S4 K04 Conversion

[DavidT]

There are a number of regulars who have them and probably an equal number who want them [img]images/graemlins/smile.gif[/img]

Why not post your views here, good and bad.

Was it worth the cost (5k vs say a dealer K03 turbo replacement of £3k) ?

Has it caused other problems (transmission etc) ?

How happy does has it made you ?

[Joshie]

I'm going to keep this short as I want to write a longer piece later on the merits and experiences of S4 ownership.

But I had the K04 conversion in September 2002, carried out by AmD through Wayside Audi.

Staggered by the difference particularly high end delivery -the car really pulled hard right up to the red line. I was very happy.

Unfortunately the turbos were wrecked by an incorrect gearbox install (not by AmD) which caused vibration and the second set failed due to a faulty MAF which caused them to run too hot.

AmD remapped the car for the third set and reduced high end thrust. I was told that this was because without the fueling (RS4 injectors and Airbox/MAF) then AmD were not happy with mapping it as it was. The car was still fast but not nearly as much fun as it was and this was a very significant factor indeed in me selling it. I was most disappointed with the performance - even crawled under the car with a mirror and digital camera to check that K04's were indeed fitted.

The point about the above is this: If you're going for the K04's it is vital, IMO, that you have the injectors, RS4 MAF and RS4 airbox installed at the same time. AmD should really be telling customers this because at peak revs the engine is on the limit of fuel that the S4 injectors can deliver.

I would also recommed getting an independent dyno plot to verify the output. On the third install AmD printed off a previous dyno plot and presented that to me so goodness knows what the engine was really putting out [img]images/graemlins/confused.gif[/img] [img]images/graemlins/mad.gif[/img].

Finally, I think it is fair to say that with 450lbft (or 480 if you're Jeff W [img]images/graemlins/jump3.gif[/img]) then standing starts at Elvington and Santa Pod are going to hurt the "delicate" transmission.

Hope this helps

[jeffw]

Was it worth the cost (5k vs say a dealer K03 turbo replacement of £3k) ?

Depends on your definition of worth it. I have a very fast car now but the changes exagerate the driveline shunt, sub-standard suspension etc ('cos your going faster !)

Has it caused other problems (transmission etc) ?

Not yet....... [img]images/graemlins/blush.gif[/img]

How happy does has it made you

I was going to buy a Fisher Fury which I now can't afford because I had to replace the turbos so on one level (when the credit card bills arrive for instance) I'm very unhappy...The otherside is when you nail the car in 3rd and your head gets snapped back into the seat and the rest of the world goes into reverse and that has a tendency to make everyone expect my wife very happy..... [img]images/graemlins/cool.gif[/img] [img]images/graemlins/laugh.gif[/img]

[Prawn]

My Conversion was done in May this year.

Partly becouse my K03's were showing signs of wear but in the main bacause I wanted more power.

Was it worth the money, IMHO yes without a doubt.
I do not see how you could get the same performance / praticality combination for an S4 + £5K.
Yes the suspension needs to be looked at in addition but lets be honest most of us complain about that and mod it anyway.

To put the package in perspective I attented a Porsche owners club track day not long after the conversion and the car would live with and pass almost anything there ie £50k ~ £85K's worth of 'exotica'.
Am I happy - you bets ya.

I do however agree with Ian about the injectors etc IMO the std ones whilst up to the job are a danger area.
My next plans are FMIC and the RS4 intake ie airbox, MAF, injectors etc + an oil cooler so the money keeps on flying away !

Any problems, none so far but lets be honest 450lb/ft through the std tranny is bound to give a problem sooner or later.
I suppose you have to accept more regular servicing and quicker wear on parts with the increase in outputs - you pay your money and you take your choice.

Overall would I recomend the conversion - damn right I would

[img]images/graemlins/biggrin3.gif[/img]

[Dippy]

AmD remapped the car for the third set and reduced high end thrust. I was told that this was because without the fueling (RS4 injectors and Airbox/MAF) then AmD were not happy with mapping it as it was. The car was still fast but not nearly as much fun as it was and this was a very significant factor indeed in me selling it. I was most disappointed with the performance - even crawled under the car with a mirror and digital camera to check that K04's were indeed fitted.

The point about the above is this: If you're going for the K04's it is vital, IMO, that you have the injectors, RS4 MAF and RS4 airbox installed at the same time. AmD should really be telling customers this because at peak revs the engine is on the limit of fuel that the S4 injectors can deliver.

I remember discussing this with you. I was never happy that AmD had advised you that the S4 injection system was adequate when there was enough evidence to suggest otherwise.

There again I think I also advise you to get the gearbox removed and refitted by the repairer and I feel guilty about that. [img]images/graemlins/frown.gif[/img]

I would also recommed getting an independent dyno plot to verify the output. On the third install AmD printed off a previous dyno plot and presented that to me so goodness knows what the engine was really putting out [img]images/graemlins/confused.gif[/img] [img]images/graemlins/mad.gif[/img].

You never told me that before. That is really not on. I would have gone ballistic. How do you know that they set up it up properly without the proof?


David,
As the others have pointed out "worth it" is subjective. Like you I would like the upgrade, because these days I find my top end power is lacking (even with the Miltek cats) - I'm too used to my stage 1 (or is it 2?) mods. However I can't justify to myself paying £5K just for extra thrills. The car is already damn fast enough for me. But if my turbos started to fail there is absolutely no question about it: I would get the KO4s.

[Joshie]

I remember discussing this with you. I was never happy that AmD had advised you that the S4 injection system was adequate when there was enough evidence to suggest otherwise.

Well IIRC AmD's reply at the time was that you could get away without it. Big question is, can you (Shaun?, Jeff?)

There again I think I also advise you to get the gearbox removed and refitted by the repairer and I feel guilty about that. [img]images/graemlins/frown.gif[/img]

Don't - it was my call mate.

You never told me that before. That is really not on. I would have gone ballistic. How do you know that they set up it up properly without the proof?

Didn't I?
Well there was no plot with the car after they had been working on it for a week although the hesitancey and jerkiness was cured. When I asked they "knocked one out" (only the graphs)and presented that to me explaining that it was in the machine somewhere but that they had forgotten to print if off. It did look familiar and indeed when I go home I checked it and it was exactly the same plot as I received when I got the flywheel fitted/second set of turbos [img]images/graemlins/clap.gif[/img].

[Prawn]

Well IIRC AmD's reply at the time was that you could get away without it. Big question is, can you (Shaun?, Jeff?)

Personally not prepared to wait and find out so I am looking at further mods to improve reliability.

[DavidT]

However I can't justify to myself paying £5K just for extra thrills

Dave, wouldn't yours be cheaper because you already have the full Miltek exhaust ?

[Andiroo]

IMHO the reason that AmD are sticking to only(!) the 400bhp conversion is the price. By simply adding £1500 worth of parts plus the appropriate labour - so say £2500, then the fuelling would easily take you up to 450bhp potential. But would you be prepared to pay the extra £2500 for 50bhp gain?

Also from first hand, AmD will not put your engine at any risk at all. They will not take your boost over 1.55Bar without serious consideration to replacement internals (pistons, rods etc), and you have to admire them for this. What change did they make Joshie, to pull back the power?

Also just out of curiosity guys, has anyone asked AmD about having this fuelling work done as well as the turbos?

Andiroo

[jeffw]

I honestly haven't been in a position where I thought I needed more power/torque or where I've thought that the fueling was inadaquate....but that might be just me....

[Joshie]

My understanding of the '400 BHP' conversion ie KO4's, Milltek and Cats plus remap is that the fueling is on the edge of what is permissible without leading the car to running lean. Running lean damages the turbos. The cost of turbo failure far exceeds the £2500 outlined in your example Andy.

Frankly if I had known then what I know now, and after hearing comments from QST (through Shaun) then I would have had no hesitation in going for the fuel and air mods - apart from being more reliable it would certainly make a noticable performance improvement.

I'm sorry to say this but I cannot help being sceptical about the 400BHP claim in the first place. Some tuners would argue that there is no way that KO4's plus Milltek plus gentle rempap (1.55 bar) would get you to 400 BHP. Indeed I had 395BHP the first time I had the conversion (in standard form my car was generating 271BHP). I had your intercoolers fitted and I got 385BHP [img]images/graemlins/confused.gif[/img]. Then I had Tanoga's flywheel fitted and the power was only back to where it was (supposed to have been) in the first place.

Atmospheric conditions, barometric pressure, temperature, relative humidity (and the twilight zone [img]images/graemlins/smirk.gif[/img]) apart how can this logically be accounted for. Larger intercoolers plus a lightweight flywheel should have devivered much more - surely?

AmD mapped the engine differently the final time. OK, granted this was the third set of turbos but the engine was not mapped to deliver any more significant power above about 5800 RPM, perhaps this is why I never got a dyno plot.

So, for what its worth my advice would be:

1. Go for the '400 BHP' conversion because it does represent good bang for buck.
2. Consider better fueling, RS4 injectors and possibly also the RS4 airbox, not necessarily for the extra power but in the interests of reliability.
3. Decide what your budget is and stick to it. Modding costs a packet and its like a drug - the more you have the more you seem to want.

One reason why I bought a car which should deliver from day 1.[img]images/graemlins/grin.gif[/img] (after gently running in, of course)

[Andiroo]

With all due respect to those concerned, and obviously in your opinion Ian, do you feel the 400bhp conversion without the £2.5k mods on the fuelling is running the fuel too lean? I would have thought a faulty MAF would have put the engine into limp mode pretty quick to save any destruction? Was it only the MAF given as reason for failure on the 2nd set?

I must admit the addition of RS4 intercoolers should have shown a decent improvement [img]images/graemlins/confused.gif[/img]

Andiroo

[DavidT]

I must admit the addition of RS4 intercoolers should have shown a decent improvement

How much more Andy ? They offer a 28 % increase in surface area but what does that translate to in terms of power and torque ?

[Joshie]

With all due respect to those concerned, and obviously in your opinion Ian, do you feel the 400bhp conversion without the £2.5k mods on the fuelling is running the fuel too lean?

Well that was the only explanation I could think of why AmD would have backed off the boost - unless you can think of another

I would have thought a faulty MAF would have put the engine into limp mode pretty quick to save any destruction?

Yes thats quite right. The limp mode manifested itself the first time in April and I was told by AmD that it was probably a dicky llambda probe caused by the hot weather (I was in France in April and it was hot c28C-30C) That is why I didn't feel that there was a problem resetting the ECU and since the limp mode event was not a regular occurance I believed it was indeed a twitchy llambda probe so I continued to reset the ECU with impunity.

Now I have to accept what AmD say and take their diagnosis at face value, but what if it was the fueling which was causing the limp mode event? It only ever manifested itself when the car was on full chat.

Was it only the MAF given as reason for failure on the 2nd set?

Yes

I must admit the addition of RS4 intercoolers should have shown a decent improvement [img]images/graemlins/confused.gif[/img]

Andiroo

Me too.

But hey, all water under the bridge now as far as I'm concerned. AmD looked after me in not charging me the earth for the third set of turbos and I know Scott would help me out if I needed it.

I just want to make it clear to people that IMHO there MAY be an issue with the fueling relating to reliability, that's all. If you're going for the K04 conversion just ask the questions, of a number of different tuners.

[Andiroo]

I would hazard a guess at 12bhp and around 18nM both at peak. Would most definitely show an improvement on a RR with like for like atmospheric conditions against OEM IC's.

But there again if Joshie had a faulty MAF at the time, maybe the benefits were hidden? Are the S4 MAF's so much different to the RS4's?

One thing that is considerably different is the cam profile and intake manifold on the S4 - both designed to give peak torque much earlier than the RS4 can. Maybe it's a question of K04's not being of adequate design (coz they are a bit dated) to spool up as quick as this without damage? Roller bearing turbo's anyone?

Another couple of points Ian, did you notice at any time at all that these turbos were so hot ie oil temp?. Would a turbo timer have helped in this case, as I know the K04's can suffer considerable damage on hot shutdown, and I've done this on several occasions without thinking [img]images/graemlins/blush.gif[/img] - been very lucky so far [img]images/graemlins/wink.gif[/img]

Andiroo