Gas mileage increase

[jason]

So last week I finally said screw it and paid $125.00 to get my broken exhaust manifold stud drilled out. I got about 40 extra miles out of my gas tank this weekend loaded with camping gear and all the windows down on the highway. Anybody else see this much improvement? I was surprised, I didn't expect to see any change in gas mileage, just that irritating ticking sound to go away.

[88pathoffroad]

Yeah, leaking manifolds can make for poor gas mileage too. Cool beans.

[jason]

That puts me at about 350 miles/tank. At this rate, the repair should pay for itself in 28 weeks. Yesssssss.

[Slick]

Yes, I noticed a HUGE difference, both in performance (I also installed the Thorleys) and gas mileage.. I had 4 broken studs in my motor...

 

cool! glad yer a happy camper!

[apc]

Same here 17.3 MPG before 19.6 after.

And I still need to get the manifolds machined, still a little ticky.

[M in KC]

Jason, my MPG numbers were almost identical to APC's after my repair. My stealer's tech described it to me this way. With the exhaust leak ahead of the O2 sensor you are drawing in more fresh air at the leak(s) and there by artifically leaning out the exhaust gas that the O2 sensor is detecting. The O2 sensor in turn is telling the motor it needs more fuel and ta da! your MPG goes in the crapper. I'm no techno genius but the theory seems to hold water. Others that are more savy regarding engine management systems on these rigs will fill in the blanks that I left out.

 

Oh and $125 clams for stud removal is not to shabby. Next, I'm going to try 88's MAF sensor trick to see if I can squeeze a couple of more MPG's out of my rig.

 

Happy Camping!

 

Mike

[wheelmanLS1]

I've always been afraid of putting in headers myself because of the broken studs. Are you guys saying I can just take my exhaust maanifold off and when I come by broken studs I can pay someone else to do it? I thought if someone did it, they'd do the whole deal.