Tune out Engine Rasp 3800 - 4400rpm - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

Gopherboy6956 · 04-25-2016, 11:17 PM

Does anyone else experience an exhaust rasp from about mid-high 3000 - mid 4000 rpm range when accelerating anything other than pedestrian speed?

I've had it as long as I have been on Vortech / Full exhaust. I figured it was a header deal, and I have a new one one the way -

But, I was talking to @JeffPerrin today and he said that it was the cam profile timing changing over, and even if you have quieter exhaust that it will still be present, and that you'd hear it through the intake.

He also thought you might be able to tune that noise out, with a very, very small power loss.

Any one else heard of this or done it? Driving me crazy.

Also - for Ref:
Full Vortech Supercharger Kit
Stock Perrin SC tune (Rich, safe)
P&L Catless Header
P&L Overpipe
P&L Catted Front Pipe
Perrin 3.0 resonated cat-back.

swarb · 04-26-2016, 12:21 AM

enjoy the vtec

Gopherboy6956 · 04-26-2016, 12:23 AM

If Only. I had a 2004 RSX-S - That was an altogether different sensation lol.

steve99 · 04-26-2016, 12:40 AM

yes happens in a lot of tunes especially for EL headers, its to do with aggressive valve timing/overlap changes to reduce torque dip.

its actually coming from intake in many cases

you either put up with noise or get some torque dip back

Gopherboy6956 · 04-26-2016, 12:58 AM

Quote:

Originally Posted by steve99

yes happens in a lot of tunes especially for EL headers, its to do with aggressive valve timing/overlap changes to reduce torque dip.

its actually coming from intake in many cases

you either put up with noise or get some torque dip back

Interesting. I'm actually changing headers as well now, going with OFT's UEL Header. Will be interesting to see what that changes. Truthfully, i'm just glad i'll have a header that doesn't intrude up into the engine bay anymore. Like I need more heat up there...

MaxxCann · 04-26-2016, 08:45 PM

Good to know that's not just me. I am flashed over to E85 EL and I get it right at 4100. Please,post result of going to UEL as that might sell me.

Riftur · 04-27-2016, 07:57 AM

I just got my OFT and tuned the car yesterday. I have the sound you are talking about but the torque dip is gone. Worth it to me.

Xero-Limit · 04-27-2016, 09:19 PM

Pull out 10 degrees of exhaust cam and it'll quiet right down. But as @steve99 said...you'll lose some power.

Gopherboy6956 · 04-28-2016, 05:39 PM

Might have to do that - It bugs the crap out of me.

steve99 · 04-28-2016, 09:47 PM

Quote:

Originally Posted by MaxxCann

Good to know that's not just me. I am flashed over to E85 EL and I get it right at 4100. Please,post result of going to UEL as that might sell me.

uel header cam timing are different and generally dont have to be as aggressive in the 4000 rpm area, so in general you will not get that noise or rassp due tune with a uel header.

i run a uel and no raasp at all

04-25-2016, 11:17 PM	#1
Gopherboy6956 Senior Member Join Date: Feb 2013 Drives: 13 BRZ Limited WRB Location: Fargo, ND Posts: 723 Thanks: 17 Thanked 296 Times in 195 Posts Mentioned: 12 Post(s) Tagged: 0 Thread(s)	Tune out Engine Rasp 3800 - 4400rpm Does anyone else experience an exhaust rasp from about mid-high 3000 - mid 4000 rpm range when accelerating anything other than pedestrian speed? I've had it as long as I have been on Vortech / Full exhaust. I figured it was a header deal, and I have a new one one the way - But, I was talking to @JeffPerrin today and he said that it was the cam profile timing changing over, and even if you have quieter exhaust that it will still be present, and that you'd hear it through the intake. He also thought you might be able to tune that noise out, with a very, very small power loss. Any one else heard of this or done it? Driving me crazy. Also - for Ref: Full Vortech Supercharger Kit Stock Perrin SC tune (Rich, safe) P&L Catless Header P&L Overpipe P&L Catted Front Pipe Perrin 3.0 resonated cat-back. __________________ I plan to live forever. So far, so good. My Build - http://www.ft86club.com/forums/showthread.php?t=31925

04-26-2016, 12:23 AM	#3
Gopherboy6956 Senior Member Join Date: Feb 2013 Drives: 13 BRZ Limited WRB Location: Fargo, ND Posts: 723 Thanks: 17 Thanked 296 Times in 195 Posts Mentioned: 12 Post(s) Tagged: 0 Thread(s)	If Only. I had a 2004 RSX-S - That was an altogether different sensation lol. __________________ I plan to live forever. So far, so good. My Build - http://www.ft86club.com/forums/showthread.php?t=31925

04-26-2016, 08:45 PM	#6
MaxxCann Member Join Date: Mar 2015 Drives: 2013 Scion FR-S Location: Stockton, ca Posts: 38 Thanks: 6 Thanked 7 Times in 5 Posts Mentioned: 1 Post(s) Tagged: 1 Thread(s)	Good to know that's not just me. I am flashed over to E85 EL and I get it right at 4100. Please,post result of going to UEL as that might sell me. __________________ 2013 Asphalt FR-86 (badge conversion) \| TRD wheels \| TRD CAI \| TRD exhaust \| TRD lowering springs \| TRD front strut tower brace \| TRD door stabilizers \| TRD member brace kit \| TRD spoiler \| TRD quick shifter \| TRD door speaker panels \| TRD seat gap fillers \| GT86 Armrest \| Red Perrin Lightweight Pulleys, Drift Button, and Reverse Lockout \| Winjet Foglights \| Full LED swap \| Custom dash and HVAC LEDs

04-28-2016, 05:39 PM	#9
Gopherboy6956 Senior Member Join Date: Feb 2013 Drives: 13 BRZ Limited WRB Location: Fargo, ND Posts: 723 Thanks: 17 Thanked 296 Times in 195 Posts Mentioned: 12 Post(s) Tagged: 0 Thread(s)	Might have to do that - It bugs the crap out of me. __________________ I plan to live forever. So far, so good. My Build - http://www.ft86club.com/forums/showthread.php?t=31925

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04-26-2016, 12:21 AM	#2
swarb Senior Member Join Date: Sep 2014 Drives: BRZ Location: Los Angeles Posts: 3,053 Thanks: 1,773 Thanked 2,451 Times in 1,271 Posts Mentioned: 79 Post(s) Tagged: 0 Thread(s)	enjoy the vtec

04-26-2016, 12:40 AM	#4
steve99 Banned Join Date: Dec 2013 Drives: FT86 Location: Australia Posts: 7,998 Thanks: 1,035 Thanked 4,987 Times in 2,981 Posts Mentioned: 598 Post(s) Tagged: 2 Thread(s)	yes happens in a lot of tunes especially for EL headers, its to do with aggressive valve timing/overlap changes to reduce torque dip. its actually coming from intake in many cases you either put up with noise or get some torque dip back

04-27-2016, 07:57 AM	#7
Riftur Senior Member Join Date: Jan 2016 Drives: 2013 Scion FR-S Location: Florida Posts: 582 Thanks: 235 Thanked 176 Times in 111 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	I just got my OFT and tuned the car yesterday. I have the sound you are talking about but the torque dip is gone. Worth it to me.

04-27-2016, 09:19 PM	#8
Xero-Limit Join Date: Nov 2012 Drives: JDL Turbo FRS, 335SC BRZ (ret) Location: Lehigh Valley, PA Posts: 932 Thanks: 368 Thanked 1,547 Times in 525 Posts Mentioned: 380 Post(s) Tagged: 6 Thread(s)	Pull out 10 degrees of exhaust cam and it'll quiet right down. But as @steve99 said...you'll lose some power.

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