Hi

Something I've been pondering for a while now, and have been prompted to ask given the recent questions about turbo upgrades on a S2. Would it be a good idea to install a K04-15 on an A4 1.8T multitronic and remap with a standard S3 map (or even possible)? I was thinking that 165kw / 280nm should be within the capabilities of the box and give better performance than simple chipping (I would imagine 140kw, 300nm) would. Also, the K04 would hold power right up into the 6000rpm range, which is great for the multronic since if you put your foot flat it sits right near 5000rpm. Unfortunately, with the K03, that's almost where the power drops off.

Anyway, just a thought, I asked Will about it some time ago and he reckons it's a bad idea . I priced a new K04-15 last year, was about R10k.

The K03s makes it power right up to the red line The older K03 died down after about 5000rpm.

You will not be able to just transfer the map because the two car's compression ratios, fuelling, MAFs etc are all different.

Audi A3 1.8T
ex "BroSpeed" RXi

I am not that familiar with with 1.8T turbo upgrades, but i would think you would need to do more than just fit a K04. You would probably need bigger injectors and a custom remap. You might also have to look at intercooling or water injection - I would prefer WI.

I am not the world's biggest fan of KKK turbos. The yanks seem to have left them behind on roller bearing technology. I would investigate roller bearing options - it won't cost much more than a new KKK K04 but is a bit more hassle. Mail me at gandalf@audiclubsa.org.za and I will put you in touch with somebody that can help you explore the options.

I have a friend who successfully installed a K04-015 onto an A4 1.8T manual. Although not an ideal upgrade, the turbo was chosen because of the ease of install, simple bolt on mod! bigger injectors had to be fitted (audi TT injectors used). As Gandalf mentioned cooling mods are essential, although in this particular application the fitment of a 2nd intercooler seems to have proved more hassle free compared the aquamist system 1s thats also installed. The problem with the water is that if not tuned properly you can actually loose power! The water on this car has been left disconnected until it is upgraded to a system 2d.

Was the upgrade worth it? well, the driver of this car thinks so although its no fireball off the line - the car is fun to drive, and a totally different beast now than it was with the K03! If you search online im sure you will find new or 2nd hand parts that prove to be significantly cheaper (even after paying the postage/customs) compared to buying locally from the agents!

i dont think that the s3 software would be ideal as the K04-015 is slightly different to the K04 used in the S3 - Will, 20vt - any advice here? Also, will torque need to be limited becuase of the multitronic?

2003 A4 1.8t

@Deepesh - I wouldn't throw out the baby with the bath water! What is your friend's problem with the water injection? In my experience, water injection is brilliant. I achieve intake tempratures which would be impossible to achieve with just an IC.

What size fuel injectors does he use and what sized water jet?

heya gandalf! Actually the water was there from when there was only 1 intercooler and K03, and it worked brilliantly! but with the K04 its been difficult to tune the water properly. It was mainly upper rpm (4500+) where the car gets very rough and looses power, however at the bottom it was brilliant for torque! the injectors are 385cc pumping @ 4bar and the 5mm aquamist jet is being used for the water. There is every intention to reactivate the water once other issues are sorted out

At its best with both intercoolers and water working merrily together, intake temps dropped to as low as 19/20 degrees under WOT and that was on a 30 degree day!

2003 A4 1.8t

@Deepesh, that is strange! If you are running a injector duty cycle of 85%, the 0.5mm jet provides 14.1% water to fuel, which is totally acceptable. Maybe you should reduce the plug gaps and try the water again.

Thanks for the feedback guys. How difficult is it to do a decent remap? More to the point, is there anyone around capable of doing this? Since my car still has a while to go before FWP expires, it's probably not worth going down that route right now. Just an interesting question whether it's more worthwhile going for an upgrade like this or a quick 'n easy chipping...

I would say start with quick n easy chipping There are quite a few options, Frieling/Revo/Apr/Chiplogic etc - and not forgetting the good ol Unichip, which until today was running the show on my friends car! he's changing to FRC this weekend so hopefully it just gets better! but for what its worth the unichip did a sterling job!

Gandalf, will mail you regarding the water injection

2003 A4 1.8t

K04-15 is a nice upgrade - keeps the stock bottom end and provides more mid and top end kick not massive amounts but good enough to keep you smiling

Around 165kw/300nm is about what you can expect with our fuel quality and it would require injector upgrade.

Torque would be an issue with the multitronic gearbox which has a limit of around 300nm - so a bit of detuning will be necessary.