Author Topic: Exhaust selection  (Read 3609 times)

Offline p7387

  • Frequent Member
  • **
  • Posts: 254
Exhaust selection
« on: October 13, 2017, 11:22:06 PM »
Hello
87 r10. 305 motor.  2wd short/fleet

I will be taking the truck to a muffler shop for a new exhaust.
I would like a dual exhaust system that sounds moderate and healthy but not loud or overwhelming

DONT WANT
excessive cab noise, Must be able to converse and listen to the radio comfortably.
No so loud that the neighbors will hear me coming from a block away
No so loud that it will annoy my wife on a long trip

I will be removing the catalytic converter and Will not be using headers.
I would also like the exhaust to exit straight out the rear, is this ok or will it create an issue?

My reaseach to date indicates the "flow master super 50" might be a good choice
Any advice or opinions would be appreciated.

Thanks

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18980
Re: Exhaust selection
« Reply #1 on: October 14, 2017, 06:55:55 AM »
Personally I think it looks and sounds better when the exhaust exits to the left and right over the axle as they did from the factory.

https://youtu.be/QEBdiW4LbI0
,                           ___ 
                         /  _ _ _\_
              ⌠¯¯¯¯¯'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline zieg85

  • Global Moderator
  • Senior Member
  • ****
  • Posts: 7543
    • 73-87 GM squarebody extended cab and conversions up to 91 R/V series
Re: Exhaust selection
« Reply #2 on: October 14, 2017, 07:50:33 AM »
Hello
87 r10. 305 motor.  2wd short/fleet




I will be removing the catalytic converter and Will not be using headers.





The muffler shop I worked at will not work on any vehicle that does not have a catalytic converter without putting one on as a complete exhaust system.  It is a federal law.  I would recommend you check with them first
Carl 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
https://www.facebook.com/groups/248658382003506/

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 439
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Exhaust selection
« Reply #3 on: October 18, 2017, 10:46:19 AM »
Flowmasters have a unique sound, and to me its too loud.

Many folks who want a quieter tone use something like the Dynomax Super Turbo muffler, combined with an H pipe, and it provides a good performance sound without being too loud.  Using an H pipe is a great way to tone down the loudness without giving up any power.

Something like the straight through Magnaflow will give you better overall flow, but will not be as quiet as the turbo muffler.

There are many universal high flow cats out there that will have minimal impact on flow.  It would save you time and trouble in the long one to have them install one.

Bruce

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13319
  • Family is not an important thing. It's everything.
Re: Exhaust selection
« Reply #4 on: October 18, 2017, 02:47:50 PM »
like stated no reputable shop will do a exhaust setup if it came with cats from the factory. plane and simple its against federal law to tamper with the emissions, even if you have no inspection or your state doesnt care and cop can still give you a ticket for it. you can get high flow cats that are 50 state legal and be good. also about having exhaust straight out the back not sure if youre talking about straight pipe with no bend for the axle or not but you should have a bend and think law may require (not sure). personally i like 45° turn outs before the rear tire and its generally cheaper due to less pip and they dont have to bend a u for over the rear axle
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18980
Re: Exhaust selection
« Reply #5 on: October 18, 2017, 04:59:47 PM »
Quote
Flowmasters have a unique sound, and to me its too loud.

Look at the link I posted. They have something for everyone, you just need to make informed decisions or you may very well end up disappointed.

Quote
ike stated no reputable shop will do a exhaust setup if it came with cats from the factory

Many shops are reputable simply due to the fact that they deliver what the customer wants and as such they thrive as a business. Every state has their own emissions standards, so regardless of how the vehicle was originally equipped, exempt is exempt.
,                           ___ 
                         /  _ _ _\_
              ⌠¯¯¯¯¯'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Irish_Alley

  • Tim
  • Global Moderator
  • Senior Member
  • *****
  • Posts: 13319
  • Family is not an important thing. It's everything.
Re: Exhaust selection
« Reply #6 on: October 20, 2017, 10:10:36 AM »
maybe a better word would of been "honest"? i know one shop in town that wouldnt touch my crew cab with the cummins UNLESS i kept or added a cat since it came from the factory like that. they said something bout being fined
If you can’t tell yourself the truth, who can you tell it to?~Irish_Alley

When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline p7387

  • Frequent Member
  • **
  • Posts: 254
Re: Exhaust selection
« Reply #7 on: October 20, 2017, 07:01:25 PM »
Thanks for all the input

In New York State there is no emissions inspection on vehicles over 25 years old, only a safety.
That said my thought is why spend the extra money on cats assuming the exhaust shop will do the work without them, Who will ever check?, why spend the extra money?
Not trying to be a smart :( by that statement just realistic.

As vile said it appears flowmaster tries to offer something for everybody.
So far my research on their site indicates the "super 50" is a moderate sound that will not make the cab noisy. Does anyone have personal experience with the super 50 or similar?

Still in the decision process
Btw- where is the link vile references?
« Last Edit: October 20, 2017, 07:08:08 PM by p7387 »

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 18980
Re: Exhaust selection
« Reply #8 on: October 20, 2017, 08:29:42 PM »
,                           ___ 
                         /  _ _ _\_
              ⌠¯¯¯¯¯'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Dr_Snooz

  • Junior Member
  • ***
  • Posts: 590
  • "I like to take hammers, and just break stuff"
Re: Exhaust selection
« Reply #9 on: October 20, 2017, 11:15:42 PM »
If my reverse engineering calculations are correct, I have one of the 40 series Flowmasters on my '90 454. The PO put it on and it was perfect for me. It made a nice throaty rumble at idle that let the family know I was in the driveway, but not the entire neighborhood. The rumble went away as you started driving with no drone on the highway. It was great.

I'm speaking in the past tense, because the cat clogged up and I had to cut it out. Now the muffler is too loud. It's not unbearable, but it is loud if I get on the gas and it drones on the highway now.

I won't hate on you for not wanting to replace expensive cats (twice!), but know that it will run louder without them, so err on the quiet side.
1989 Chevy Suburban V-2500, 5.7L, TH400

1990 Chevy C-3500 Ext. Cab, 7.4L, 3L80

2009 Chevy Silverado 1500 WT 4WD, 4.8L, 4L60

Offline 75gmck25

  • Frequent Member
  • **
  • Posts: 439
  • 1975 GMC K25 Camper Special, 350/TH350/NP203
Re: Exhaust selection
« Reply #10 on: October 30, 2017, 05:27:35 PM »
You will still need to find a cooperative shop if you want to go without the cats.  You don't need cats to pass emissions inspection; however,  it is still illegal for a shop to remove them if they were part of the original factory setup and it is for a street vehicle.  They may not want to risk getting fined.

Bruce