Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - View Single Post - Rotrex vs Turbo (AVO) for Track use (transient response, IATs, heat management, etc)

glamcem · 03-18-2014, 03:19 PM

As the title says I would like hear about your experiences exclusively for track use, and supporting data of any sort would be highly appreciated. And yes, I searched but couldn't find anything other than the subjective opinion(s).

FYI, I plan to use OEM DIT oil cooler that comes with Forester(yes, I know) and Koyo radiator regardless of the FI application to help eliminate the heat issues (even before the FI route to be exact).

I have owned turbo cars in the past and even though I liked the rush/kick of the turbo for the street use, I was happier with NA cars when it comes to heat management, linear power delivery and reliability for longer spirited driving and track use.

Below are the information I gathered so far on both FI application:

Turbo advantages:

Makes more power at the given boost level (more efficient)
More low and midrange torque
Less noise meaning less need for muffler/resonator on the exhaust
Upgradeability, ability to unleash more power down the road
Avo kit looks very appealing and simple and has the stock-like appearance ( but at the end it's a turbo)

Turbo disadvantages:

A bit more complex project since it generates more heat which requires more heat insulation to prevent heat soak issues (wraps, turbo blankets, hi-temp coating ..etc)
Possible lag and unpredictable power delivery (may not be the case for smaller turbo setups)
Transient response is somewhat delayed even with smaller turbos
More prone to back pressure so it possibly requires a larger exhaust setup

Rotrex advantages:

More like a "turn-key solution" because of the simplicity and reliability
Boost builds up as the engine speeds increases so less load on the low RPM levels to the engine (which ultimately affects the reliability), it makes the most power on top end so only when you need it.
Less heat due to its design (some people claim that they can touch the intake after dyno pulls)
Linear and predictable power delivery that feels like a higher displacement engine under the hood, better transient response
KW claims the stock exhaust and header car made 270whp on dynojet which is more than adequate for me

Rotrex disadvantages:

Lacking the advantages of the turbo ( see above) and
Possible belt issues (I think it's addressed on the newer kits though)

I am not really worried about the dyno numbers since after owning Corvettes and bikes everything feels pretty slow anyways

I wanted to switch to a lighter platform after owning high HP cars mainly because I felt the weight is the single most important thing when it comes to track use. That being said, I also think the car is lacking a little bit of power and if Subaru offered a ~250-270 whp BRZ from factory I would get that in a heart beat instead (even if the cost would be 6-7k higher than what it is now). Hopefully, one of the FI applications will address this and I will be able to get the power levels I plan and get rid of the notorious torque/rpm dip in the process

03-18-2014, 03:19 PM	#1
glamcem Senior Member Join Date: Oct 2013 Drives: 2022 BRZ Limited Location: Orange County Posts: 1,553 Thanks: 997 Thanked 607 Times in 404 Posts Mentioned: 32 Post(s) Tagged: 1 Thread(s)	Rotrex vs Turbo (AVO) for Track use (transient response, IATs, heat management, etc) As the title says I would like hear about your experiences exclusively for track use, and supporting data of any sort would be highly appreciated. And yes, I searched but couldn't find anything other than the subjective opinion(s). FYI, I plan to use OEM DIT oil cooler that comes with Forester(yes, I know) and Koyo radiator regardless of the FI application to help eliminate the heat issues (even before the FI route to be exact). I have owned turbo cars in the past and even though I liked the rush/kick of the turbo for the street use, I was happier with NA cars when it comes to heat management, linear power delivery and reliability for longer spirited driving and track use. Below are the information I gathered so far on both FI application: Turbo advantages: Makes more power at the given boost level (more efficient) More low and midrange torque Less noise meaning less need for muffler/resonator on the exhaust Upgradeability, ability to unleash more power down the road Avo kit looks very appealing and simple and has the stock-like appearance ( but at the end it's a turbo) Turbo disadvantages: A bit more complex project since it generates more heat which requires more heat insulation to prevent heat soak issues (wraps, turbo blankets, hi-temp coating ..etc) Possible lag and unpredictable power delivery (may not be the case for smaller turbo setups) Transient response is somewhat delayed even with smaller turbos More prone to back pressure so it possibly requires a larger exhaust setup Rotrex advantages: More like a "turn-key solution" because of the simplicity and reliability Boost builds up as the engine speeds increases so less load on the low RPM levels to the engine (which ultimately affects the reliability), it makes the most power on top end so only when you need it. Less heat due to its design (some people claim that they can touch the intake after dyno pulls) Linear and predictable power delivery that feels like a higher displacement engine under the hood, better transient response KW claims the stock exhaust and header car made 270whp on dynojet which is more than adequate for me Rotrex disadvantages: Lacking the advantages of the turbo ( see above) and Possible belt issues (I think it's addressed on the newer kits though) I am not really worried about the dyno numbers since after owning Corvettes and bikes everything feels pretty slow anyways I wanted to switch to a lighter platform after owning high HP cars mainly because I felt the weight is the single most important thing when it comes to track use. That being said, I also think the car is lacking a little bit of power and if Subaru offered a ~250-270 whp BRZ from factory I would get that in a heart beat instead (even if the cost would be 6-7k higher than what it is now). Hopefully, one of the FI applications will address this and I will be able to get the power levels I plan and get rid of the notorious torque/rpm dip in the process __________________ 2022 BRZ Track Build (A New Chapter)