Made a thread since i wasnt getting any feedback in the official intake thread.

Ive tested two intakes. a custom intake i made vs the factory oem air box. Both were tested on a dyno jet and on the street using virtual dyno.
Heres my dilemma - the OEM intake made about 3hp more than my custom intake on the dyno jet. Back to back same day. The car is tuned by Jeff Evans with the custom intake. The tune was not changed when i swapped the stock intake on. But, the car is tuned on Link G4x with AEM wideband using Closed Loop at WOT. so, the ecu makes minor fuel changes to keep AF ratio at target.

Now, the kicker is the custom intake continuously shows more horsepower using Virtual Dyno on the street. The test were back to back, on the same day (i also ran this test before on a different day and got the same results).
The custom intake requires more Injector PW (actual) to maintain AF ratio. And, the map readings continually show less vacuum under WOT through mostly the entire RPM range under WOT runs.

another noticeable point is the custom intake is consistently 10-15 degrees cooler on IAT.

So, is the custom intake truly making more power on the street? is the oem box just too heat soaked on the street?

Here is a pic of the custom intake:
it is a 3 1/2" with velocity stack that reduces down to 3" before the throttle body. It gets fed fresh air from around the side of the radiator.


Here is the DynoJet plot:
Blue Run 005: Custom Intake tuned
Red Run 006: Oem intake on same tune
Green Run 007: Oem intake on same tune
Purple Run 008: Oem intake on Stock ecu




Here is the Virtual Dyno Plot:

Red: Custom Intake tuned
Green: PUFFO Intake same tune
Blue: Oem Intake same tune

Ignore the AF graph numbers. But the curve is right.




Here is the MAP Log from the Virtual Dyno Street Pull:

Pink: Custom Intake
Yellow: OEM intake
Green: Puffo Intake



Here is the Injector PW from the Virtual Dyno Pull:

Pink: Custom Intake
Yellow: OEM intake
Green/White: Puffo Intake




So, which Intake really makes more power on the street?

 

I think part of the issue when we are talking a few hp, is sample size. I kinda take these types of intake tests with a grain of salt due to that. When testing you need many samples of each setup and then average them to get a good set of numbers. So many variables at play. Example... at the last dyno day I attended, we only got 2 runs. Car never moved off the dyno, same conditions, etc, on a Mustang Dyno. My car made 224 on one and 227 on the other pull. So there is 3hp variation with back to back pulls with it never leaving the dyno, on a good dyno setup. Unless a ton of pulls were made and averaged, I consider a few hp to be in the noise of variability. And on the street, the variable count goes up further.

I think the most you can take from this is that you do see a change in AFR requiring more fuel with the custom intake. That does indicate that it may be getting more air in. And it is getting cooler air which also indicates it is likely working better. So that is some indication that the custom intake may be better. Now how much? Likely less than 3hp but not enough samples to tell.

 

This is the type of feedback I was hoping for. Thank you. All of this makes sense.

 

Pro drag racers will always tell you to believe the track times and not the dyno. When a car is moving down the roadway it is different than a dyno with many variables. Is the dyno a great tool and useful? Yes, but not perfect

Pulse width is a good measure (assuming equal afr) of actual airflow (ve) for the engine.

Also, depending on how Jeff setup ignition trims, lower iats may also allow you to run more timing.

Some really good tuning and building theory over on speed-talk.com if you dig around

 

Solid advice. Even though the IAT's were higher for the OEM intake, there was no ignition getting pulled at those temps.

 

So even given that no ignition trims were at play, the amount of timing the cylinder wants for peak pressure to occur at the right time to make peak power does change with compression temperature, and compression temperature is impacted by intake air temperature. This is due to the burn speed/turbulent flame front speed that changes with temp

I screenshotted a few posts from a well respected member on speed-talk.com below, I really think you would get a lot from perusing that site:





While these numbers may be specific to a different engine, the theory holds.

 

solid info silentwrath. thank you. i will start looking at speed-talk as well. I really made this post to try and get more active on s2ki. I miss how active the forum was 10 years ago.