Exhaust restriction/velocity and torque

[Pranav]

I'm told it's because it creates a vacuum where that breather enters the back of the TB. Were one to relocate that upstream of the intake restrictor, it ought to reduce that oil consumption cause by the suction on that hose.

Oh yeah I forgot the LT1 has that crappy TB breather port. I never moved my breather hose to the intake elbow on the LT1 because I was always scared of making that part of the intake oily and then suck contaminated crap into the opti since it feeds from the same area.

LS runs off the intake hose, way better. I'm down to a few ounces of oil in the catch cans per weekend outside of COTA and Cresson.

[Rsmith350]

I'm re-doing my exhaust due to a couple landscaping adventures. I will be doing a 2" all the way back and use baffles for restriction Pranav. Maybe we can collaborate.

[Pranav]

Last year I ran on a 54mm restrictor on a brand new motor, 297/260.

After a full season, this winter I reduced my 2.25" pipes to 1.875" for about 18", and put in thicker gear lube, ran 304/261 on a 57mm.

I'll take it.

[drecords]

Last year I ran on a 54mm restrictor on a brand new motor, 297/260.

After a full season, this winter I reduced my 2.25" pipes to 1.875" for about 18", and put in thicker gear lube, ran 304/261 on a 57mm.

I'll take it.

7 ft-lbs of torque is impressive

[Supercharged111]

Last year I ran on a 54mm restrictor on a brand new motor, 297/260.

After a full season, this winter I reduced my 2.25" pipes to 1.875" for about 18", and put in thicker gear lube, ran 304/261 on a 57mm.

I'll take it.

Did it nose over harder up top though? You running stock y pipe?

[Pranav]

Yes on stock y pipe, my "restrictor" pipes are simply what connect the manifolds to the y pipe in place of the cats.

Downstream of the y pipe is a 3" pipe and dynomax straight muffler.

I need to pull up.my old dyno to compare the curves.

[Pranav]

Comparing my charts it did not nose down any further up top; same peak HP at the same RPM. I just gained more lower range torque and the it looks like the peak torque number is a few hundred RPM earlier.

Same HP at the same peak RPM, just more torque and earlier/lower in the range.

Remember, it wasn't JUST the pipes, I took out some intake restrictor and also did run thicker gear lube this time for more protection.