#21  
Old 07-12-2020, 07:41 AM
prostreet64's Avatar
prostreet64 prostreet64 is offline
Ultimate Warrior
 
Join Date: Jul 2007
Location: Gainesville, Fl.
Posts: 1,324
Default

I run the Dynomax Super turbos on the Trans Am and my son runs the Ultra Flows on the Bird. Both are great mufflers; just depends on what level of noise you are comfortable with for street driving.

__________________
69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car.

79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads,Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.72 @ 126 so far... no tuning yet.
  #22  
Old 07-12-2020, 08:43 AM
alanmay0 alanmay0 is offline
Chief Ponti-yacker
 
Join Date: Nov 2017
Location: Texas
Posts: 612
Default different exhaust sound not expected

This is why I was looking for a different set of mufflers.

OK so I bought the intake manifold gasket kit that included the piece that you could use to cover the crossover exhaust ports on the intake manifold thinking this would help the paint from discoloring on the manifold.

There is an unexpected side result of covering these ports. The exhaust, at least on my car, sounds much different. when under mild to heavy acceleration the exhaust sounds kind of like a machine gun being shot. Not quite as loud as a machine gun but this is the best way I can explain it.

Has anyone else experienced this??? Do you think a different muffler might stop this sound.

Does anyone know why it has changed the sound????

Thank you

  #23  
Old 07-12-2020, 09:37 AM
prostreet64's Avatar
prostreet64 prostreet64 is offline
Ultimate Warrior
 
Join Date: Jul 2007
Location: Gainesville, Fl.
Posts: 1,324
Default

Blocking the exhaust crossover is pretty common to reduce the heat transfer to the carb. On my Olds 403 and on Curt's Pontiac 400 we blocked the crossover for that reason since we race the cars and are looking for any little benefit we can find. We also have x-pipe crossovers which change the exhaust tone to some degree, but in any case there is no drone or the 'popping' sound like you describe in your current setup.

__________________
69 Bird w/1970 400 block(409 cubes), #64 heads, hyd. roller, Q-jet by Jeff E., original interior, ps, pdb, th350, and 3.73 gears. Pump gas, street driven muscle. 3800 lbs. race weight. Best, 11.39 @118, my son's car.

79 T/A w/463, Scat crank, Eagle rods, Icon pistons, Lunati solid roller, 262/270, KRE 325 heads,Northwind intake, QF950 carb, full interior, ps, pdb, th350, and 3.73 gears. Pump gas, 3650 lbs. race weight. 10.72 @ 126 so far... no tuning yet.
  #24  
Old 07-12-2020, 10:02 AM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
 
Join Date: Dec 2001
Location: The United States of America
Posts: 31,294
Default

A Popping sound in the exhaust sometimes is a clue for an air leak into the exhaust.

So now the unburned fuel left from the last combustion cycle and some nice fresh air to mix with it and plenty of heat to cause the burn (popping noise).

Look for an air leak in the area of your exhaust cross-over block-off plates.

Tom V.

__________________
"Engineers do stuff for reasons" Tom Vaught

Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.
  #25  
Old 07-12-2020, 10:03 AM
The Champ's Avatar
The Champ The Champ is offline
Ultimate Warrior
 
Join Date: May 2002
Location: Rochester, MN
Posts: 2,534
Default

I have blocked crossovers, 2.5" exhaust with an x pipe crossover and have never had a drone or "machine gun" sounds coming from my exhaust using the DynoMax Super Turbo's.

  #26  
Old 07-12-2020, 01:05 PM
boostmaster boostmaster is offline
Chief Ponti-yacker
 
Join Date: Jul 2011
Location: Kentucky
Posts: 506
Default

Any opinions good/bad on the Goerlich Xlerator (x110 or x122)??

Looking at purchasing RARE HO manifolds and they recommended the exhaust package.

The few clips I've found online sound pretty good (muscle car grumble without race car noise)

Wondering if there were any real world opinions.

  #27  
Old 07-12-2020, 01:05 PM
alanmay0 alanmay0 is offline
Chief Ponti-yacker
 
Join Date: Nov 2017
Location: Texas
Posts: 612
Default

Thank you I will do that.

  #28  
Old 07-12-2020, 01:59 PM
Tom Hand's Avatar
Tom Hand Tom Hand is offline
Exhaust Guru
 
Join Date: Dec 1999
Location: Lee's Summit, MO, USA
Posts: 994
Default

If the Xlerators are 3" in and out and 14" shell, they will be rather loud. If they are 18" they should really nice.

__________________
Tom Hand
  #29  
Old 07-12-2020, 07:19 PM
alanmay0 alanmay0 is offline
Chief Ponti-yacker
 
Join Date: Nov 2017
Location: Texas
Posts: 612
Default

well I removed the intake manifold today and removed the intake gasket, the one with the inserts to block the exhaust crossover. It seemed to me that it may have been sucking air on both sides of the insert from the opening where you can see the push rods, don't know exactly what those openings are called. I put on a new gasket that had the openings and then covered the openings with a very thin piece of aluminum. Put it all back together and the popping was still present. So there is no other cause of the popping other that sucking air?? Could it just be the result of having no crossover exhaust. My exhaust is stock except for it being 2.5" vs 2.0" pipes.

Thanks for your help.
alan

  #30  
Old 07-12-2020, 08:31 PM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
 
Join Date: Dec 2001
Location: The United States of America
Posts: 31,294
Default

First thought would be to forget about the blocked cross-over and put two scock intake gaskets on the engine and see if you still have the popping.\

Then the popping is caused by some other part vs the intake manifold seal.

Tom V.

__________________
"Engineers do stuff for reasons" Tom Vaught

Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.
  #31  
Old 07-12-2020, 11:35 PM
alanmay0 alanmay0 is offline
Chief Ponti-yacker
 
Join Date: Nov 2017
Location: Texas
Posts: 612
Default

I have plans to do just that. The popping did not start until I put the gaskets with the inserts to block the cross over on.

  #32  
Old 07-15-2020, 01:03 PM
GTOEARL GTOEARL is offline
Member
 
Join Date: Apr 2014
Posts: 41
Default

If you’re looking for originality especially in the sound of your exhaust I recommend gardener exhaust. I put it on my 66 Gto and it sounds great just as it did leaving the factory.

https://www.gardnerexhaust.com/exhau...xhaust-system/

  #33  
Old 07-15-2020, 01:08 PM
GTOEARL GTOEARL is offline
Member
 
Join Date: Apr 2014
Posts: 41
Default

[QUOTE=boostmaster;6160245]Any opinions good/bad on the Goerlich Xlerator (x110 or x122)??

Looking at purchasing RARE HO manifolds and they recommended the exhaust package.

The few clips I've found online sound pretty good (muscle car grumble without race car noise)

Wondering if there were any real world opinions.[/QUOTE




I have Gardner exhaust on the 66 Gto with HO stock manifold.

https://www.gardnerexhaust.com/exhau...xhaust-system/

  #34  
Old 07-15-2020, 02:45 PM
Pecosbill's Avatar
Pecosbill Pecosbill is offline
Ultimate Warrior
 
Join Date: Jul 2002
Location: San Antonio, Texas
Posts: 1,635
Default Gardner Exhaust

I’ve had Flowmasters on one of the 64’s we owned and, while it was a fun drive it wasn’t something you’d want to listen to on even a short trip. When I rebuilt my 64 convertible I opted for a Gardner Exhaust system, which is a pretty faithful reproduction of the original one that came on the car. I am very happy with it, as I can hear the radio and my passengers now.

If you want the best of both worlds, get a Gardner muffler set along with some electric solenoid controlled cutouts. That way when you’re feeling your oats you can open ‘em up and let it rip and then close it off and have a nice quiet ride.

__________________
Save yo Confederate money, boys, the South is gonna do it again!
Pecosbill
  #35  
Old 07-16-2020, 05:22 PM
geeteeohguy's Avatar
geeteeohguy geeteeohguy is offline
Ultimate Warrior
 
Join Date: Dec 2009
Location: Fresno, California
Posts: 5,313
Default

Quote:
Originally Posted by lust4speed View Post
Walker Dyno Max Super Turbos have cured so many ills on our club members' cars. Has a low throaty idle that just never gets obnoxious as the RPM's increase.
I've had these on my '65 GTO since about 1991. They sound great, not too loud, no drone at all. No cross-over either. Heddman headers and 2.5" all the way back to the splitters.

__________________
Jeff
  #36  
Old 07-16-2020, 05:27 PM
389 389 is offline
Suspended
 
Join Date: Mar 2018
Location: Pittsburgh
Posts: 561
Default

#17749 Walker Super Turbo s..

They will be very quiet at first but will sound real nice once broken in after a few thousand miles..

  #37  
Old 07-16-2020, 10:38 PM
MUSLCAH MUSLCAH is offline
Ultimate Warrior
 
Join Date: Sep 2015
Location: N.H.
Posts: 1,920
Default

Man......you guys are getting old....with this quiet exhaust talk. I only get to drive my GTO for 6 months when it’s not raining or blistering temps.....so I want to go back to my youth ,when Iam behind the wheel.....

  #38  
Old 07-16-2020, 11:00 PM
Tom Vaught's Avatar
Tom Vaught Tom Vaught is offline
Boost Engineer
 
Join Date: Dec 2001
Location: The United States of America
Posts: 31,294
Default

Quote:
Originally Posted by MUSLCAH View Post
Man......you guys are getting old....with this quiet exhaust talk. I only get to drive my GTO for 6 months when it’s not raining or blistering temps.....so I want to go back to my youth ,when Iam behind the wheel.....
I am OLD but I don't act like a young kid who just got a drivers license when He was 16 years old either. JK. Do what ever makes you happy as long as there are no people around you in danger at the time.

My exhaust gets loud with a push of a button. And no cop can give me a ticket for having cut-outs. LOL!

Tom V.

__________________
"Engineers do stuff for reasons" Tom Vaught

Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward.
  #39  
Old 07-17-2020, 06:19 PM
MUSLCAH MUSLCAH is offline
Ultimate Warrior
 
Join Date: Sep 2015
Location: N.H.
Posts: 1,920
Default

Quote:
Originally Posted by Tom Vaught View Post
I am OLD but I don't act like a young kid who just got a drivers license when He was 16 years old either. JK. Do what ever makes you happy as long as there are no people around you in danger at the time.

My exhaust gets loud with a push of a button. And no cop can give me a ticket for having cut-outs. LOL!

Tom V.
My Birthday is today....so I need to burn some rubbah.....@64...lol

  #40  
Old 07-18-2020, 04:14 PM
geeteeohguy's Avatar
geeteeohguy geeteeohguy is offline
Ultimate Warrior
 
Join Date: Dec 2009
Location: Fresno, California
Posts: 5,313
Default

Quote:
Originally Posted by MUSLCAH View Post
Man......you guys are getting old....with this quiet exhaust talk. I only get to drive my GTO for 6 months when it’s not raining or blistering temps.....so I want to go back to my youth ,when Iam behind the wheel.....
The turbos sound great when you get on it, but not ghetto loud like the kids Mustangs sound at all speeds. (like the intake valves are burnt/popping)...
Good taste IMO (speaking softly and carrying a big stick) trumps loud mouth bravado every time. Takes other people into consideration as well. (Not everybody likes hearing an obnoxious exhaust).

__________________
Jeff
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 02:15 PM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017