For some time we have discussed the possibility of producing a cold air intake system for the Lotus Elise/Exige 2ZZ-GE vehicles.
We did some market research and discovered that there are currently at least 9 intake systems available for the Elise/Exige in the aftermarket. These range from a $70 Cup Car air box mod, up to the beautifully crafted carbon fiber and aluminum intake from ReVerie.
We also found that most of the discussions regarding aftermarket intake systems on the Elise/Exige ended with the conclusion that the ECU will "tune out" any initial gains.
What bothered us was that we did not see any proof of these claims. Nor did we find a single power increase claim or dyno chart with any of the intakes currently on the market.
We temporarily converted our shop car back to N/A to see exactly what is going on with aftermarket air intakes.
The kind people at Portland Speed Industries let us on the dyno and we got to work.
Here are the specs of our test vehicle:
-2006 Elise
-Stock 2ZZ-GE
-Stock exhaust system with catalytic converter
-92oct Unleaded Pump Gas (10% Ethanol content)
-Stock ECU, no reflash, no modifications.
Our first task was to baseline the stock intake. This intake had been on the car for several weeks and had seen several hundred miles.
We did three runs and found it to be very consistent. These runs are shown below. Average max horsepower is 172.1Hp
Shown here is the uncorrected graph. This is the raw output from the dyno. We did not want to correct these numbers since we are comparing run-to-run and not trying to compare with another dyno graph from a different day or different vehicle or different climate.
If you want to read more about dyno testing, read this article from MotoIQ.
Our next task was to install a short intake with a MAF sensor welded on it. A prototype piece was quickly fabricated and installed. We used a K&N cylindrical air filter. We also reset the ECU before running this intake.
Once again, we did three runs and found excellent consistency.
Comparing the average max HP from the stock runs to this intake, we see an increase of about 5.3Hp (177.4 compared to 172.1).
Not willing to stop there, we experiemented with different lengths of pipe to see if resonance tuning could be used to squeeze out a few more gains.
This setup was the same as the previous except for an extra 4" section of pipe was added between the MAF sensor and the air filter.
The extra 4" did not help power. Average maximum Horsepower for the three runs dropped to 176.5HP.
It looked as if resonance tuning this intake was not going to help.
We did have one more configuration to test. We decided to go extra long and just see what effect it had on the performance.
We removed the short 4" section from the previous testing and reset the ECU. Then we installed an 18" long 90 degree elbow.
Shown in this graph is the long pipe (blue line) compared to an earlier short pipe run. We only did one run because air fuel ratios got too lean for our comfort and also it was obvious this was loosing power big time.
This testing fairly conclusively proved that the best intake for the 2ZZ-GE is fairly short.