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Discussion Starter #1
...are not encouraging. Dave (DAVESNELLING) just popped over to do a few more runs after last Sat's install of the Injen intake. The initial results (posted below) didn't show anything, but were written off due to the ECU needing to adjust. He reset the ECU on Sunday and has sincxe put about 300 miles on it over the course of 4 days. After the install, he immediately noticed a loss in the low end of the powerband and a gain above 5200 rpms. Upon the new runs tonight, I observed this as well. The original times from Sat. are: (get the full story here: http://www.infinitifx.org/phpBB2/viewtopic.php?t=1318)

#1 DAVESNELLING's stock FX35 RWD (1/8 tank of gas)
1. 7.17
2. 7.16
3. 6.88
4. 7.07
5. 7.06 (auto)
ave manual runs = 7.07 sec 0-60

#1.5 DAVESNELLING's FX35 RWD immediate post Injen install
1. 7.06
2. 7.21
3. 7.01
4. 7.27 (just BARELY tapped the rev limiter; I'll throw this one out for the ave, anyway)
5. 7.20 (auto)
ave good manual runs = 7.09 sec 0-60

Tonight's runs: (1/4 tank, all manual mode, same place, same conditions)
1. 7.26
2. 7.28
3. 7.23
4. 7.21
5. 7.02
6. 7.19

That's an average of 7.2 sec 0-60. SLOWER.

The one run of 7.02, I hit the shift at 6500, whereas all the others were at 6700, so there's something to be said for technique, however, I feel I was consistant enough throughout the other runs and Sat's runs for these times to be compared to one another. I though to check his tire presures tonight: 32 psi hot; a bit low IMO, but he hasn't changed them since Sat. Could there be anything to be had here? Othere theories include:
-MAF moved to different location with Injen setip
-Length of intake tube changed with Injen setup
-ECU may still need more time to adjust since it was totally reset
-Injen's dyno and R&D was on an AWD. Perhaps the increased load on the engine in an AWD car reacts differently to the intake design than a RWD car?

Just brainstorming here, but at any rate, the car is slower than stock and neither one of us are very impressed with the intake at this point. Our next course of action is for him to keep driving it and the next time we have a meet, we'll do more runs, then put the stock intake back in followed by yet more runs. If it gets quicker immediately after switching back to stock, we'll have our answer.

As for the sound of the intake: I have to say I prefer the Stillen/Z-tube combo. The Injen is louder and has a tinny, metallic resonance at higher RPMs that I don't particularly care for. Acceptable if it made the car faster, but...

So what's up with the dyno results that Injen posted and the contradictory evidence presented here? Ideas?
 

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Our next course of action is for him to keep driving it and the next time we have a meet, we'll do more runs, then put the stock intake back in followed by yet more runs. If it gets quicker immediately after switching back to stock, we'll have our answer.
A lot of work, but that should resolve the questions. If the performance turns out to be worse with the injen (vs stock) then there must be something wrong with the way the ECU is responding. Doesn't seem like the tiny displacement of the MAF sensor should make that much difference. :? Also, are you comparing sound quality as heard from the cabin or the outside (or both)?
 

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I'm not bashing Injen, but from previous experience with them on my Lexus IS300, I went through 3 versions! All of them lost HP at the bottom end and gained some on the top.

The only time I was happy with Injen was when it was paired with my Area51 piggyback ECU. The problem was that it would set off a check engine light.

I ended up returning all 3 versions and stuck with a Tom's drop in filter with a real carbon fiber intake tube.

Injen looks nice, but doesn't perform in my book.

I'm happy with my Z-tube/Stillen set up! :D
 

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Discussion Starter #4
particlefx said:
Our next course of action is for him to keep driving it and the next time we have a meet, we'll do more runs, then put the stock intake back in followed by yet more runs. If it gets quicker immediately after switching back to stock, we'll have our answer.
A lot of work, but that should resolve the questions. If the performance turns out to be worse with the injen (vs stock) then there must be something wrong with the way the ECU is responding. Doesn't seem like the tiny displacement of the MAF sensor should make that much difference. :? Also, are you comparing sound quality as heard from the cabin or the outside (or both)?
Not that much work, really. It's the only way I can think of (short of dyno testing) to get difinitive results. I respect what Sonoman1 has siad regarding his Injen and it DOES feel quicker to my butt dyno b/c of the way it opens up the top end and the noise does something to your subconscience as well, but Dave notices a loss in the bottom end and the numbers don't support any performance gains (in fact, the opposite).

The placement (even the angle) of the MAF can have a big impact (don't ask me why). Not saying that IS the case, just one variable among many; the Injen is a drastic change in intake design compared to, say, the Stillen/Z-Tube combo, which keeps the stock configuration and just adds a larger filter and omits the resonators.

As for the sound, my observations were made from inside the cabin with the windows up, AC and radio off, while I was making the G-Tech runs. It is noticable louder than the Stillen and comes from, as I said, a resonance in the AL tube that doesn't sound as attractive to my ears. I don't mind a good agressive sucking sound and the accompanying louder exhaust note, but I can do without the tinny resonance; makes it sound too much like a ricer part IMO.
 

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As has been well documented. I am not a patient person. That having been said- (and $332 spent, 280 for CAI and 52 for the Heat shield still in plastic wrapper) I would be interested in hearing how injentech interprets this. In looking over the Dyno charts (in their whole) it appears that there was no loss in torque or HP, along the graph, and yet our data directly conflicts this. I am unconvinced, as I believe MGFR is, that this is it. No one puts out a Dyno Provenb Product to reduce your performance. Did we do something wrong? Hard to screw up a tube. Did I inadvertantly get the wrong P/N ? The paperwork said RD 1995; We are looking for a little help and encouragement. If Injen says "Hang in there , it will happen" I will believe them, and hang in there. Am i the first to notice this? How long did it take the other Injen users, on other cars, to get it slotted to the electronics? I did read a thread on this forum somewhere that said Injen recommended resetting the ECU after 1200-2000 miles because our ECU is very stubborn.
 

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Injen's dyno and R&D was on an AWD. Perhaps the increased load on the engine in an AWD car reacts differently to the intake design than a RWD car?
Hey I'd be willing to put Dave's injen in my FX next time... :D

Anyway, I wonder if installing the injen in the "short ram air" mode (without the extension tube) would make a difference.
 

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I was wondering about that also, then I could use the shiney Polished Heat Shield.
 

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Discussion Starter #9
Ok, I'm not an engineer, just a car nut gear head who likes to tinker and spends WAY too much time on the internet researching these things, so this'll be in simple terms everybody can understand.

Regular resetting of the ECU IS NOT the answer. The issue of how our ECU adapts to mods has been hashed to death on the Z forums. At first, it was thought that the ECU adapted to effectively negate any mods that you installed. This is not the case (well, sort of). OBDII programming seeks to maintain a (programmed, manufacturer set) optimal set of A/F values and the like to keep emissions down (I'm sure there are other reasons as well). What this means is that when you install a bolt-on mod (intake or exhaust related), the A/F the computer sees will be changed and the computer will attempt to adapt to the mod to stay within it's values. In essence, this DOES take away some of the potential gains of the mod, but not all, as it can only adapt so much.

In comparison, older cars running OBDI computers did not do this, so whatever mod you slapped on, your A/F was directly affected; to **** with emissions. This is just one of those things we have to live with. As I stated, the computer can only do so much, so you may not gain the full potential of the bolt-on, but you will get some of it. This has been proven with dynos from various mods on the Z, including the Crawford plenum. They'd put it on, dyno right away and see top gains (before the computer adapts), then come back and dyno a couple weeks later to dyno again and the gains were a bit lower, but still there (in the case of the Crawford, they went from 19 HP gained at redline to 17; not a big effect, but there are other factors which I'll attempt to explain next.).

The extent of this effect is also dependent upon where the mod is in relation to the various sensors the ECU uses to monitor things and adapt itself to. The gains from an intake are pretty succeptible, b/c the increased airflow is directly measured by the MAF and interpreted by the ECU (Some of you may have heard of a resistor mod people used to do on their MAF to atempt to fool the computer into thinking that there was not increased airflow.). The Z-tube fares better b/c it is after the MAF; same with the plenum.

Dynos have shown that with these mods, our A/F is a bit outside of what is considered optimal, but still within safe limits. The solution to getting your A/F optimal AND getting the full potential out of your mods is a custom UCU flash, such as Technosquare offers for the Z and G (they haven't done the FX yet, but it wouldn't take much for them; they'd just need a volunteer in their area). Crawford maintains that resetting the ECU IS NOT neccessary, but they do acknowledge that it can adapt a bit, lowering the maximum potential of the mods and the optimum A/F and have recently worked with Technosquare to create an ECU flash specific to their package of mods.

I should also note that Crawford does not believe in using aftermarket intakes. One reason is that the Z's intake design is very good to begin with (so a simple drop-in K&N is best), but another is that they've never experienced any intake that has actually done anything positive for the car (likely b/c of what the ECU does with the MAF data. The current intake of choice for Z owners is the JWT Popcharger b/c it does the same for the Z as the Stillen does for us: replace the stock airbox with a larger filter and heat sheild, while retaining the stock configuration This simply allows more air in to feed the mods BEHIND the MAF. I side with crawford in that I believe an intake by itself will not do anything for you, but having the extra capacity to feed other mods is always good.

Bottom line regarding the ECU is that you should actually see the greatest gains from a bolt-on mod immediately after installation, before it has a chance to adapt (this may be contradictory to my previous comments that I thought the ECU needed to adapt before you'd see your full gains, but the more I think about it the more this makes sense.). This is why Injen is saying to reset the ECU every so often: b/c as the ECU adapts to the intake, you lose your gains. As I've stated before, the only thing I've ever noticed the one time I reset my ECU (out of curiosity) was really crappy gas milage, as the computer has to relearn EVERYTHING.

Make sense?
 

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MustGoFastR said:
...are not encouraging. <snip> That's an average of 7.2 sec 0-60. SLOWER. <snip> So what's up with the dyno results that Injen posted and the contradictory evidence presented here? Ideas?
Wow! These results are very disappointing to say the least. Sorry about this Dave. I would hope that the ECU would be adjusted at this point.

The Injen dyno graph shows gains across the rpm band so it should be faster period.

If Injen still uses the ECU adjusting as a reason I think that sounds more like an excuse than a actual reason why a product would not produce results. What gives?
 

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Surely there is a logical explanation. I do not believe that Injen or anyone else for that matter, would market a product that reduces performance. I'll patiently await injentechs comments.
 

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Since the main question here is the issue with the MAF and the ECU adjusting to either a mods benefit or detriment, have any of the Z guys used a MAF Translator before? I've seen the LS1 f-body and Vette guys use this tuning tool to their advantage. Heck, I've seen that some of the DSM guys convert their MAFs over to LS1s and use MAF Translators as well.

The MAF Translator allows you to adjust the air/fuel ratio and timing advance across the RPM band. Do you think that will help us here?

Any thoughts?
 

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Discussion Starter #13
I have heard mention of something like this: a manual adjustment tool. However, you'd need dyno time to tune it properly and I'm not sure how the ECU would react. The flash would be my choice, if I were going to do it.

At any rate the main question here is whether or not the Injen intake actually does anything positive for your car in terms of real world performance. Dynos are all well and good, but real world street performance is what counts in the end.
 

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Discussion Starter #14
DAVESNELLING said:
Surely there is a logical explanation. I do not believe that Injen or anyone else for that matter, would market a product that reduces performance. I'll patiently await injentechs comments.
fair enough. I'd like to hear what he has to say as well.
 

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MustGoFastR said:
At any rate the main question here is whether or not the Injen intake actually does anything positive for your car in terms of real world performance. Dynos are all well and good, but real world street performance is what counts in the end.
Yes that is the main question but my point is that there may be an overall issue with the FX's ECU/MAF systems. If doing mods is shown to be pointless because the ECU adjusts detrimentally every single time, aren't we just wasting our time buying mods until we can find a fix?
 

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Discussion Starter #16
Golden Boy said:
MustGoFastR said:
At any rate the main question here is whether or not the Injen intake actually does anything positive for your car in terms of real world performance. Dynos are all well and good, but real world street performance is what counts in the end.
Yes that is the main question but my point is that there may be an overall issue with the FX's ECU/MAF systems. If doing mods is shown to be pointless because the ECU adjusts determentally every single time, aren't we just wasting our time buying mods until we can find a fix?
If you re-read what I posted above, this is not entirely the case. Intakes are simply the hardest hit; anything behind the MAF will be affected very little (as shown by the Crawford info.). As my G-Tech numbers show, my mods have not been negated. The "fix", if you want to call it that, is for someone with a few mods in SoCal to make a run up to Technosquare so they can get a flash on file for us or to try one of these plug-in tuners (have to read up on My350Z on those).
 

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Going to give a call to Injen and discuss w/them. Patience my ***!
 

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Discussion Starter #18
:D Go get 'em, Dave!
 

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I must be the one you've all been waiting to hear from :) First off, the dyno graph shown was performed on an AWD, immediately there is a difference to RWD. The second and most important thing is that, there are way too many variables. Anything associated with the engine is a factor, cooling temperatures, atmospheric pressure, oil, even where you guys are located are factors. Please do not get me wrong, I am not using this as an excuse, but I am stating that everything is a factor. I can bet you that our dyno sheet cannot be duplicated due to all these different variables. All dynos are different no matter where you go.

Please correct me if I am wrong, but you performed this test on a G-Tech Meter system? Was a dynojet used? Dave is right that we would not produce and market a product that actually loses power. That would be death on our part :), but consider this, everyones setup is not the same as to wear on engine, mods, etc. and although a G-tech meter (if it was used) is a nice form of measurement, it is not exact and also, it would not be able to measure what an actual controlled dyno facilities can do.

Again, please do not take offense to my reply, as this is necessary since we're here to learn from each other and I'm more than happy to receive feedback from you guys :) My whole purpose is just this, to answer questions and concerns you guys may have.

In regards to the ecu, you can view it two different ways. You can reset the ecu if you are comfortable with doing that. We usually suggest to do this with any car that has air flow meter. On the other hand, you can also just allow the ecu to calibrate itself over time, which utimately it will do on its own, correcting its learning curve. When we engineer our systems, we do countless tests in order to accruately account for A/F ratio. The height and location of the MAF sensor is very crucial. Along with length of piping, diameter, materials, etc. *NOTE* When re-installing your MAF sensor, please make sure it is secure and clean!

Again, I have to reinforce that there are too many variables in any given tests. Our system, according to the dyno sheets gains its power on top end, low end gains being minimal and was done on an AWD. Also, I for one personally like the more aggressive tone of the system :D

Guys, feel free to email me. I'm here to help! So Dave and guys, don't lose faith!
 

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Discussion Starter #20
Thanks for posting your input. I don't believe anyone is directly trying to compare your dyno results with our G-Tech results (read the first post in this thread for my test methods and a link to the full story). What we ARE looking at is the fact that you claim (and show with a dyno) that this system produces gains and are applying that knowledge with our tests, which, so far, provide conflicting information. The only comparison we make is that of before and after G-Tech runs on the day of the insatall, with subsequent runs 5 days after an ECU reset and 300 miles under identical conditions. We are not gauging HP #s with the G-Tech, only 0-60 times, as this is where we really want the performance increase (who cares if you gain HP, but make the car slower where it counts?). You are correct in that the G-Tech may not be a perfectly acurate instrument, but it IS a viable tool for comparing before and after results of mods on your own car to see if the mod has done anything for you, provided you have consistent conditions and technique. If there is anything flawed with my logic, please feel free to explain.

What we are basically asking for you is if you have any idea why we are experiencing decreased performance. :?:
 
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