getting better milage out of a 4L
ive done some research and have buddys that have done the same to there jeeps
run 2 1/4 inch high flow muffler you can leave your stock exhaust tube just replace the muffler you will be able to gain about 2-3mpgs. dont increase pipe size you increase flow with bigger pipe you change your power curve even just going to 2.5 inch exhaust will hurt your milage.
a cheap throttle body spacer can gain up to 2-3mpg on a stock engine for a 4L you can find them for as cheap as 35dollarsUS
on older 91-98 jeep 4L HO, the intake volume is 2600cc's by changing to the 99+ intake with the 4200cc intake the runners are designed to have similar length in runners doing a vacumm test the 2 inner runners will pull the least and the 2 outer ones will pull the most and so on. you can rework the runners to try and get the same airflow youll come close but wont be able to get them all eqaul unless you can weld aluminum. but is it really worth that. yes itll help your milage but reallly is it worth it to gain just a fraction of a mpg gain.
theres a venturi in the airbox cover its more restrictive then good you can remove it for a 1mpg gain. theres a bit of a venturi on the throttle dont machine that away. right now im trying to design a throttle body spacer designed for a bored out throttle and see if we can get a gain over the other other throttle body spacers. |
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