Intake, Header, HFC, CBE = Too Lean?

chris410

When you tune, don't aim for "lean" you will end up with peak numbers, you want the car to allow timing to remain consistent so at times, actually running it "slightly" rich will not give you the peak numbers but it will give you an increase overall.

Of course, don't run it too rich...you want your a/f ratios to be a few points under "lean"
Also, if your car tends to pick up power at any point try actually adding a little fuel in that area instead of leaning it. You'll find that your timing will actually remain consistent VS getting that peak and then having the car pull timing to redline.

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Chris
Current: 2014 WRX Stage I + SPT / 2013 Hayabusa 202HP
Former:09 370Z 7-AT PW/Ark Type 2 exhaust/Evo R lip/TSW Nurburgring carbon

NewlyIMPORTed

so basically once I put my CBE on the car considering i have the G3 and berk HFC i will need a tune immediately?

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2011 WRX STICobb Accessport, Nameless Performance exhaust, COBB SF Intake, COBB downpipe, 20% tint, Work Emotion XD9's

chris410

The "safe" thing to do would be having a dyno with an A/F meter to see where you are at. You can drive the car, but not beat on it too hard until you at least confirm that your air/fuel ratios are within tolerance. That and you could be giving up power by not having it tuned.

Better safe than sorry!

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Chris
Current: 2014 WRX Stage I + SPT / 2013 Hayabusa 202HP
Former:09 370Z 7-AT PW/Ark Type 2 exhaust/Evo R lip/TSW Nurburgring carbon

Zsteve

The tunes really do help bring things in order. MY AFR at idle is 14.6 and when at WOT it drops into the 12s. My MAF readings I took said my stock box with drop ins gobbled up 240 G/S when stepping on it and Im only 8-10 degrees above ambient temps. The tune gav e the car some decent gains and has my AFRs where they should be. Worth the money since you get a diagnostic device too.

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2010 LS3 C6 Silver coupe corvette

Nick911sc

This thread was super informative. I never would have thought some cars with G3 CBE and HFC would have issues with running lean.

So my question is after reading this thread(since I have some levels of ocd)

When I eventually install HFC and CBE on my car, there will be 0 danger of running lean if I stay with the stock intake without a tune? These 2 things would be my only engine mod.

Zsteve

you will be fine without a tune. And if you just do K&N drop ins you will be fine too as that way you wont be changing the size or location of the MAF section and it will still let the car breath better. And if you decide to do a tune, the canned maps will get you some extra gains too.

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2010 LS3 C6 Silver coupe corvette

Daishi

From what I can tell by looking at the intakes I believe you would be ok with Injen intakes.. the problem with the stillens is that the tubing is too thick where the maf is. The Injen intake is actualy tuned for proper a/f ratios and runs close to stock size tubing where the maf sensor is. I know every car is different but ive always had good results with injen intakes on all my cars. Most of my cars had full catless exhausts and injen intake with no issues what so ever.

Zsteve

Not sure what the thickness of the piping has to do with anything at the MAF location. Its about the diameter of the piping, and that is how some intakes are making the gains they are, is that they make the MAF size a little bigger tricking the ECU on the actual amount of air coming in (more air coming in but the ECU thinks less is coming in cuz the larger pipe means less velocity, if I remember the explanation to me before about this) which then causes the ECU to adjust in a way to make more power.

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2010 LS3 C6 Silver coupe corvette

Daishi

Zsteve that's exactly what I meant your just being too literal on my word choice. I meant diameter instead of pipe thickness.

BalanBro

That's right. A larger pipe will have slower airflow than a smaller pipe at a given flow rate. Think of it like a garden hose: when the end is open, a large volume of water slowly pours out. Now you put your finger over it, and all of a sudden the water moves out much faster, but the amount of water coming out is pretty much the same. What you did was in effect make the hose act as if it were smaller.

This concept is important once you know how a maf sensor works. Basically, it's a wire that is heated to a target temperature by an applied voltage (aka "hotwire"). As faster air goes over the wire and cools it down, more voltage is applied to compensate. It is this voltage that the ecu uses to calculate the required amount of fuel.

In a nutshell, it's like this: larger pipe-->slower air-->less cooling of hotwire-->less MAF voltage from ECU-->less fuel injected-->leaner air/fuel mixture.

I think exhaust and HFC's alone have little effect on A/F ratios, as any additional airflow gained by these systems is still going to be metered by the MAF and more fuel will be injected accordingly.



Wow. Sorry, that was boring

neveucd

Ok I am pretty much understanding what goes on now from this thread. But looking at my numbers from a Uprev tune on a 7at w/ Injen CAI, FI CBE and HFC's I feel kind of jipped. I also didn't get any of the special valet or anti theft maps. The tuner told me only one map was needed/loaded for my application, and a second would only be necessary if I wanted to run a different fuel. Help me to understand, is this about normal? I understand Mustang Dynoes read lower then the rest. So I'm probably making around 300rwhp?
Also thinking about getting short headers, so I would need to retune it again correct?

Vehicle: 2009 370z
Mods: Exhaust
EMS: UpRev
Base HP/TQ: 272/215
Final HP/TQ: 280/221

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GTM Stg. 2 TT||F.I. CF 18" Res. CBE||GTM 3" Downpipe ||Injen Cold Water Intakes||UpRev||Work Gnosis GS2||Hankook||Tein Monoflex||Hawk||Seibon||Aero Jacket||

semtex

Your gains are actually better than what a lot of people, including myself, have been seeing (probably because you don't have that many mods yet, so there's more to be gained from a tune). Whether or not you'll need a re-tune with short headers depends on what they do to your AFR (which is absent from the sheet above). Honestly, I doubt you'll need a re-tune just due to headers. What you want to do ideally is finish getting all your bolt-on mods first, and then do the tune. That way you only pay once. I'm not sure why you think you're making 300whp when your final HP number is 280. You're making 280, not 300. Now, I have no idea which exhaust you have. Depending on which one you have, 280 could be good or mediocre. Which one do you have?

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"There are no small accidents on this circuit." -- Ayrton Senna
316.8whp & 248 ft/lbs (Dyno Dynamics) | 319whp & 256 ft/lbs (DynoJet) (04/23/10)
Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

Push370zzz

Did I just miss...or was there a decision on whether the canned maps nearly match a regular tune for the A/F ratio?

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Range Rover Sport Supercharged
Nissan 370z Touring + Sport

G37Sam

Pic is too small bro

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Vegitto-kun

And even if the dyno reads lower I doubt that they would read 20 hp less

Some people barely get over 300 even with intake, exhaust and other bolt ons