I figured I'd post up a copy of my Mazdaspeed K04 A4 build that I posted on Audizine. The idea was to see if I could transplant a full Mazdaspeed K04 (including the MS turbine housing) into an A4 on the stock exhaust manifold. So with no further adieu....
I've often wondered if you could install a K04-0081 from a Mazdaspeed in the stock turbo location. Quite frankly I'm amazed that no one has tried yet. If you think about it, it's about the perfect sized turbo for someone who wants a legit 280-300 CHP on stock internals with a good powerband between 3000-7000 RPM.
Size wise, it's almost identical to a T28, but with a compressor which is better suited to the higher pressure ratios that a small displacement engine like the 1.8T requires to make power.
Well, rather than spitball and speculate, I just went out and found myself a used Mazdaspeed K04, along with the intake manifold and cat for a whole $120 and hooked it up to a cut-out exhaust.
As you can see, all you need to do is make a bracket out of 3/8 plate steel and bolt the turbo to the stock manifold
mazdaspeed k04 5 by
zimbu themonkey, on Flickr
The only thing you need to do is cut one of the bolt holes out (lower left side) to clear the motor mount
mazdaspeed k04 2 by
zimbu themonkey, on Flickr
mazdaspeed k04 4 by
zimbu themonkey, on Flickr
**You can also port the wastegate out a few mm. I hogged it out to 24 mm. So not quite as big as a Frankenturbo, the properly sized Mazdaspeed exhaust A/R ought to keep backpressure in check**
You can re-use both the stock water lines and the oil feed. However where I got hung up is that the oil return didn't fit properly and I collapsed it as I tried to wrestle the turbo in to it's new home.
Personally I think this should be a game changer as it proves that you can do a turbo upgrade for under $300 as long as you have some basic fabrication skills.
If I was to do it over again, I would just get a 5 bolt to V band flange for $50. But if you can find a turbo for $150, V-band discharge for $50 and assorted odds and ends for the intake for another $100, then you have a perfect alternative to the next cheapest thing (a Frankenturbo) which costs over 3 times as much.
Fast forward a couple weeks and here was the finished product. Good thing that I had 300+ km to cover as I had to make about 10 revisions to my tuning file before I got it running right [:p] Let me tell you, tuning 630cc Dekas on a Narrowband ECU is a major PITA!!!!
That said, the car goes like a raped ape
Here's some pics of the final product.
20170808_135151 by
zimbu themonkey, on Flickr
20170808_135320 by
zimbu themonkey, on Flickr
I want to point out what I found to be a VERY worthwhile addition to my setup.
This box that I made around the intake made a huge impact on my IAT's.
Without it, my average IAT's were about 90C and went upwards of 110C under full load pulls.
With the insulated box, my IAT's dropped to about 35C (ambient temps were about 25C) and topped out at 60C after a 1-2-3 gear pull (stock intercooler).
All I needed to make it was a sheet of Aluminium, a cutting disk and some insulating matting. Took me all of about an hour to make. So well worth it if anyone replicates my intake design.
20170808_135246 by
zimbu themonkey, on Flickr
Finally, I went on to fabricate a 2.5 inch exhaust for the car.
20171010_212351 by
zimbu themonkey, on Flickr
20171009_221633 by
zimbu themonkey, on Flickr
20170908_200619 by
zimbu themonkey, on Flickr
That said, initial impressions of this turbo with a free-flowing exhaust are very favorable so far.
In 5th gear on the highway, (so about 2500 RPM- 3200 RPM) it generates about 3-4 PSI positive pressure whenever I touch the throttle.
- 7 PSI is reached at about 3200 RPM
- full boost appears to be on tap from about 3700 RPM onwards.
As well, in stop and go traffic, it generates enough torque I can now get away with short shifting around 3200-3500 RPM instead of having to constantly wind it up to 4500-5000 RPM.
Overall, very similar to my old GTRS (2860) elim I had on my Passat.
Hopefully full boost and throttle response will drop down even further when I ditch the stock charge plumbing and install that 2.5 inch FMIC. I'll try and post up some logs later this week to confirm my initial impressions.
All in all though, I can say for certain now that this turbo setup is a FANTASTIC alternative for someone with some fabrication skills who wants something in the 275-300 CHP range but doesn't want to break the bank getting there.
All in all, if I had to buy all the materials to replicate what I have now, (so MS K04/2.5 in exhaust/2.5 FMIC/630 Dekas/misc other parts and lines) it could be done for under $1000 as long as you were thrifty in the classifieds and did all the fabrication and tuning yourself [up].
Fortunately, most everything you see here I was able to cannibalize from parts I had laying around, so as the title suggests, I'm only into this for about $300 and about a 1,000,000 hours in labor lol... [:p][/QUOTE]
