# Most fuel efficient exhaust system?



## clbarrett (Jan 17, 2010)

I need a new exhaust system on my 94 hb 3.0. probably gonna change out the old manifolds too. Would like to go with the most fuel efficient design i can find. I was wondering about the diameter of the pipe from the engine back, 2" mabye? Any Ideas? Thanks.


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## rogoman (Dec 16, 2004)

Stay with the OEM size exhaust piping. Going larger will probably have a negligible effect on MPG and it may reduce the low speed torque. For better overall efficiency, make sure the CAT is good.


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## TheRepairMan (Jun 30, 2009)

rogoman said:


> Stay with the OEM size exhaust piping. Going larger will probably have a negligible effect on MPG and it may reduce the low speed torque. For better overall efficiency, make sure the CAT is good.


+1, exactly!

-R


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## clbarrett (Jan 17, 2010)

thanks for the info. by chance do you know the oem pipe diameter off hand?
Also has anyone tried a chip for better gas mileage? Do they work?


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## smj999smj (Jan 1, 2006)

The "chips" are worthless.


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## TheRepairMan (Jun 30, 2009)

smj999smj said:


> The "chips" are worthless.


 Yeah, that's my experience with performance chips, also. 

Guys that change chips or have their vehicle's ECU remapped are usually looking for more all out power rather than street economy. Generally, economy is sacrificed for an increase in power. If not by the chip itself, buy the act of driving much harder to take advantage of that power increase.

-Roger


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## clbarrett (Jan 17, 2010)

Thanks for the feed back on the chips, good stuff to know. Any suggestions on a reasonably good exhaust system for less $$ and maybe a manifold or 2?


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