Intake, Header, HFC, CBE = Too Lean?
 

Anyone running all 4 items? I hear that if you run all 4 parts you will lean the car out too much. Any feedback from members running or that have tried this set-up?

idk alot of people are running HFC CBE CAI though im curious to find this out too

Stillen guys told me that all 4 will make you run too lean. Thus, you'll need a tune.

are you fine just running three though? haha

According to them, yes. Three is fine, four is not without a tune.

when I first got my car the exhaust would get some black gook on the intake tips, I guess it was running a tad rich but after the CBE and K&N drop ins, no black gook so Its running a little lean just with that. Cobb access port on the way, wed maybe.

dang i guess after I install the agency power exhaust i will be getting a tune

i thought the all powerful nissan ecu would add fuel when needed?

I have done extensive dyno testing and I can tell you with our headers and CBE the car does not run too lean. However, when you throw Stillen Gen III intakes into the equation it will need a re tune. The A/F will be way out of whack and in the mid to high 13 ratio!

Just to prove my point about not being too lean look at the A/F dyno chart here. This dyno chart is from my LTH thread. You can see the comparison between our HFC/CBE vs. our LTH's/CBE:

http://i371.photobucket.com/albums/o...Headers_AF.jpg

One more thing I would like to add. From just a performance standpoint, I feel that any aftermarket intake for this car is a WASTE of money. :mad: From all of the dyno testing we have done, the gains have been very minimal and in most cases next to none! I have dyno charts that shows a car losing mid range power and some torque in trade of 3 horsepower up top. :gtfo2: For $500+ and the time or money to install it, I feel that you can spend your money elsewhere. Buy the K&N drop ins and call it a day!

If anyone has any questions comments or concerns PLEASE do not hesitate to ask. I can show dyno charts with many different combinations. What I can tell you is that the stock intakes do the job just fine... even with long tube headers installed.

Thank you,

Tony

How come some threads and also Stillen are claiming impressive gains from the G3?

http://blog.stillen.com/wp-content/g...yno_402852.jpg

That's over stock, so they aren't going to show those high gains on a car that's already got exhaust mods done.

I'll take the other side and say they ARE worth it if you stay N/A as they help you eek out that last bit of power for your dyno numbers and sound really cool, but even with 18 whp gains over stock, you'll never feel it. Just look at that Stillen graph... the stock air boxes are super efficient 'til nearly redline (I think the stock pull on that Stillen graph is a little misleading -- it shouldn't fall flat on it's face like that at 6.5K) so the gains you see on paper can't really be felt because they're at the very end of the rev range.

The numbers are impressive with a stock exhaust! Look at the numbers, this is a stock baseline. So the Stillen intakes uncork power in a stock exhaust application. Congratulations to all of those who are running around with a stock exhaust and Stillen Gen III intakes. I know I am sounding a little hostile and for coming off that way I apologize to you ahead of time!

The bottom line (dyno proven) once you change the exhaust system you free up the almost all of the power & torque. (I said almost all) Then you do the intakes, you will see they are not doing much of anything until close to 7000 RPM's! Like I said, I have seen cases where you lose some low end and mid range. We all know usable power is 3500-6800 RPM's, not 7000-7300!

Thank you, Tony

You took the words right out of my mouth...

Tony

I am betting they make a justifiable difference if you run the car at a track where the engine bay is hotter than normal driving conditions and they are actually pulling colder out from in the front of the car instead of in the engine bay. Basing things from a dyno is only a small part in the initial performance gains while getting things tuned to help have the motor run at better conditions because everything there is suppose to be in near perfect conditions. Not to mention a fan blowing air at 15 mph is not same as the car moving faster than 15 mph. A fan to keep the car from over heating from a 15 second pull is not a great test to base off of for intakes. If you do a couple of consecutive pulls, you will watch the horse go down as car generate heats. Add these long intakes and I bet you see better gains than stock ones once the car is a more severe condition than perfect dyno temps. I know you can prove that and are aware of it F.I. Inc. and I know it is true because I was an intern for Dynojet in Belgrade, MT when I was in college in Bozeman. I have seen more than a enough dyno runs and pulls and data to say if you run the car for more than 60 seconds hard and get the car hot that any sort of descent CAI that can bring in colder air to the engine helps teh performance. Thus the point of an intercooler on a S/C or Turbo set-up. Kind of common sense if anyone thinks about it, and yes the stock intakes are great for OEM but things can always be better than OEM to help squeeze extra juice out of NA motor.

Nice thread!

I'm running the Res Test pipes with the CBE (both F. I.) including K&N filters. If I was to go to the long tube headers there may be a too lean scenario? Getting a tune then would be the fix and provide a nice addition down at the mid + RPM range?

I'm curious how much more a tune would provide with my current set up as well.

The stock air boxes are cold air intakes. They isolate the filters from the heat of the engine bay and source cold air from outside... the same air that the Injens and G3s breathe.

The reason the Injens and G3s gain at the very end of the range is because the stock system becomes slightly restrictive beyond ~7k RPM.

Temperature wise, the G3s/Injens/Stock should all be very similar as they are all sourcing air from the same place.

I have a feeling once COBB finalizes the VVEL tuning aspect of the accessport, an intake will definitely be a worthwhile modification, since the motor in theory should be able to take in more air at the top end (assuming Nissan does not already have the cams at maximum lift).

Taken from another thread, see link below.

G37Sam drives a G37 and has Stillen G3 Intakes, FI Test Pipes & Catback and UR Crank Pulley.

He did an UpRev Tune and got 34HP and 32TQ gains.

http://www.the370z.com/tuning/13882-...ned-uprev.html

This is amazinggggggggggg.

My understanding is that the issue really has the potential to show when headers and HFCs are used together. Add in CBE & CAIs and then you run the risk of knock and/or engine damage...

what is running lean? I probably know it in other terms but does it mean that the engine isn't pumping enough fuel and air in the cilinders?

Very good counter response m4a1mustang....

I don't have a CAI...I was initially planning to get one, but after reading all of the posts here and dyno results, I totally changed my mind about it...In one thread, I recalled seeing similar results in reference to the CAI gains...Tony was right, most of the gains are seen at 7k and above....and like "Matt" said in another thread, I don't think any of us are planning to run our Z's at 7K plus majority of the time....

I just don't feel that the minimal gain of horsepower up top, is worth the loss of torque and power in the midrange....

Ideal Air/Fuel ratios for a N/A car are in the 12.5 to 12.8:1 range. Too lean would be in the mid 13:1 range.

Turbo cars like to run richer in the mid 11's as more fuel is used to cool the combustion and keep detonation under boost controlled.

damnit so if I get HFC + exhaust I would have to find somebody that can tune the ECU up.

horray for more money to spend

In simple terms -- too much air, not enough fuel. Running rich would be the opposite.

Self admittedly, I know jack squat about A/F ratios, but i'm curious... my AP says that i'm running an avg. of 14.2-14.4 at idle, is that a normal idle ratio? is it only considered running lean at a specific RPM?

To a point, like most ECU's.

You are fine! Optimum A/F ratio at idol is 14:7! Now WOT (Wide Open Throttle) You reallly want to be in the high to mid 12 range once you get above 4-5000 RPM. At the lower RPM's the A/F being leaner will not be catastrophic to the engine. However if you run it the high 13's low 14's in the upper RPM range you can cause serious damage to the engine. Detonation will occur inside of the engine and you can actually hear it if it is real bad. Bottom line, it is not enough fuel.

Thanks, Tony

I totally agree. On my TT mustang @ 25PSI we are at 1000 RWH! My A/F throughout the entire curve is 11:4-11:7. Keep in mind, I am also running unleaded 109 octance VP race fuel in order to achieve this.

Tony

There are 2 fuel control systems. The first, when at idle or partial throttle, is controlled by the MAF and 02 sensors who are constantly sending readings back to the ECU to maintain ideal Stociometric ratios (14.7:1). This is called closed loop. An A/F gauge will bounce around a lot as the mix is read and constant corrections are sent to the ECU. When you go wide open throttle (open loop), the fueling defaults to some pre-built fuel maps in the ECU. These are usually slightly modified by the Long term fuel trims (correction factors) that are determined over time by the adjustments the 02 sensor Has been making. Typically the Z corrects from a slightly rich tune.
As Parts are added (Exhaust, Intake, HFC's), the rich correction is reduced as the Fuel trims approach Zero. Add Zero to the pre-built map and you'll have a bit more power due to the leaner mix.. (richer is slower). To truly see how closely you are to optimum, read the A/F ratio at WOT as is the case with all dyno plots.

In this picture, Additive is the short term fuel trims, Multiplicative is the long term trims:
http://images51.fotki.com/v747/photo...ueltrim-vi.jpg

Tis why I love this forum, lots more people smarter than I, learn somethin new every day, thanks, +1 rep to you sir.

No you do not. If you run the HFC's and CBE your car will not become too lean. The ECU will correct and do it's job. Here is why the intakes change the A/F ratio's so much more than the exhaust system.

Inside your stock intake tube is a MAF (Mass Air Meter) As the air rushes by it, it samples that air. It works directly with the ECU and is calibrated specifically for the car. If you change altitude your cars A/F ratio will change. Meaning being at sea level opposed to driving in the mountains. In the higher altitude your car will actually be richer. Here is why, the air is thinner up there, your car naturally will take in less air. It naturally wants to lean out due to this and in most cases the ECU will compensate by dumping too much fuel and make the car rich. The MAF and ECU are designed from the factory to do this. However, they only work to a certain extent being that the elements from one place to the next are too different. If it worked perfectly your A/F would be optimum wherever you drove.

Now if you put an aftermarket CAI on the car that changes the location of the MAF or the tubing diameter it will change everything. The car is not calibrated for it. In the case of the Stillen Gen III intakes with exhaust & headers the intakes are causing the car to run way too lean. This is why you need a re tune so at the least amount you can bring the A/F ratios back to where they need to be. I know this how you may ask, over the past two days I dynoed a car that had Stillen Gen III intakes with our exhaust components and the car was borderline unsafe in terms of A/F. We re tuned the car, picked up alot of mid range power and low end torque just be getting the A/F back in the 12's. To be continued I am sure...

Thanks, Tony

Tony, thoughts on the injen intakes? From what I remember thee MAF tubes are virtually identical in diameter (injen vs stock).

Still waiting on those results Tony :tup:

Ha...ha...ha

I already got the stillen gen 3 CAI's installed

It's not the diameter of the intake tubing, but actually the diameter of the tube where the MAF reads the airflow. You'll notice some designs run a larger pipe, but neck them down at the MAF. As Tony said, this needs to be tuned to the car. I do a lot of work in this area and recently have been experimenting on the Z. As you open up the tube at the MAF, the air flow actually slows down and the fuel system signal is reduced (this is basic physics). This is why some intakes make more power. Since filter restriction is not really a big factor, it is this subtle fuel adjustment that is making the difference. The Z is naturally a bit rich...Lean it a bit to bring it to optimum A/F ratios and you make more power.

The stock MAF tubes are tapered a bit from a 2.34 to 2.36 Internal diameter. I've recently revised my Custom CAI and cut some new tubes at 2.39 with a Venturi taper at the leading edge. These have resulted in a Zero Fuel trim correction over 150 miles now, which indicates they are pretty much on the money. The car runs very strongly. For more info on this you can read my page here: Modshack | Stage 2 MOFO (BAMM)

http://images20.fotki.com/v533/photo...MG_2349-vi.jpg

http://images110.fotki.com/v570/phot...MG_2353-vi.jpg

As far as fitment, quality and overall looks I think hands down they are the nicest. I am throughly impressed with them!

As far as performance I have not dynoed a set yet. I hear mixed reviews from customers and until I dyno them I just don't know. What I can tell you is the filter location is closed off from the world and cold air will have a really hard time getting up in there. Now if you modified the bottom of the fender well liner by drilling holes in it to create perforation you will obviously allow more air to get to them. This is the goal, right! Cold Air!!! Now, it is very simple theory if you can keep the bends to a minimum, allow the filters to get cold air and mimic the stock tube size to keep the maf calibrated then you should pick up performance across the board. I think Ingen has achieved two out of three. If you look at their tube it looks like it was designed off of stock with a smaller diameter where the MAF is located. They also claim that it is dyno tuned and calibrated in the R&D process. The bends are also long sweeping bends that are as minimal as you can make them given the room they have to work with. Remember less dramatic bends, less restriction. The only one of the three that they do not have is the cold air factor. Like I stated before, the filters are hidden from the world. I know about the hydrolocking issue from water getting in them and this is part of the reason why they are where they are but has it really ever happened to anyone with this car???

A tune seems like a great solution to the problem.

Very impressive, you should market this if it works in the long run. Got to run, have alot of exhaust and headers to build...

Thanks, Tony

problem now is where the hell will I find a place that is actually good at tuning/solving these problems -_-

So, I have the Injen intakes on my car. I also ordered the FI CBE. According to what's being said here I can get HFCs or test pipes WITHOUT having to worry about tuning the car yet?

Just trying to decide if I should pull the trigger on set of HFCs/Test pipes while I wait for my FI exhaust.:)

You can add either the HFCs/test pipes or the Headers, but not both without tuning. I would recommend the HFCs.