K03s/K04 hybrid turbo - advice please

[Nautilus]

Dear Ladies and Gentlemen,

I'm going to replace my K03s turbo the next summer for a hybrid which would use the same housing and ancillaries and I hope will provide about 240-250bhp at the flywheel.

The car is a 2005 LFR (Continental European version of a LC), AUQ engined. Right now it has the following engine mods:

- Dimsport (Race2000) remap
- BKR7E sparkplugs
- Forge DV006
- Powerflex dogbone
- 105/110mm flex pipe to airbox
- Forge TIP + throttle body hose + PCV hose
- BoostFactory! uprated SMIC
- 3" Borla downpipe
- NewSouthPerformance PowerGasket+
- polyfoam-insulated hoses
- self-made grounding kit (120 amp rated wires)

Right now it makes around 210bhp top power just below 7000rpm with a very flat power curve (200bhp at 5000rpm, 202bhp at 5700rpm and so on) and 236-243 lb/ft from 3000 to 4000rpm, slight variations in absolute numbers are due to the place where dyno tests were made.

I'm interested into a hybrid using K04-023 wheels in a K03s housing, so that it would fit "plug & play" on K03s ancillaries.

The first option that came to mind was the APR K04 hybrid, which is quoted to fit AWD, AWW, AWP, AWV, and APH engines, but not AUQ. However, Awesome GTI sells it as a direct fit for Golf/Bora/A3/TT/Leon/Octavia.

I'd also be interested in a CR Turbo hybrid.

A remanufactured unit is not an option - it has to be a factory-quality item, profesionally balanced on a balancing machine by a reputable company.

Which other options do I have, strictly K03s housing hybrids, in an acceptable price range?

Thank you,

~Nautilus

 

[BBoy82]

Hiya,
I dont mean to rain on your parade, or show you up, but hybrid turbos ARE remanufactured from standard turbo housings. They remachine the impellor and compressor chambers, fit different sized impellors/compressor wheels depending on characteristics required, and fit different bearings, thrust washers, seals etc.
They are essentially a mixture of different turbo components, hence the name hybrid.
Im also not sure exactly what info you are after, as it seems you have listed the main options available to you anyway...

 

[Nautilus]

Thank you.

I'm asking based on members' experience (it hardly makes sense to ask directly the manufacturer, as they'll naturally praise their product as the best ):

- Do APR K04s or CR Turbo hybrids fit an AUQ engine?

- Do they match the connections/fittings of a stock K03-0052, so they fit the ancillaries (T.I.P., downpipe, oil/water pipes)?

- Are they built to factory quality standards on balancing machines? (Plenty of Romanian owners of Diesel cars remanufactured their turbos only to get friendly recommendations to not run at top power and rpm afterwards, since they were re-assembled on a "guess" and not balanced. Petrol engine turbochargers are exposed to even higher temperatures and stresses)

- Did other members who tried one of the two options available or other K03s/K04 hybrid experience reliability issues? It barely makes sense to risk a blown turbo

Regards,

~Nautilus

 

[adam cupra 20vt]

You can get 240bhp from a stage 2 on a KO3s.

 

[Damoegan]

] - Do APR K04s or CR Turbo hybrids fit an AUQ engine?

- Do they match the connections/fittings of a stock K03-0052, so they fit the ancillaries (T.I.P., downpipe, oil/water pipes)?

You can get 240bhp from a stage 2 on a KO3s.

I'm pushing 237bhp and 267lb/ft on mine

 

[slappy_dunbar]

Thank you.

- Do APR K04s or CR Turbo hybrids fit an AUQ engine?

- Do they match the connections/fittings of a stock K03-0052, so they fit the ancillaries (T.I.P., downpipe, oil/water pipes)?

The BORG WARNER (3K) K04-001 is designed as an upgrade to the K03 series for transversal motors. It is fabricated with the identical housings so it looks identical and fits as such. You need to be mindful, though, that the introduction of the very similar K03-052 (K03s) more or less obsoleted the K04-001

- Are they built to factory quality standards on balancing machines? (Plenty of Romanian owners of Diesel cars remanufactured their turbos only to get friendly recommendations to not run at top power and rpm afterwards, since they were re-assembled on a "guess" and not balanced. Petrol engine turbochargers are exposed to even higher temperatures and stresses)

- Did other members who tried one of the two options available or other K03s/K04 hybrid experience reliability issues? It barely makes sense to risk a blown turbo

Regards,

~Nautilus

You need to research the quality on an individual basis. Remanufacturers have available to them OEM parts, high quality Asian aftermarket parts, and poorer quality choices as well.

The exact design of a hybrid K03/K04 is also dependent upon the vendor. But generally here is a breakdown of the possible configurations:

2078-series compressor installed in an otherwise OEM-spec K03s. Expect 230bhp
2078-series compressor installed in a K03s with modified turbine wheel. Expect 235+bhp
2075-series BorgWarner K04-001. This is an OEM part, not a hybrid. Expect 240bhp
2275-series compressor installed in a K03s with modified turbine wheel. Expect 260+bhp

 

[markgb]

You can get 240bhp from a stage 2 on a KO3s.

What else is needed for a stage 2?
I presume at the very least an upgraded exhaust, what other the a Blue flame is recommended?

 

[Damoegan]

What else is needed for a stage 2?
I presume at the very least an upgraded exhaust, what other the a Blue flame is recommended?

Miltek..

Stage 2 requirements are:

Turbo back exhaust
Forge TIP
Forge DV
High flow panel filter/open cone filter
A FMIC is recommended too.

 

[adam cupra 20vt]

I've not seen a Blue Flame exhaust for a LC?

 

[Nautilus]

Thank you all, but see, there is a problem: I've searched for a K04-023 hybrid (50/56mm wheels, the type used on 210/225bhp engines) in a K03s "snail", not a K04-001 (50/50mm). There was even an article floating around which warned against K04-001, which would give only slightly higher bhp compared to a K03s and is not as strong and able to run at high boost without problems. If the APR kit only provides a K04-001 setup I'd rather keep my money or invest in a new remap, custom made on a dyno.

The local record gained on a K03s without water/meth injection was a very flat power curve with a maximum of 222 bhp and >210bhp from ~3700rpm to ~6500rpm, which would beat many non-turbo cars with much higher bhp figures, but the tuner warned this was a "race stage" and did not quote the boost attained... The real gain compared to my setup had been the mid-range power and the >285lb/ft torque , not the absolute maximum

Regards,

~Nautilus

 

[adam cupra 20vt]

Your going to need a custom map for a hybrid anyway so why don't you get a custom map for your standard turbo and get the 240bhp your after with stage 2 mods?

 

[jamiebennett81]

Miltek..

Stage 2 requirements are:

Turbo back exhaust
Forge TIP
Forge DV
High flow panel filter/open cone filter
A FMIC is recommended too.

I am thinking I should have done that Hybrid write up by now.....

 

[slappy_dunbar]

Thank you all, but see, there is a problem: I've searched for a K04-023 hybrid (50/56mm wheels, the type used on 210/225bhp engines) in a K03s "snail", not a K04-001 (50/50mm).

It sounds like you are describing your ambitions on the compressor side. You are looking to incorporate a K04-02x (the "x" here denotes a wild-card by the way, it is not used literally) compressor wheel. Sized at 42 inducer / 56 exducer, it is too large to fit in the housing you wish to use. This eliminates the housings from K03-52, K03-53 & K04-001. So if you want to proceed with a 42/56 compressor side you will need to begin with a larger housing, such as the K04-02x.

There was even an article floating around which warned against K04-001, which would give only slightly higher bhp compared to a K03s and is not as strong and able to run at high boost without problems. If the APR kit only provides a K04-001 setup I'd rather keep my money or invest in a new remap, custom made on a dyno.

While a K04-001 is not meaningfully more powerful than a K03s, it is nevertheless more powerful. For a K03s to match the output of an -001, it will be stressed to the point of (catastrophic) failure.

The local record gained on a K03s without water/meth injection was a very flat power curve with a maximum of 222 bhp and >210bhp from ~3700rpm to ~6500rpm, which would beat many non-turbo cars with much higher bhp figures, but the tuner warned this was a "race stage" and did not quote the boost attained... The real gain compared to my setup had been the mid-range power and the >285lb/ft torque , not the absolute maximum

1. take the above with a grain of salt
2. "race stage" = "don't try this at home"

The K03s is a 210 bhp turbo, any more than that you are risking damage. If you seek more, I have listed some alternatives above this post.

Good luck.

 

[Damoegan]

I am thinking I should have done that Hybrid write up by now.....

 

[Damoegan]

....The K03s is a 210 bhp turbo, any more than that you are risking damage.

Wrong...

There are lots of people on here running 220bhp+ on a k03s, myself inclided.

 

[slappy_dunbar]

Wrong...

There are lots of people on here running 220bhp+ on a k03s, myself inclided.

How do you know that? On what fuel? What is your basis for the claim?

 

[Damoegan]

Because I have seen them run on the dyno.

The highest fuel commonly available in the UK is 99RON. Thats what I run, My las dyno run was 237bhp and 267lb/ft..

My last 3 dyno rund have all been over 225bhp and 2 of them were on the standard exhaust.

 

[slappy_dunbar]

Because I have seen them run on the dyno.

The highest fuel commonly available in the UK is 99RON. Thats what I run, My las dyno run was 237bhp and 267lb/ft..

My last 3 dyno rund have all been over 225bhp and 2 of them were on the standard exhaust.

Obviously you're spoiling for a fight. Instead, re-read what I posted. I never indicated "impossible". The tenor was more along the lines of "unwise".

 

[Damoegan]

Obviously you're spoiling for a fight.

Not at all mate.

Perfectly saft to run a k03s at 220-230bhp+. Very rarely do you see people on here talking about there k03s going pop. Its the k03 that maxes out at 210-220bhp and people have more problems with.

 

[Nautilus]

It sounds like you are describing your ambitions on the compressor side. You are looking to incorporate a K04-02x (the "x" here denotes a wild-card by the way, it is not used literally) compressor wheel. Sized at 42 inducer / 56 exducer, it is too large to fit in the housing you wish to use. This eliminates the housings from K03-52, K03-53 & K04-001. So if you want to proceed with a 42/56 compressor side you will need to begin with a larger housing, such as the K04-02x.

Thank you.

The K03S turbos have 44mm turbine wheel / 51 mm compressor wheel compared to a K04-001, so as we see the restriction is on the hot side. If a 56mm compressor would not fit a K03S housing, why not use the hot side from a K04-001 and get a 50/51mm turbo?.... Do the downpipe flange and manifold flange match a K03S manifold?...

(BTW, are there tuners who make this combo, K04 turbine / K03S compressor, because if they are the topic has already found a conclusion )

"Common wisdom" says small turbine wheels reduce turbo lag to the point of elimination, but I've not heard people complaining of K04 as laggy turbos

~Nautilus