# Big Turbo 2.5/07k Build Thread



## Aaron994 (May 18, 2009)

*Introduction*
Hello all. A friend mentioned that I should contribute my latest endeavors to this forum. I wasn't even aware there was a special thread for our "odd" little engines. I'm happy to be here and enjoy open discussion so feel free to comment and ask questions. We're all here to help each other.

*Table of contents( Vortex | caddyfab.com)*

Installation - Oil Jets | Original
Installation - Crankshaft | Original
Installation - Pistons and Rods | Original
*Disclaimer*
I am not an expert and am not liable for any damage caused by advice given or instructions followed. At the end of the day I am a enthusiast but not an expert. I do my best to back up any claim or opinion with scientific or documented proof. Use any of these ideas at your own risk.

*Quick Note*
I spun up a build site to track everything in a bit more detail (I will keeps this thread updated as well for ease of discussion). It allows me to format everything correctly but more importantly not have to rely on photobucket or other image hosting sites. All images will work all the time for historical quality. View the site here: https://caddyfab.com

*About me | skip to next section if you don't care *
I am a programmer by day and VAG enthusiast living in Chicago. My past rides have been all over the map. Favorite was probably the MK4 R32; I wish I never sold that car. Engine builds are probably my favorite part of car DIY's. There is nothing better than that first start after all the meticulous hours committed.

A lot of my day job requires documentation and translation of complicated ideas and work streams into readable content. This will be my first time fully documenting any build I've done so feedback is appreciated. I hope this helps others in their quest for more power.

*Original Engine Specs*

Motor sourced from a Pick-and-Pull out of a 2006 Jetta with 78k on the odo.
BGP Engine Code - 150HP
Because of earlier year it has a forged crankshaft
Accident to warrant sending to the junkyard was in the rear of the vehicle.
*Performance Modifications*
Below is a short list of the major performance parts being used for this build. Anything listed below has already been purchased and waiting to be installed.

Full machine shop workup including - Overbore to 83mm, Align hone of crankshaft with performance main bearings, cleaning of all oil ways and freeze plug replacement
JE Ultra Series 83mm Bore Pistons
Integrated Engineering Tuscan Connecting Rods
King Racing Main Bearings
Mahle Connecting Rod Bearings
Almost every OEM part replaced regardless of wear
ARP Main Studs
Injector Dynamics 1300cc injectors
Garrett GTX 3576R Gen II Turbo
That's about it for the introduction for now. I will add more as questions arise or I remember things to add. Thanks for reading. Stay fast.

Here are some pictures to start things off. Coming back from the machine shop.


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## Darepoole (Sep 3, 2019)

Aaron994 said:


> *Introduction*
> Hello all. A friend mentioned that I should contribute my latest endeavors to this forum. I wasn't even aware there was a special thread for our "odd" little engines. I'm happy to be here and enjoy open discussion so feel free to comment and ask questions. We're all here to help each other.
> 
> *Disclaimer*
> ...


Hell yeah this is awesome can’t wait to see this come together


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## Aaron994 (May 18, 2009)

Darepoole said:


> Hell yeah this is awesome can’t wait to see this come together


Thanks mate


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## Aaron994 (May 18, 2009)

*Breakdown and installation of TTRS Oil Jets*
Yes the heading above is correct. I am using oil jets from the TTRS in this build.

*Why use them?*
One simple reason...we are going forced induction; we need more oil feed! When a piston comes down in the engine there is pressure created that forces its way down into the crankcase. Now in the stock BGP engine the oil jets are correctly sized to overcome this pressure and reach the parts necessary each time. However, with forced induction the turbo is cramming even more pressure into the cylinder; this also increases the pressure of blow back gasses. In the TTRS, Audi made sure to modify the oil jet to be sure it could overcome this increased pressure in a turbo application.

*How are they different?*
Audi achieved the extra output needed with two major changes to the jet assembly.

First, the banjo bolt. In the BGP engine we have a bolt with two holes for oil to flow through. In the TTRS however while these holes are a smidge smaller there are twice as many for a total of four. This allows more oil to easily flow through the bolt and into the jet tube. One thing to note while im not sure if it is a benefit over the BGP bolts is the refined relief valve location.

See images below (TTRS on left, BGP on right).


















Second is the jet tip. Two differences here. TTRS has a larger opening for a "thicker" shot of oil rather than the more "misty" spray of the BGP version. Also the taper of the jet end is amplified to increase the pressure of oil shooting out. Think of a garden hose when you put your thumb over the end. See image below (TTRS on left, BGP on right).









*Installation*
Nothing fancy here. Simply hand thread in and torque to 27 ft lbs. per the VW erwin specifications.

















Obligatory beer picture to end the post. Stay fast.


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## Maurice Epp (10 mo ago)

Aaron994 said:


> *Breakdown and installation of TTRS Oil Jets*
> Yes the heading above is correct. I am using oil jets from the TTRS in this build.
> 
> *Why use them?*
> ...


Is there a certain amount of boost at which it would be safe to just leave the stock ones? We’re going for 10 psi… or is it safe to say they need to be upgraded if going turbo?


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## Aaron994 (May 18, 2009)

Maurice Epp said:


> Is there a certain amount of boost at which it would be safe to just leave the stock ones? We’re going for 10 psi… or is it safe to say they need to be upgraded if going turbo?


That is a great question.* I don't have the exact answer from a PSI perspective.* I'm sure someone could calculate what the possible pressure or velocity is of the blow by gasses and back up the recommendation with some data; however I am not equipped to test that. With that said there are two points that might help you....

*For stock:* Plenty of projects have ran the stock oil jets in a turbo application and been fine. Most turbo kits you see on the market also do not mention doing anything with regards to oil supply or jets.
*For upgrade:* When it comes to lubrication of your internal components...my opinion is there is no such thing as "too much" oil supply in this space. This is assuming your pressure is optimal to feed any upgrades or changes made with no detrimental side effects to other components' oil needs.
Getting back to your question of *"Should I upgrade/change my oil jets?"*. The best I can say is why not?. My goal is to leave as little chance possible for oil starvation. I will have increased pressures and larger wrist pins that I want to be sure are receiving the necessary if not more than needed oil supply. It could even be classified as overkill. However *for $130 squids I think it is worth the quick upgrade.*

I hope this helps! Stay fast.


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## Maurice Epp (10 mo ago)

Aaron994 said:


> That is a great question.* I don't have the exact answer from a PSI perspective.* I'm sure someone could calculate what the possible pressure or velocity is of the blow by gasses and back up the recommendation with some data; however I am not equipped to test that. With that said there are two points that might help you....
> 
> *For stock:* Plenty of projects have ran the stock oil jets in a turbo application and been fine. Most turbo kits you see on the market also do not mention doing anything with regards to oil supply or jets.
> *For upgrade:* When it comes to lubrication of your internal components...my opinion is there is no such thing as "too much" oil supply in this space. This is assuming your pressure is optimal to feed any upgrades or changes made with no detrimental side effects to other components' oil needs.
> ...


No, I figured there’s no good way to test something like that without spending a ton of money. Also been doing some research and there seems to be a lot of guys that leave them at what they’re at and boost their vehicles. But I also strongly agree with you on the point that there’s never enough lubrication. So that leaves it up to preference I guess🤟 Thanks a bunch for the response🙏


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## Aaron994 (May 18, 2009)

*Installation of Crankshaft*
The crankshaft. Possibly the most important part of the entire project as nothing can happen without it. This has made the start of the build feel like it has officially started. Everything machined and ready to simply drop in and torque down. I wanted to take immense care in being sure everything was done perfectly so I naturally snapped less pictures of the process. Enjoy what I did produce.

King Racing Bearings were left installed from the machine shop. I did not have to do anything but verify everything looked correct.
















Next I set in the new OEM thrust bearings. No pictures actually installed but I do have some close ups of the thrust bearing and bearing cap.

















Next I laid the crankshaft in.









Unfortunately I don't have any images of the ARP main stud installation. One thing to note is the tolerance for these studs does not allow the bearing to "slip"
over the studs when tightened down fully. What this means is for each bearing cap I had to hold and fiddle it around a bit while hand tightening each stud. Not a problem just something to note as most engines cap and stud installation you can simply put the studs in and then place the caps over and tap down.

Next was torquing everything down. Now because this stud kit is put together by Integrated Engineering and not ARP there is a lack of instructions for the "kit". However, because the bottom end of an 07k and 1.8T are near identical I simply used the official 1.8T instructions from ARP. I have attached the instruction sheet below.

































And here is a gif of the end result


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## Darepoole (Sep 3, 2019)

Aaron994 said:


> *Installation of Crankshaft*
> The crankshaft. Possibly the most important part of the entire project as nothing can happen without it. This has made the start of the build feel like it has officially started. Everything machined and ready to simply drop in and torque down. I wanted to take immense care in being sure everything was done perfectly so I naturally snapped less pictures of the process. Enjoy what I did produce.
> 
> King Racing Bearings were left installed from the machine shop. I did not have to do anything but verify everything looked correct.
> ...


Beautiful shots! You are making me jealous cant wait to start putting my motor back together. Been waiting on my cp pistons for like 3 months


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## Aaron994 (May 18, 2009)

Darepoole said:


> Beautiful shots! You are making me jealous cant wait to start putting my motor back together. Been waiting on my cp pistons for like 3 months


Waiting on my JE's now ha!


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## 4MotionMongrel (Apr 7, 2006)

Gonna be following this thread, excited to see what comes of it, keep up the good work.


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## Aaron994 (May 18, 2009)

*Installation of Forged Internals*

*Parts used*

JE 83mm Forged Pistions - 337967
Integrated Engineering Tuscan Rods
Mahle Motorsport Race Rod Bearing
*Tools used*

ARP 83mm Piston Ring Compressor
TEKTON 1/2 Inch Drive Torque Wrench
*Torque Specs*

ARP 2000 Rod Bolts - 50 ft/lbs
Oil Pump Bolts - 19 ft/lbs (25nm)
Next is installing the parts that will be taking the brunt of our high horsepower beating; pistons and rods. First some glamour shots.


















During this whole process I was laser focused on making sure everything was done correctly. Due to this I didn't get any photos taken during the rod and piston assembly; I know shame on me. But I at least came out of my focus tunnel to snap a finished product before installation picture.









*Beer featured above --> **Xtra Dubl Benthic*










Next I started laying in pistons. The ARP ring compressor and plenty of lube had them dropping in with little effort.



























All that was left was to bolt the oil pump back in and snap the final picture.


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## CreatorAmongFriends (Feb 15, 2008)

Any updates on the build?

Sent from my Pixel 4a using Tapatalk


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## Leafy0 (Dec 4, 2020)

Just for curiosity's sake. Did your engine have torx or hex bolts holding the oil pan on. Gathering more data on the rumor that torx bolts = forged crank.

Did you do the thrust bearing mod? The big RS3/TTRS guys always allude to it, even showing some machining for it, but never really go into detail, it almost seems like they're adding a second thrust bearing.


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## Aaron994 (May 18, 2009)

Leafy0 said:


> Just for curiosity's sake. Did your engine have torx or hex bolts holding the oil pan on. Gathering more data on the rumor that torx bolts = forged crank.
> 
> Did you do the thrust bearing mod? The big RS3/TTRS guys always allude to it, even showing some machining for it, but never really go into detail, it almost seems like they're adding a second thrust bearing.


If you are referring to the lower oil pan (steel portion) yes I did remove torx bolts during disassembly.

I did not do the thrust bearing mod. First I am hearing of it. You have me intrigued.


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## Leafy0 (Dec 4, 2020)

I actually found the thrust bearing mod later last night just putzing around the project pad in boredom. It's to use an AAN (I think, the old i5 engine) thrust bearing. You can find it in the 07k swap section on there.


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