:confused: Ok can someone please clarify something for me in dare I say not too technical terms

What is the difference between the KO3 & the KO4 & are there more than one type of each

Secondly someone has offered to tweak a turbo for me, am I better buying a s/hand KO4 rather than a s/hand K03 & what sort of price is reosnable for s/hand turbos

The Octy 4x4 has KO3 as standard, any problems in changing to a KO4

Okay I'll crawl out of the wood work and ask what Ko4 and 3 are.

Not got a clue being a numpty.

Okay I'll crawl out of the wood work and ask what Ko4 and 3 are.

Not got a clue being a numpty.

Turbochargers fitted to the VAG 1.8T engine.

Turbochargers fitted to the VAG 1.8T engine.

Ah - petrol talk

They are fitted to many engines not just VAG... Rover K series turbos also use them.... for instance

K04 is a bigger brother to K03...

there is no K03 sport but this is a common term to describle the later models of K03

there are getting on for 100 variants of the 2 turbos... so its impossible to describe them all...

so its impossible to describe them all...

ah go wan!!! ye will...

sorry, its friday

So do I take it the KO4 is better then

Is it a straight swap for the KO3 on the Octy 4x4

As someone has offered to tweak a turbo for me, am I better buying a s/hand KO4 rather than a s/hand K03 & what sort of price is reosnable for s/hand turbos.

As there are so many variations which are the best to go for & if Im trawling round the Scrap yards what vehicles are they likely to be on

Do a search on the forum here and there is plenty of information on the turbos

Andy

Any more thoughts/help

This is somewhere in the forum.....

The Question

Can the K03 turbo (5303 988 0011 or 5303 988 0053) be directly replaced by the

K03S (5303 988 0052 or 5303 988 0026) in terms of the intake and exhaust housing

dimensions?

Is K03S the correct designation for the latter turbo mentioned above?

Obviously if a K03S was fitted an engine map could be changed to suit, but would

a standard turbo map for the K03 be suitable for running a K03S on?

or would a loss of power be expected? and are the characteristics of the two

very similar?

I hope you can assist with the above and any information you could supply would

be gratefully accepted.

It's taken me a couple of weeks to get a response, but the response was well

worth it, I think y?u'll agree.

The Answer

Dear Sir,

thank you for your interest in our products.

First of all, we don't produce any turbo that we call K03S. But I hope I can

answer your questions with the following explanations.

All the following turbos have the same installation dimensions and

thermodynamical performance. The differences are only in the actuator that

opens the turbine bypass valve:

K03-011 (5303 988 0011) 150 hp, 65 N actuator

K03-026 180 hp, 85 N actuator

K03-035 180 hp, 85 N actuator

K03-044 150 hp, 65 N actuator

K03-045 156 hp (Ibiza Cupra), 85 N actuator with 2 ports

K03-049 150 hp (Sharan/Alhambra), 65 N actuator

The 180 hp versions have an actuator with a higher opening force due to the

higher exhaust gas pressure (which is a consequence of the higher boost

pressure). Otherwise the valve would be pushed open by the exhaust gas

pressure.

The following turbos are a further development (since 2000) and have an

improved and slightly larger compressor while using the same turbine (still

with the same installation dimensions):

K03-052 180 hp, 85 N actuator

K03-053 150 hp, 85 N actuator

K03-058 150 hp/180 hp, 85 N actuator

Consequentially, putting a 180 hp turbo on a 150 hp engine will not bring

about any change in performance, but putting on a K03-052/053/058 instead of

the older versions will bring a slight improvement in engine efficiency.

Additionally, with re-mapping the ECU you can achieve about 215 hp without

danger of overspeeding the turbo. With the older turbos, 195 hp is the

limit.

With the K04 that's also commonly used (5304 950 0001) the power output

should not be more than 220 hp. That means, changing a K03-052/053/058

against a K04 does not make a lot of sense.

I hope that these details answer your questions. If you need more info, one

of our service distributors will be glad to help you. Their addresses are on

our website www.turbodriven.com.

Mit freundlichen Gr??en/Best regards,

BorgWarner Turbo Systems GmbH

And a post ....

I've had a K03, K04 and K03S and the above comments just don't ring true. I don't want to get into the BHP numbers achieved other than to ask if the figures quoted are flywheel or wheel figures as most US tuners tend to only quote WHP.

The K03 and K04 are dated weak turbos in comparison to the K03S. The K04 can move more air than K03S at the same pressure, however the K03S is considerably stronger so can run higher levels of boost. From what I have seen comparing BHP figures there is usually only around 5bhp difference in peak power between the K03S and K04. The big difference is the K03S' stronger midrange and much higher torque. If the two turbo's rolling road graph's were compared the following would be observed:

K03S - Torque comes in early and with a big spike, holds well in the midrange but drops off towards the end. This is reflected in the power with a steep rise but flatenning earlier.

K04 - Torque comes in later due to later spool up, spike isn't has high but torque is flat and holds upto the higher revs. Power is more uniform upto the high revs.

The end result is peak power is about the same for both, they just get there in different ways.

As for the K03 it's a bit pants, low torque and not much happening after 5krpm. With just a remap they give about 185-190bhp with loads of other mods you should be happy if you break 200bhp.

I hope this helps...

Thanks, interesting read