Blew a turbo, turbo recommendations?

[Nemesis2747]

So I'm 90% sure my passenger side turbo called it a day. I've had the car almost 2 years, bought with 136,000 an intake, cat back, and 300hp tune. Its at 151,000 and just finished changing the oil. After a highway pull the turbo in boost sounds very similar to the "dentist drill" i read about in turbo death posts. I'm taking it to a shop in a week or so for a final word. But this is why i bought the car in the first place. I want to replace those K03s and put some worthy turbos on it. Anyone have recommendations? I don't expect to pay to do rods so I'm keeping the stock block. I was looking at Frankenturbos.

[happy2B5]

BW K04. To get the most out of any turbo upgrade you will need a new tune and supporting fueling component upgrades. You a 6mt or tip?

[4rings2turbos]

F21 or K04 are your options on stock bottom end, recommend not touching meth or E85 without it. Both have run successfully. Correct installation means everything when it comes to longevity so be sure to get that right.

Turbo lady sings LOUD when she does. You'll know 100% when they give up the ghost.

[happy2B5]

I think there are plenty of larger framed turbos (RS6, RS6-R, k24, tial 605's, etc) safely ran on stock bottom end for thousands of miles in the B5 world. Would expect the same results and succes here. Heck, I had a B5 S4 with stock engine and RS6-R turbos, tune and fueling, meth for 20k+ miles and K04 prior to them. Engine was healthy. 440whp/475wtq on the RS6-R setup. It really comes down to a safe and reliable tune with proper supporting mods and a well maintained car imo.

[Nemesis2747]

Wow, thanks for the input so far. i dont really have E85 where im located. So 93 is what im pumping. Its a 2003 6 speed 2.7, im doing the clutch and flywheel at the same time. Thinking single mass and an RS4 clutch. Hoping to throw in Meth injection but most likely to happen after the turbos go in. And who makes a tune? Car was flashed with GIAC but theres gotta be something more custom for big turbos. Downpipes are on the list, the car already has a 320LPH high flow fuel pump from when the original one died. Injectors? I don't know. And the sound that comes out of that side of the engine now.... makes me scared to go into boost. But sounds like a bad ass super charger. I bet the car is in good shape, dealer records going back all the way. Just have to keep in mind the timing belt in 20K or so.

[4rings2turbos]

I suppose when I think of running a bigger turbo I think of using it for what it is and maximizing it. I think 440/475 is right in the upper end but still efficiency of an F21/K04, but 605/RS6, ect can push much more and to reign them in or to retard the torque onset would either be wasted money or even more laggy than they already are compared to a K04 and the K04 housed F21. Technically you can run any BT on a stock block but you can't use it to it's potential or even reach efficiency without it being dangerous. All that said I don't disagree with you that it can be done, or for a long time. For the cost of rods it's a worthwhile for being safe than sorry and I would consider it a supporting mod.

Only my opinion with my own research without personal experience so I'll be the first to say take the above with a grain of salt. Heck, I'm doing rods on my K04 build.

One thing I do 100% agree with you on is it all comes down to tune.

[happy2B5]

I agree that doing rods simply makes sense and opens up the turbos (larger) to true potential. The power numbers on my old car were on CA91.

OP, it really depends on what your goals are. My personal opininion is a healthy "plain jane" K04 setup is great. Quick spool, tried and true reliability, fun and fast enough to know you upgraded for a long time. Keep it simple. You can make good power especially on 93 with little concern of damage. GIAC tuned stage 3 K04 has been around for a long time. And yes, you likely will want 60 lb injectors, maybe convert to a Hitachi maf (if not already), upgraded side mount ics, open up your exhaust. Popular route is 3" dp's. But, for a K04 setup, a full 2.5" setup turbo back is enough flow.

[4rings2turbos]

a full 2.5" setup turbo back is enough flow.

Thank you for saying this. SOMEone (you know who you are) keeps telling me I need to go bigger with my exhaust.

[happy2B5]

And please, do not think you need some fancy, poorly made tubular manifolds. Only reason I put in RS6-R at the time was because car I purchased has a set of vast log manifolds. They cracked at about every joint. What a mess. The stock manifolds are more than fine. Yes the inside runners can fail, but I have seen far less reported issues compared to poorly made after market manifolds. Luckily I had the original ones and they went back on during the new turbo install at recommendation of jhm

[4rings2turbos]

This kind of first hand experience is great to know.

You see a lot of budget builds and I see value in that. But this being my daily and wanting to keep it for a long, long time and reliability and longevity being a big factor means I'm sticking with K03 much longer than I might have and doing it the OG way with all the supporting mods. All the info of what's worth it and what's wasted is hard to wade through though.

[SteelyS6]

Bit off topic , but I want to go stage 3 next year and I have an APB block with 190,000kms sitting here doing nothing. I would like to build it over the winter and possibly go as far as rods. Can this APB be dropped into a 2004 allroad with a few modifications? I know valve covers would need to be switched for push down coils, but I would be powdercoating them anyways. My thoughts on turbos would be F21's or JHM RS6-R unfortunately only on 91 octane as thats all thats available around these parts.

[Nemesis2747]

While i would love a car that rips my face off when i floor it, it isnt very practical for me. Most of my driving is sitting in traffic. Im taking into consideration the price of the upgrades. Does anyone know if the engine HAS to come out to do rods? Or can everything be removed with the engine still in place? Ive heard the crankshaft and pistons can take a beating but the connecting rods shatter with detonation. I agree that undertuning a big turbo sounds like a waste of money, but putting one on then doing rods later might be a more realistic option for me. And i was debating some tubular manifolds. Ive heard the welding on the cheap ones breaks off and murders turbos. If stock is enough, stock it is. And when u guys say turbo back exhaust, is that high flow precats and highflow cats with 2.5 piping? I was thinking 3 in down pipes (no cat) and a highflow main cat and 3 Inches all the way to the Muffler. I leave my house at 5am everyday so i might not want 3in.

Goals are a fast sleeper/ daily driver. And sometimes late at night i find some exotics on the highways. The last time i tried to keep up with a Ferrari i might as well have been standing still. Reliable but powerful. 450-500 HP sounds sweet. North of 500 would be awesome but having to do rods and i bet the car isnt the most reliable with that much power keeps me away. But who makes your tunes?

[4rings2turbos]

APB/manual BEL are more similar than auto BEL. VCs and appropriate tune/I think slightly modified harness is needed but super duper easy and doable.

For daily I went back and forth K04 spool/reliability or BT top end. In the end I decided unequivocally K04. I drove an F21 on E85 (torque onset retarded due to stock rods (in the end it killed the block anyway)) and I was severely disappointed with the lag. It made me appreciate my K03s even more and made me decide I'll do whatever I can to keep the spool in the low RPM range. I agree that a K04 sized turbo is super nice for a street only daily. It's quick for sure, and you'll be hanging with the exotics if you build it and tune it right.

Honestly if K03s were cheaper I'd just stick with them for a while. Boost them to everything they could take, longevity not a concern with E85. I've seen E85 K03s in 400whp/tq range :O now imagine having that punch around town at such low RPMs. Big fun factor. (until 4th gear)

[Bordom]

APB/manual BEL are more similar than auto BEL. VCs and appropriate tune/I think slightly modified harness is needed but super duper easy and doable.

For daily I went back and forth K04 spool/reliability or BT top end. In the end I decided unequivocally K04. I drove an F21 on E85 (torque onset retarded due to stock rods (in the end it killed the block anyway)) and I was severely disappointed with the lag. It made me appreciate my K03s even more and made me decide I'll do whatever I can to keep the spool in the low RPM range. I agree that a K04 sized turbo is super nice for a street only daily. It's quick for sure, and you'll be hanging with the exotics if you build it and tune it right.

Honestly if K03s were cheaper I'd just stick with them for a while. Boost them to everything they could take, longevity not a concern with E85. I've seen E85 K03s in 400whp/tq range :O now imagine having that punch around town at such low RPMs. Big fun factor. (until 4th gear)

I heard there was a 400whp K03 car somewhere. Have any details?

Everything graciously mispelled by Android

[Royal769sr]

So. Where to start? Why is it that everyone thinks just because you put a bigger turbo on you Have to max it out? Your going to make more power anyway but maybe running at max would increase the chances of killing the turbo faster. I really am not sure how much harder I "can" push my Rs6s but I'm not sure I'm ready to cross that limit. Torque is torque so can tune your car to have similar early torque as a ko4 and not blow the motor. Similar I said not exactly.

Some turbos are capable of running 50psi. How many of us push past 30? Not running at max is not a waste if it's still more than a ko4 at max plus meth.

Rods would be nice but I would have to upgrade any bolts down there too. And I'm pretty sure no way you can change the rods out in car still. Plus why on Earth would you want to put yourself through that? You would need a lift and I think getting a engine host is easier then finding lift... EVEN IF it was possible.

And why is longevity not a concern with e85? Plus who wants too keep removing the motor for constantly blowing your turbos?

Sent from my SM-G930T using Tapatalk

[Royal769sr]

Also putting an APB in is super easy and very obvious when you have the 2 together what needs to change over

Sent from my SM-G930T using Tapatalk

[4rings2turbos]

So. Where to start? Why is it that everyone thinks just because you put a bigger turbo on you Have to max it out?

Because turbos have an efficiency range and a minimum boost. You don't have to max it out but who's paying more money for a turbo that a smaller turbo can do?

Longevity for a turbo is not a concern with E85 because boost gets turned down and timing get 'turned up'.

An RS6 can be similar to K04 in boost onset but for me in particular I'm not interested in giving up even 200rpm. It makes such a difference in driveability and doesn't bode well for wanting to punch it around town without having to wind it up constantly.

Want to def say there's many ways to stage 3 a 2.7T. It's all in the objective and personal preference.

[4rings2turbos]

Plus who wants too keep removing the motor for constantly blowing your turbos?

This might possibly be in reference to my maxed out K03 comment. I in mind I would crank them up to whatever the absolute max boost is before diminishing return and if they were super cheap and lasted at least 6 or 7k miles that would be more than a year's worth of miles for me.

But the reality is that new K03s are like 8 or 900, not 3 or 4. So not likely I will be doing that. But probably will run them at like 28psi after I buy my K04s. See how long they last.

[Royal769sr]

E85 allows you to turn the timing up while keeping boost high as well. Or you can just turn up timing if your fuel system cannot handle the extra load. Also you mentioned efficiency. Doubtful 28psi falls in k03 efficiency range but I don't know. Sounds like a bunch of hot air (pun intended). But why work the turbo harder to peak at the power a bigger turbo can do the "whole" Rev range comfortably? You are right that there are a ton of ways to do this and I like the friendly competition. Helps us when we come across the unsuspecting Evo :)

Not trying to get in an argument just my interpretation is all

Sent from my SM-G930T using Tapatalk

[LINDW4LL]

OP, I'd look into 3 options depending on what the majority of your driving consists of. All will run you in the ballpark of ~ $1,800, and all can be safely run to their potential on 93 octane with the stock rods.

BWK04s
Frankenturbo F21s
SRM K24 RS6

Can't go wrong with K04s. Being an OEM turbo for the RS4, they're known for reliability and have a very quick spool. For torque around town, they can not be beat. They have a huge punch in the low-mid range and are optimal IMO if most of your driving is racing around the streets of NYC or in traffic. (390-400whp)

The F21s are still K04 framed turbos but with larger wheels. Thus they're a bit slower to spool but have better top end. (420?whp)

The SRMs have a larger RS6-K04 based exhaust housing and wheel, and spool the slowest of the three, with it really hitting max boost around 4,000, but have much better top end. You can see like 450-475whp (ballpark) with these on 93.

---

Also, here are two graphs showing the early torque advantage of the BWK04s (as compared to F21s). The K04 kicks ass in the low-mid range.

[ChicagosPhantom]

, open up your exhaust. Popular route is 3" dp's. But, for a K04 setup, a full 2.5" setup turbo back is enough flow.

Well 2.5">2" (stock)
So Ya go bigger or go home! lol

Thank you for saying this. SOMEone (you know who you are) keeps telling me I need to go bigger with my exhaust.

Let's find that "someone" and steal his DS screaming turbo!He deserves it,such a bastard!

[ChicagosPhantom]

While i would love a car that rips my face off when i floor it, it isnt very practical for me. Most of my driving is sitting in traffic. Im taking into consideration the price of the upgrades. Does anyone know if the engine HAS to come out to do rods? Or can everything be removed with the engine still in place? Ive heard the crankshaft and pistons can take a beating but the connecting rods shatter with detonation. I agree that undertuning a big turbo sounds like a waste of money, but putting one on then doing rods later might be a more realistic option for me. And i was debating some tubular manifolds. Ive heard the welding on the cheap ones breaks off and murders turbos. If stock is enough, stock it is. And when u guys say turbo back exhaust, is that high flow precats and highflow cats with 2.5 piping? I was thinking 3 in down pipes (no cat) and a highflow main cat and 3 Inches all the way to the Muffler. I leave my house at 5am everyday so i might not want 3in.

Goals are a fast sleeper/ daily driver. And sometimes late at night i find some exotics on the highways. The last time i tried to keep up with a Ferrari i might as well have been standing still. Reliable but powerful. 450-500 HP sounds sweet. North of 500 would be awesome but having to do rods and i bet the car isnt the most reliable with that much power keeps me away. But who makes your tunes?

Turbo-back means full exhaust from the turbos to the tips.

Good old saying "picture is worth a thousand words" is so strong in this one:
uploadfromtaptalk1464928917590.jpg
There's ton of variations in each option,depending on how many mufflers,resonator and what type,crossover pipes....

[ChicagosPhantom]

Nice little info in this thread,C5 section looks a bit more alive,finally!
It's cool to see different opinions and who appreciate what....traffic zippers or highway rockets.haha
I'll think I'll have both eventually,one sooner then other,just to figure witch one gets what future life.

[doug97gxe]

Wow, thanks for the input so far. i dont really have E85 where im located. So 93 is what im pumping. Its a 2003 6 speed 2.7, im doing the clutch and flywheel at the same time. Thinking single mass and an RS4 clutch. Hoping to throw in Meth injection but most likely to happen after the turbos go in. And who makes a tune? Car was flashed with GIAC but theres gotta be something more custom for big turbos. Downpipes are on the list, the car already has a 320LPH high flow fuel pump from when the original one died. Injectors? I don't know. And the sound that comes out of that side of the engine now.... makes me scared to go into boost. But sounds like a bad ass super charger. I bet the car is in good shape, dealer records going back all the way. Just have to keep in mind the timing belt in 20K or so.

A lot of websites are outdated .. not sure where in NYC you are but tons of E85 Stations in Bronx, Queens, Brooklyn and Yonkers.. even in Greenwich CT http://www.ethanolretailer.com/flex-fuel-station-finder

[happy2B5]

Don't get me wrong, I loved my 3" dp to 3.5" single exhaust on my B5 2.7. Dare I say, it was a better exhaust note than my v8. And, I don't think you will be hurting yourself by using 3" dps with K04's but its not 100% necessary. A well made full 2.5" system will suffice. If you need cats for emissions testing or morals, then just do one per bank in the main cat location downstream. My 2.5" system was the techtonics tuning true dual. Nice system.

Had a buddy with a tial allroad, full 3" dp to 3" exhaust piping. I didn't love the way it sounded. Too much. It needed at least mid reonators in place.

[4rings2turbos]

I would crank them up to whatever the absolute max boost is before diminishing return...but probably will run them at like 28psi after I buy my K04s. See how long they last.

Two different situations here, 28psi is definitely beyond the point of diminishing return and I would only do that in an attempt to destroy them when I'm ready for stage 3, i.e. parts in hand. All just for kicks.

Helps us when we come across the unsuspecting Evo :)

YES this is really what it's about isn't it? Crushing other's dreams on the street? Haha

Not trying to get in an argument just my interpretation is all

No this is great, everyone in here is doing a really nice job hashing it out and I like the points you're coming across with. Definitely not black and white and comes down to priority.

[4rings2turbos]

Well 2.5">2" (stock)
So Ya go bigger or go home! lol


Let's find that "someone" and steal his DS screaming turbo!He deserves it,such a bastard!

Get outta here. I'm gonna put my heat shields back on. That should buy me two or three days to catch you in the act haha.

[JTown77]

Those of us now 10's of thousands invested over any potential return are very interested in performing this exact same procedure in the future. From my most recent experiences, a turbo back exhaust will cost you as much or more money than a turbo setup. And DP options suck, it's billy boat or nothing essentially. And do the timing belt now! Don't wait as for the money your throwing at the car a couple of hundred more is nothing but good insurance.

[Nemesis2747]

Just did a some research and i confirmed my fuel pump can take E85 and a gas station that pumps E85 somewhat nearby. I can buy a regulator or have one installed. If i go the E85 way, i can ditch the water/meth? And where can i get a tune for twin K04s/RS-6RSes/F21s and E85? I understand that i get less mileage but you can advance timing and spool turbos faster. Can i have 2 maps on my ECU? 93/91 and E85?

[4rings2turbos]

You won't necessarily lose mileage. More than one tuner has been able to math MPGs on E85. You don't HAVE to ditch the w/m but you definitely can if you want to.

[brokenwrench]

Can i have 2 maps on my ECU? 93/91 and E85?

I'm by no means an expert on the Motronic ECU, but in theory it should be able to accommodate a wide range of octane levels in the fuel, assuming it's possible to open up the spark timing enough. All ECU's I've worked with typically try to advance the timing to the point of knock, at which point it then sweeps the timing a little retarded, then sweeps advanced again and so on until the ECU "learns" where the timing limits are based on the octane of the fuel. The early 2000's GM flex-fuel vehicles had a sensor in the fuel line which would measure the octane level of the fuel before it enters the engine, kind of in anticipation of the timing maps that would be needed, but the ECU would still sweep back and forth to accommodate the specific conditions at the time of combustion. But those were also NA engines, not sure how the Motronic handles boost + octane. As far as whether the Motronic ECU can accommodate multiple maps, I have no idea but most likely not.

This, of course, is also all based on the assumption the C5 2.7t uses narrow-band O2 sensors....



Sorry to waste anyone's time, this was probably a worthless post

[Nemesis2747]

As far as whether the Motronic ECU can accommodate multiple maps, I have no idea but most likely not.

I found GIAC will tune for K04s and E85 and have "on the go" program switching for E85 and pump gas. And APR has mode switching too. The GIAC E85 and K04s say its for the B5 S4, i know nothing about this but isn't the 2.7 A6 very similar?

[happy2B5]

Very similar. It should not be too big an issue to have 2 different switchable maps for fueling

[Nemesis2747]

Based on the information i can find through google, and here I've come to this: K04s are RELIABLE, F21 Franken turbos have slightly less spool but more power high into the rev range, RS6-RSes have great power after 4k rpm and boost for days. Tials are for rich people. Is this correct? Im leaning towards JHM's chopped up rs6-rs turbos. But Im debating BW k04 reliability vs more power. I would like to max out the stock block somewhere around 450 wheel horse on pump gas 93 and who knows on E85. I also wouldn't like to have a turbo explode on me next year on my way to work.

[JTown77]

Based on the information i can find through google, and here I've come to this: K04s are RELIABLE, F21 Franken turbos have slightly less spool but more power high into the rev range, RS6-RSes have great power after 4k rpm and boost for days. Tials are for rich people. Is this correct? Im leaning towards JHM's chopped up rs6-rs turbos. But Im debating BW k04 reliability vs more power. I would like to max out the stock block somewhere around 450 wheel horse on pump gas 93 and who knows on E85. I also wouldn't like to have a turbo explode on me next year on my way to work.

I think we have done the same reading. I am leaning towards the K04's myself, as enough torque to break stuff is usually what I enjoy the most.

[brokenwrench]

I found GIAC will tune for K04s and E85 and have "on the go" program switching for E85 and pump gas. And APR has mode switching too.

If this is true, then I stand happily corrected

This is good info for when I eventually get back around to my own 2.7 project.

[Nemesis2747]

So i randomly found someone on craigslist that is parting out their stage 3 S4 because they cant get enough $$$ from it altogether. What are your instincts for a set of used K04s. Or views on buying second hand turbos in general. Im saving like $1k from what he paid to JHM. His auto tranny went to the junkyard in the sky and he doesn't want to fix. He swears they have less than 10K on them but like im gona take his word. I bet you guys are looking at this like im crazy......

[Royal769sr]

I bought used rs6 oem turbos that I knew were run hard and needed a rebuild. Rebuilt and all good ever since

Sent from my SM-G930T using Tapatalk

[NuGGet_PuFFer]

I think we have done the same reading. I am leaning towards the K04's myself, as enough torque to break stuff is usually what I enjoy the most.

CHURCH.

[Nemesis2747]

So my turbos are starting to leave a smoke screen on the road and I have the cash ready to go. Pulling the trigger on Rebuilt K04s, JHM lightweight flywheel, b7 rs4 pressureplate and GIAC E85 and 93 flashloading tuning with 55lb injectors and the hitachi MAF sensor and piggie pipes. If i have the cash before it gets cold im throwing in some 034 Motorsport Bipipes and maybe a water meth kit. I do want to address some TLC needed for the car like Timing belt, valve covers, and i think the factory sport suspension has had enough. And some new CV joints, control arms and tires. BBK with 4 piston Audi Q5 3.0t calipers in the spring hopefully. Does all this make my car stage 3? Thanks for everyone's help.