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Exhaust pipe diameter

  
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Exhaust pipe diameter

 
Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 02/10/13
05:29 AM

Hi all
Collecting material for a new exhaust system on my 79 350 Corvette,and was wondering what diameter pipe would be most beneficial.According to a Haynes manual, as a general rule,5.0 to 5.8 run "well" with 1-7/8 to 2 inch diameter,with the more powerful ones using 2-1/4.Engines over 6.8 liters almost always use 2-1/4 to 2-1/2.

Aluminized 2-1/2 inch pipe I can get really cheap,but I'm not sure it won't kill my low end torque any more than the cam change did.Will be using the stock ram horn manifolds,and downpipes.The rest of the "Y" system will be junked.

Myself, I don't believe that a larger than stock ,say 2-1/2 inch, would have much,if any, adverse effects on performance, but who knows?

Any thoughts?  
The older I get,the faster I was.

redneckjoe69 redneckjoe69
Everything in my driveway’s a Chevy | Posts: 612 | Joined: 02/10
Posted: 02/11/13
06:10 AM

hey Ravoll !       are you saying that your going with dual exhaust?    2 1/2", duals are fine for a smallblock, IMO.   3" is pretty overkill.  

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 02/11/13
11:09 AM

Hi Joe,
Yeah going with duals and flowmaster mufflers, but retaining the stock ram horns for now.

3 inch gun barrels are to big.Did that years and years ago to a very good running 70 Cutlass,improving the top end slightly,while losing low end torque. I've been studying/ re-learning head and exhaust flow for the last year or so,picking up where I left off 25/30 years ago.Just gathering info for the fun of it,and to understand what has changed over the years.
Have read in multiple articles lately that a big pipe allows the exhaust pulse to slow down quicker, destroying the scavenging effect created behind the pulse.Makes an engine lazy at low revs.  
The older I get,the faster I was.

redneckjoe69 redneckjoe69
Everything in my driveway’s a Chevy | Posts: 612 | Joined: 02/10
Posted: 02/11/13
04:07 PM

ive got 2 1/2" duals with flowmaster super 44s on my "poor mans corvette",{camaro, lol}.    although the car runs great, the flowmaster drone is annoying to me.   after i installed them, i ended up coming across some articles & charts  stating flowmaster is one of the worst flowing muffs. Confused    its basically a name and noise.   im seriously considering cutting my muffs off and running something quieter.    i did make some baffles, and they helped alot, but really choked the power when i got into it.    put an H-pipe on and it helped a little.     i think im gonna keep the mandrel bent 2 1/2" pipes and run some 3" muffs.   just use some adapters to step up the pipe size before the mufflers.  
  spintech makes sidepipes for your car if thats something you would consider?
http://www.spintechmufflers.com/

   just my experience/opinion.

 edit.   these are the mufflers i was talking about.
http://www.classicchambered.com/classic/products.html  

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 02/13/13
03:30 PM

Hi Joe,
My super 44's sound OK ,and not to loud (or my neighbor would have already pitched one). Reason being is I still have the 2/1/2 system ,running through a single cat that's been gutted,and stock ram horn manifolds.When I got the car the factory mufflers were still on it and it droned like crazy at residential speeds.People could "feel"it coming down the road.I cut em off and hung a set of Borlas on it.It didn't run any better, but it didn't drone as bad.At least I could listen to music again.A buddy of mine over here has a 74 SB vette with blackjacks,duals,and super 44's. It drones much worse than mine ever did.At around town speeds the rearviews are completely useless.C3's are an acoustical nightmare anyway, and very windy at "cruising altitude"
I cain't knock the "poor mans corvette". I was always a fan of the 2nd gen Camaros and T/A's.Had a 71 Camaro I drove in high school ,and a 73 T/A some time later.El Caminos and 442's also over the years
When my wife and I started looking for a project car 2 years ago,we were looking for a 2nd gen f body.Most what we found here in Germany were "Dr.Frankenstein" models.You know,Highjackers,Mad Max hood scope,3 spoilers, 6 antennas,metalflake 70's porno paint jobs,and leopard skin interior with monkey fur dashboard.And maybe a set of fuzzy dice or chain steering wheels here and there. Tongue And all that on one car.
Bought the vette instead ,not cause I was a fan but because it had slots. Grin,and was untouched by the Dr..  
The older I get,the faster I was.

Ravoll Ravoll
V-6 Camaros rule! | Posts: 85 | Joined: 02/12
Posted: 02/13/13
03:46 PM

The classic chambered models make me think of glasspack/ cherry bombs.
I cain't find the sidepipes at spintech.My wife don't want them anyway.
Dragging short stubby legs across hot sidepipes will ruin the weekend.Plus I have a historical registration. I need to keep an "outward" factory appearance at best.Side pipes only came factory on the 69 stingrays.  
The older I get,the faster I was.

68scott385 68scott385
I have an SS396 tatoo | Posts: 325 | Joined: 07/09
Posted: 02/13/13
05:44 PM

Icon QuoteRavoll:
Hi Joe,
My super 44's sound OK ,and not to loud (or my neighbor would have already pitched one). Reason being is I still have the 2/1/2 system ,running through a single cat that's been gutted,and stock ram horn manifolds.When I got the car the factory mufflers were still on it and it droned like crazy at residential speeds.People could "feel"it coming down the road.I cut em off and hung a set of Borlas on it.It didn't run any better, but it didn't drone as bad.At least I could listen to music again.A buddy of mine over here has a 74 SB vette with blackjacks,duals,and super 44's. It drones much worse than mine ever did.At around town speeds the rearviews are completely useless.C3's are an acoustical nightmare anyway, and very windy at "cruising altitude"
I cain't knock the "poor mans corvette". I was always a fan of the 2nd gen Camaros and T/A's.Had a 71 Camaro I drove in high school ,and a 73 T/A some time later.El Caminos and 442's also over the years
When my wife and I started looking for a project car 2 years ago,we were looking for a 2nd gen f body.Most what we found here in Germany were "Dr.Frankenstein" models.You know,Highjackers,Mad Max hood scope,3 spoilers, 6 antennas,metalflake 70's porno paint jobs,and leopard skin interior with monkey fur dashboard.And maybe a set of fuzzy dice or chain steering wheels here and there. Tongue And all that on one car.
Bought the vette instead ,not cause I was a fan but because it had slots. Grin,and was untouched by the Dr..


You said a mouth full there!

I agree that cars are getting harder to find without being monkey-pumped. I too will not touch a car that has been obviously crescent-wrench/vice-gripped to a shadow of it's former self.



FWIW, I have 2.5" full exhaust w/h-pipe on my 75 Monte Carlo and use Terminator mufflers. I find that pipes that exit the rear are less annoying that those that exit out the side. It's not as loud as some vehicles I've had.  
68scott385 68scott385 68scott385

redneckjoe69 redneckjoe69
Everything in my driveway’s a Chevy | Posts: 612 | Joined: 02/10
Posted: 02/14/13
08:02 AM

aw man, you guys are hating on the leopard stripes. Frown  Grin
051802 120100
Grin

  i wish i still had that old 78 camaro.   its hard to find a 2nd gen in nice shape for a decent price anymore.  

pepsi1 pepsi1
Big Block power for the win | Posts: 940 | Joined: 03/11
Posted: 02/14/13
10:22 PM

Hi Rav

2.250" to 2.500" will not hurt the performance at all. The 44's are a good muffler I used them on my 2006 Impala. They have a nice tone....I only have a 3.9 V6 in this Impala...

Bob