Is this normal? New CAI, rpm fluctuation when braking to a halt. - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

sccm · 02-07-2021, 06:13 PM

Hi,

I installed a Grimmspeed CAI on my A/T 86 the other day. Maybe this is paranoia but after paying attention more I noticed that when braking at stoplights, as my RPM decreases to a certain amount <900, it fluctuates up a little bit, maybe from 750-850 as my speed decreases and I come to an idle. No clue if this happened before the install.

I have no other issues, the car runs smoothly and my throttle response feels somewhat better. No lights on the dash, no sounds or anything abnormal I could think of. Pressing on the brakes at rest does nothing to increase RPMs.

Is this just normal for the A/T for this car or after installing a new intake in general? For the record, I still am learning a ton and just getting into working on cars, so this probably sounds stupid. The one thread I searched didn't really give me an answer. Thanks

tomm.brz · 02-07-2021, 07:03 PM

you have nt retuned and rescaled the maf against the new intake
this is what you get

x808drifter · 02-07-2021, 08:52 PM

Sell/Return intake.
Put stock one back on.
Get better filter for the stock system.

Problem solved, money saved.

sccm · 02-07-2021, 09:04 PM

Ok.

So since I'm keeping it on, should I let the ECU adjust itself over time, reset it, or just open-flash tune it

x808drifter · 02-07-2021, 10:04 PM

Does OFT have a tune for that intake?
If yes, do that.

If no.
Custom tune.

Lantanafrs2 · 02-07-2021, 10:47 PM

That's not much fluctuation. I wouldn't worry about it.

86TOYO2k17 · 02-08-2021, 02:27 AM

Normal
Grimmspeed doesn’t need MAF scaling it’s designed to mimic OEM.
It can be optimized with a tune but by no means necessary.
Don’t worry about it.

jflogerzi · 02-14-2021, 11:48 PM

Let the ECU learn. Were you running the AC or Heater? I notice the car will dip sometimes with heat and alot with A/C...

02-07-2021, 06:13 PM	#1
sccm Junior Member Join Date: Jan 2021 Drives: 2020 Toyota 86 Location: VA Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Is this normal? New CAI, rpm fluctuation when braking to a halt. Hi, I installed a Grimmspeed CAI on my A/T 86 the other day. Maybe this is paranoia but after paying attention more I noticed that when braking at stoplights, as my RPM decreases to a certain amount <900, it fluctuates up a little bit, maybe from 750-850 as my speed decreases and I come to an idle. No clue if this happened before the install. I have no other issues, the car runs smoothly and my throttle response feels somewhat better. No lights on the dash, no sounds or anything abnormal I could think of. Pressing on the brakes at rest does nothing to increase RPMs. Is this just normal for the A/T for this car or after installing a new intake in general? For the record, I still am learning a ton and just getting into working on cars, so this probably sounds stupid. The one thread I searched didn't really give me an answer. Thanks

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02-07-2021, 07:03 PM	#2
tomm.brz Senior Member Join Date: Jan 2017 Drives: brz 2017 hksv2 Location: italy Posts: 2,280 Thanks: 515 Thanked 1,121 Times in 811 Posts Mentioned: 70 Post(s) Tagged: 0 Thread(s)	you have nt retuned and rescaled the maf against the new intake this is what you get

02-07-2021, 08:52 PM	#3
x808drifter LMGTFY Join Date: Mar 2016 Drives: 13 FRS, 91 Miata Location: Lava Town, HI Posts: 2,776 Thanks: 5,561 Thanked 3,650 Times in 1,625 Posts Mentioned: 15 Post(s) Tagged: 0 Thread(s)	Sell/Return intake. Put stock one back on. Get better filter for the stock system. Problem solved, money saved.

02-07-2021, 09:04 PM	#4
sccm Junior Member Join Date: Jan 2021 Drives: 2020 Toyota 86 Location: VA Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	Ok. So since I'm keeping it on, should I let the ECU adjust itself over time, reset it, or just open-flash tune it

02-07-2021, 10:04 PM	#5
x808drifter LMGTFY Join Date: Mar 2016 Drives: 13 FRS, 91 Miata Location: Lava Town, HI Posts: 2,776 Thanks: 5,561 Thanked 3,650 Times in 1,625 Posts Mentioned: 15 Post(s) Tagged: 0 Thread(s)	Does OFT have a tune for that intake? If yes, do that. If no. Custom tune.

02-07-2021, 10:47 PM	#6
Lantanafrs2 Senior Member Join Date: Jan 2018 Drives: 2013 frs red Location: South Florida Posts: 3,575 Thanks: 2,583 Thanked 3,134 Times in 1,686 Posts Mentioned: 6 Post(s) Tagged: 1 Thread(s)	That's not much fluctuation. I wouldn't worry about it.

02-08-2021, 02:27 AM	#7
86TOYO2k17 Senior Member Join Date: Jan 2018 Drives: 2017 toyota 86 Location: PNW Posts: 2,131 Thanks: 336 Thanked 1,189 Times in 781 Posts Mentioned: 16 Post(s) Tagged: 0 Thread(s)	Normal Grimmspeed doesn’t need MAF scaling it’s designed to mimic OEM. It can be optimized with a tune but by no means necessary. Don’t worry about it.

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