How To Choose A Turbo


Selecting A Turbocharger

It’s no longer necessary to use black magic or cast a voodoo spell to choose the right turbocharger. Turbonetics makes it easy! Each family of turbochargers features Turbonetics Top Performers based on the displacement and power. While there are many other variables to consider, these will certainly get you started. We have over 125 years of forced induction sales and engineering expertise in our building to help you select the best possible combination of turbochargers and intercoolers. Feel free to contact Turbonetics and or any of our distributors, if you have questions. The dealer locator feature is available online at the top right hand corner of the site.





• Think in horsepower not boost.

• Boost is just a number that you will have to run on your engine to make a certain horsepower.

• How much power do you want to make? Be realistic, the more accurate that you are, the better tuned your forced induction system will be.

• Can your vehicle (not just the engine, but the entire setup) handle such power?

• Remember the turbocharger is generally not the weakest link.

•Forged pistons, connecting rods, head studs, etc.

• “As much as possible” is not a goal.



• What are you using the vehicle for?

• Race or street use?

• The way that you will be using the vehicle dramatically changes the sizing of the turbocharger and intercooler needs.

• Your choice of transmission type and gearing will greatly affect the performance and characteristics of the turbocharger, keep this in mind.



• Will the turbocharger(s) fit in your vehicles space constraints? Consider using differently sized compressor housings to more easily fit a given location.



Most street/autocross/drift enthusiasts will prefer a smaller turbocharger due to its fast response. A turbo system equipped with a smaller turbocharger is generally considered more fun to drive. The tradeoff is the final power output of the setup. On another note, dedicated track cars are aimed for peak power over boost response. There’s no doubt track cars spend more time in the upper RPM than average street cars. So, a small sacrifice in boost response is offset by the huge power potential. Larger frame turbochargers are preferred by track car owners due to their maximum power capacity. For most street applications the best solution for selecting turbine wheels and turbine housings, is to choose the smallest wheel diameter available that meets the horsepower level wanted.


It is also important to remember that response/spool-up time is greatly affected by turbine wheel diameter and turbine housing A/R. The A/R sizing can be used as a tool to fine tune the response range in the RPM band. The smaller the A/R, the faster the turbocharger will be able to spool up from the increase in exhaust gas velocity entering the turbine housing. Backpressure has become a major tuning issue associated with high performance turbocharged engines and the turbine wheel and turbine housing A/R are both critical to maximizing the performance of the turbo system. Backpressure is the pressure that the exhaust gas generates trying to enter into the turbine housing inlet. If backpressure becomes too great (a 2:1 ratio), the exhaust gases can not escape the cylinder head and can possibly cause major tuning, performance and durability issues. It is important to try to keep the backpressure to boost pressure ratio as low as possible and should be no greater than 1.5:1 for best performance (Example: 15 psi of boost to 22.5 psi of backpressure).


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Turbo Matrix .pdf54.88 KB