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Hello all,

****Please can only those with direct experience with this topic respond?****
I dont want to start a massively long thread with a million and one questions drowning/diluting the topic.

Quite clearly the only way I am going to be happy is with an RS4 or replacing the turbos on my S4.

I would NOT go K04 - cause if the motor is out, I will spend the extra and go for Hybrids.

Having spoken to Doug - its a bit of a grey area as to what you can expect to achieve. Some cars perform REALLY well, others just average. So my questions are as follows:

1. When the motor is out what must I replace?

- Turbos (duh)
- Clutch - what clutch?
- Engine/trans Mounts?
Anything else?

2. Now what is the flow limit of the S4 exhaust manifolds? Should these be replaced while the motor is out if aiming for over 450BHP

3. What is the flow limit of the S4 heads & when would they need replacing? I would assume about 420-50 is the best I can hope for on standard heads.

This is what I plan to do maybe, possibly:

Stage 1:
Take motor out, fit Hybrids on new manifolds. Install an uprated clutch & replace engine mounts & fit an APR snubmount.

£4k estimate sound right?

Run car as is for a while till I feel the need to go further

Stage 2:
Upgrade fuel pump & injectors + Install FMIC.

Remap to 400-430?

How much is this going to cost me roughly?


Stage 3:
If I so feel the need... upgrade the heads, downpipes, cats and see if I can crack 480+

How much will this cost me & what else will I need to replace? Inlet manifold, RS4 MAF & inlet tract??

***************************
Does all of this make sense and what am I missing?

I know many of these questions have been answered in dozens of posts with varying opinions. I want to concentrate each EXPERIENCED PERSONS thoughts into one post. This can not only help me, but others in the future too.

Thanks guys

The first question you need to ask is - how much power do you want, the next question is how much can you afford.

Choice of parts etc, will depend on those. More than 450bhp will be big money as this is pushing the flow limitations of the engine (you need serious headwork, custom manifolds, intake etc. ). Above that, I wouldnt even bother unless you have 15k to spend.

Can you expand on what kind of power figures you are thinking of?

Speaking from experience. Speak to MRC....they are the Gurus on this engine...

Cheers

Mik

I agree with Mik - and again from experience.

My experience to date has told me not to go down the Hybrid route. I know others have had the conversion with success but mine has not benn 100% successful and the performance figures for my car are good but not where they should be. It is an aweful lot of money to spend for it not to work. Having said that, on other cars it may work fine...

Hybrids + other bits (that should be done when you have gone that far) is going to at least double your £4k quote. But MRC or other tuner can give an accurate figure. Remember you have to do the whole lot. Engine, turbo's, IC's, clutch, cooling, fuelling, exhaust, brakes, suspension, lighting etc

You can do in stages, so chop up the brakes, suspension and lighting but all the engine and exhaust mods
need to be done at same time.

Just my 2p worth....

Rob

Get yourself an RS4 Engine ...

I did a lot of work on my S4 engine a few years ago, but have never looked back after I replaced with an RS4 engine.

I know a man that should be able to find you an engine and speak to you about fitting, as their is a lot to consider as far as installation goes but I would recommend it if your funds permit.

The approx going rate for an RS4 engine and fitted?

GrahamS4 wrote:The approx going rate for an RS4 engine and fitted?

I got mine for 6k with gearbox/clutch/flywheel/IC's/Airbox etc.

Fitting costs are hard to say, becuase I had a preface lift S4 I replaced my wiring loom so I could fit the RS4 ECU etc. I think, but don't quote me, if you have a facelift model it is possible to fit the RS4 engine without replacing the wiring loom.

Remember you can sell the S4 engine as well to recover some costs.

You say dont go down the Hybrid route... but if you just bought K04's - you would always want more. I would want the motor to come out once and once only. It is not a HUGE amount more for hybrids, so may as well go the full hog.

I think I am safe in assuming my stage 1 would cost no more than 4k unless I did fancy things with the turbos and went for expensive exhaust manifolds.

Stage two I am really not sure what the costs here are?

Stage three only if I go over the 430HP mark - this is when the hybrids will come into their own, but this is a VERY costly bit that I dont see myself doing dont think.

I know an RS4 motor is the way forward, but I am thinking of doing this in steps enjoying each gain bit by bit. My engine with only 40k on it serviced every 5k should be in fantastic condition to be modded, I will be hard pushed to find an RS4 engine - never mind a good one.

I would do exhaust manifolds and reduce the compression ratio on any engine with at least K04s!!! They run so much better than engines without that!


HTH,

Mihnea

Ahh, didnt think of that - lowering compression - is this difficult or a simple headgasket change sort this? And if the heads are coming off then surely be worth getting a set of NA head fitted? Again money money money - but this can be done in my stage 3...

Now - can anyone answer

What is the BHP flow limit of the S4 exhaust manifolds?

What is the flow limit of the S4 heads & when would they need replacing - 420HP?

i have k04's all the RS4 intake system including IC's green top injectors and NA cylinder heads..when my turb,s go pop i,ll remove my engine and start the conversion.. the bottom end will be balanced with the deck hights done and every manifold will be matched ported,anything that dont need to be on the engine will be removed and everything that generates power will be done rite..
ive seen an S4 engine with a VR6 throttle body fitted and it works well so i can lose so much unwanted pipe work,breather system if i decide to go that route..
its all about the money leon..ive taken my time and sourced the parts i needed..it wont be an RS4 when its done but it,ll be fun..

KeroK66. You need to re-align your pricing and budget mate. I would get with MRC sooner rather than later. Hybrids are going to START at approx £3.5k.....then you can add mods onto that figure.

Bearing this in mind your £4k figure is way off the mark.

why hybrids , try full rs6 turbos . so as i do , start buying the parts bit by bit , so when you do the job all you have too pay for is the labour still the same price but not as bad as in one go . g

Question that I hope MRC and/or Mik can answer...

Lowering the compression... did it help on Miks car? He was pushing just under 390bhp. With all the other mods that does not seem particularly good. If he had not lowered compression - would he have got any less? And with the lower compression do you lose any bottom end power/responsiveness?

@scoobydood: as far as I know Mik's car is running 294 HP at the wheels (IME that's around 400 crank HP depending on RPMs) and a massive 460 ft-lbs of torque, something which can very rarely be achieved on stock compression. I didn't think his car lost any bottom end power/responsiveness, at least he hasn't lost any torque, that's for sure!!!

@Scoobydood

Lowering the compression is good for the engine as it helps reduce detonation. In my experience, the more boost a car runs, the worse it will feel off boost - so yes it will hurt responsiveness slightly (didnt think it was an issue on the S4 - wheres my Bimmer is shocking).

So the car will run lots more boost than stock, however the engine will not necessarily flow enough for it to produce more power - other factors need to be considered - the primary bottleneck is probably the Intake manifold IMHO. I was looking to tune the car much more than the way it is currently, so it made sense to lower the compression when the heads were off for engine inspection.

I was going to do complete RS4 intake (or custom), NA heads, MRC manifolds and Miltek Dual or larger. Think that would give you a good 50bhp gain at least as the engine will flow well both intake and exhaust side and you can then max the K04's. If you want more - bigger snails is the only way.

HTH,

Mik