MetalMan's 1.8T FrankenTurbo (F4H-L, F21) Build Thread
 

To start with, many people on this forum have asked about FrankenTurbo, but relatively little information has been delivered. To my knowledge I'm the only B5 guy in these parts running the FrankenTurbo setup, so I'd like to share my experiences. Feel free to ask any questions!
Now, prepare your eyes:

IN THE BEGINNING...
Back in January 2010 I had saved up enough ($4000) to buy my first car, a '98.5 A4 1.8TM (FWD) with 110,000 miles and plenty of paperwork. This choice was made after doing a bit of research and understanding the vast modding potential of the 1.8T compared to the 2.8.

For quite a while the mods I did were relatively insignificant to this build thread, but you can see a whole list of my mods in my "Garage".
I knew that over the course of time as money was saved my car would become somewhat of a tuner car. To what extent, I had no clue; but in all future maintenance and work performed I desired to ensure my A4 would remain a properly performing and daily-drivable vehicle.

That said, one of my first upgrades was a brake swap to the TT front calipers and A8 rotors, along with Hawk HPS pads. The FWD B5 has no options for upgrading the rear brakes so I simply installed new rotors/bearings and Hawk HPS pads.

CHIPPED!
In August 2010 my car visited a local Euro tuning shop to have the ECU flashed to GIAC's K03 file. Prior to that I installed a TT225 DV, and after arriving home threw in NGK BKR7E plugs (0.028" gap).

The car was a whole different beast, and I couldn't help the grin on my face :eek:. Considering my daily driver for 3 years prior to the A4 was a 1997 i4 Camry, this was a huge improvement. As you can imagine the flashed ECU only served as a stepping stone.

CRASH! :(
On the first day of my senior year of college (University of California, Irvine), September 23, 2010, I was late to class and also was thoroughly enjoying my drive to school. I semi-raced a street bike with pleasing results and had unnaturally elevated confidence in my car.

Coming toward a left-hand turn from an offramp, I wanted to make a yellow light so I took the turn fast, too fast... Back end stepped out, I corrected to the right, and being FWD it caught traction and hooked - stuffing the right front corner into a curb and deploying the front passenger side airbag in the process.
As a result of this incident I have spent ~$2000 paying out-of-pocket to fix things (used rear axle beam with new guide bushings, new set of control arms/TREs, used airbag module, new set of wheels/tires, new pair of tires due to improper alignment, etc). And still there is no airbag in the front passenger seat.

Around the time of the crash I had been thinking about upgrading the sway bars, and I strongly feel that had I done so earlier the crash would have been averted. In any case, after saving up for a bit I installed Neuspeed front and rear sway bars from MJM Autohaus after they hooked me up with an awesome package-deal price.

FMIC
I think it was back in March 2011 when the inkling to install a FMIC overcame me, while thinking about my power goals. After much research and pricing the Godspeed FMIC kit caught my eye. The intercooler core and piping fit decently, but a couple of the silicone couplers and all the clamps were complete crap. Shortly after the FMIC I threw in a BlinkTek heatshield to further reduce the intake air temperature.

Naturally, the next step would be upgrading the turbo...

FrankenTurbo Purchased/Installed
 

SELECTION CHOICE
For quite a while I knew in the back of my mind I would overall be happiest with a stock-frame-sized turbo. For a while I was considering the K04-0015 due to its easy fitment. I also thought about the GTRS but factoring in a high flow manifold along with the price of that turbo I was quickly turned off. Also, pretty much any larger turbo wouldn't spool as early as I might prefer.
Around the time when I started digging into turbo upgrade options FrankenTurbo was building steam. It didn't take long to realize this would be a solid choice for me. The hard part was saving (I was nearing college graduation too...).

So I bought a FrankenTurbo F4L-H kit some time in June 2011. To make sure I was properly prepared for this task I also bought new oxygen sensors, all new gaskets, exhaust mani nuts and studs (ended up reusing the old studs), and an 034 Motorsport 3in. high-flow cat.

INSTALLATION:
The FT exhaust mani shows vast improvement over the stock manifold. It has larger runners and a thicker base where the turbo mounts. Both of these caused some interferences:
-the original support bar holding the turbo to the engine block is no longer usable since the FT exhaust mani lowers the turbo 1-2 inches
-the oil return line is compressed more than usual because the turbo sits lower. This hasn't effected durability of my stock oil return line.
-it became quite a bit more difficult to install the exhaust mani-to-head nuts because the larger exhaust runners provided less wrenching room. I hacked up a combination wrench and that works pretty well.
-the turbo mounting bolt/lock washer closest to the engine had to be put in place before installing the FT exhaust manifold. I found this out after already installing the exhaust manifold once.

Also, with the 034 3in. high-flow cat, there is less room to tighten the turbo-to-cat nuts. I needed the turbo dismounted from the FT exhaust mani to get to the nuts (crank the HFC onto turbo before mounting turbo), and even then I had a huge challenge tightening 2 of the nuts. EDIT: The nuts I'm referring to are the OEM-replacement nuts which require a 17mm wrench or socket. I found locking nuts which use a 15mm wrench/socket that allow the cat to be easily mounted/dismounted from the turbo. Their part number is 18301737774 and can be purchased from many different places. I've gone through probably a dozen of these nuts and haven't had a single issue with them.

One last issue: it's been a weekly occurrence that I have to retighten turbo mounting bolts, since about two-thirds of my exhaust and the whole turbo weight rest on the exhaust manifold.
This is a known issue, and FrankenTurbo now uses studs instead of bolts to mount the turbo. Soon I'll be switching over to these. EDIT: This is no longer an issue for me. I use the studs along with 034 Motorsport's super-high-heat anti-seize and locking nuts, along with 034 Motorsport's K03/K04 locking tab. I tighten the nuts incrementally up to 44 ft-lbs.

To me, the above list is definitely not a deal-breaker, more like a list of things to be aware of to ease the installation process.

On a more positive note: the turbo performed incredibly on the first start! I had the FrankenTurbo turbo inlet pipe (TIP) installed and compared to the stock TIP the turbo noise was far more audible, and beautiful. Also, running the GIAC K03 file I gained an extra couple PSI (I think due to the wastegate setting) and was able to hold boost better in higher RPMs.

ICM DELETE AND ATW COIL PACKS
Shortly after this I also opted to switch to the newer bolt-down ATW style coil packs. This involved:
-removal of ICM and bypassing its wiring
-adding in new wiring and rewiring all wires to each of the coil packs, starting at the very back of the engine
-installing new connectors for the coil packs

Benefits:
-No more ICM!! This is prone to failure and is a major annoyance when running a cone filter. Not to mention the cost to replace when it fails...
-Cleaner engine bay - less mess around the intake.
-Stronger spark since each ATW coil pack has an ICM built-in. Supposedly this allows a bigger spark gap which provides a better burn.
-ATW coil packs are almost half the price of AEB coil packs. Do I need to say more?

After all this I had a new-found love for my car. But once again this was merely another stepping stone...

GIAC PC-16 Tuning
 

Next stop: appropriate tuning. Up to this point I had many conversations with Doug @ FrankenTurbo. One of them was regarding tuning: there was no off-the-shelf tune for my car. Pretty much if I wanted a "proper" tune I would have to dish out ~$600 to a place like Malone Tuning or C2 Motorsports or Unitronic. I didn't want to spend that much money.

GIAC PC-16 TUNE
I research things, a lot. To say I am uninformed would be like saying children don't enjoy hitting dangling cardboard/paper mache figures filled with sweets.
One of the neat things I learned is that GIAC does not charge an upgrade fee when you have your ECU reflashed. So that meant the only money I would pay to have my K03 ECU flashed to PC-16 (GIAC's top K04-0015 tune) would be a labor fee. Yes. I even had a guy drive out to me, pick up my ECU only, reflash the ECU, bring the ECU back, and collect $100.

That's one obvious GOOD reason for choosing PC-16. Other reasons:
-It is my understanding that the FT is like a high-performing K04-0015 but with a larger wastegate port, more aggressive compressor wheel, etc. To me (and Doug agrees) this means my car should fare pretty well with a K04 tune.
-For a big-company (APR, GIAC, etc.) the PC-16 is often regarded as the most aggressive K04 tune for the drive-by-cable B5.
-GIAC headquarters is located about 5mins from where I work. How cool is that??!?

SUPPORTING MODS
Every non-noob here knows that improved performance requires improved components.
GIAC says PC-16 requires relatively new oxygen sensors, FMIC to keep intake air temps (IAT) below 50 deg C, clean air and fuel filters, and proper spark plugs.

A free-flowing exhaust is an obvious requirement as well. The day after being flashed to PC-16 my car underwent exhaust work. Here's what I went with:
-Magnaflow 14815 muffler (already had), Magnaflow resonator (already had).
-Milltek 2.5in. downpipe for Quattro. I haven't found only a downpipe for the FWD B5, so I had to choose a downpipe for Quattro. Turns out this was a slight issue because the pre-flex-section transmission mounting point is different on the Quattro downpipe than the FWD downpipe. Oh well.
-Mandrel-bent 2.5in. downpipe-back piping, with 3-bolt flanges between downpipe and rest of the exhaust.

FUELING
Originally the PC-16 tune was written using Bosch 31lb. injectors and a 3-bar FPR. Nobody these days uses Bosch 31lb. injectors.
I originally chose Genesis 315cc injectors and a 3bar FPR from U.S. Rally Team.
Most people find that a fuel pressure of ~2.8bar is ideal when using 315cc injectors on this tune to keep the air/fuel ratio in check at WOT.

Later I bought the ECS Tuning adjustable fuel pressure regulator (AFPR) and fuel gauge combo and dialed it in to 2.8bar. Note: setting the AFPR must be done with the engine running, and the vacuum hose removed from the AFPR (basically it has to be set at ambient pressure).

OBSERVATIONS
I really liked the base PC-16 setup with the FrankenTurbo kit. Boost built up early and held through 6000+ RPM. The more aggressive timing of the PC-16 was also noticeable.
One thing I was surprised by: compared to the GIAC K03 tune, PC-16 boosted maybe 1 PSI higher. So for me PC-16 only gave me more aggressive timing and semi-proper fueling for my engine.
Unfortunately my car experienced a boost spike in 2nd gear that would exceed 25 PSI, which can be deadly. For the next couple of days I took it easy awaiting the arrival of a BoostValve manual boost controller. My intention was to still allow the N75 to do its job, but use the MBC to limit max boost (and thus eliminate the boost spike). I installed it in parallel to the N75 as recommended by BoostValve.

Even before PC-16 (with FrankenTurbo) I was logging MAF values around 180 grams/second. With PC-16 I was consistently able to hit 187 g/s indicating I was maxing out my MAF. That's a lot of airflow!
But then I knew I would want to raise the measurement ceiling of the stock MAF sensor, and so a next phase was imminent...

Hillbilly Tuning!!!
 

At one point during a conversation with Doug I learned that AEB only runs closed-loop fueling in part-throttle. As soon as the throttle reaches WOT the ECU goes open-loop (narrowband O2 sensor is useless at WOT). So this means that use of an AFPR on an AEB engine is for controlling the air/fuel ratio at WOT. This opens up tuning possibilities...
Also since there is no MAP sensor incorporated into AEB the ECU can’t monitor boost levels. Another plus!

As soon as Doug brought “Hillbilly Tuning” to my attention I was hooked. The idea here is you can use a larger diameter MAF housing with the stock MAF sensor to trick the engine into thinking it’s receiving less air than it actually is. By my measurements the stock MAF housing inner diameter is 2.445in. while the FrankenTurbo MAF housing ID is 2.745in. This equates to a 26% increase in cross-sectional area.

FUELING
With the engine reading air intake 26% low it is imperative to increase fuel delivery capacity by about 26%. In my case if I were to keep the same fuel pressure (2.8 bar) then I would need 397cc injectors. After searching around and pricing injectors I learned that the least expensive next step up for injectors (that directly fit AEB) are Delphi 440cc from U.S. Rally Team. At $50 a piece they fit perfectly and work quite well. But being a higher flow rate I needed to do some math to figure out the new fuel pressure:
(Based on the PC-16 with 315cc injectors and 2.8bar fuel pressure, and incorporating 26% required increase)
New_Fuel_Pressure = old_fuel_pressure * (1.26 *315 / 440)^2 which gives a value of about 2.3 bar or 33.5 psi.

BLOW-THROUGH MAF
With these major details figured out it was time to get to business. At the time I was also researching blow-through MAF setups, where the MAF is placed somewhere between the turbo and throttle body. I determined I could fabricate new cold-side intercooler piping and incorporate the MAF there. That piping ended up like this: 2.5in intercooler ---> 45deg 2.5-2in reducing silicone elbow ---> 2in 90deg aluminum elbow ---> 45deg 2-3in reducing silicone elbow ---> 3in MAF housing ---> 3-2.5in reducing silicone connector ---> throttle body.

I wanted to do blow-through to allow more space for a filter setup and also just to experiment with it. I bought a BPI 3” flow stack and an AEM DryFlow 6” cone filter so my turbo will have no issues breathing.

One of the big reasons people advise against blow-through setups is due to the contaminants in the intake tract from the PCV system and turbo blow-by. While I can’t eliminate blow-by I can pretty much eliminate crap from the PCV system. Now I have a catch can where the headlight washer reservoir was, with tubing that places the catch can in series with the PCV system.

People also say that the higher temps reached after the turbo don’t play well with the stock MAF sensor; whatever. After a month and a half I’ve had no issues with my car's ORIGINAL MAF sensor in blow-through configuration.

BACK TO HILLBILLY TUNING...
This process, if done wrong, can blow the engine because it is up to the user to ensure proper air/fuel ratio at WOT. Too rich and you’re wasting fuel and losing power; too lean and your ECU will cut back timing due to high combustion temperatures (avoiding pre-detonation) and thus you lose power. From what I’ve read 11.5:1 or slightly lower is a good choice when running pump gas (91 octane for me).

To find out what your A/F ratio is without being on a dyno you need a wideband sensor/gauge. No way around it. I went with an Innovate Motorsports MTX-L gauge/sensor. The gauge itself has the wideband controller built-in, and it allows logging and has 2 analog outputs. So here’s how I configured this:
-Installed the wideband sensor where the stock primary O2 sensor goes, after the turbo and before the cat
-wired an analog output from the MTX-L gauge to the stock O2 sensor wiring
-left the 2 white heater wires on the stock O2 sensor intact, to prevent O2 sensor heater fault codes
-have the stock primary O2 sensor dangling from the secondary firewall
-bought a column pod to mount the MTX-L wideband gauge/controller

OBSERVATIONS
With fuel pressure dialed in, the rest has been history. The ECU adjusts fuel trims at idle and part load to bring the combustion to stoichiometric levels based on data received from the primary O2 sensor.

Through this setup I gained an increased boost threshold while still using the N75!! So I dialed in my MBC to limit boost to 24-25psi; the max my boost gauge will read and also a safe limit for a stock block. The FrankenTurbo setup does not disappoint and it holds boost extraordinarily well into higher RPMs despite enabling high boost levels as low as 2500 RPM.

Yesterday I reconfigured my MAF back to the stock location with a standard AEM Dryflow 3” cone filter so I could compare it to blow-through. In the stock location it’s a very tight fit due to the length of the 3in MAF housing.
Anyways, I’ve found that blow-through MAF tends to respond quicker, which actually causes the engine to stumble a bit more around idle until it stabilizes (I blame Audi LOL). Part-throttle responsiveness improved slightly which is nice. Twice I checked the MAF sensor (while in blow-through) for contaminants and then cleaned it, and found the MAF response never changed before/after cleaning (a good thing).

When switching to a larger MAF housing without changing the MAF scaling in the ECU's tune it is normal for the readings to be off at lower air flow levels. What does this mean? Well for me this means that around 2000 RPM regardless of the gear I'm in, my wideband gauge will often show A/F ratios of 16-17.5 compared to the ~14.7 it should be at. Basically the MAF sensor is telling the ECU there is less airflow than there actually is because its voltage scale is shifted at these lower air flow levels compared to the ECU’s MAF scaling.

In any case, my car performs very well for the amount of money I spent. I never have regretted my decision to stray from the BT route. At this stage it would be useful to do a few runs on a dyno but I personally don’t think it would be necessary.

Performance Logs
 

Performance Graph, stock K03 with GIAC tuning, FMIC, intake heatshield, cone filter.
Attachment 30909

FrankenTurbo F4H-L, GIAC PC-16 tune, 19psi, 034 Motorsport 3in high-flow cat, cone filter, 315cc injectors, 3bar FPR, 2.5" downpipe-back exhaust with Magnaflow resonator and muffler.
Attachment 30910

Same setup as above, but with 3in. blow-through MAF, 22psi, large cone filter, 440cc injectors, 2.3bar AFPR.
Attachment 30911

Tribute to FrankenTurbo
 

An important driving factor for me to go the FrankenTurbo route compared to some other K03/K04 hybrid route was the customer service. Doug @ FrankenTurbo has been hugely instrumental in my entire build, before and after the sale. Seems like he’s always responding to my emails faster than I can respond to his emails (that’s saying a lot).

Who knows where I’d be without his support, but I know that I wouldn’t be able to share such great success with you today if it weren’t for him!!!

Pictures!
 

Out with the old K03 and stock cat:
Attachment 30832

The stock exhaust manifold and FrankenTurbo exhaust manifold. Notice the larger and smoother-flowing ports:
Attachment 30833

034 Motorsport 3" high-flow cat and new O2 sensors!
Attachment 30834

In with the new FrankenTurbo stuff:
Attachment 30835

Blow-through MAF and oil catch can (under coolant reservoir):
Attachment 30836

Showing cold-side intercooler piping:
Attachment 30837
Attachment 30838

Engine bay, sans cover over valve cover and cover over air filter (normally these are on):
Attachment 30839

Conversion to ATW coil packs, notice the clean wiring that goes to them :) :
Attachment 30840

Dangling stock primary O2 sensor, only has its 2 white heater wires connected (running a wideband O2 sensor in the primary location):
Attachment 30841

So what does it put down to the wheels?

Wish I knew! Haven't been to a dyno, you want to lay out the funds for me to do so? :D
K04 Turbo Upgrade Kit - 1.8T - B5 A4 (97 - 01) - A4 - Audi - PRODUCTS

AWE claims 247hp and 295 ft-lbs at the crank, with a standard K04/PC-16 package. The FrankenTurbo flows higher and I've got more fuel available, so I would guess I should be pushing ~260hp and 310ft-lbs at the crank, or ~225-230hp and 270-280ft-lbs at the wheels.

Seriously excellent thread MetalMan. Please keep it coming. I'll move this to the tech forum and sticky it once you've finished up the bulk of your posting with your current info. Just shoot me a message when you're ready.

Definitely one of the best threads in recent memory to show up here.