Test Pipes -- My View

[Jacko3]

I recently installed my Strup Testpipes on my car on Saturday evening. I must say that test pipes produce a most delightful and exhiliarating sound you could ever have in a car--makes you drive the car harder so that you can hear the sound.

I also noticed that the car now revs up a little faster. Of course, you will hear some little chatter underneath the car---I think that is normal.

However, as you drive, you get to smell the exhauat in small whiffs, especially when you decelerate, and especially if you drive with your windows down. I am not sure if most Gs can get around this issue completely. Perhaps overtime, the exhaust smell will recede. But this wouldn't deter any die-hard G-35 enthusiast, at all. Generally, when going fast, you don't smell anything at all.

I also noticed that gas mileage has dropped by a bit, especially with the gas being blended with ethanol. It would appear that gas mileage is worse at relatively lower speeds than at relatively high speeds (I am not yet sure about this as I am still studying this phenomenon). what is most important here is that there is a drop in gas mileage. Perhaps, tuning the car to lean it out a little, would be a good idea.

There is indeed a gain in horsepower that you can feel. This is no joke at all. Ratio of horsepower gain to cost of test pipes is perhaps the most I have seen so far. Perhaps the design of the test pipe maybe a factor here---Strup is known for making excellent headers and test pipes.

The drop in torque at low RMPs as i had expected, appeared very limited and in some cases insignificant. Over 3000 RPM, the horsepower gains moved the car quite effortlessly, that it was easy to go over the speed limit without knowing it---it began to bring to mind in its infancy, the effect of a power adder like a turbo or supercharger would have on driving behavior. Judging by this effect, I am reconsidering whether to get a power adder at all, as I can see that a power adder will consume gas (poor MPG), and cause the to go faster and thus, lead to potentially more traffic tickets (just an observation, muse, and evaluation).

Again, the cats were heavy---another weight saving on the G. When the test pipes were installed, the CEL did not come on at all. Of course the test pipes was installed with a CEL Fix or a spark plug anti-foulers. I drove all day and the CEL never came on at all. However, I went to the movies with GF and on our way home, the CEL came on. This morning, I disconnected the negative battery terminal for over 5 minutes and reconnected it back, and the CEL light was off. However, I went to Autozone to check the code and it said P0420--we all know what that means.

I have no idea if the CEL will come back on. But I do know it is worth waiting to see and hopefully report back to you all on the consistency with which it comes back on or if it stays off for a long time. Although, I did notice that when the CEL came on, the gas mileage became worse and terrible. So, I would advice anyone to get that CEL removed as soon as possible, and not to drive for extended periods of time with the CEL.

Another issue with the test pipes is that there is a droning noise when you brake with the clutch---this is annoying and can give a headache. The way i battle this deone is to drive at lower speeds with higher gears. For example, I can go 40 miles an hour in 4th gear instead of the usual 3rd gear i used to use. I can now go 55 miles an hour in 5th gear instead of the 4th gear as i used to---this seems to reduce the droning effect. But the temptation to gun the car is there.

But most of all, I cannot begin to tell anyone or even describe to you how beautiful the sound of a G-35 Coupe can be when you are WOT with a test pipe----truely remarkable. Of course, the sound will depend on the type of catback exhaust you have---I have the Stillen TD Catback Exahust, and it is truely a sound to behold when I gun that car.

So, the real question is, is it worth it to have a test pipe? The answer depends on if you are a tree hugger or not, if you love loud sounds or not, if you care about gas mileage and its cost or not, if you are thrilled by a real sports car sound or not, if you can handle droning sounds or not, if you can remove the CEL readily or not, etc.

There is no straight answer to this test pipe issue. All I know is that I am enjoying it as a part of my modification deal. However, I know someday and somehow, i will remove the test pipe once I begin to experience diminishing utility or returns or if it becomes more trouble than it is worth in the future. For now, I have no CEL light and the car drives like a dream.

Most of all, i would advice that you get the right tools to get the job done. The 02 sensors can get stuck in the cats. If you can't get the tools, let a good mechanic help you out.

I hope to post the Stiillen Exhaust sound once i re-learn how to use my camcorders. I don't know why i am even in the 21st century to begin with .

I forgot to add that my car is a 2007 G-35 Coupe 6MT RAS NAV.

Modified by Jacko3 at 10:55 AM 9/14/2008
Modified by Jacko3 at 1:43 PM 9/14/2008

[SteveTheTech]

Sounds like fun. With the noise difference it is hard not to push it farther.

If I were you I would print the APP relearn and manual Idle Volume Learn procedure and keep them in your glove box. As disconnecting the battery will reset both of these parameters.

Pretty good review though the CEL did set in less than 24 hrs ,right? And its still illegal,

[Jacko3]

Steve:

What was the APP relearn and Manual Idle Volume Learn mean? Can you provide me with the link or post the procedures? Thanks.

[Jacko3]

Steve:

Just confirmed from my mechanic that i don't need to do an APP relearn or manual idle volume learn since I don't have a problem with my idling. Though, i do see why it might be handy in case that happens.

[SteveTheTech]

Exhaust Valve Timing Control Learning (M/T models)DESCRIPTIONExhaust Valve Timing Control Learning is an operation to learn the characteristic of exhaust valve timing controlmagnet retarder by comparing the target angle of exhaust camshaft with the actual retarded angle ofexhaust camshaft. It must be performed each time exhaust valve timing control magnet retarder is disconnectedor replaced, or ECM is replaced.OPERATION PROCEDUREWith CONSULT-II1. Start engine and warm it up to normal operation temperature.2. Set shift lever in neutral position and confirm that following electrical or mechanical loads are not applied.– Headlamp switch is OFF– Air conditioner switch is OFF– Rear defogger switch is OFF– Steering wheel is in the straight-ahead position, etc3. Keep the engine speed between 1,800 and 2,000 rpm.4. Select “EXH V/T CONTROL LEARN” in “WORK SUPPORT”mode with CONSULT-II.5. Touch “START” and wait 20 seconds.6. Make sure that “CMPLT” is displayed on CONSULT-II screen.Without CONSULT-II1. Start engine and warm it up to normal operation temperature.2. Set shift lever in neutral position and confirm that following electrical or mechanical loads are not applied.– Headlamp switch is OFF

Learning completed : CMPLTLearning not yet : YET

BASIC SERVICE PROCEDUREEC-79

Revision: 2006 August 2007 G35 Coupe– Air conditioner switch is OFF– Rear defogger switch is OFF– Steering wheel is in the straight-ahead position, etc3. Keep the engine speed between 1,800 and 2,000 rpm at 20 seconds.Accelerator Pedal Released Position Learning DESCRIPTIONAccelerator Pedal Released Position Learning is an operation to learn the fully released position of the acceleratorpedal by monitoring the accelerator pedal position sensor output signal. It must be performed each timeharness connector of accelerator pedal position sensor or ECM is disconnected.OPERATION PROCEDURE1. Make sure that accelerator pedal is fully released.2. Turn ignition switch ON and wait at least 2 seconds.3. Turn ignition switch OFF and wait at least 10 seconds.4. Turn ignition switch ON and wait at least 2 seconds.5. Turn ignition switch OFF and wait at least 10 seconds.

Throttle Valve Closed Position Learning

DESCRIPTION

Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve bymonitoring the throttle position sensor output signal. It must be performed each time harness connector ofelectric throttle control actuator or ECM is disconnected.OPERATION PROCEDURE1. Make sure that accelerator pedal is fully released.2. Turn ignition switch ON.3. Turn ignition switch OFF and wait at least 10 seconds.Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.

Idle Air Volume Learning

DESCRIPTION

Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specificrange. It must be performed under any of the following conditions: Each time electric throttle control actuator or ECM is replaced. Idle speed or ignition timing is out of specification.PREPARATIONBefore performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied.Learning will be cancelled if any of the following conditions are missed for even a moment. Battery voltage: More than 12.9V (At idle) Engine coolant temperature: 70 - 100°C (158 - 212°F) Park/neutral position (PNP) switch: ON Electric load switch: OFF(Air conditioner, headlamp, rear window defogger)On vehicles equipped with daytime light systems, if the parking brake is applied before the engineis started, the headlamp will not be illuminated. Steering wheel: Neutral (Straight-ahead position) Vehicle speed: Stopped Transmission: Warmed-up– For A/T models with CONSULT-II• Drive vehicle until “ATF TEMP SE 1” in “DATA MONITOR” mode of “A/T” system indicates less than 0.9V.– For A/T models without CONSULT-II and M/T models• Drive vehicle for 10 minutes.EC-80BASIC SERVICE PROCEDURERevision: 2006 August 2007 G35 CoupeOPERATION PROCEDUREWith CONSULT-II1. Perform EC-79, "Accelerator Pedal Released Position Learning" .2. Perform EC-79, "Throttle Valve Closed Position Learning" .3. Start engine and warm it up to normal operating temperature.4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.5. Select “IDLE AIR VOL LEARN” in “WORK SUPPORT” mode.6. Touch “START” and wait 20 seconds.7. Make sure that “CMPLT” is displayed on CONSULT-II screen. If“CMPLT” is not displayed, Idle Air Volume Learning will not becarried out successfully. In this case, find the cause of the incidentby referring to the DIAGNOSTIC PROCEDURE below.8. Rev up the engine two or three times and make sure that idlespeed and ignition timing are within the specifications.Without CONSULT-IINOTE: It is better to count the time accurately with a clock. It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuithas a malfunction.1. Perform EC-79, "Accelerator Pedal Released Position Learning" .2. Perform EC-79, "Throttle Valve Closed Position Learning" .3. Start engine and warm it up to normal operating temperature.4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.5. Turn ignition switch OFF and wait at least 10 seconds.6. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.7. Repeat the following procedure quickly five times within 5 seconds.

ITEM SPECIFICATIONIdle speed A/T: 650 ± 50 rpm (in P or N position)M/T: 650 ± 50 rpm (in Neutral position)Ignition timing A/T: 15 ± 5° BTDC (in P or N position)M/T: 15 ± 5° BTDC (in Neutral position)MBIB0238EBASIC SERVICE PROCEDURE

Revision: 2006 August 2007 G35 Coupea. Fully depress the accelerator pedal.b. Fully release the accelerator pedal.8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stopsblinking and turned ON.9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.10. Start engine and let it idle.11. Wait 20 seconds.12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within thespecifications.13. If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carriedout successfully. In this case, find the cause of the incident by referring to the

DIAGNOSTIC PROCEDUREbelow.

DIAGNOSTIC PROCEDURE

If Idle Air Volume Learning cannot be performed successfully, proceed as follows:1. Check that throttle valve is fully closed.2. Check PCV valve operation.3. Check that downstream of throttle valve is free from air leakage.4. When the above three items check out OK, engine component parts and their installation conditionare questionable. Check and eliminate the cause of the incident.It is useful to perform EC-141, "TROUBLE DIAGNOSIS - SPECIFICATION VALUE" 5. If any of the following conditions occur after the engine has started, eliminate the cause of theincident and perform Idle Air Volume Learning all over again: Engine stalls. Erroneous idle.

[SteveTheTech]

I will clean that up after the Pats game. I just wanted to get it to you asap.

[Jacko3]

Thanks steve:

I am going to print this out and keep in my car just in case. Thanks a million. Take care.

[phil4watching]

I got really lazy, and didn't finish. Do you like the test pipes?

[Jacko3]

Yep!

[Jacko3]

My GF is crazy about my test pipes. She loves it. Now I am having to pry her away from making me drive too much as gas prices are too high.

And, in addition and in adjustment to my earlier comments, after a few days of driving with test pipes, I noticed that the torque in the car does not actually get lost. Rather, it gets pushed towards much higher RPMS, unlike without test pipes, when the torque was more evenly distributed across RPM ranges. The useable torque at lower RPMS now makes the car behave a little more like a V-6 than a V-8---easier on the clutch for daily driving, but at higher RPMS, the car becomes a beast while behaving a little more like a V-8.

With the test pipes, I noticed I no longer have a constant need to rev up to 6,000 or 6,500 RPM. I am more well behaved now on the road. The car now revs up a little faster as well. Test pipes are great.

I also had to replace one of my post-cat 02 sensors---costs about $170 at a Nissan dealership, because one of them was not screwed in properly, and it got loosened and was dragged on the ground/road---the threads on our 02 sensors are very delicate--can be easily destroyed--pay attention to his, and don't forget to use an anti-seize when installing one. Well, the effect of this change in 02 sensors is that the gas mileage of the car has come back to what it used to, before I added the test pipes---it is just as efficient with test pipes as without it.

So, it would seem that the newer the 02 sensor, the more accurate the computer can determine the correct air-fuel mixture. It would then make sense to change the post cat 02 sensors, if you have mods on, more frequently than what the manufacturers suggest, in order to maintain a more accurate and properly working car. Perhaps, if you have the cash, every 35,000 - 45,000 miles seems about right for replacement of post 02 sensors. If you have no mods, i doubt you have anything to worry about.

And like I said before, once your 02 fails or once your CEL comes on, our cars automatically shifts the air-fuel ratio to a relatively rich mixture which translates to really bad MPG---you can see it as the needle literally moves, as you drive. And this bad MPG would occur even before the final CEL comes on, as our Gs have to go through several cycles before throwing the CEL.

So, your MPG if getting worse or good, and if you don't have a CEL, is one of many good and surrogate indicators that all is either not well or all is good, with your car, before the CEL comes on.

I will keep you posted as the weeks continue about this test pipe. For me this is more of an experiment than anything else.


Modified by Jacko3 at 8:52 AM 9/18/2008

[Tampa G35 Sedan 6MT]

wow you boys have been busy today lol!

[Jacko3]

As i continue to test the test pipes, my CEL came on 24 hours after re-installing the new O2 sensors. Again, I disconnected the negative terminal only of the battery for 5 minutes to clear the CEL. Since then, the CEL has not come on at all, and I have been flogging the car for a while now, to see if enough gases will trip the CEL. I guess the CEL fix actually works. So, when you install a test pipe, the CEL wil come on within 24 hours of installation. Clear that light by disconnecting the negative terminal of the battery for 5 minutes and then reconnect.

Now, as far as MPG is concerned, it appears the car uses gas better at higher RPMS than at lower RPMS, especially in the 4th gear. I am not sure why this is the case. As always, the 3rd gear is the worst gas guzzler on the 6MT. The 2nd gear is also bad with gas but not as much as the 3rd gear.

Beleive me, the test pipe sound is the best---starting the car and letting it idle in the garage is a joy to listen to---Stillen really made an awesome exhaust system. The only thing you have to worry about is the drone that can actually give you a headache---not to worry you can alter your speed by driving 40 miles an hour in 4th gear and 30 miles in 3rd gear to reduce the droning sound. And the horsepower gain at 4,000 RPM and beyond, is real. Just wanted to provide an update so far. If the CEL ever comes on, I will let you know.

[dasoupdude]

You gotta love the Ferrari Growling cold start as well.

[Jacko3]

Yep! Saw a Youtube clip and I was impressed.