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#1 |
Registered User
Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Exhaust Question
I had flow master 40s installed on my truck shortly after buying it. It had a good sound up until I swapped the cam and heads. Now at WOT it pops like glass packs and sounds like crap. Could something I changed cause this change in sound? It runs good and it sounds ok cruising, but when I get into it I hate the sound.
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-Jason USN Retired |
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#2 |
Parts and more parts
Join Date: Nov 2003
Location: Lebo, Kansas (middle of nowhere
Posts: 6,821
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Re: Exhaust Question
Just a thought, it sounds to me, that you may have a valve floating under WOT and the popping is coming from that.
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Frank |
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#3 |
Registered User
Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
How would I check that?
Edit: I was reading up on valve float on the web. It sounds like valve float causes a dramatic loss of power higher in the RPM band. I am not experiencing any power loss. The engine runs great, it just sounds like crap. (When I say crap, I mean it doesn't sound the way I like it to sound) The engine doesn't miss, starts easy, idles and runs smooth, runs great, awesome throttle response since the upgrades. The tone of the exhaust has changed.
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-Jason USN Retired Last edited by Hugh Mongus; 07-21-2014 at 04:34 PM. |
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#4 |
Senior Member
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Location: Cedar Park, Texas
Posts: 7,500
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Re: Exhaust Question
Your new cam probably has more overlap (when the intake and exhaust valves are both open). Did you install a "bigger" cam?
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#5 |
Registered User
Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
Yes, I installed the Lunati 60102.
I called a local mechanic today. He told me the engine is probably breathing better with the vortec heads and larger cam which will alter the sound of the engine. Would you guys agree?
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-Jason USN Retired |
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#6 |
Registered User
Join Date: May 2014
Location: Anderson South Carolina
Posts: 14
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Re: Exhaust Question
Really hard to diagnose from the description... When you say pop under acceleration I think misfire.
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#7 |
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Join Date: Apr 2014
Location: CA
Posts: 27
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After porting my heads, the exhaust sound changed dramatically. If you changed heads and cam it will sound diffrent. I noticed it as soon as I fired it up the first time. Sounded rasper and louder at idle and full throttle. I think it sounded much better after. Your probably making enough noise now the super 40s can finally come alive.
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#8 |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: Exhaust Question
That's flowmasters. They are made to make a stock truck sound like it's not stock. When you hook them to something more robust than stock you get...what you got. A loud irritating exhaust that doesn't sound all that great.
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#9 |
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Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
I am probably going to buy some Borla mufflers. I hate hitting the gas right now the sound makes me cringe.
Thanks for all the input.
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-Jason USN Retired |
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#10 |
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Location: Okmulgee, OK
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Re: Exhaust Question
Are they true duals? If so, do you have an H-Pipe or X-Pipe?
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#11 |
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Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
They are true duals. No cross pipe. Would a cross pipe make a difference in the sound?
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-Jason USN Retired |
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#12 | ||
"I ain't nobody, dork."
Join Date: Sep 2007
Location: Whidbey Island, Washington
Posts: 8,940
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Re: Exhaust Question
Could be a lean condition. Bigger cam needs more fuel, and probably a little more advance in the ignition.
Gary
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#13 |
Registered User
Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
I ordered a Holley Street Avenger for it that will be here tomorrow. I am currently using a Eddy 1405 which I am tired of messing with. I have a feeling the mixture is in fact a little lean.
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-Jason USN Retired |
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#14 |
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Join Date: Mar 2005
Location: Durham NC
Posts: 216
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Re: Exhaust Question
I know flow masters are popular, but I never cared for them on any vehicle that didn't have catalytic converters on it. If you change mufflers, look into the dynamax ultraflo mufflers. I think it's one of the best mufflers made. Good flow, but not too loud.
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#15 |
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Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
To give you all an idea of what I'm looking for, the video below is a Borla video. Around the 2:05 mark of the video they talk about Borla Touring Exhaust. That is the sound I'm looking for. My truck sounded similar to that prior to the upgrades.
https://www.youtube.com/watch?v=fISsmDRSXgY https://www.youtube.com/watch?v=X1uHhUixiAs
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#16 | |
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Join Date: Jan 2013
Location: Mickleton, NJ
Posts: 1,776
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Re: Exhaust Question
Quote:
I've never been a fan of Flowmaster sound. The open chamber design just doesn't sound "good" to me. Any turbo style muffler will sound closer to what you want, but they are all a little different. Borla is nice stuff, but pricey.
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Shawn 1970 Chevy C-10 SWB, 350, TKO 600 5 speed My build http://67-72chevytrucks.com/vboard/s...d.php?t=559881 |
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#17 | |
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Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
Quote:
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#18 |
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Location: So Cal
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Re: Exhaust Question
>>T3AMCH3VY
Really hard to diagnose from the description... When you say pop under acceleration I think misfire. << I am thinking the same thing. You didn't say what ignition and I wonder about plug gap. You changed heads and possibly increased C.R. ?? You may need to close plug gap.
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#19 |
Registered User
Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
Well, the clown that did the head swap for me cracked the porcelain on the #1 plug which caused an arc from the plug to the block . When I pulled that plug out it was gapped at .055, so I gapped the new plug the same and reinstalled it. The ignition is a new Accel dizzy with a high output coil.
It's definitely not a misfire. It runs fine. Think more 12" glass packs under heavy acceleration. The raspy popping you here with glass packs is what I'm getting from my flow masters. I hate that sound.
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#20 | |
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Join Date: Jan 2013
Location: Mickleton, NJ
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Re: Exhaust Question
Quote:
Probably has nothing to do with your sound though
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Shawn 1970 Chevy C-10 SWB, 350, TKO 600 5 speed My build http://67-72chevytrucks.com/vboard/s...d.php?t=559881 |
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#21 |
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Location: Okmulgee, OK
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Re: Exhaust Question
If you're sure it's not mechanical and just scavenging sounds from exhaust, throw and H pipe or X pipe on it.
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#22 |
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Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
I actually just got off the phone with flowmaster. The tech said the bump in compression is throwing the sound off. He said an H pipe would fix the sound problem. I called the exhaust shop that installed my exhaust and they are going to install an H pipe for me tomorrow for $30. Hoping that really fixes it.
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#23 |
Registered User
Join Date: Jan 2014
Location: Tulsa, OK
Posts: 360
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Re: Exhaust Question
Thanks for all the input and suggestions everyone. Hopefully tomorrow everything will be ok. If not I will be back.
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-Jason USN Retired |
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#24 | |
Account Suspended
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
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Re: Exhaust Question
Quote:
http://s851.photobucket.com/user/BWF...tml?sort=3&o=1 at idle outside it sounds like this: http://s851.photobucket.com/user/BWF...tml?sort=3&o=0 Much mo bettah than blowmasters! |
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#25 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,720
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Re: Exhaust Question
Balance pipe makes a huge difference with flowmasters. My buddies big block Chevelle sounded like crap without it while my Camaro sounded sweet with pretty much the same setup except the balance pipe.
I hope that cleans yours up.
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