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Old 06-14-2008, 04:42 PM   #3 (permalink)
aerohead
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inflation pressure

Quote:
Originally Posted by Goldenfrog View Post
I have 2 different brands of tire on my car. They are all the same size but have different max PSI ratings. The front pair have a max of 44 and the rear set max is 35. I had them inflated to max with Nitrogen today, 44PSI front and 35 PSI back. I was wondering how this might effect safety and MPG of my car.

It's a 1993 Plymouth Voyager with a 2.5l 4cyl. 95% of my driving is under 35mph, short trips where the engine never really warms up. I am guessing under these conditions I'm not going to see any difference in MPG.

I was thinking of trying a hot air intake but I'm unclear as to how that works. I always heard that your car performs better with cooler air from outside the hood.

Any input would be appreciated. Thanks
I do not have any current data.The data I do have suggests that while under-inflation robs fuel,over-inflating shows no significant improvement in economy,and can have a deleterious effect on brake bias,effecting oversteer/understeer characteristics of the vehicle.Inflation pressures are established by the carmaker for brake bias,favoring understeer,where the front tires break loose first,and a simple steering input restores direction.Personally,I'd stay with carmaker specs,regardless of max. pressure ratings.Saving a fraction of fuel is not worth your safety.
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