# 2012 2.5 jetta turbo or no?



## Imjorden (Sep 30, 2013)

So I've read tons of forums of bad and good things about turbos, I would just like to know your opinion on them, good experience or a bad one? Which set up you think is best, do you think it's a good idea to put on in or just to do other mods? Any input would be awesome as I am currently debating on getting a turbo.


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## kurtsayin (Mar 16, 2013)

It's a big investment, but it's the fastest way to big horsepower. I'm still on the fence whether to go turbo our just do everything possible with a naturally aspirated set up.


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## Rabbid Rally Rabbit (May 5, 2013)

Depends what you want. FI isn't as reliable as just getting an SRI and a new tensioner, but it's the only real way to get big power right now.

The real issue with NA build for this motor that almost nobody does fully custom software for it. Increasing compression and running ITBs and custom cams would definitely make power, but good luck finding someone to tune it.


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## thygreyt (Jun 7, 2009)

i dont fully get why people talk about "turbos not being reliable".

More parts to break? sure... but so what? its not the quantity of parts available for breaking, its their quality. 


I just returned from a 2400 mile trip, no issues on my 2.5T... its so good and reliable that i didnt even bother to "prep it" for the drive... i just hopped on one morning and left.

I dont burn oil, and i daily drive the car with an ~80 mile round trip. To this day, i have ~13k on the turbo'ed car in 7 months? from mid march to today.

Jordan, GTACanuk, is a 2.5T as well.. and i know he went to sowo AND H2o (like me) on his 2.5T and he didnt have a single issue.

So tell me again: why is a turbo 2.5 any less reliable than the NA counterpart?


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## INA (Nov 16, 2005)

thygreyt said:


> i dont fully get why people talk about "turbos not being reliable".


because every single 2.5 20V N/A motor that became turbocharged was a project and projects are deemed unreliable & costly. 
In all honesty the most reliable Turbo set up for this motor that is affordable is an OEM TTRS set up. You don't have to worry about manifold's cracking and the turbocharger will be available for years to come.


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## Rabbid Rally Rabbit (May 5, 2013)

INA said:


> because every single 2.5 20V N/A motor that became turbocharged was a project and projects are deemed unreliable & costly.
> In all honesty the most reliable Turbo set up for this motor that is affordable is an OEM TTRS set up. You don't have to worry about manifold's cracking and the turbocharger will be available for years to come.


Wait, has somebody managed to pull that off?


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## Rabbid Rally Rabbit (May 5, 2013)

thygreyt said:


> So tell me again: why is a turbo 2.5 any less reliable than the NA counterpart?


More to go wrong introduces more to go wrong. That's just a fact of the universe. You're dealing with custom setups on a car that can't be port flashed and unless you're experienced with highly modified cars you won't know how to deal with the quirks of low volume and custom parts.

Fact is, your car is reliable because you have skills and an attention to detail most people do not. What you deem easy just isn't to most people, Fred.


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## disphunktion (May 18, 2002)

I am turbo since more or less last winter and personally, if I knew how much it would have costed me in the long run, I would have never done that 

I'm not saying that it's not fun to drive it or anything, it's just I could have used that money differently. 

I guess that's part of modifying a car, always something else to do :laugh:


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## [email protected] (Jul 1, 2009)

In my view, the only way for a 2.5 owner to justify a forced-induction modification would be for it to meet these criteria:

great value
solid reliability
safe performance

Otherwise all of you would choose not to do it or to simply buy a different car.


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## magics5rip (Mar 17, 2004)

Rabbid Rally Rabbit said:


> More to go wrong introduces more to go wrong. That's just a fact of the universe. You're dealing with custom setups on a car that can't be port flashed and unless you're experienced with highly modified cars you won't know how to deal with the quirks of low volume and custom parts.
> 
> Fact is, your car is reliable because you have skills and an attention to detail most people do not. What you deem easy just isn't to most people, Fred.


:thumbup: Adding a turbo system to an OEM NA engine is for people with the knowledge to fix future issues or someone with deep pockets. Reliable is a relative term...


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## kurtsayin (Mar 16, 2013)

I have to ask, if you would have done things differently, please specify how you would have spent your money if you could do it all over again. 

I am weighing my options between going all out NA vs turbo. I expect turbo to come with quirkiness, but I also expected my VW to be quirky too, and it's been nothing but a joy through the modification process - granted, I've done nothing be relatively simple bolt ons.


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## kurtsayin (Mar 16, 2013)

Doug, Gonna do wheels, tires and suspension next, then hoping you guys have a turbo kit available for consideration.


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## Rabbid Rally Rabbit (May 5, 2013)

kurtsayin said:


> I have to ask, if you would have done things differently, please specify how you would have spent your money if you could do it all over again.
> 
> I am weighing my options between going all out NA vs turbo. I expect turbo to come with quirkiness, but I also expected my VW to be quirky too, and it's been nothing but a joy through the modification process - granted, I've done nothing be relatively simple bolt ons.


The ECU on these is the real PITA with NA. Going all out is not really feasible since ITBs are going to set you back a fortune. Assuming you could get the BMW V10 ITBs working on the 2.5L, you'd probably have to do what the ITB Rabbit did and use the stock TB as a controller to avoid the position sensors screwing all your hard work to hell.

As for an SRI build, you'd need to get IE's upcoming cams and probably 12:1 internals w/ a TTRS crank or get your stock crank knifed. TBH, I'd overbore while you're at it. Then, to get those last 20 horsepower, you'll need a fully built head with a P&P. That's probably a 250-275WHP build.

If you've got *tons* of money, skip all that, get a Bosch Motorsport ECU 15:1 pistons, a TTRS head, TTRS crank (have it knifed) custom cams, the BMW V10 ITBs and get Jeff to write you a tune that'll get the direct injection working. I looked into this, but I'm not willing to spend $25K into a 300WHP car that would inevitably shake like a mother****er, and build power slower than a turbo.


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## A1an (Mar 22, 2007)

Keep in mind that going "all out" naturally aspirated really makes a car no more unreliable than a custom turbo setup. Each side has its own host of potential issues depending on how crazy you get.


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## Rabbid Rally Rabbit (May 5, 2013)

A1an said:


> Keep in mind that going "all out" naturally aspirated really makes a car no more unreliable than a custom turbo setup. Each side has its own host of potential issues depending on how crazy you get.


I'd say that the edge of reliable is an SRI, 11.5:1 internals, and cams. That's probably the end of comfortable for a DD too.

You can pick up a lot of speed from gearing the transmission too. An 02J out of an older 1.8T GTI will still get decent milage whilst picking up some pep, or an 02J-B out of the 2.slow if you don't care about milage.

If the OP has an auto, swap a DSG and retrofit paddle shifters no mater what the heck you do --DSGs may not be as fun as a stick, but they're sure faster.


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## kurtsayin (Mar 16, 2013)

Definitely on board to do some of this stuff.

My thoughts were SRI, Headers to full exhaust then possibly I turbo set up. I didn't realize there were custom cams to be had or that any of the TTRS stuff could be got gotten.

Is there a sticky for internal upgrades or transmission swaps for the 2.5? I think cams and
higher compression would be awesome


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## Rabbid Rally Rabbit (May 5, 2013)

kurtsayin said:


> Definitely on board to do some of this stuff.
> 
> My thoughts were SRI, Headers to full exhaust then possibly I turbo set up. I didn't realize there were custom cams to be had or that any of the TTRS stuff could be got gotten.
> 
> ...


The ONLY header that makes power costs $1000 bucks. It's a waste of money if you're going to turbo it later. 2012s and 2013s have an individual tube header, so that's an OEM+ upgrade over the POS on earlier 2.5Ls.

The NA VW 2.5L and the Audi 2.5T effectively share a bottom end casting mold. The head is significantly different in that it's direct injected. Getting direct injection working in a car it doesn't come in would cost a fortune, and just isn't worth it IMHO. You can swap the TTRS crank, but you'll need to get an 8 bolt flywheel (easily done.) 

The best internals are built by IE right now, as is the newest SRI setup and the upcoming cams. If there are cams, there are blanks --and you can get blanks ground for custom cams. If you get an SRI, get yourself IE's upcoming serpentine belt tensioner. The stock tensioner can't handle over 6500RPMs and throws/shreds belts like crazy.

Get upgraded mounts too. BFI makes the best for the 2.5L right now. As for exhaust, a 2.5" catback, and a high flow cat are best for an NA 2.5L car whereas a 3.0" + test pipe is ideal for a turbo car, but loses power in an NA situation. 

Any current 4-banger VW transmission fits the 2.5L. The best acceleration for a manual is had by a 2.slow gearbox, and if you have an auto, grab a DSG and paddle shifters out of a MK5/6 GTI. Any which way you go get a lighter flywheel. There are a few guys with GTI 6-speed gearboxes in this forum --seems like a great upgrade IMHO, and I'm looking into it personally.

The 2.5L is in an explosion of new parts right now. It sure took long enough, but it's finally getting some aftermarket options.


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## kurtsayin (Mar 16, 2013)

This is a great response, and I'm revising my plans accordingly!

I have a great tuner shop in town that isn't Volkswagen specific, but they build gorgeous street cars, race cars, etc... I've done all my own bolt ons. Where should I go for the hard stuff?


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## Rabbid Rally Rabbit (May 5, 2013)

kurtsayin said:


> This is a great response, and I'm revising my plans accordingly!
> 
> I have a great tuner shop in town that isn't Volkswagen specific, but they build gorgeous street cars, race cars, etc... I've done all my own bolt ons. Where should I go for the hard stuff?


I use a place called Dubsquared in DFW for the stuff over my head, but I live 400+ miles from DFW so I do almost everything myself. They'll be doing my snail install, but I have a palsy in my right hand so I'm not steady enough to tap the block for the oil return.

You've got a 2008, so you don't have to send off your ECU for a tune. If you want to keep your current intake, get a C2 SRI and get a C2uner flash for it. It'll fit with any upcoming turbo kits since it keeps stock throttle body location. 

If you want the IE SRI, buy it from Bluewater and the intake from IE. The have Jeff write you a tune for it. There's the full IE kit with a tune, but frankly, if I were you, I'd rather just tune it in my own garage. Not to mention you'll get custom options going directly through UM that IE doesn't offer.

You can do an SRI and flash yourself. Screw paying for labor on a manifold install IMHO. Same for the header (I really think he late model OE header is a better buy than any aftermarket ones.) Do both yourself, have them coated in ceramic and then wrap the header in titanium wrap. You should really wrap the whole darn exhaust in titanium wrap IMHO. Get the RAI high flow cat and a 42dd or NLS O2 spacer. I have a custom high flow cat I built using a Tsuedo midpipe and a magma flow cat, but it was a real PITA so I wouldn't recommend it.

If you have a motor support brace, just do the mounts yourself too. If not any good shop can do it.

For your suspension, I'm kinda torn between choosing an all poly bushing setup and camber plates or getting a high durimeter rubber setup from 034 motorsports. I will definitely be getting rear LCAs from them and a full set of Passat front control arms and all 4 aluminum knuckles. Get Koni or Bilstien coils depending on whether you want a smooth car or a track setup, Konis are super smooth, but Bilstiens are firmer for the track. Then there's the Unibraces which apparently rock when combined with Audi subframe bolts.

NA builds need reduced rotational mass in any way possible. The aluminum control arms and knuckles are key as are lighter brakes --I went with 991 calipers and 2-piece drilled GTI rotors since that's significantly lighter than the stock setup and cost all of $750. Get a clutch line while you've got your bakes apart --you've got to bleed anyways. You can easily do that yourself too, but get a power bleeder.

Hope that helps.


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## Rabbid Rally Rabbit (May 5, 2013)

Oh another option for the suspension is OEM Drivergear springs and Koni Gold shocks. Rides smooth and handles well in every car I've ever driven with them. It's not a big drop, but it's enough --and the dual valving in the FSDs keeps you on the ground on ****ty roads so you have better traction.

And get a limited slip diff when you do the transmission. It costs, but the OEM diff is ****. You spin tires a lot less with an LSD.


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## dhenry (Feb 10, 2009)

i think you should get a tune for SRI, catback, upgraded mounts & suspension, then go turbo.


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## kurtsayin (Mar 16, 2013)

That's where I'm at. Just got Tein springs, gonna stick to stock shocks until they fail, and I have Hotchkis rear sway kit on its way.

Really want the IE SRI as my next mod purchase, and hoping to modify the APR CAI to make it work.


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## [email protected] (Oct 2, 2013)

Well, back on topic...

The 2012/MKVI Jetta 2.5L platform is a very unfriendly one to mess with. The ECU is annoying, power steering setup hampers aftermarket manifolds, and when trying to inquire various vendors, I have gotten nothing but open ended, non-specifics.

Bench flashing via send out would be the only option and there is no real 'plug-and-play' kit in terms of turbo for the MKVI Jetta.

It is doable, but it is far from being as cost effective as the MKV 'add to cart & checkout' setups.


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## Rabbid Rally Rabbit (May 5, 2013)

[email protected] said:


> Well, back on topic...
> 
> The 2012/MKVI Jetta 2.5L platform is a very unfriendly one to mess with. The ECU is annoying, power steering setup hampers aftermarket manifolds, and when trying to inquire various vendors, I have gotten nothing but open ended, non-specifics.
> 
> ...



It's the ECU that really kills things to be honest. There's something holding up port flashing or even full custom software for US VAGs. 


I'm STILL trying to get a FlexFuel tune for an MED17.5 ECU on a VAG. The MED 17.5 is cracked for port flashing on Euro VAGs, every single Ford, some GMs, a few Mopars, the majority of Subis, Mazdas and other cars it's in in the US.

Someone in the US VAG tuning world needs to step up and figure out how companies like SCT, Hondata, Cobb, Bluefin and the rest of the companies port flashing the MED 17.5 are getting the keys. SCT was given the keys to the MED 17.5 in the Ecoboost 2.0 and 1.6 --but they've flat out told me they weren't handed and didn't buy the keys they're using for the Duratec 2.2 and 1.6 NA Fords. Cobb got into the Mazdas somehow and the guys in Austin said they did it in house. Bluefin says they bought some from VAG EU and that they decrypted others. Hondata probably got them just given to them --they don't ever do decryption.

Eurodyne won't step up and support the 2.5L and they've told me they aren't going to 

I don't get what's going on on these particular cars --but it's only the ECU that's really holding things up.


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## Forty-six and 2 (Jan 21, 2007)

What are the limits when using the factory internals with a turbo setup? Is it possible to make decent power on a low mileage motor, only swapping out the hardware ARP, and a fresh oil pump? Somewhere in the 300-400 whp range?


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## Rabbid Rally Rabbit (May 5, 2013)

Forty-six and 2 said:


> What are the limits when using the factory internals with a turbo setup? Is it possible to make decent power on a low mileage motor, only swapping out the hardware ARP, and a fresh oil pump? Somewhere in the 300-400 whp range?


The safe limit really seems to be 400WHP. Your axles can't take that, but the motor sure can


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## Streetliight (Sep 5, 2011)

Rabbid Rally Rabbit said:


> The safe limit really seems to be 400WHP. Your axles can't take that, but the motor sure can


What degree of "safe" are we talking about? I'm going to be buying the JDL kit when I get back from my deployment in April, and I was planning on doing internals as well until I read that the motor is safe until 400whp. Is it truly safe to drive hard? For instance, I do autocross for fun, and a bit of track racing racing (not really, it's a thing called Tanacross up in Alaska, the closest thing to a road course we have. Think Top Gear test track.), and I would hate to pop the motor because I thought I was "safe". 

My mod list really only includes the JDL kit, LSD, clutch kit, full BFI mounts all around, IE SRI, and maybe a short shift kit. I'd also do water/meth injection since we only get 90 octane in Alaska 

With a set up like that, am I safe to drive semi-hard with stock internals? 
Also, are there any other parts I should get? I haven't compiled an official parts list yet, that was just off the top of my head.


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## Rabbid Rally Rabbit (May 5, 2013)

Streetliight said:


> What degree of "safe" are we talking about? I'm going to be buying the JDL kit when I get back from my deployment in April, and I was planning on doing internals as well until I read that the motor is safe until 400whp. Is it truly safe to drive hard? For instance, I do autocross for fun, and a bit of track racing racing (not really, it's a thing called Tanacross up in Alaska, the closest thing to a road course we have. Think Top Gear test track.), and I would hate to pop the motor because I thought I was "safe".
> 
> My mod list really only includes the JDL kit, LSD, clutch kit, full BFI mounts all around, IE SRI, and maybe a short shift kit. I'd also do water/meth injection since we only get 90 octane in Alaska
> 
> ...


1st, call UM about racing at 400WHP on stock internals. Jeff is the source we're all quoting about the 400WHP limit. UM has turboed god only knows how many 2.5s that's why we trust his judgment.

We only get 90 here too. I'm getting tuned for FlexFuel because E85 solves that. If you can get E85, get tuned for FlexFuel.


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## Streetliight (Sep 5, 2011)

Rabbid Rally Rabbit said:


> 1st, call UM about racing at 400WHP on stock internals. Jeff is the source we're all quoting about the 400WHP limit. UM has turboed god only knows how many 2.5s that's why we trust his judgment.
> 
> We only get 90 here too. I'm getting tuned for FlexFuel because E85 solves that. If you can get E85, get tuned for FlexFuel.


I definitely wouldn't be right at 400whp, probably closer to the high 200's and low 300's. My ultimate goal is a 350whp DD/weekend warrior, and by the end result, I think I'd probably do internals anyways. I'd be on stock internals for probably a year or two, and racing AutoX once a month, so I'm thinking I'd be fine. thygreyt hasn't had any issues on his stock internals, and IIRC he's over ~300whp @12psi or something, with a W/M setup. That sounds amazing to me 

Also, I plan on calling up UM when I get back to the States, as I'll be having them do the software for sure. I'm sure they'll have plenty of pointers and advice and "do's" and "don't"s regarding the build. 

We don't get E85 up here either. You basically HAVE to run water/meth. Our only other options up here is to buy race gas by the barrel and mix it, but I'm really not wanting to do that for a DD, as it would lose it's DD-ness :laugh:

I was just curious as to whether or not you can run that sort of power (~300-350whp) on stock internals, and NOT have to worry about the motor every time you go WOT and hit boost.


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## Rabbid Rally Rabbit (May 5, 2013)

Streetliight said:


> I definitely wouldn't be right at 400whp, probably closer to the high 200's and low 300's. My ultimate goal is a 350whp DD/weekend warrior, and by the end result, I think I'd probably do internals anyways. I'd be on stock internals for probably a year or two, and racing AutoX once a month, so I'm thinking I'd be fine. thygreyt hasn't had any issues on his stock internals, and IIRC he's over ~300whp @12psi or something, with a W/M setup. That sounds amazing to me
> 
> Also, I plan on calling up UM when I get back to the States, as I'll be having them do the software for sure. I'm sure they'll have plenty of pointers and advice and "do's" and "don't"s regarding the build.
> 
> ...


What is it about living where a raw material is from and not being able to get the finished products they make with it? I've got active oil fields about 10 miles from my front door and refineries are within a day's drive, but I can't get 93.

We have a massive trucking industry around here --there's got to be trucks coming through with 93. The local car clubs here are all trying to get one of the filling stations to carry 93, but we just can't get one on board.

I'm currently dumping a few quarts of race fuel into my tank with every fill --so I feel your pain on the hassle of doing that to a DD.


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## Streetliight (Sep 5, 2011)

Rabbid Rally Rabbit said:


> What is it about living where a raw material is from and not being able to get the finished products they make with it? I've got active oil fields about 10 miles from my front door and refineries are within a day's drive, but I can't get 93.
> 
> We have a massive trucking industry around here --there's got to be trucks coming through with 93. The local car clubs here are all trying to get one of the filling stations to carry 93, but we just can't get one on board.
> 
> I'm currently dumping a few quarts of race fuel into my tank with every fill --so I feel your pain on the hassle of doing that to a DD.


Yeah, I know! People in Alaska can work the pipeline all day, and never see the best of their finished product. Oh, the irony...

I'm not currently doing that on my car, I don't know enough about the science behind it to bother messing with it, and I'm still on a stock ECU, so meh. 

I guess I'll have to call Jeff at UM and discuss my goals with him. I'm sure he'll have an answer. I appreciate the input from you though, for sure! :wave:


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## Forty-six and 2 (Jan 21, 2007)

Good to hear. I'm starting on a 2.5 swap into my mkI TT. Just curious if it would make more sense to source a low mileage motor, so that I can hold of on the internals portion of the build until later in the coming year.


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## Rabbid Rally Rabbit (May 5, 2013)

Forty-six and 2 said:


> Good to hear. I'm starting on a 2.5 swap into my mkI TT. Just curious if it would make more sense to source a low mileage motor, so that I can hold of on the internals portion of the build until later in the coming year.


It depends. If I were you I'd want to do the internals using a TTRS crankshaft, and that'll mean you need a new 8-bolt flywheel as opposed to the stock flywheel.

It only means you have to buy two flywheels and maybe two clutches. That's your call.


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## Forty-six and 2 (Jan 21, 2007)

Rabbid Rally Rabbit said:


> It depends. If I were you I'd want to do the internals using a TTRS crankshaft, and that'll mean you need a new 8-bolt flywheel as opposed to the stock flywheel.
> 
> It only means you have to buy two flywheels and maybe two clutches. That's your call.



When time comes to swap the internals, I will be plenty satisfied with an IE and JE combo. Cutting that $1500+ expense, to start with, would be nice. If the factory internals can handle 300-400hp for a year, that would allow me to have it up and running just after the year's end.


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## Rabbid Rally Rabbit (May 5, 2013)

Forty-six and 2 said:


> When time comes to swap the internals, I will be plenty satisfied with an IE and JE combo. Cutting that $1500+ expense, to start with, would be nice. If the factory internals can handle 300-400hp for a year, that would allow me to have it up and running just after the year's end.


Then get a low mileage late model 2.5L with a 2008 ECU and wiring harness. The newer motors are stronger but the 2008 ECU supports a MAF so it's more tunable. 

When you do internals, get IE rods and pistons w/ a TTRS crank unless you have a factory forged crank. I'm going to move to a TTRS crank myself because the 8-bolt fly is a better part anyways.


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## Forty-six and 2 (Jan 21, 2007)

Good to know. Thanks for the info.:beer: I'm will be looking for a good motor in a few weeks. Im pretty excited about this build and swap! It will be a first in the TT world.


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