Long tubes and factory exhaust

[brotten]

Has anyone on here ever ran long tubes header with an electric cut out back into the factory exhaust system?

 

[Z-56 Hoe]

I've been here since the start, and I can't remember anyone running a setup like that. Why the Factory muffler?

 

[Big Buttons]

I've seen similar set ups like that but really there is no point of using that oem muffler. I have a cutout on mine exiting basically right under the pass door. When it is closed it goes out the back to a flomaster super44. If you dont want something that loud get a magnaflow.

 

[brotten]

I've ran out and cut the exhaust off of every vehicle I've owned in the last 16 years but now that I having sleeping kids it's nice not to have loud pipes and annoying drone on long trips...

 

[shakedown067]

I have longtubes with cats and stock muffler, for now. The ZO6 heads made it a tad louder and the rasp a bit more pronounced though. Have a custom magnaflow system in the works.

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[Mr. Merk]

I have longtubes with cats and stock muffler, for now. The ZO6 heads made it a tad louder and the rasp a bit more pronounced though. Have a custom magnaflow system in the works.

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241 Heads are off of LS1s. Are you sure you didn't get 243s? Those are what comes on Z06s and 07+ 5.3s. Only the Z06s had the sodium filled valves.

Also how much did you mill them? I know 243s need .020-.030. They 241s need even more due to their larger CC

 

[shakedown067]

Hmm, I'll have to look into it. I know the shop said they had the sodium filled valves, not that I was looking for them. Maybe they were added on with the car's previous build. They are 241's and from all I read didn't need to be milled down, although I should have done it anyway for a slight boost in compression. Hope to get it tuned on the dyno after the exhaust is done and see what kind of power she puts down. She certainly had a very noticeable increase in mid-range power, slightly better in the low-end.

 

[Mr. Merk]

If they weren't milled, you definitely lost compression.

Casting Number 706 and 862
Head: 1999+ 4.8L / 5.3 Liter Truck
Material: Aluminimum
Part Number:
12559862
12561706
Combustion Chamber Volume: 61.15cc
Compression Ratio: 9.5:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 1.89 inches
Exhaust Valve Diameter: 1.55 inches

Stock Head Flow Numbers
Chamber 61.15 cc----0.100--0.200--0.300-- 0.400--0.500---0.550---0.600
Intake 200 cc----------63 ---128----179-----210----218----221-----226
Exhaust 70 cc----------54 -- 93 ----121----145-----163----168----174

Casting Numbers 241, 806, 853
Head: 1997+ LS1 5.7 Liter Passenger Car
Material: Aluminimum
Part Number:
12559806 (1997-98) Chambers = 69cc
12559853 (1999-00)
12564241 (2000-03)
Combustion Chamber Volume: 66.67cc
Compression Ratio: 10.1:1
Intake Port Volume: 200cc
Exhaust Port Volume: 70cc
Intake Valve Diameter: 2.00 inches
Exhaust Valve Diameter: 1.55 inches

Stock Head Flow Numbers
Chamber 66.67 cc------0.100--0.200---0.300---0.400---0.500---0.550--0.600
Intake 200 cc------------67----122-----178-----215-----219-----223---227
Exhaust 70 cc------------52-----97-----133-----156-----170-----76----180

 

[shakedown067]

Well, guess I should have tuned in here sooner. I knew I should have milled it. I'll just need to slap on a supercharger.