Rotary Extreme Dyno Day

Intro: Ever since Mazda changed the declared Mazda RX-8's horsepower rating from 250 to 238, people start to disbelieve any kind of horsepower claim they see.  Rotary Extreme is the first company that makes a dyno proven intake system for the RX-8.  Unlike most companies that will just tell you what they claim the horsepower gain will be, we post SAE corrected dyno sheets.  Now we take a step further that we invited enthusiasts such as yourself to come down to the dyno and show them the gains in front of their eyes on their own cars!  This time, rx8club forum members, blksf8, rx8guy, brothervoodoo, and Mr. Weston whose forum name we don't know participated.  

Dyno Procedure and Comparison:  Dyno testing is a very complicated process.  There are many environmental factors that will affect the final reading such as ambient temperature and humidity.  Those factors can be corrected by the dyno software according to the SAE standards.  There are factors on the car itself that will affect the reading as well and the most important ones are intake temperature and coolant temperature.  On modern cars such as RX-8, the ECU will compensate for intake temperature and coolant temperature.  The colder the air, the more power the car is going to make.  If coolant temperature is below normal operating temperature, the ECU will step in to protect the engine.  You will see those effects with the following runs and they will be explained in more details.  To conduct a accurate session, you need to make at least 3-4 runs for each configuration. The reason is that  by doing so, the coolant temperature will reach a maximum and consistent value for different set up and the intake temperature reading will be more accurate.   You want every factors that will affect the horsepower reading to be the same among different setups except  the variable (product)  you are trying to test.  We test each setup at least 3-4 runs on the dyno without any kind of cooling off period on the dyno.  When we are ready to test another setup, we will let the car cooled for 5-10 min to give car a rest.  Sometimes it takes longer because we need to swap the product on the dyno. It's very important that the product you are testing is swapped on the dyno when the car is still strapped down for the most accurate result.  We only test the car in 4th gear which has enough load to show accurate horsepower and the rpm moves up slow enough to have accurate a/f data logging.  We will run the new configuration 3-4 times on the dyno and the procedure repeats for the next setup. 

Dyno Sheets from Blksf8 (GT 6 speed, 1500 miles, DSC equipped)

For fair comparison, you will need to compare either the best run from each group or the worst run from each group to account for the heat soak factor. Let's say if we compare the 1st run with our intake with the last run from the stock setup which is totally heat soaked, our intake will show a much higher gain because the heat soaked engine makes less horsepower.  From the following graph, you will see our intake gain 14 HP at the wheel but it doesn't.  Most companies will use this method to make their HP claim more favorable but we at Rotary Extreme only post accurate and honest result.  

Below shows the first run with Rotary Extreme intake vs. first run with stock intake when the engine is at normal operating temperature.  You will see with the Rotary Extreme Intake, there is a max of 8 horsepower gain.  

Blow shows the last run with the Rotary Extreme intake vs. last run with the stock engine. In both cases, the engine is severely heat soaked since we have run them from 35-120 MPH back to back 4 times without any cooling off period on the dyno. You will see even at completely heat soaked situation, the Rotary Extreme still makes more power than the stock intake throughout the power band. 

The dyno sheet below shows you how we take the car from 35 mph to 120 mph in 4th gear on the dyno with consecutive runs with the stock intake.  Each run takes about 30-40 sec to perform.  We do run after run without any cooling off period.  You will see heat soak does play a big factor on HP reading.  

The dyno sheet below shows the same kind of runs with the Rotary Extreme intake. Again, no cooling off period to ensure the most accurate result.  

On the dyno, we also test the effect of the top cover on the intake and we found out on the dyno, the cover has an effect on HP rating. With the cover on, the HP curve goes below stock from 6200 to 7200 rpm but climbs right back with the same gains as the intake without the cover on after 7200 rpm.  During the 6200-7200 rpm period, the a/f ratio dropped below normal which reduces HP.   We need to do more investigation on the cause of drop of a/f.   We still suggest you to use the top cover with the intake system.  

Dyno sheets from Mr. Weston (a base 6 speed without DSC, Rotary Extreme intake and Rotary Extreme Spec V exhaust equipped).

The effect of coolant temp is very drastic.  The following dyno sheet shows a base 6 speed car without DSC equipped.  Before we put it on the dyno, the car has been sitting for a while so the coolant temp is below normal operating temperature.  Looks how much HP loss there is compared to the 2nd run when the 1st run brings the coolant temp back to close to normal.  The 3rd run brings the coolant temp back to normal and it gains more power.  The 4th run has almost the same power curve as the 3rd run without any significant sign of heat soak vs. a car without a cat-back exhaust system.  You 

We put back the top cover and found out little loss of HP on the top end but the a/f curves almost overlap completely.  

Dyno Raw Data:  Before, we were criticized  by a few individuals on the rx8club.com that we do not release any raw data of dyno testing.  We were the first company that makes a dyno proven RX-8 intake and with all the competitors out there who might misuse our data for their own benefit, we were refrained from releasing it.  Right now our dyno proven intake has been out on the market for 6 months and it's the most used intake on the market.  We feel we have enough supports from all the loyal customers so we are going to release the raw data right now.  To view the raw data, you will need to dyno the view program from Dynojet at the following link.  Please download the user manual so you know how to use the program.  

http://www.dynojet.com/downloads.shtml

When you download the raw data, you will need to open the software first and then open the raw data within the program.  Due to the concern of misuse our raw data by certain individuals, we will only provide the raw data from the worst runs from each configuration so they will not use our raw data and compare the worst run of our intake system of which is totally heat soaked after 3 consecutive 35-125 MPH runs on the dyno with the best run of the stock intake with just 1 run of 35-125 MPH and post it on the public forum to undermine our business.  In that case, the stock intake will seem to perform better but after you have studied all the above, you should know that kind of comparison is totally inaccurate.   

Raw Data from Blksf8:

Please download the raw data zip file by right click and save target as here.

Raw Data from Mr. Weston:

Please download the raw data zip file by right click and save target as here

Please note that during his runs, the ignition pick up was not working properly so the torque curve is way off.  Torque is calculate from HP and RPM so if the RPM signal is not accurate, the torque curve cannot be displayed properly.  You can view HP vs. Speed and A/F vs. Speed

We will try to do more dyno runs in the future and post more technical data on the website and on the forum. Thank you for your support.

Rotary Extreme Team

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