Hello All,

I have recently purchased my 03 G35 Sedan, and have held off installing aftermarket components (sitting patiently in my garage), while awaiting the arrival of my GTech RR. Now that it has arrived, I have installed, calibrated and set a baseline to test off of. I will be measuring the modifications to my vehicle in the most scientific method I am capable of - in hopes to educate myself and you guys to the real world changes that I experience.

The following experiments will be made relative to a stock set up
A. AEM Cold Air Intake vs. Stock Airbox/Stock Filter vs. Stock Airbox/Free-flow Filter
B. Stillen G2 Catback Exhaust
C. Stillen Ceramic Coated Headers
D. Gordgee Grounding Gear 10 wire + Shift time analysis

Experiment A will be published today, with experiment B to be published by Dec 1, 06, and experiment C to follow shortly. Please read on for experiment A...


Experiment A

Problem: How does the installation of a Free Flow Filter in the factory Airbox and the installation of an AEM Cold Air Intake effect the power output of a 03 G35 Sedan relative to stock, in relation to RPM?


Controlled Variables:

• Stock 03 Sedan w/ Full Tank (without me) @ 3580 pounds, weighed on two seperate scales prior to testing.
• Weight throughout testing +/- 20 pounds (fuel between full & 3/4 - vehicle weight kept within 0.1 percent)
• Weight corrected for Driver
• 2nd Gear Test @ WOT between 3500 and 6700 RPM
• Consistant staging points (2 total - 1 in each direction +/- 6 inches)
• Opposing directional runs to factor slope and wind resistance
• Slope measured less than 3 feet over track
• Temperature differential of 3 degrees over "intake" testing period
• 94 octane fuel used (10% ethanol blend - Mowhawk)
• 10 runs per Scenario
• Headlights on, audio & climate systems disabled
• VDC Disabled

Independent Variables: Scenario One, Two & Three

In chronological order over 4 hour span
Scenario One: Bone Stock Car - Factory Airbox w/ Stock Filter (refered to as FAb w/ SF) - Average Plotted in Black - Baseline Measurement
Scenario Two: Factory Airbox w/ Free-flow Filter (refered to as FAb w/ FFF) - Average Plotted in Red
Scenario Three: AEM Intake (only mod from stock) - Average Plotted in Green
Scenario Four: Bone Stock Car- Factory Airbox w/ Stock Filter (refered to as FAb w/ SF)
Scenario Five: Factory Airbox w/ Free-flow Filter (refered to as FAb w/ FFF)
Scenario Six: AEM Intake (only mod from stock)

Dependent Variables:
Horsepower and Torque relative to RPM

I wanted to ensure the accuracy of my results, thus, the re-testing of each of the 3 setups in Scenarios 4, 5 & 6. These tests mirrored the results from the first 3 tests within very small tolerances, therefore disregarded from the expressions graphed below.

60 Samples Taken - Best Average Representation from Tests 1, 2, & 3 plotted. The characteristics of the plots are expressed in all dataplots recorded.


Observations:
Relative to Stock

• The FAb w/ FFF had significant gains over that of the Factory Filter.
• The AEM CAI had an overall similar gains to that of the FAb w/ SF.

AEM vs. FAb w/ FFF

• No obvious difference below 5300rpm.
• Between 5300 and 5800rpm, AEM did NOT perform as well as the FAb w/ FFF, with the AEM averaging a 2HP drop.
• Between 6200 & 6700rpm, the AEM outperformed the FAb w/FFF averaging 3.5HP.

Conclusion:
The performance gains over Stock with both AEM and FAb w/ FFF are very similar in overall gains. Although the AEM looses power between 5300 & 5800 RPM, it makes up for it in the 6200 to 6700 RPM range, assuming WOT applications. Therefore, on the street or track, the FAb w/ FFF may perform better, yet on the drag strip, I would choose the AEM.

The performance increase of the AEM at the very top end suggests that it may compliment a VQ35DE that breaths heavier, over a stock setup.
Major disadvantage to the AEM CAI is the risk of water inhilation and engine damage. Differences not immediately related to performance inlude the AEM's throaty growl under high load. Also, the FAb yeilds a lesser thermal responsive medium (plastic) than the heat conductive metal used in the AEM, effecting intake temperatures. The AEM would benifit from a thermal insulated wrap to increase performance, however negligible.

We will test the Stillen G2 Dual Catback Exhaust next. This will initially be tested on a stock setup, and tested again with the AEM CAI to see what differences in performance occur. Stay Tuned...


STAY TUNED FOR FURTHER EXPERIMENTS, AND PLEASE FEEL FREE TO GIVE FEEDBACK! Especially if you have advice on making the test more accurate, as I think I've covered all my bases...

 

These measurements are apples and oranges when compared to dynometer readouts...

Although the HP & TQ may seem abnormally low, they have been proven to be very close to accurate by other GTech users. These figures plotted by the GTech readouts take into account the drivetrain losses (tested in 2nd gear - auto-tranny), altitude, rolling resistance as well as aerodynamic drag.

The formula for HP loss due to aerodynamic drag is:

Cd: Drag Coefficient
A: Frontal Area In square feet
V: Speed In MPH

(Cd*A*V^3)
150,000 = HP Loss

* *
*
Assuming:
Cd: 0.27 (0.26 w/ aero package) on 2003 Sedan
A: 26.2 sq.ft. (estimated by car and driver)
V: 60 MPH @ 2nd gear (5AT) @ 6500 RPM

HP Loss: 10.2 HP @ 60MPH
Where as it is 81.5 horsepower at 120MPH, as it requires 8 times as much energy for every time you double speed. (Remember this when you're on the highway, and you're trying to save gas).

A good calculator for Horsepower loss at altitude can be found at http://www.wallaceracing.com/braking-hp.php

Therefore, at 3500 feet, a 260 HP normally asperated engine should loose approximately 27.3 HP.

The 2003 Coupe's automatic 5 speed transmission has a 2nd gear ratio of 2.26:1. I cannot information at this time to weather that is the same as the Sedan.

 

Thanks for all the work. I look forward to more test results.

 

Well, back from the garage, just finished installing the Stillen Catback Dual Exhaust. It fits like a glove, nice work Stillen. I'm a little disappointed at the volume, I was told to expect a little more classy, quiteness - but we'll see how it sounds once it's broken in.

I have completed a couple of runs at my track - but I would like to have more detailed results before posting... So far, we're seeing about a 6 to 8% increase in HP at the top end - so stay tuned.

 

Is this done with the stock resonator or Z tube? I don't suppose you want to do comparisions of the stock resonated intake tube vs the non-resonated Z tube?

There have been speculation that the resonator acts not only as a sound deadening device but something that enhances low end power too.

 

very nice work cant wait to see what else you find out

 

I have ordered a aftermarket Z-tube, so I will be testing that one too. I'll let you guys know what the results are

 

Great job tylersphile!

Its good to see people doing independant controlled testing of their modifications. Its really needed in this industry.

As for recommendations, there are several things I would have done differently, but this is only because of what I have learned through doing lots of dyno testing myself.

Not that you need to do it every time, but try another test group. A control test group. Don't change anything on the car during the whole test sequence but do all the pulls as you did previously and plot them out.

Some ECU's tend to gravitate to performance mode and some toward lazy mode. And some ECU's shift back and forth between the two. If your cars ECU tends to shift around, you will see a shift in your test results even though you won't change any hardware on your car.

Based on my past experience and seeing your plots above, it looks like your ECU may have been shifting variables around during your test sequence.

You can do some quick and easy testing to see if this is the case.
Repeat the filter test procedure to a "T" without actually changing the filter.
And i mean to a "T"!

You may be pleasently surprised.

Tony

 

^Pleasantly surprised....as in "little or no difference between the stock filter and free flow filter"?
Thanks for all of the testing!

 

Hey jjellyneck! I havn't seen you post in a long, long time. Whats up!

Even with no hardware variables changed, there is potential for a performance shift. It depends on how the ECU is feeling.

This is also why I purchased a UTEC. The UTEC holds the ECU variables constant and thus cuts out the nonsense and games our ECU likes to play.

 

Thanks for the advice Hydrazine, I thought I accounted for all variables, but I guess not - I'm glad I asked for advice. Would a ECU reset prior to each run accomplish the same thing? I'm not aware of the learning pattern after a reset - does it set it to the most agressive mode by default? or right in the middle? Maybe I should just buy a UTEC - it's on my list...

Ty

 

Wow, this is a very good thread. I was expecting more "butt dyno" crap but I am impressed!

 

Its hard to say if the reset will change anything, but if it does, it will change to the higher performance mode map.

Some times it will and others it won't.

 

Hydrazine,
I've been super busy with a business I've started. Now I'm looking around at mods once again--just light mods. So far I've done the Z tube, then high flow cats and then your 3/8" spacer--in that order. All are worthy mods it seemed. Your spacer and the cats each seemed to make a slight difference throughout the RPM range--good stuff! The Z tube seemed like it was positive as well, but maybe not as detectable. All butt dyno.
I'm interested in air filters, and not sure if I'll see any improvements, so I've stayed with stock paper.
Love your products and your testing!

 

Thanks jjellyneck!

I dont think the filters will do much more than the paper as long as the paper is clean. And based on all the plenums I've opened up, the paper filters do a much better job cleaning.
You could do something like a Stillen box or JWT pop charger and make a little more juice.

BTW Congratulations on your new business! What kind did you start up?