K04...GT2X...GT28r...GTRS/GT28rs - Official Turbo Comparison

[mioStile]

I've just about had it...I've searched high and low, close and far. It's time to TURBO COMPARE on a new level. I have got to get the kinks (pros and cons of each turbo) out of my system (actually...into my system because I still don't understand them fully). So far, this is what I have---

K03 - Stock.

K04

Nice OEM replacement. Spools insanely fast and the torque makes you feel
like your riding a high hp car. Also, you get the all-beautiful turbo spike that some of us seek. However, a lot of hp is not made, making the existing kits a bit expensive for the relatively small power gains. However, the kits do allow you to run only a turbo and few supporting mods successfully/safely. DV is necessary, while an upgraded exhaust and fmic is recommended, but not needed. Further, a common claim is that, while the K04 produces much more power than Stage 1, and a bit more than Stage 1+ (in the form of smoother torque, though still with a lot of kick), people are left desiring more power after they've had it for a few months. This turbo can be tweaked a bit, and if the driver has the money to spend, tuners like MTM have produced K04's with supporting mods that are good for as much power as a BT setup. However...$$$$$$$$$.
K04 Dyno

MTM K04 Dyno


GT2X (BT)

It seems like a wolf in sheep's clothing. It is not quite as big as a GTRS/GT28rs, which means a spool time almost as quick as a K04. And on top of that, it's good for almost 300 crank hp. Power comes on near 3000 rpm, and lasts up until 6000rpm. Finally, as its torque comes on in full by 3,000 rpm, you get an intensified turbo spike of those in the K03 and K04s. It's perfect, right? WRONG - Evidently, it's only oil-cooled (not also water-cooled, like the GTRS), which means that it has a tendency to have a shortened life. This makes a turbo timer almost necessary. Somebody also has gone as far as to say that it is better for the turbo if you don't rev high for the last few miles before the car reaches its destination (I don't understand this at all). On top of that, it's not a ball-bearing turbo, but rather a thrust-bearing turbo (I don't understand what difference that makes [not from a hardware perspective, but from a symptom point of view]). Next, to my knowledge (I'd love someone to prove me wrong), there exists no solid software tuning for it.
ATP Dyno (a bit ambitious)


GT28r (BT)

This is the turbo provided by AWE Tuning. Again, to my knowledge, this differs from the GTRS/GT28rs in that the turbine is of smaller diameter than those present in the GTRS/GT28rs. Unlike the GT2X, it is both oil- and water-cooled, making use of newer technology and prolonging life. Now, while the housing is quite a bit larger than the GT2X, this turbo takes quite a bit more time to spool. Now, while it produces similar hp/tq numbers as the GT2X (maybe a little more), significant hp does not kick in until ~3700 rpm. Torque does not kick in until 3500 to 3700 rpm, as well. However, the power/tq (especially tq) deliverance is much smoother, lasting until 5500-6000 rpm. While this corrects the lack of high-end power inherent in the K03 and K04s, it requires you to rev your car much higher...which is flat out not good for your engine (unless it has been upgraded with stronger internals). Also, with this turbo, it now becomes absolutely necessary to run an upgraded catback exhaust and highly-recommended fmic if you want to see the numbers previously-described...safely. A HFC/Test pipe is not required, but will help gain some horsepower. Keep in mind, however, that with a HFC or test pipe, more pollutants will enter the environment and your car will not pass smog tests. Also, some people have claimed that, despite the $3,695 price tag, the kit is not well-engineered (I don't understand why).
Dyno


GTRS/GT28rs

Highly-revered, and supported by great software. The full kit, with supporting modifications (sold by EuroCode Tuning), produces octane-dependent power of up to 400 crank hp. However, with premium pump gas and a slew of supporting mods, you will most likely see ~350 hp range. Torque exists at ~320-340 lb/ft based on dynos I've seen recently. While this kit contains the same sized housing as the GT28r, it has a larger turbine wheel, which allows for more flow, which leads more efficiency, and therefore, more hp. However, as it is larger, it takes even more time to spool, resulting in useable power only after 3700 to 4000 rpm. While I've never ridden in/driven a BT A4, higher-revving in this kit is required to utilize the power available. Understandably, this puts a lot of pressure on the engine, creating the potential for more problems. A DV, FMIC, and upgraded exhaust system become a necessity by this point. While a GTRS eliminator kit is another popular option, low boost and relatively no timing is required to keep EGT's down. So, don't expect to see more than 230 hp/260 tq (I assume this is crank hp/tq, but am not entirely clear. This info was gleaned from a dyno performed by EcodeTuning here - http://www.ecodetuning.com/gallery/D...GTRS_91oct.jpg). However, this kit is incredibly "tweakable," and many people see many different numbers based on what supporting modifications they use.
Dyno


GT2871r

This turbo kit is yet another variation of the GT28 series. While the housing is still the same size, the turbine wheel is a bit larger than the GTRS/GT28rs, allowing for yet more flow, more efficiency, and therefore more power. If the entire kit is purchased, you are privy to an octane dependent 450hp at the crank. However, the cons of this turbo, aside from the added stress on engine internals, is that it takes even longer to spool, keeping significant power from hitting until 4000-4200 rpm. This power holds (with only slight decreases in hp and tq) until 7000 - 7500 rpm. Similar to the GTRS/GT28rs, a dv, upgraded exhaust, exhaust manifold, fmic, and turbo inlet pipe are needed to run this kit safely, and actually achieve the power numbers quoted by the kit. Again, similar to the GTRS/GT28rs, there is an eliminator kit available for this setup. And, as for the same reasons stated above for the GTRS/GT28rs eliminator setup, you will only see 300 crank hp / 305 tq.
Dyno


Notes - Now, for my questions - I wanted to go with the GT2X, but after doing research, it became clear that it was not reliable. You mean to tell me that there is no turbocharger that spools fast, has usable power down low (aka between 2000 and 6000 rpm), and is both oil- and water-cooled for reliability. Then I'd say...GT28r - However, it seems to take a bit long to spool, and I'm afraid it takes away my beloved turbo spike (I'm not a fan of overly smooth power in a turbo car). Still, for some reason, people seem to say that the GT28r kit is not the best. Why is this?

[Jet Jockey]

One big problem with your little exercise...

Different dynos and different conditions mean all the data cannot be compared!

[A4ringedONE8T]

The 28R GIAC kit for sure has a torque spike, this is what has grenaded the motors with this setup. With the GTRS and larger turbo's the power is more gradual and therefore puts less stress on the internals. If you think a GTRS doesnt have power till 6k your incorrect, a GTRS will have you in the seat and be on its way by 4k rpm, a 71R a few hundred later. After you have driven a GTRS/28RS/... car, the low RPM spike is crap and sucks more than you think its good right now. GTRS power is much more usable than any K03/K04 setup. Those turbo's are so off/on that its ridiculous, when you want a bit of power you cant, you get the whole thing. A big turbo is much more controlable, when you want to granny drive you can and stay clear of boost, when you want power or need it, its there on a complete different level. If you are trying to talk yourself into a smaller turbo because you like the spike you are nuts. Drive a BT car, afterwards K03/K04 power and torque spike is hardly something to desire!!!

[martini]

it looks like you have gtrs and gt28rs as almost the same thing.... theyre very different

[Tgr_Clw]

Actually yeah. While the tq spike of a K04 setup is fun, it does get a tad annoying.

[Greg@DTH]

it looks like you have gtrs and gt28rs as almost the same thing.... theyre very different

Not really...

[QuattroRocket]

To be more accurate there are two GTRS turbo setups available through E-Code tuning in eliminator setups, allowing for a mostly stock mounting option and a stock exhaust manifold, basically a bolt on upgrade.

Then there are the top mount Garrett GT28 series turbos which require different exhaust manifolds and are more of a custom option. Some serious modders have gone to GT30 series Garrett turbos for even more power potential.

And everything pretty much from the K04 up will require a new upgraded clutch.

[absolutegtr]

I find this thread EXTREMLY interesting...

I am facing the EXACT dilema. I dont know which setup to go with, I like teh idea of the K04 spike....but then again, why not go big or go home?

But then again, I do ALOT (if not all) city driving, so the K04 low end torque would be ideal....Plus relaibility is a MAJOR if not THE concern

I dunno, lol

[AudiA4_20T]

I find this thread EXTREMLY interesting...

I am facing the EXACT dilema. I dont know which setup to go with, I like teh idea of the K04 spike....but then again, why not go big or go home?

But then again, I do ALOT (if not all) city driving, so the K04 low end torque would be ideal....Plus relaibility is a MAJOR if not THE concern

I dunno, lol

honestly if your going BT and know your going to want it big, build your engine first

[martini]

Not really...

when you look at the supporting hardware you need to run a GT28RS vs a GTRS they are obviously different.

If someone reads this and heads to the store and buys a GT28RS they are going to be looking at an entirely different problem then if they bought a GTRS. of course performance wise they are not that different...but the probably shouldnt be grouped together for a thread like this..

thats all i was saying

[Greg@DTH]

Why would they not...the GT28Rs is found on the APR setup and their is an AWE option available.

Supporting hardware with the REVO software is pretty much the same.

440 or 430cc injectors, a FMIC, testpipe or HFC, exhaust and a clutch to hold 500TQ.

[Groove1797]

octane should be noted

[doublezero30]

i too wonder many things about turbo upgrades. one of the being if the gt28rs kit seen at http://www.ecodetuning.com/shop/cart..._detail&p=1362 needs a new manifold or if you could bolt that up to the stock manifold?

[Greg@DTH]

i too wonder many things about turbo upgrades. one of the being if the gt28rs kit seen at http://www.ecodetuning.com/shop/cart..._detail&p=1362 needs a new manifold or if you could bolt that up to the stock manifold?

That link you posted does not bolt up to the stock manifold, it come with it's own manifold. Some people consider that hardware obsolete because you can make the same power with a GTRS Eliminator (which looks more OEM and the programming is more refined).

Give me a second and I will post up pictures of the link you posted installed on my car.

[Greg@DTH]

[dirtybrd]

A red x?

[Greg@DTH]

A red x?

Ill rehost it, comcast must not like hotlinking.

[doublezero30]

That link you posted does not bolt up to the stock manifold, it come with it's own manifold. Some people consider that hardware obsolete because you can make the same power with a GTRS Eliminator (which looks more OEM and the programming is more refined).

Give me a second and I will post up pictures of the link you posted installed on my car.

you know, now i kind of feel dumb. haha...just looked at the link again and it clearly says it comes with a turbo manifold. how much would a kit like that cost to have installed anyway? obviously it would vary by shop, but an estimate would be good enough...since ive got absolutely no clue.

[Greg@DTH]

$800 labor would be fair

[mioStile]

One big problem with your little exercise...

Different dynos and different conditions mean all the data cannot be compared!

I apologize for angering/misleading anyone. While I am thoroughly familiar with that fact, I found it a bit difficult to find a dyno that had tested the same a4 with each of the setups I discussed on the same day with the same ambient conditions. This thread is meant to act as a guideline for people beginning their search into the world of upgraded turbos.

Actually yeah. While the tq spike of a K04 setup is fun, it does get a tad annoying.

I could definitely understand that it might if it is a constant facet of the K04's performance. Is it really hard to keep the torque spike from occurring by shifting early? Or, is it just something that can't be kept from occurring because of the physical characteristics of the turbo?

To be more accurate there are two GTRS turbo setups available through E-Code tuning in eliminator setups, allowing for a mostly stock mounting option and a stock exhaust manifold, basically a bolt on upgrade.

Then there are the top mount Garrett GT28 series turbos which require different exhaust manifolds and are more of a custom option. Some serious modders have gone to GT30 series Garrett turbos for even more power potential.

And everything pretty much from the K04 up will require a new upgraded clutch.

Solid point. However, I was under the impression that these two turbos (gtrs and gt28rs) performed very similarly? Am I correct or no?

octane should be noted

This is also an awesome point that I didn't address. I know octane relates directly with timing. Would you mind expanding upon how octane levels affect the different turbo sizes?

That link you posted does not bolt up to the stock manifold, it come with it's own manifold. Some people consider that hardware obsolete because you can make the same power with a GTRS Eliminator (which looks more OEM and the programming is more refined).

Give me a second and I will post up pictures of the link you posted installed on my car.

THIS IS HUGE! 400hpA4 - would you mind expanding upon why some people consider the gtrs eliminator to be less obsolete when compared to the gt28rs? Do they perform the same (feel the same)? Does one require the addition of an HFC/test pipe and the other doesn't? Which one produces more usable power? Does the gt28rs kill your transmission if you're running a tip because of the torque compared to the "smoother" delivery of the gtrs?

[Greg@DTH]

The reasons the ATP full GT28Rs setup you have posted is considered obsolete are as follows:

1.) Price...you are looking at $2,200 for a turbo, oil and coolant lines, a exaust manifold, a downpipe and a 3" MAF housing with cone air filter.

2.) The MAF housing is worthless, it sits 6 inches off of the turbo inlet and will NEVER produce a accurate reading for programming.

3.) The downpipe...does not mate up to OEM or aftermatket exhaust without modification

4.) The exhaust manifold...more of a bitch to bolt up that the upgraded eliminator manifold.

The maximum power you will see out of this setup on a B6 1.8T is 335AWHP. This is how much I made on my car and how much EuroCode made on another customers car.

The GTRS will bolt up to the OEM manifold or a upgraded ATP manifold. You can retain all of your emissions stuff

A OEM cat or a aftermarket test pipe will work with it.

You can retain your OEM MAF and stcok airbox

It makes 335AWHP just like the full GT28RS

The CHRA, turbine and compressor wheels are the same as the full GT28RS, good things come in small packages.

[Greg@DTH]

This is the setup I recommend

http://www.ecodetuning.com/shop/cart...t_detail&p=504 and this http://www.ecodetuning.com/shop/cart...relate=1&p=466

Ask for the Delphi 440cc injectors.

[osofast10]

this is a great post... thanks

[mioStile]

this is a great post... thanks

Thanks dude - I really hope it helps! A special thanks to GREG@DTH for all his help, and for everybody else who posted up.

[LavaSurfer]

So if I understand correctly, does the APR stage 3 kit come with the GT28RS turbo that you speak of? From the pictures I found, it doesn't look like a GTRS.

I was under the idea that the APR kit came with the "full" size turbo that might edge out the GTRS kit as far as overall flow. So that's why it costs a little more and it makes pretty high numbers (300whp range on 93)with a "safe" plug and play tune.

[eddier]

This is the setup I recommend

http://www.ecodetuning.com/shop/cart...t_detail&p=504 and this http://www.ecodetuning.com/shop/cart...relate=1&p=466

Ask for the Delphi 440cc injectors.

what about that setup w/ a tip tranny? :)

[doublezero30]

wait so if the GTRS bolts up to the stock manifold, and i already have, intercooler, exhaust, DV...ide need a clutch and injectors (and obviously software)...could i just buy the GTRS hardware kit? or does that not come with the turbo?

[absolutegtr]

Honestly, what setup is the all our best/cheapest/easiest to install?

If I had the money I would go the APR route...since the tune is plug and play...which turbo can I go to get that "plug and play" SAFE tune!

Is there anybody here that has a BT A4 as their daily driver (I drive over 400 miles a week)

[Spinnetti]

Honestly, what setup is the all our best/cheapest/easiest to install?

If I had the money I would go the APR route...since the tune is plug and play...which turbo can I go to get that "plug and play" SAFE tune!

Is there anybody here that has a BT A4 as their daily driver (I drive over 400 miles a week)

I have the eurocode/atp GT28RS that 400hp linked you to, setup with all the supporting mods including ER Comp FMIC, APR exhaust, test pipe, ceramic 6 button clutch and LWFW. I take the kids to school every day in it. Drivability is fine, but I had to learn how to drive all over as its weaker down low, and the LWFW makes stop and go traffic a chore. Make sure you have a good shop, and I'd recommend having a turbo support fabbed up = the "kit" (more an assemblage of parts) doesn't have one. It will probably cost more than you expect to have installed and done right too. Doing all the work myself except the clutch install, I have about $6000 in it (better to buy a used S4 prolly). That said, its pretty smooth and the REVO software is the best I've experienced (Started with APR Stage 1, 1+,2+.... and had problems with every single part I got from APR -exhaust is broken now)

[9744RR]

Honestly, what setup is the all our best/cheapest/easiest to install?

If I had the money I would go the APR route...since the tune is plug and play...which turbo can I go to get that "plug and play" SAFE tune!

Is there anybody here that has a BT A4 as their daily driver (I drive over 400 miles a week)

My wife's drives the family A4 with a GTRS kit daily.

[9744RR]

what about that setup w/ a tip tranny? :)

Tip tranny and the GTRS is fine. Just don't launch the car.

[absolutegtr]

/\ So the GTRS Eliminator is the 2871r right?

[jcs4]

/\ So the GTRS Eliminator is the 2871r right?

NO..its a 2860 w/ a custom turbine housing to match the stock manifold. The eliminators come in both a 2860 (GTRS) or 2871 variant.

[absolutegtr]

NO..its a 2860 w/ a custom turbine housing to match the stock manifold. The eliminators come in both a 2860 (GTRS) or 2871 variant.

Ok, but the more "common" variant used for our A4's are the 2871....right?

[A4ringedONE8T]

/\ So the GTRS Eliminator is the 2871r right?

As said above, a GTRS is closest to a GT28RS but physically is a bit smaller. A 71R Elim is the same as a GTRS except it has a 71mm turbine wheel in the same housing

[A4ringedONE8T]

Ok, but the more "common" variant used for our A4's are the 2871....right?

No, a GT28RS (AKA Disco Potato AKA GT2860R) is the most commonly used. This is the basis for the GTRS as well as the turbo thats used with APR 3+

[1.8quattro]

Honestly, what setup is the all our best/cheapest/easiest to install?

If I had the money I would go the APR route...since the tune is plug and play...which turbo can I go to get that "plug and play" SAFE tune!

Is there anybody here that has a BT A4 as their daily driver (I drive over 400 miles a week)

Mine is a daily driver, I do a good 300+ mi a week. The big difference really is getting used to the clutch in traffic (I have the stock flywheel though), but other than that it's perfectly drivable.

[mioStile]

So if I understand correctly, does the APR stage 3 kit come with the GT28RS turbo that you speak of? From the pictures I found, it doesn't look like a GTRS.

I was under the idea that the APR kit came with the "full" size turbo that might edge out the GTRS kit as far as overall flow. So that's why it costs a little more and it makes pretty high numbers (300whp range on 93)with a "safe" plug and play tune.

The APR Stage 3+ kit does come with the GT28rs and it does come with the best exhaust manifold on the market, as well as a safe software program. However, it is a bit conservative in power delivery---REVO will be a bit more aggressive. Also, while it does produce the highest, safest amount of hp, the GTRS is more than capable of reaching the same numbers.

wait so if the GTRS bolts up to the stock manifold, and i already have, intercooler, exhaust, DV...ide need a clutch and injectors (and obviously software)...could i just buy the GTRS hardware kit? or does that not come with the turbo?

The hardware kit includes the actual Garrett GTRS turbocharger, as well as necessary gaskets and oil/water coolant lines. When you're ordering, I'd run your current parts by Eurocode just to make sure you've got everything you need. Keep in mind, the hardware kit does not include injectors, spark plugs, or software.

[AudiA4_20T]

I'm going to have to disagree with Greg on this, although the GTRS has been proven to make the most power out of the GT28 series turbos, theoretically it should not.

A full turbo setup should allow for a quicker spool and more top end power becuase flow is restricted with the GTRS setups on the inlet and stock manifold outlet. A full turbo setup would allow for more flow which means more power and a quicker spool because the turbo is breathing easier.

So, although Greg is right, I feel like it all depends on the tune and the GTRS tune seems to be perfectly done. However, this is why the APR Stage 3+ spools quicker and has more power

[9744RR]

The APR Stage 3+ kit does come with the GT28rs and it does come with the best exhaust manifold on the market, as well as a safe software program. However, it is a bit conservative in power delivery---REVO will be a bit more aggressive. Also, while it does produce the highest, safest amount of hp, the GTRS is more than capable of reaching the same numbers.



The hardware kit includes the actual Garrett GTRS turbocharger, as well as necessary gaskets and oil/water coolant lines. When you're ordering, I'd run your current parts by Eurocode just to make sure you've got everything you need. Keep in mind, the hardware kit does not include injectors, spark plugs, or software.

Correct. You can also make a GTRS programmed with REVO very safe and conservative by turning down the boost and timing with an SPS3. Or, you can make it very aggressive by doing the opposite.