Exhaust leak affecting MPG? (1 Viewer)

[torqueluvr]

Hi all,
1987 JDM BJ74 13BT auto 288K. Bought it about a month ago, noticed that the exhaust manifold is cracked and needs to be replaced. I was wondering how much this would affect my MPG as it is absolutely terrible (12-15mpg city and highway). This driving was done in 0-15 degrees celsius over a week.

Now I realize that the turbo would not spool properly with the leak, causing a lack in power, but should it effect my fuel economy this much?

Planning to do air filter, oil filter and fuel filter and oil change this week. Other than getting a new exhaust manifold ($400-$650, and if anyone knows of any used ones, i'll buy you a case of beer), are there any other huge factors for fuel economy?

Tanner

 

[Nexxussian]

Yes.

If the turbo isn't spooling you aren't using the fuel, just pouring it out the pipe.

As you are doing that, you have to keep your foot in it further fir seady state (ie at cruise) and keep your foot in it longer when you are accelerating, or climbing a hill.

I don't know what one of those manifolds cost, but if you're handy with a welder the cost of parts to make a weld ell manifold is likely cheaper than the combination of the fuel you are burning and the potential for damage to the turbine and the exhaust valves.

 

[Big Blue 84BJ60]

If your going to weld your manifold, your going to have to heat it up nice and hot 500 f and more if possible, i say this because cast iron is brittle and can crack further, and in different spots due to expansion from welding heat.

 

[tbailey4]

I had luck brazing my 3b manifold still holding going on 3 years. Used two torches one with a rosebud. Clamped it to box tubing or something flat then got everything glowing red.