hugely different turbo within its map, but might just be the better of the two for my car?

Offline superchargedpolo

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Re: Re: Re: K03 or K04?
« Reply #3 on: September 05, 2008, 06:48:20 am »
I really don't know much about turbo charging but I am pretty sure the K04's are/were fitted to the higher powered 1.8 and 2.0L audi and VW's.  The current S3 has one and I am almost certain the Edition 30 Golf has one.  The standard mkv golf puts out 200 odd bhp and the Edition 30's are down as 230bhp, but I think this is more a marketing thing, as the majority of owners are seeing higher rolling road figures on stock cars.  Also I think they were fitted to the old S3 and 225bhp TT's etc.  

So in summary if you are planning a good bit over 200bhp I think the K04 is the way to go.

But do you want any more than 113bhp in a Mk3 Polo.......regardless of subframes and LSD's.........would be fun to see though.

Cheers
Craig

Offline jez1272gt

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Re: Re: Re: Re: K03 or K04?
« Reply #4 on: September 05, 2008, 10:57:41 am »
From what i understand the K03 and the K03's' is the same turbo (housings, internals etc) - its the externals, ie  wastgate that make the 's'...
...hence why ...
"there was never officially a K03s available. None were ever marked as such" when the American dude asked VAG.

When turbo'ing a G an uprated wastegate is best used so therefor a a normal k03 is suitable as the standard wastgate is disgarded!

The K03's' was fitted to the Audi S3, the Mk4 Golf 25th Aniversary and the Seat Cupra R's.
The K04 was/is fitted to the higher power VAG motors.. Ie 225 TT

I'm also not 100% but i remember when chatting to Steve a while back about the K04 needing a different exhaust manifold and/or downpipe to the K03.... i may be wrong though.

I know that Steve was thinking about K04'ing his tin can a while back but he said there were complications.

We discussed a K04 for my 1341 build but decided it was best to K03 it for the time being.. A K03 is good for around 215-220 running silly boost and the correct set up (depending on your engine) anything more than this and you will need to go K04. The K03 is the ideal turbo for a small engine and as you mentioned is noteably a legend for all round driveability and power delivery.

Fitting a K04 to a 1341 will just mean a easier life for the turbo as stretching its legs will probably result in engine failure! I suspect that a K04 would be best fitted to a 1W 1.5 diesel bottom end... just my thought on it.

I say try it - that way i will have someone to learn from if it goes tits up - lol....

Offline Andy

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Re: Re: Re: Re: Re: K03 or K04?
« Reply #5 on: September 05, 2008, 05:36:29 pm »
On a 1341cc with a big valve head you're absolutely fine to push a K03 to 16-17psi before it starts getting remotely inefficient - don't know where you got 10psi from! Suggest you do the maths again.

The limiting factor on the turbo is usually the max rpm, which is proportional to flow - not boost. So for the same turbo 21psi into a lawnmower engine is lots easier than 15psi into a 5.7l V8. Bear in mind that many 20v tuners will run the K03 at 19psi or more on an 1800cc 20v engine that'll flow more air than an 8v Polo small block could ever dream of - so even pushing it to 21psi or so on the Polo lump isn't going to be stressing it.

High inlet temps are usually a sign that you're hammering your turbo hard. However, even running 20psi on a 25degC ambient day I've not seen inlet temps much beyond 35degC thanks to a decent intercooler - so I'm not worrying. Crudely using a type K thermocouple and meter on Yoof's setup indicated his was pretty similar.

Yoof has only used the gas on the drag strip and dyno, it's not in for regular use as his gas bottle is strapped to a spare passenger seat base... So when he says it spools quickly, that's without the nitrous. The gas is whacked in on the strip around 3k, just as the turbo's spooled. Not much point below then as it's wasted in wheelspin anyway. The gas is what makes the car break 200bhp though, I'd say it's around 190bhp without it.

It's worth mentioning camshafts at this point too - a 3F cam with a K03 means you can have 15psi of boost at around 1500rpm on a 1341cc lump. Which sounds great, 'til it completely runs out of puff at 5k. That's why the PSD turbo cams were a fair bit lairer than a 3F cam, which means the good stuff doesn't start to happen 'til around 2.5-3k, but you get a more useable powerband to 6-6.5k.

If you want a driveable car to use on track and road then go for a K03 if you've got a 1341cc bottom end or smaller. If you're after dyno figures or a track car stick a K04 on instead. You'll make higher numbers, but it'll shift your powerband up some more. You could swap to a tamer cam to move the powerband down - but you'd likely loose the higher peak bhp figure in doing so. In short, you can't have your cake and eat it otherwise we'd all be running Garrett GT40Rs.

I agree with there being no such thing as a K03s - Borg Warner will tell you that all day long. Aside from minor revisions in the wheel sizes/design, the only significant difference is actuator spring strength as already mentioned.

You're right in saying that a K04-015 should fit straight on, Passat power figures seem to suggest 200bhp for a K03 and 230-240bhp with a K04. I'm not sure that you can directly translate those to a Polo setup though. There are a few K03'd cars out there now, and many people are claiming silly power figures - but those I know that've been on the dyno have made no more than 190bhp without nitrous.

When I get some more time (when the Polo's not 100  miles away from me) I intend to finish doing my high boost maps. I've made 133bhp @ 7psi and 175bhp @ 15psi at Emerald, and am working on a 21psi map which should see 190bhp or so as the butt dyno suggests it's a lot pokier than at 15psi. I'd like to try to push things further than 21psi, just to know at which point it becomes pointless running any more boost from a K03.
« Last Edit: September 05, 2008, 05:42:57 pm by Andy »

Offline breadman

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Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #6 on: September 05, 2008, 07:40:40 pm »
Thanks for the input and replies.
Andy, the map I saw for the K03 was on some American site. I'm sure it was showing it to be becoming inefficient at circa 10psi? Obviously I was wrong, thats fine and its information like yours that helps me make my mind up about which one to use.
BTW, I wasn't implying that Petes car spooled up quickly because of the nitrous. I know (hope?) he only uses the nitrous on the track!
My base engine is Poloaces/Alan Lawrences old 1341 unit from his black G40. I'll be getting a turbo specific cam for it when I finally get it ready to run along with all the other turbo related goodies!
Feel free to give any further details or advise Andy and co, even if its stuff I already know.
Cheers,
Richard.

Offline hayesey

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Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #7 on: September 05, 2008, 07:53:02 pm »
yeah but you can't really say "it becomes inefficient at 10psi" because 10psi on one engine is a totally differnent air flow than 10psi on another engine, as per andy's lawnmower and v8 example.

The pressure ratio you see on compressor maps doesn't mean the pressure you see on a boost gauge (not suggesting you thought that though), it's the pressure at the compressor outlet divided pressure at the compressor inlet.  The pressure you see on a boost gauge is totally dependant on the engine as a whole.
« Last Edit: September 05, 2008, 07:53:51 pm by hayesey »

Offline Yoof

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Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #8 on: September 05, 2008, 08:28:22 pm »
Richard,

I've been tempted with a K04 a fair few times now, but I keep asking myself why...

The polo on the road with no nitrous will happily outdrag a E46 M3, that's a circa 330bhp OEM Flagship Model.... how much more do you want!

To beat it on the strip you'll need something quicker than an RS4, getting into RS6 times (high 12s)- the cash/investment to go that bit quicker is quite large- and the expense of your gearbox too...

It's always nice to say you have the most bhp- lots of people claim 220bhp+ I know of few FWD G40s in the 13s, even fewer in the 12s (although there are some over the pond) and if it's track work you're building the car for, I'd advise the larger turbo, but with an increase in capacity too.

My set-up makes 16psi @ 3k- that's G40 Lader type boost delivery, with the added reliability factor of a turbo  LOL

With a plate diff, subframe, and approx 190bhp and me in anger mode, there's not much that can keep up on the road- small engined bikes included!

Hopefully in a few weeks if it dries out I'll stick some vids up of the Polo going against a Bentley Arnage- perhaps your opinion of the K03 will change then  :D

Offline breadman

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Re: Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #9 on: September 05, 2008, 08:54:00 pm »
Pete, I don't have any negative or otherwise opinions of the K03 at all. I just want to make sure that I fit the most appropriate turbo that I can rather than fit X only to find out later find out I'd have been better off fitting Y. I'm attempting to do it once and do it properly ya see.
I'm not trying to get 220BHP or anything. I'm just aiming to get in excess of the power the engine originally had along with the increased reliablity factored in by using a turbo.  
Do get those videos up though Pete, should make some good viewing.
Cheers,
Richard.

Offline Yoof

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #10 on: September 05, 2008, 09:38:04 pm »
The point I was trying to illustrate (allbeit badly) was that bigger isn't always better- obviously you'll have more bhp at the end of it, but there's always a comprimise...

Perhaps look into the GT range of Garretts, there's a few which fall between the walls of a K03 and K04, whislt using fairly modern (last 8-10years) turbo technology, unlike the K0 series.

Happy to Help- if you're at Polo Show I don't mind showing you round the car and having a proper chat  LOL

Offline Tav

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #11 on: September 05, 2008, 10:22:02 pm »
This is an excellent read...sort of thread that'll make this forum a better read than certain others.  Interesting stuff!

Offline breadman

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #12 on: September 05, 2008, 10:22:31 pm »
Unfortunately the Garrett GT series turbos are a bit out of my price range. The smallest of the roller bearing ones is the GT25 and that's too big anyway. GT22 in the right trim could be used, but again its all more money.
I think I'll end up going with the tried and tested Rothe manifold and K03. As I said at the beginning, I'm gonna be a sheep and follow the herd!
I'd love to see your car Pete, but I won't be going to the Polo Show, the majority of what's there ain't my scene.
Hope this bloody weather sorts itself out though, I'm going to the Brighton Speed Trials on Saturday week. I bloody love that and can't wait.
Thanks again for your input Pete and co.
Cheers,
Richard.

Offline Rob

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #13 on: September 06, 2008, 01:38:31 am »
This thread makes me think about my cousins Toyota Starlet GT turbo, His first turbo setuo spooled rediculously early which he thought would be a good thing but after driving it soon changed his mind, Then he changed setup and went for some fuck off grat big turbo - Fair play it Made 265 bhp (1.3 16v) but when driving in anger unless he gets the gear change absolutly spot on it wont be on song in the next gear. So once again he's in the process of revising his setup. Infact he tried to follow me down a local back lane and struggled big time - Now your thinking go on the G - But i was in my boggo standard Mk4 golf GT TDI 115 LOL

In hindsight he would of been better off being a sheep as others seem to have been achiving good results utilising a uniform approach. The Ko3 / turbo cam seems to be proving itself - I think finer refinement / smaller tweeks are the way to go

Offline Andy

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: K03 or K04?
« Reply #14 on: September 08, 2008, 07:18:24 pm »
[quote pid=3911 author=breadman date=1220649751]Unfortunately the Garrett GT series turbos are a bit out of my price range. The smallest of the roller bearing ones is the GT25 and that's too big anyway. GT22 in the right trim could be used, but again its all more money.
I think I'll end up going with the tried and tested Rothe manifold and K03. As I said at the beginning, I'm gonna be a sheep and follow the herd![/quote]
Thing is, unless you're willing and able to put in the time/money to do all the research to make the right turbo choice for yourself, following the herd is the easiest route.

Not sure what's making you say the GT25(54) is too big - I think it might be quite well matched, if the roller bearing technology giving quicker spool-up is as good as it's cracked up to be. I'm trying to save up for a house at the moment, so doubt it'll be me that tries it first! A Garrett GT17 from a Saab 9-5 LPT might not be a bad choice either - good for 230bhp when pushed on a chipped 2.3l 16v 9-5 motor.

Rob makes a good point though - there's still lots of minor tweaking to be done with a K03 yet. E.g. Yoof's pushed it with nitrous, but still isn't making the most of it running Digifant. I've not put nitrous on mine yet (nor re-fitted my Aquamist) because I've still not finished tinkering with Emerald. That's ignoring all the messing about with camshafts, cylinder heads, inlet manifolds etc. that could be done.
« Last Edit: September 08, 2008, 07:25:53 pm by Andy »