Help on mods required

[Druggie]

What are the specs of the ko3s and ko4 turbos?

What boost levels can they run ?

What is the hp limit of
1) the turbos
2) the stock intercoolers
3) the rs4 intercooler
4) the stock heads
5) the rs4 heads
6) the bottom end


How restrictive is the stock exhaust?
Is this the first mod or is an ecu change or something else?


Starting to plan my modifications


Thanks in advance for everyones help

Cheers

[Golich]

Best best bang for buck is the ECU. Waste of money CAT back only you need the complete Sport CAT replacement to let the KKK03s breath they have a noticebly limited volumetric capacity and die off at 5400 on a chipped S4. I believe the CAT replacement lifts this limit to 6000rpm.

I believe the K04s with the CATs and CAT back option is good for about 390-400bhp. Depending on whether you believe the various tuners rolling roads. While it works well, there have been some concerns about inadequate fuel at full thottle.

The RS4 intercoolers, MAF/airbox, fuel pump, injectors KKK04s CATs and CAT back is good for 450bhp.

Even the RS4 heads and exhaust manifold don't improve on this - much. About 458bhp - I think. This is what the RS4 achieves with a remap and sport CATS. But I dare say the torque is better.

But by far the best value for money is the baic remap at £900. The full exhaust is another £1600 on this I think? Then your into £4.5-5K for the 450bhp improvement. With the cost of RS4 heads at 5K for the pair they are not worth it IMHO.

MTM reported this was about the max for KKK004. then you were onto hybrid turbos.

[Druggie]

Thanks. Very informative.

What boost levels can the k03s and k04s run at?
What is the main difference b/w the 3 and 4s. Is it the turbo just larger or is the exhaust size bigger or ?
Are the hybrids cheaper than 4's?

Does anyone use a single front mount or a rs4 intercoolers sufficient?

Thanks

[Dippy]

Don't forget that it is all about a BALANCE between performance and reliability. Increasing torque and power increases stresses and that increases the average time to fail. So what these components can achieve if pushed is not necessarily a good idea unless your S4 is for track purposes only and you are happy to do regular engine rebuilds.

Look at what the tuners offer and make a comparison. Most of them will agree on what each stage of tuning should achieve and this indicates that they have used their engineering judgement and experience to find the correct balance. In the US a company called GIAC offered the X-chip which pushed the boost way higher than other tuners. Most people agreed that the X-chip is only suitable for 'risk-takers'.

The K03 can overboost to about 1.3 bar. Much more than that is dangerous (but as I put in my other post, don't quote me on that).

The K04 is essentially an 'overbored' K03 with large turbine (ports enlarged too). It can overboost to about 1.5 bar, but I'm not sure on the exact limit.

I'm not sure about hybrids - I believe they are effectively tuned versions of the Borb-Warner products. Some of the RS4 guys have hybrid K04s and gas flow is definitely higher.

The definition of what intercooling is sufficient depends on your driving and of course your climate!

Also don't forget that the RS4 engine has a LOT of different components, including hardened ones. If you are not satisfied with the probable absolute max of 430 hp for a K04'ed S4 with RS4 intake/fuelling, then it makes sense (cost wise) to go for an RS4 engine transplant + mods, or of course an RS4!

Lastly, Golich underrates the value of free-flow cats on a stage II (or is it III) S4. My S4 pulls strongly to the rev-limiter (7200 rpm), which it certainly did not before I had the full Miltek system fitted.

[Druggie]

So initially exhaust and remap are the mods to go for.
Then brakes , suspension and finally ko4s and rs4 intake/fuelling mods.

Should keep me busy then for the next few years...

Cheers

[S4RS4]

So initially exhaust and remap are the mods to go for.
Then brakes , suspension and finally ko4s and rs4 intake/fuelling mods.

Should keep me busy then for the next few years...

Cheers

As soon as you up the boost with a remap, your inlet air temperatures will rocket. RS4 (or better) intercoolers will make a difference on all but the coldest of winter days. These should be on your list as soon as you have the car remapped.

[Dippy]

So initially exhaust and remap are the mods to go for.
Then brakes , suspension and finally ko4s and rs4 intake/fuelling mods.

Should keep me busy then for the next few years...

Cheers

Actually I'd recommend suspension first, and probably brakes second, because the stock set-up is not really up to even a stage 1 remap.

Also what do you think about the gearshift throw - most of us find it too long and fit a short-shifter.

[Druggie]

It feels nicely weighted compared to my rex and seems to glide in pretty well except for some notchiness in 3 and sometimes in fourth.
The change into fifth is so smooth and i would assume all changes should be like that. I mentioned it to the dealer before i bought the car and he had it checked out by the head service technician. He said that this is normal but i have my doubts. It seems to get even notchier the hotter the oil gets after some driving. Is this the norm or are all shift silky smooth?
Will the quickshift improve shift quality?
Or just speed it up but make it a harsher shift ? This is what i discovered with my rex when i added a quickshift mechanism.

[Druggie]

PS ...
I will be changing my brakes with ap 4 spot calipers i had originally fitted to the rex which i took off before trading.
I dont think there would be any probs with that.
Its the mounting brackets that will need to be fabricated as well as new hats as the discs are still in good nick. I have the dba5000 discs with removable hats.
Suspension will have to wait a little longer. Maybe sooner if i can sell all my rex bits for good prices...