Articles tagged with: Consistency

Intake comparison on 4AGE 20V BlackTop

on Tuesday, 07 February 2012. Posted in Using PerfExpert

Performances difference between the original plenum and open velocity stacks

Here's a little comparison that has been done on Stephane's Toyota AE82 Twin Cam GT : seeing with PerfExpert the difference in torque and power between the original plenum (without the air filter) and open velocity stacks.

To perform reliably this test it was necessary to proceed as following :
- Always launch the car from the same mark on the road
- Always WOT at the same mark on the road
- Take measurements at the same direction of travel
- Be sure to follow the PerfExpert basic measurement procedures (phone calibration performed, impeccable phone fixation, little wind, free road, lift windows...)
- If the car remained parked in a while then drive a few minutes at medium speed to cool the engine bay in order to always make the measurements under similar engine bay temperature conditions 
- For each setup (plenum or open stacks), perform at least two measurements having less than 2% deviation to confirm their reliability. Indeed non-repeatable measurements (differences of more than 2%) reflect a poor phone fixation or poor conditions (road, wind...).


Toyota Corolla AE82 Twin Cam GT


At first, measurements with T3 open stacks

Toyota 4AGE 20V blacktop open stacks

PerfExpert 4AGE 20 blacktop cornets 1

PerfExpert 4AGE 20 blacktop cornets 2


Here are the results with this setup :
- 159.6hp at 7300rpm et 131.8Ft.Lb at 5500rpm
- 159.1hp at 7300rpm et 133.2Ft.Lb at 5300rpm



Lets see now the results with the OEM plenum and OEM stacks. Unfortunately we didn't have a cold air feed to the plenum for the tests. And note that the curved OEM stacks had been cut by the previous car owner...


4AGE 20V blacktop plenum 14AGE 20V blacktop plenum

PerfExpert 4AGE 20V blacktop plenum 1

PerfExpert 4AGE 20V blacktop plenum 2


Here are the results with this setup :
- 150.4hp at 7200rpm et 128.2Ft.Lb at 5200rpm
- 151.3hp at 7200rpm et 130.4Ft.Lb at 5200rpm

This shows a clear advantage of open stacks in power (more than 5%), and a slight advantage in Torque. But the most interesting is to see the curves comparison. Here is a Google Doc with an overlay made ​​from a fusion of data exports made ​​from the application :

Toyota 4AGE 20v blacktop : open stacks VS plenum

Not enough room for the legend so I'll give more details here :
- P1 & P2 are the 2 power curves in open stacks setup
- T1 & T2 are the 2 torque curves in open stacks setup
- P3 & P4 are the 2 power curves in plenum setup
- T3 & T4 are the 2 torque curves in plenum setup

Note that with the plenum there is a little more torque before 4000rpm and less torque after. So really, even if the open stacks give more torque maximum value, the plenum give a more torquey engine at low rpm.
A pity that we didn't have a 100% stock plenum (whose stacks are not cut) and the original airbox + filter. The comparison would have been even more interesting.

Highlight your PerfExpert vs Chassis Dyno comparison

on Monday, 22 June 2015. Posted in Announcements

Send us your comparisons to better convince the most skeptical ones about PerfExpert accuracy

Highlight your PerfExpert vs Chassis Dyno comparison

Most people find it hard to believe that a smartphone application can measure power and torque with an accuracy very close to chassis dynos, without any connection to the car or without any external measuring equipment. They generally think of a hoax, because they cannot imagine the real potential of the modern phones sensors, especially when they are combined with powerful algorithms and calculations. Thus, providing them the proof with "PerfExpert vs Chassis Dyno" comparisons seems to be the solution.

What could be better than seeing this proof brought by other car enthusiasts who tested PerfExpert by themselves?

If you carried out this kind of tests you can contact us to transmit us your results, by sending us the following elements :

  • A copy of the full report of the chassis dyno result, in other words, the result sheets, perfectly readable, scanned or photographed
  • An Image export of PerfExpert measurement curves, and, if possible, with two PerfExpert tests carried out under the same conditions (same road, same direction, same starting point, same day)
  • The links towards your tests on the Web PerfExpert Network
  • And for the fun, if you agree, a beautiful picture of your car, outside and/or on the chassis dyno! :) We will hide the license plates if they appear.

We will gather them in our Google + collection of PerfExpert vs Chassis Dyno comparisons.

Speaking about PerfExpert around you and showing that it is a reliable application when it is correctly used allows us to keep on improving it and creating new features! As a user, you now know how to answer those who ask you about the application's accuracy and reliability compared to chassis dyno's. In fact, this is often the first question people ask when they discover that the PerfExpert application allows them to measure your car engine’s power and torque using only your smartphone!

Here is an comparison example from our collection :

PerfExpert Car Dyno=> Power : 301cv / Torque : 370Nm

Cartec Chassis Dyno => Power : 300.5cv / Torque : 371Nm

Nissan 350Z

Nissan 350Z chassi dyno result

Nissan 350Z PFX result 


DIY phone mount

on Friday, 25 April 2014. Posted in Using PerfExpert

How to perform consistent measurements easily using the cheapest phone mount solution

DIY phone mount

To perform consistent, accurate and reliable Dyno and Timed Run tests with PerfExpert, you must ensure that all the measurement conditions are met.

One of these conditions is that the phone must be one with the car during the test : its sensors must perfectly "feel" the car's movements, and no other parasite movement or vibration. So you must pay close attention to the phone mount you use, and check that the phone position reach the PerfExpert mounting requirements. In the dyno test video tutorial, the phone is secured by a very strong windshield mount, equipped with a large suction cup and a very short, solid arm.

There is a much cheaper way to have your phone correctly secured in your car, and that allow you to immediatly perform tests : using the original box of your phone, the passenger seat, and a heavy book!

Remove the cover of your phone's box and all unnecessary packaging

DIY Phone mount 1DIY Phone mount 2DIY Phone mount 3DIY Phone mount 4DIY Phone mount 5

Put the phone inside the box and shake it sideways to check if the phone can move

DIY Phone mount 6DIY Phone mount 7

Prevent any phone movement by wedging it inside the box

DIY Phone mount 8DIY Phone mount 9DIY Phone mount 10

Make the power button accessible if needed

DIY Phone mount 11DIY Phone mount 12

Put the box on the passenger seat, and wedge it against its backrest

DIY Phone mount 13

If needed, you can stall the box with heavy objects located on its sides and/or in front of it

DIY Phone mount 14

Ok! You're ready to test your car!