I am thinking about putting a straight pipe on my 88 ford bronco. i am leaving the cat on. will this lower my gas mileage or change it at all?

 

I think not. Straight pipe will not lower your gas mileage but will maintain it and just give your car better performance.





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how to save gas

 

Straights can create better flow of exhaust gas but I'm not sure if it can increase fuel mileage.

 

No effect,
No power difference,
No damage.
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The only thing you would change is the sound.
In theory it would run lean on fuel, but it won't in the real world because assuming your O-2 sensors are working they will compensate.

 

Why do you want to leave the cat? I got considerably more power when I cut mine and put the straights on. Gas mileage improved too

 

I straight piped my truck completly granted there is and arguement that if theres no back pressure the engine will loose some power in the low and mid range. Thats a theroy and in no way true, if your really worried about it like i was at the time throw in a TBI or Carb spacer i noticed a big improvement on the butt dynoo

 

Straight pipe has no effect on engine performance and it's not going to lower the fuel efficiency. The only worse thing about it is its noise; yes it has a very loud and annoying sound.

 

at first your milage will be amazing because your afraid to sick your foot in it because of tickets however youll eventually build some confidence and develope a lead foot to hear the pipes flowin'. you will see a drop in low end proformace but that powers not lost its just put in the high RPM range so youll have to mod your engine to compensate if it drives you crazy like me. but dont run true duals use your exhisting header Y pipe and then use a second Y pipe to split into duals that should prevent crackling if you use the right size pipe and keep enought back pressure to insure you exhaust valves dont cool to quickly.

 

 

wrong about the damage it will burn your valves if you dont have any back pressure and if its before 1975 or 85 i cant remember off the top of my head but you can run open headers with baffles to make a little bit of back pressure and get away with it