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Audi TT225 Compound Turbo Build

37K views 239 replies 26 participants last post by  Anyclamp 
#1 · (Edited)
Ok, I have a build thread for this in the TT MK1 forum, but I figure I'll post it here too since I'll be meeting alot of you guys as soon as its done. Enjoy :D

Motor built and installed with powder coated valve cover and SEM intake mani









Both turbos back from welding and powder coat






 
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#29 ·
Well, we wont know till its done I guess, that is unless you, yourself have built a compound setup before...must have missed that build thread:)

JC has done a similiar setup before, and I have complete confidence in his abilities. If he says it will get me to my power goals then I have no reason to question it.

Yes the 38mm by it self is a restriction, and yes the smaller turbine housing is a restriction, but the combination of the two should supply the 60-1 with enough flow to make my desired power. As I said before, if the 38mm isn't large enough to get the job done, it will be replaced with a larger wastegate.
 
#28 ·
what are you doing for stand alone and boost control for both circuits, that is going to be a chore to get to run smoothly and you should look into building a bypass for the first stage turbo. Not only will the exhaust restriction prevent the potential spool of the second stage but the EGTs are going to quickly limit your available power for any duration of time.
 
#30 ·
what are you doing for stand alone and boost control for both circuits, that is going to be a chore to get to run smoothly.
Im using maestro to tune and as far as boost control, right now each turbo will be preset to a specific psi, running off the wastegates. Later I plan on running tandem boost controllers, one for each turbo but controlled by one source(preferably a touch screen) so I can adjust my boost while maintaining the pressure ratio between the turbos.


and you should look into building a bypass for the first stage turbo. Not only will the exhaust restriction prevent the potential spool of the second stage but the EGTs are going to quickly limit your available power for any duration of time.
What your describing is a sequential turbo setup, only one turbo is actually producing boost at a time. The smaller one for down low power and then through a solenoid of some kind, the small cuts out and is bypassed just as the larger turbo comes on hard. Totally different setup then what I'm doing and a whole lot more complex. The whole point is to keep both turbos spooled, just bypassing the extra exhaust gasses around the smaller one through the wastegate and back into the larger turbo. The smaller never stops feeding the larger turbo in my setup. The wastegate isn't meant to supply the larger turbo with 100% of it's flow, it's just there to bypass the excess exhaust that the smaller turbo doesn't need to maintain its preset pressure. Being as that this has never been done before on our cars, its going to have to be alittle trial and error before everything is perfect, but I know its doable...I hope:laugh:

As far as the EGT's, Im not 100% on how hot this sucker is really going to be. Im going to be running E85, and direct port W/M injection so I'll have to wait and see how high my temps actually get.
 
#32 ·
Is he running one wastegate or two? It was explained to me by a diesel guy that the way they run and tune their compound setups is they only use one wastegate on the small turbo, crank up the boost, and control it by tuning their fuel down till they hit their desired level of boost. If that is the case, they don't have to worry about bypassing turbos and what not. I wish my setup could be that easy:laugh:
 
#51 · (Edited)
We still have to relocate the battery to the trunk, do the entire fuel system, fab the piping for both WG's, fab the exhaust pipe coming off the big turbo, make an elbow with a flange that runs between the turbos, fab the charge pipe out of the small turbo, send all the piping out to be ceramic coated, route all new vacum hoses, hook up all the electrical crap, install my new subframe, and tune. I'm sure there is more but those are the big things I can think of at the moment.

Being as that my car is the biggest project he as and it has been in there longer than anyone else's I would think my car would take priority but I guess JC doesn't see it that way. I told him in the beginning that time wasn't an issue and I just wanted it to be done right, but when I dont go over there for a week or two and find out that nothing has been done thats just rediculouse. Thats probably happened 10 times in the last 6 months. Thats not the only problem either, his lacky he's got working for him doesn't understand how much money goes into a car like this. The guy isn't careful with anything so now the edges of both doors are dinged up from hitting the lift, my bumper is cracked in several places along the bottom, the powder coat on one of the turbos is scratched where he hooked the ground for the welder to it, my wheels are scratched to sh!t, and a bunch of other stuff I'm not happy with. Either way, I'm giving JC 2 weeks to finish the job and if he cant deliver, I'm taking it somewhere else.

Look up fast times motorsports (owned and operated by JC)...that is where the car has been worked on for the last 6 months, hell you can even call ask about my car if want:)
 
#52 ·
Well it's official, I'm towing the car from fast times motorsports on Thursday, 40 miles south to Rob's Speed Shop. I've been in contact with him for about a week and he says he would be more than happy to finish the build. Seems like a real stand up guy. Pretty excited about it, only thing is I'm about $4700 into it already and now I'm gonna have to pay Rob to make sure it's done right this time. It's a headache but if it gets my car done, its well worth it.

On a side note, mad props to tyler for suggesting Rob, thanks a ton.:beer::beer::beer:
 
#55 ·
Yeah I'm pretty excited to get it down there. I was gonna have rob pull the motor to check clearances and make sure fast times didn't screw anything up, and now thats turned into doing a full 2.0 stroker setup. I can already see this is gonna get a whole lot more expensive:laugh:
 
#56 ·
Well I got my car over to Rob's yesterday and he was just full of bad news. After taking a look at everything that JC had already done, he came to the conclusion that we cant really use any of it!!! Both turbos are bad enough that he wont put them on the car. The Header is totally F*cked. The runners are too small for my HP goals and they aren't even port matched to exhaust flange. He doesn't like the SS piping that JC used for the IC piping, and wants to change it to aluminum. Pretty much we are starting from scratch. First things first, he's going to pull the motor and have his audi tech check everything out to make sure Jensen's machine shop didn't mess anything up, then we can start doing the stroker. Needless to say I'm pretty pissed about the whole situation. I called JC today about getting some of the money back for the work he did, or didn't do. Came to an agreement and I'm getting $2200 back for both turbos, both wastegates, and for the header that he screwed up. Not a total loss but just enough to sting:mad:

Rob suggested just doing a single setup instead of the compound. Not sure how I feel about it, but at this point it would save me some money. What do you guys think?
 
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