Quote:
Originally Posted by Offroadford4x4
after the truck is done, than I will pull the exhaust, gut the cat out and find a better flowing muffler (not a fart cannon from some ricer). I will also look into the EGR delete, along with making my own highflow cold air intake which will probably require turning or relocating the battery so I can put a larger intake into the fender. I'm also going to look into insulating the intake manifold somehow since it's on top of the exhaust manifold. I'm sure that heat transfer does nothing to help economy or performance. I'll also be tearing down the original motor and looking over things like the cyl head to see where improvements could be made such as the bowls behind the valves and how well the ports match the manifolds. if I can increase the flow, I can increase the overall volumetric efficiency of the engine gaining both more power, and better economy (so long as I keep my foot outa it).
I'm not really shooting for major gains, but I would like to see an average of around 30-35 mpg combined driving while retaining the auto trans.
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I can tell you with a very high degree of certainty that gutting the cat will not help anything at all unless it is a shot, plugged up cat- and I've never seen one of those. Don't go there.
EGR block off: go ahead and experiment; I have. Didn't help anything. If the system is functioning properly then "If it ain't broke, don't fix it"!
Same with cold air intake. Try it and let us know what it did. I removed the "restrictive looking" airbox intake and saw no gains.
Re: warm intake manifold: well if we are driving for economy that's a good thing I would think. It's not like it gets blazing hot anyway.
Port match- go for it. I've done it on one of my '84s (carb) but not on the '94. Remember if it is at anything less than WOT it probably isn't going to do anything as the throttle blade itself is the big gorilla restriction in the room. And if you're driving for econo on any particular tankful it will not see any WOT at all.
So then when everything's running right and without a bunch of do-nothing mods it should return up to 30-33 on good tanks. But not every tank unless you have better driving conditions (no extreme winter).