Tuning out flat spots?

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14-11-2017, 12:52 PM
Lerlo

Tuning out flat spots?

Hi all,

So Ive just installed a CPL CAI intake and am getting a flat spots at about 3k rpm.

Im currently on AFM tune and I think the flow turbulence on the CPL is causing this. I guess that's the reason why the stock airbox has those fins.

Datalog shows spiked to 16 AFR!

My question is how do one tune out these flat spots? I have re calibrated the MAF/AFM voltage vs S.Trim and its still there.

Or do I finally have to go to a MAP tune? I'm dreading the extra work involved with fuel tables.
15-11-2017, 05:46 AM
Hondarally

Can't help with your specific problem but what was egt when you hit 16 afr? That's the important factor and will tell you whether your engine will live or die. Tuning to afr is arbitrary and never gives you the full picture.
15-11-2017, 11:59 AM
amant02

Quote:

Originally Posted by Lerlo

Hi all,

So Ive just installed a CPL CAI intake and am getting a flat spots at about 3k rpm.

Im currently on AFM tune and I think the flow turbulence on the CPL is causing this. I guess that's the reason why the stock airbox has those fins.

Datalog shows spiked to 16 AFR!

My question is how do one tune out these flat spots? I have re calibrated the MAF/AFM voltage vs S.Trim and its still there.

Or do I finally have to go to a MAP tune? I'm dreading the extra work involved with fuel tables.

Go to someone who knows what they are doing before you make it worse.

Flat spots when intake is played with it in my experience if the tune is good, you have a leak some where causing air not to flow smooth.
15-11-2017, 06:58 PM
Lerlo

Quote:

Originally Posted by amant02

Go to someone who knows what they are doing before you make it worse.

Flat spots when intake is played with it in my experience if the tune is good, you have a leak some where causing air not to flow smooth.

I'm not an expert but I think I know what I am doing.

The issue with the FN2 is it runs on MAF/AFM sensor which requires a linear flow regardless of the mass flow rate.

Aftermarket CAI do not have the stock fins that provide a linear flow for the sensor.

Typically, a MAP (Manifold Pressure) tune will need to be done to bypass this issue.

I am just asking if anyone here have experience tuning using the AFM sensor because there may be something I do not know.

I have only tuned MAP previously and would like to learn more and I kinda like the ease of AFM tuning.
15-11-2017, 07:15 PM
Lerlo

Quote:

Originally Posted by Hondarally

Can't help with your specific problem but what was egt when you hit 16 afr? That's the important factor and will tell you whether your engine will live or die. Tuning to afr is arbitrary and never gives you the full picture.

Hi, thanks for your response.

I may have caused some confusion. Im not getting 16AFR at redline.

Im just getting 16 AFR at 3k rpm for a fraction of a second in part throttle closed loop.

Reason is definitely the turbulent flow over the AFM/MAF due to my CAI.
17-11-2017, 01:47 AM
amant02

Quote:

Originally Posted by Lerlo

I'm not an expert but I think I know what I am doing.

The issue with the FN2 is it runs on MAF/AFM sensor which requires a linear flow regardless of the mass flow rate.

Aftermarket CAI do not have the stock fins that provide a linear flow for the sensor.

Typically, a MAP (Manifold Pressure) tune will need to be done to bypass this issue.

I am just asking if anyone here have experience tuning using the AFM sensor because there may be something I do not know.

I have only tuned MAP previously and would like to learn more and I kinda like the ease of AFM tuning.

WTF?

Okay so I googled some Pictures, Im assuming your talking about a FN2R.

Mate ill be honest with you, you have no idea what your doing.

1. Them Fins your referring to, are there for sound reasons. (most likely)
2. One should not attempt to tune, without knowing how to do so.
3. Its not unusual for honda's to get flat spots after doing things I/E/H, untuned.
4. As far as I Know, when you play around with intakes in a MAF car, you change the scaling on MAF. Its easy to make power from a tune, its getting it to behave properly(drive nicely) is the hard part.

So heres the conclusion - Just go to someone who really knows what they are doing and if your nice them, they might teach you what you lack.
Tuning is a black art, there are secrets these guys hold on to. Its how they make money.

I can confirm this, cause my cars CAI works in a similar way with MAF sensor bunged on the pipe, I have no flat spots and I have paid for over 6hours dyno time.