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Remap Calculators – Turbo, Exhaust, Intercooler +more

Picture of a turbo charged engine. Turbo charged engines have a higher VE than normally aspirated engine usually.

Volumetric Efficiency Calculator has a variety of engine tuning/remap calculators to guide you to the parts you need to get the power & performance you want.

If you just want to calculate how much power an off-the-shelf remap will give you, check out the websites of companies that do remapping.

What the calculators on this page do

Engine tuning/remaps can put other parts under stress. With these remap calculators you can get an idea of the weak links on your engine.


-If you have a horsepower target in mind, use these calculators to get an idea of the parts you need eg turbo, intercooler, exhaust, intake.

Engine Tuning/Remap Calculators

Intercooler Size Calculator

What size intercooler do you need for the power you are running?

What size intercooler piping do you need?

How efficient is the intercooler you have now?

All these questions can be answered with the intercooler size calculator

Turbo Size Calculator

To calculate the turbo size you need, you need to be able to analyse turbo compressor maps.

This calculator gives you the numbers you need to analyse turbo compressor maps. It also tells you how you can find the data you need, to use this calculator.

Use your dynograph data to see how close you are to the limits of your turbo

Exhaust Size Calculator

Enter the horsepower of your engine and this calculator will give you an approximate recommendation of the exhaust pipe size you need. It also gives numbers that are 20% larger so if you tune your engine later, the exhaust shouldn’t be a restriction.

The calculator also gives you the speed of the exhaust gas for your given horsepower. Use the diameter recommendations and the exhaust speed to narrow in on the exhaust size you need.

Engine Volumetric Efficiency (VE)

Find the VE of your engine at different RPMs by using the data off a dynograph. You need to VE numbers to use the turbo size calculator.

Calculate Power from Torque

This calculator gives you the power of the engine when you enter your torque and RPM.

Use this calculator if you want to see the power potential of your engine.

For example your engine makes peak torque at 2000 rpm. With this calculator you can enter this peak torque number at a higher RPM to see how much extra power you can get from your engine, if you can move peak torque higher in the RPM range.

You can move the torque higher in the RPM range if you fit a bigger turbo and/or bigger camshafts, for example.

Engine Horsepower Calculator

Calculate the horsepower of your engine without a dyno/rolling road. Use a video camera to time the acceleration of the car. Plug the times into this calculator to get power and torque at different RPMs

Air Filter Size Calculator

Is your air filter big enough for the power your engine is making? This calculator will give you a ball park figure of the ideal filter size.

Other Car Calculators

These calculators are not generally relevant to remaps.

If you are using an aftermarket standalone ECU or piggbyback ECU, the knock frequency calculator could be useful.

The fuel economy calculator can give you an idea of what happened to your fuel economy pre and post remap.

The wheel alignment calculator, not really relevant at all to this article but it’s on the site, you may find it interesting

Knock Frequency Calculator

If you are using an aftermarket knock detection system, you will need to know the knock frequency of your engine. This calculator gives you the approximate knock frequency of your engine when you enter the cylinder bore.

Wheel Alignment Calculator

If you want to DIY your wheel alignment you will be measuring distances in mm. This calculator converts the distance measurements into degrees. Toe, Caster and Camber calculators included.

Fuel Economy Calculator

Want to check if your trip computer is accurate? Want to check if the amount of fuel measure at the gas station is accurate?

If so, the fuel economy calculator can help.

Enter the distance you traveled, the price of the fuel per litre/gallon and the cost of the fill up and the calculator spits out your fuel economy.


As I said at the start of the article, if you just want a remap calculator that tells you how much power you can get from a remap, the best place to look is on the websites of the companies that do remapping.

Off-The-Shelf Maps

You find your car on their website and they will list the options available off-the-shelf, no need for a remap calculator.

Companies will usually give a few options eg Stage 1, Stage 2 etc and details of the parts they recommend for each stage.

The calculators on this page are for a guide only, companies that do remapping, especially if they specialise on a specific engine, will have hands-on experience of what products work and they may even have complete packages to sell you with everything you need.

These tuning/remap calculators are not designed to be a substitute for the recommendation of the professionals working on your car.

Custom Remaps

If you are approaching tuning your engine from the perspective of a power goal, finding the parts you need to get that power goal and then having a company remap the car with the parts fitted.

In this case these calculators can guide you in that respect also. But again, speak to person that will be tuning/remapping your car. They will probably have a list of known parts that they have tried and tested, which they know will get you to the power and performance levels you want, in the most cost effective and user-friendly way possible.

This page was last modified Apr 9, 2022 @ 4:09 pm

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