Nissan 370Z Forum

Nissan 370Z Forum (http://www.the370z.com/)
-   Intake/Exhaust (http://www.the370z.com/intake-exhaust/)
-   -   Intake, Header, HFC, CBE = Too Lean? (http://www.the370z.com/intake-exhaust/16437-intake-header-hfc-cbe-too-lean.html)

m4a1mustang 03-24-2010 10:13 AM

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

LiquidZ 03-24-2010 10:15 AM

Still waiting on those results Tony :tup:

Vegitto-kun 03-24-2010 10:20 AM

Ha...ha...ha

I already got the stillen gen 3 CAI's installed

Modshack 03-24-2010 10:29 AM

Quote:

Originally Posted by m4a1mustang (Post 461762)
Tony, thoughts on the injen intakes? From what I remember thee MAF tubes are virtually identical in diameter (injen vs stock).

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

F.I. Inc. 03-24-2010 10:35 AM

Quote:

Originally Posted by m4a1mustang (Post 461762)
Tony, thoughts on the injen intakes? From what I remember thee MAF tubes are virtually identical in diameter (injen vs stock).

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???

CrownR426 03-24-2010 10:36 AM

A tune seems like a great solution to the problem.

F.I. Inc. 03-24-2010 10:38 AM

Quote:

Originally Posted by Modshack (Post 461806)
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

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

Vegitto-kun 03-24-2010 10:39 AM

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

Diocletian 03-24-2010 11:17 AM

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.:)

Smallywood 03-24-2010 12:37 PM

Quote:

Originally Posted by Diocletian (Post 461895)
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.

Vegitto-kun 03-24-2010 02:01 PM

wait so HFC/test pipes and the headers are seperate?

I thought that the headers replaced both of them.

kannibul 03-24-2010 02:06 PM

Quote:

Originally Posted by Vegitto-kun (Post 462207)
wait so HFC/test pipes and the headers are seperate?

I thought that the headers replaced both of them.

Long Tube Headers replace the stock manifold and the cats (or HFC, or Test Pipes)

Short Headers replace the stock manifold only.

Vegitto-kun 03-24-2010 02:08 PM

I see.

so lets say I go intake, header, exhaust. would I need a retune?

semtex 03-24-2010 02:09 PM

Quote:

Originally Posted by Vegitto-kun (Post 462219)
I see.

so lets say I go intake, header, exhaust. would I need a retune?

It would certainly be prudent, yes.

Smallywood 03-24-2010 08:33 PM

Does anyone have a dyno chart of their car that has or currently is running all 4 mods? or all 3 mods to include long tube headers?

I'm curious to see the a/f ratios...


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