all_bark

iTrader: (5)

Some people have been saying that they put on a new intake and lose power, some say they put on a new exhaust and get no power gains, other say that that the gains are there but the ecu takes away those mods by readjusting to the change through its sensors.

Are these claims false? Nissan says the ecu will not readjust to cut mod benefits.

What is the case, what is your opinion? I want to add an injen intake and want to know if it is just a big waste of money until the ecu crack comes out.

What does everybody think? Or KNOW FOR SURE?

let the opinions come forth!

350z4steve

iTrader: (1)

well put it this way..Im thinking if nothing really worked for the Z and it was all "smoke and mirrors" then why would they bother putting out and in the process be still developing aftermarket stuff if it really wasn of any added benefit?Hopefully this isnt just the "emperors new clothes syndrome"..

FLY BY Z

I believe what a dyno shows more than I believe what a Nissan rep has to say about it. The rep probably (and I am not stating a known fact) does not even know what we are talking about if we ask him/her about an ECU compensating for increased airflow through timing retardation and/or fuel flow adjustment. It is the same as the response we have gotten from Bose. Canned.

The word of Nissan is not gold although some, who swore mods were not making power, now treat it as such. I guarantee you that the person at Nissan who responded to the ECU inquiry is not the person who wrote the program that resides in the ECU hardware that he did not construct. How valid could that be? Not as valid as dyno results showing no gain right before our eyes, I tell you that.

FLY BY Z

It is. People will buy it to customize their auto. They want something different than the rest of the crowd. It's not to say that once the ECU has been cracked and a program or two perfected the mods won't work. I am sure they will. I can't think of anything else on this car that has the capability of reducing or increasing the effectiveness of a mod other than the ECU.

Personally, I think that the intake is absolutley fine in and of itself and did not see any reason whatsoever to install a CAI. If a CAI did show gains and there was no ECU conundrum, I could not see it producing more than a couple crank HP anyways. There is nothing restrictive about the intake and don't fool yourself, the stock intake is getting cold air from outside the engine bay.

Some people buy things because they exist.

350z4steve

iTrader: (1)

In that case go with what does work in the sense of adding more usable power to the wheels..working with what you got HP wise changing out the underdrive pulleys (lighter ones) will get more HP to the wheels from the crank.

all_bark

iTrader: (5)

just because "a nissan rep" says so does not make it so! what about the dynos that shows no increases (or loses) when redynoing after a mod (like intake or exhaust)? Are they posting fake dynos?

I believe that the ecu does reset but after it is cracked (chebosto seems to have a great handle on that) it will allow the mods to actually show there true gain. My opinion means nothing because I know nothing but hey, its my opinion and I got lots of bark to back it up!

So is THAT YOUR FINAL ANSWER?

shaneotool

Guy's with the V6 Altima are adding intakes and exhausts and running 1/4 mile times of 14 sec or less. - so they are getting performance gains without the ecu negating them.

Why then would nissan use an ecu that negates performance gains in their sportscar? The car that would most likely have performance mods done to it? Doesn't make sense.

I think the intake on the Z is already about as good as it gets, just a huge tube running straight to the engine, not much to be gained here.

Take a look at the intake on a V6 Altima, the air goes through a tiny slit, takes a 90 degree turn, goes through a twisty maze with multiple resonators - I think thats why they show gains with an intake (which are still moderate <10whp), and we don't.

MannishBoy

iTrader: (1)

The Crawford headers, for instance, were dyno'd after quite a while of driving, including a trip from Nashville to Atlanta.

Power can be made, but the stock intake box isn't really that restrictive, so the supposed CAIs aren't really adding a lot. The factory exaust is probably pretty sufficient for the the unmodded engine, so exhausts aren't producing a ton of power on their own.

I think that we'll start to have people figure out combos of additive mods, that work together much better than seperately. In other words, plenums, headers, exhausts, etc might equal gains more than the sum of their parts in some cases. In others, maybe not.

*shrug*

I think we've just got an engine that was pretty tweaked in general from the factory.

elektrik_juggernaut

at first, i believed that the ECM negated mods......mainly because i read it here, and felt it in my car.......here is what really happened: 1. I put an intake on my car.......2. I got used to it.......3. I didn't realize the bonus HP anymore

After an Injen CAI and several thousand miles in between the install and my last dyno, i have found that there are gains that stick.

I had an informal dyno done recently on a different one than the one quoted in my signature. The guy running it said i was probably running closer to 255rwhp. I didn't get the printout from that one, so i'm not claiming it.

A lot of factors come into play here. If i dyno on a cold day, i will have more HP than if i dyno on a hot day. If i'm running Exxon Gas, i will have more HP than if i'm running Joe Schmoe's Gas. If i'm closer to my last oil change, i will have more HP than if i'm overdue.

xZlr8

This is BS. The ECU will make adjustments only to balance the new modifications. Injen proved this by driving the car for 10-15 minutes between modifications to let the ECU learn the changes. If you add an intake and more air is sensed by the MAF the computer will respond by increasing the fuel so that the air/fuel ratio is once again appropriate. More fuel and air (in the correct ratio of course) = more power. The ECU will not then decide to take your power away by retarding timing or some lame notion like that. However, if you remove the CAI you will return to your original HP as the computer will dial down the fuel to once again normalize the ratio. Some people are stating they noticed a drop in HP over time on the dyno. Ok, well it's a different day with different conditions. Injen tested by waiting 3 minutes between each run. How long do you think it takes a computer to "learn" the change and decrease your power? It's a computer, it's fast, i seriously doubt it would take it weeks to make the change back to no hp, being as it gave you hp in a couple of seconds after your install. Here's the write-up, think about it and make your own conclusion. http://www.injen.com/350z_testing.html

Chebosto

iTrader: (43)

didnt want to come to this but...

how can you trust a three minute pause inbetween dyno runs? yea. i'm sure that a good representation of an actual car under test.. obviously you need to take a pull once its on, and after the car has been running for a while for the ecu to learn the mod is on..



here's what the service manual says...

Javi

It has been three months and over 2000 miles since I installed my Injen intake and last week my Z still was 1.5mph faster in the trap speeds before the install (at the 1/4 with even more tire spin than stock) and I can still pull a car lengh on 2003 M3's all day long.
I'm still waiting for the ECU to take the fun away...

D'oh

The ECU does not compensate for "mods".

It compensates for rich/lean, as well as knock.

If you can increase airflow then you should get HP as long as you aren't inducing know and therefore causing the computer to retard the spark timing.

Cheston had said (and I believe I am remembering this correctly)that he saw the computer pull timing when they were tuning, and others have said that some of the cylinders run leaner than others.

I therefore think a few things are going on.

1. The stock exhaust and intake (especially intake) are already pretty damn good.

2. Changes to the intake may tend to cause some cylinders to run even leaner than others, leading to knock and causing the car to retard timing, which is effectively negating some of the gains. I personally believe that we are really just seeing that the intakes provide a very slight gain in the first place.

3. Dyno's are NOT perfectly repeatable, and when you factor in different conditions, it is likely that any marginal gain (like those from most CAI's) will be lost in the noise.

4. I want to see some dyno's of Doug's headers and plenum that show losses over time. I believe that the gains provided by these well researched and designed mods will not be lost due to ECU compensation, because they are not creating a condition in which the ECU tries to "detune" the engine. Also, I'd like to see some dyno's of the Borla True Dual exhaust that has been advertized as making some impressive gains. I doubt those gains will go away either (unless they are "overstated" in the first place).

So, yes, the ECU can compensate for certain things, but none of them are "HP" or "mods" directly.

-D'oh!

stx

From my personal experience the ECU didn't negate my gains after three months of driving my car. I have dynos from three months ago to a few weeks ago and they both have gains from my baseline.

In my opinion the companies that have investments in programming the ECU's are the ones feeding this misinformation about the ECU negating gains because they want to convince people they need to buy their ECU. What better way to do that then get on the internet and say the ECU negates all mods. Now I do believe you can get some gains from the ECU but I know they don't negate your mods. If it does it didn't negate my mods, so how do you explain that?

Those are my experiences and thoughts on this matter.

westpak

iTrader: (19)

I think the problem is that the performance gains we can get from the mods available are so small (5-8HP) that it is hard to accurately measure whether the ECU is negating them or not due to the lack of accuracy of doing Dyno's, there are so many variables on getting consistant dyno runs that it is almost impossible to duplicate dyno runs.

Someone without mods could a dyno at say 4000 miles and then a follow up at 6000 miles without any mods in between and they will probably get different results.

It would be much easier if we had a mod that made like 25-30HP and was more noticeable to see if the ECU had an effect but as long as we are talking 5-8 HP will not have an answer.

xZlr8

good post!

1. Maybe the intake and exhaust are "pretty good" but they can be made much better (i.e. 23hp from intake and exhaust)

2.The ECU will detect the increased air from the CAI and compensate by increasing fuel, not retarding timing.

3. You're correct, dynos vary and this is probably the variation some, and i repeat some, are reporting (i've seen no such variation).

xZlr8

f

That is still only talking about the ECU trying to maintain the correct ratio over short and long intervals. The long term trim is only another means of insuring the proper balance. It has nothing to do with any other systems of the car running less efficiently in order to negate your power from mods. Why would it do that? The air flow sensor will see more air and up the fuel to compensate thus giving you more power. This maintains the ratio, so that optimal combustion occurs...not to maintain 287 hp and screw you out of power. And you can trust a 3 minute pause because it is quite long enough. It doesn't take that long for the sensor to detect the increased air and increase your power accordingly. Nor does it take that long to go back to baseline after you remove the CAI.

dr_gallup

That is exactly what every ECU does and what lets us modify EFI engines (within limits) and realize power increases without modifying the ECU. We mod engine, air flow increases (hopefully), ECU detects A/F ratio change, ECU increases fuel flow, horsepower goes up. In the bad old days of carburators we had to take the things apart and put in bigger jets.

The only way the ECU could negate air flow increase would be to dial back cam or ignition timing. I can not say for a fact that it doesn't because I have no experience on the Z's exact hardware but I work for a FIE manufacture and none of our systems or any of our competitors that I have experience with work like that. I know this is a new system so maybe... but why?

I expect that the reported dialing back of power is due to testing inaccuracies or uncontrolled vairables like fuel octane. It is very difficult to do repeatable, accurate dyno testing and believe me, the typical speed shop dyno is neither. How many times have you seen a speed shop correct for humidity? No one I've seen posting results is using reference fuel, just what ever they bought last week. You can never buy the same pump gas twice. How tightly you tie the car down to the dyno affects slip, how accurately you align the car to the roller affects scrub. Both of these will change frictional losses. Anyone looking for better than +/- 5 HP had better be doing it on the same day with the same dyno with the same fuel without removing the car from the dyno and hope the weather doesn't change too much. That is the reality of testing.

Ben Davis

I do not see the ECU doing anything out of the ordinary.....

I do see a new car without alot of time to test and tune mods, so what we are getting is the best LOOKING parts a given company can manufature in a short period. Wait until the Gen II parts come out and i ebt we see more gains. I think that the exhaust is prolly fine as is, it's pretty free flowing IMO and plenty wide. The intake seems fine as well. Headers i havent really looked at, and headers also take time to develop, primary length and size, collectors, angle, equal length,.....

Ben

TJZ

I say it doesnt.