nismology

iTrader: (8)

MAF sensor voltage.

2slow

iTrader: (6)

Ahhh. Then I was wrong; I keep getting hung up on vehicles not using fuel trims for open loop operation. Whatever metric is used to define load (MAP, MAF, or a calculated/correlated value) is calibrated beyond normal operating parameters (VE). Eventually this ability will run out as peak MAF/MAP voltage or injector duty cycle is achieved.

nismology

iTrader: (8)

To my understanding it's a simple formula to determine load as far as these ECU's are concerned: (X) MAF sensor voltage + (Y) Engine speed = (Z) Injector pulse width. The only way the a/f would change is if the target open loop a/f ratio at that particular load cell is different; otherwise it should remain the same.

throttlehappy46

Nearly all OBDII vehicles require short and long term fuel trims(for emissions compliance testing) which is why often an 'ECU reset' will make the car feel quicker for a few days until fuel trims kill power again by adding too much fuel or retarding timing etc to take into account engine wear, poor O2 sensor output etc.

Nissan ECU's do not carry an 'AFR target' but a base injection pulse width for a certain cell value in open loop. Hence why using a Z32 air flow meter requires a complete retune as it is not trying to maintaina certain AFRs but a base injection pulse for a given amount of air.

Once a change is made to the induction or exhaust system, the volumetric efficiency of the engine will change allowing the engine to run more ignition advance(choked up exhaust promotes more exhaust valve heat and hence more detonation prone etc so reduced timing as an example) but by offering a colder and denser air, the knock retard map is likely to allow more timing with the benefit being that a stronger induction can be generated on the next intake stroke due to a thorough combustion from more timing and denser oxygen air on the just emptying exhaust stroke leaves more vacuum inside the bore, which increases volumetric efficiency

Narrow band O2 sensors are just not accurate enough for open loop AFR control

Aaron92SE

iTrader: (128)

Yes, I was only talking about open loop AFR.

Clashez

iTrader: (5)

were could find out how to drop a 3.5 in a 1995 maxima

2slow

iTrader: (6)

How do fuel trims affect ignition timing?

The ECU should carry a base map of fixed injection durations and closed loop AFR targets. The AFR targets can be set with either a software target and a 'wideband' sensor or by a 'narrowband' sensor which activates around a fxed AFR. Without performing more research I do not know how the 5.5 Maxima handles this operation. Without an AFR target, the system would have no feedback error and would be unable to make corrections (via fuel trims). The base map acts as the default settings in the event of oxygen sensor failures and open loop operation.

When changing to another MAF (Z32, etc.) a new calibration is necessary as the new MAF's correlation of voltage to air flow is different. Consequently, this correlation must be 'taught' to the ECU as the original base map references MAF voltage and will no longer provide the correct AFR.

Yes and no. Increasing VE (air flow) allows more fuel be burned and more chemical energy converted to motive power. Supplying a cooler intake air charge will increase an engine's knock limit (decrease octane requirement) and allow increasing ignition timing towards MBT.

Yup, that is why most vehicles use 'wideband' primary oxygen sensors.

2slow

iTrader: (6)

That is correct, usually it is in tabular form with X & Y as axis and Z as the table values. The target closed loop values are almost always a lambda of 1, where other operation modes (WOT, catalyst protection, etc..) use open loop fuelling.

Prophecy99

iTrader: (1)

free bump
I'm having someone else install this was just thinking of worst case scenarios, and say something like that happened as in pbn85's case. What would be the consequences of this? Just short term? or long term?
Im just curious, I would hope my fav shop could handle this.

I have these in my living room by the way. Can't Wait !

Scottwax or anyone who has paid a shop- Do you remember what you ended up paying additionally in your sparkplug+spacer change?

Rochester

iTrader: (3)

I paid a mechanic for this work... if I back out the cost of a new VC, and guess how much to back off for the extra work involved because of the rear VC being trashed and having to clean oil out of the spark plug tubes (damn 5.5 gen covers)... I think the specific cost was around $250.

That's the best guess I can give from my experience.

Worth it? Yes sir, it was.

Aaron92SE

iTrader: (128)

It is a pretty rare occurrence for a shop to be this careless with the application of RTV. I wouldn't worry about it. If you get the keys back and your car doesn't idle smoothly and you have acceleration issues, then something is wrong. And the shop may have to install it again. Of course, they will eat the added expense of cleaning off the Spacers and doing the work over again. A shop should always stand by their work. It pays to do your research on a particular shop before you hand over your keys to make sure they do good and honest work.

The estimated labor time to install the Spacers is 2-3 hours. Do not let a shop charge you for more than 3 hours. But if they are replacing the valve cover or spark plugs at the same time, then labor will be increased slightly.

Most fair quotes I've seen to have these Spacers installed range from $150 to $245. While speaking with one of my customers recently, he was happy with the customer service at one performance shop in South Florida that installed the Spacers for $190 labor. I think this is a very fair price, especially considering they appear to build some pretty nice race cars there.

Prophecy99

iTrader: (1)

Thanks Aaron for your follow up. Great to know. Cant wait for this, my first true performance mod on any car.

Rods03Max619

iTrader: (5)

You will be like Damn Best Bang for the Buck....

Prophecy99

iTrader: (1)

I can't read the install directions that come with the spacers right now so I dont know if they answer this question.

What type of RTV Silicone Sealent should be used for the spacers? It seems like there are many types.

If it is not specified in the directions which it probably is. I need to inform the guy doing the install. As of now all I have to tell him is to keep all old parts.

Thanks.

Froggmann

iTrader: (6)

I used standard Permetex Blue RTV. No Leaks. The biggest thing to keep in mind is to allow the RTV to get a little tacky (Spread then wait a minute or two) before putting that part on the engine. Also you need to use a super thin layer of RTV. Too much and it either makes a mess or causes an air pocket that causes a vacuum leak.

BTW here's the PDF of the instructions: http://nwpengineering.com/VQ35DE_FWD_Instructions.pdf

Just saw that the instructions call for black RTV

Prophecy99

iTrader: (1)

thanks alot froggman

Aaron92SE

iTrader: (128)

Blue RTV will work as well. But Black RTV is recommended.

As Froggmann already mentioned, a thin layer is all that is needed. Most people apply way too much and it gets messy and squeezes out of the intake port and can slightly hinder airflow. I would suggest to make sure the Spacers are wiped clean and the intake manifold surface is clean and free of gouges. Once the mating surfaces are clean, all that is needed is a paper thin layer of RTV around each intake port of the Spacer. Do this to both sides of every Spacer.

I recommend to apply a marble sized amount of RTV on the tip of your index finger and smear it smoothly around each port on the Spacer. Make sure it's a consistent and smooth layer of RTV. If the layer is thicker than poster board paper, then it's too thick and you'll probably see it squeeze out once you torque everything down.

Also, once you have RTV on both sides of the Spacer, you will want to stick the Spacer directly on the manifold. Push it firmly straight down and leave it. Do not let it slide laterally once it's stuck to the manifold.

I love the 1 Minute Gasket made by Permatex. It's much easier to apply. I cut the nozzle very small and apply a TINY bead around each intake port. Then I go back with my finger and smear it around the port. I will wipe the excess RTV off my finger from time to time. Again, a consistent, beautiful paper thin layer of RTV is all that is needed.

Prophecy99

iTrader: (1)

i probably will copy ur reply word for word and hand it to the guy, Thanks aaron. Look forward to my very first true performance mod, they're being installed tomorrow morning.

Froggmann

iTrader: (6)

You're gonna love them.

Aaron92SE

iTrader: (128)

No problem. Also, make sure he gets a copy of the Installation Instructions.

Please let me know if you have any more questions.

VQMagic

iTrader: (1)

Just installed mine today and now have every single bolt on plus DW 440cc injectors and 255lph. Called and asked why there we're two spacers for the LIM. LMAO. I've never taken off the LIM didn't really think before calling haha. I did apply more RTV than needed but I torqued everything down and cleaned the ports before sealing everything up. I don't really notice any sound change but my car is loud as hell up front with intake and headers. No leaks. Butt dyno felt great.
Overall I'm more than satisfied with the results and the spacers and bolts looked great. Highly recommend this mod. Now need a tune and JWT stage 2 cams and I'll be done modding this thing.

NmexMAX

iTrader: (22)

With those 440's you really do need some AFR conditioning.

VQMagic

iTrader: (1)

Yea it's been running pig rich for awhile. For now they act as an anti-tailgater mod lol. Nothing like a big *** fireball at there bumper when I downshift.:

Aaron92SE

iTrader: (128)

Thank you. I'm glad you are happy. That's good that you wiped down the ports before bolting everything back up. You don't want RTV squeezing out and hindering airflow. If your mating surfaces on the manifold and Spacers are clean, all you need is a paper thin layer of RTV to make a good seal.

Also, a tune would be a great thing to do right away. You'll notice a pretty decent gain from leaning out the AFR and advancing ignition timing.

7speed

Aaron, is there a way to only order all the bolts/studs that come with the spacer kit. And about how much?

Aaron92SE

iTrader: (128)

Yes, all the hardware for the VQ35DE Maxima Thermal Intake Spacer Kit is $15.00 plus $6 shipping via 2-3 day Priority Mail. You may place your order anytime by sending a Paypal payment to sales@nwpengineering.com. Please be sure to mark the payment as "Goods" and specify the correct shipping address. Do not include your shipping address in the message box.

Please let me know if you have any more questions.

7speed

Thanks

Be on the lookout funds sent.

REDL1NE

iTrader: (2)

Read through 21 pages...WHEW!

Good work sir. Ill be getting one in the short future.

Aaron92SE

iTrader: (128)

Thank you. I have received your payment. I'm sorry I haven't contacted you earlier. I recently had a very close family member die this past weekend and things have been hectic.

But everyone's orders will ship within the next day or two. You will receive an email with package information soon. Thank you for your business!

Thank you. And good job to you too on reading through this huge thread. Please let me know if there is anything I can do or if you have any questions.

7speed

Hope everything is better for you and the family.

Appreciate the hardware. I'm glad the tb bypass nozel was included, because I forgot all about doing that.

Spacers are in 7hrs later (basically didn't have a good seal first time and had to take apart and redo, so it was like doing job twice).

I thought I saw this somewhere but can't remember. ?? Since car fired right up and no chk engine light or idle issues... Do I need to do any of the relearns?

Unklejoe

iTrader: (6)

You really don't need to do the idle relearn unless you cleaned the throttle body, but WHY NOT.

Aaron92SE

iTrader: (128)

Thank you. Yes, the family is doing ok. The best we can be.

You don't have to do any of the procedures if your car is running properly. I've never had to do any of them on any of the installs I've done. But, like Unklejoe said, it won't hurt to do the procedure. Even if you just want to practice them, go ahead and feel free. The Idle Air Volume Learning procedure can be tricky to get the timing right. If you are not within a 1 second accuracy with your timing, then it probably won't work.