Several Engine/Fuel Upgrades - All at Once Better?

[Tacedaddy]

I'm running 3.55's with 245/26/75

all the homies must be jealous you running 75 inch rims and all

and even if you typed that backwards you have 26 inch rims... DONK

 

[whitexj98]

My jeep runs great and when I hit 140k I ran a can of BG 44k then replaced the upstream o2 sensor, wasn't having any issues or codes but I did gain back about 2 mpg. NTK o2 sensors are pretty cheap from rockauto.

 

[yaromb]

Hey all,

Quick question. I am planning on doing several upgrades in the next few weeks, in order to hopefully gain back a few MPG's (and maybe a little power too), that I will be able to take advantage of for the whole summer. I am planning:

Cowl Air Intake
Bored Throttle Body
784 Injectors
Replace all 4 o2 sensors (don't have record of them ever being changed)

Would it be best to do all of these the same day, so the computer only has to re-learn its fuel settings once?

Also, what is the best way to reset the ECU?

Go for it. I just did it (except the O2 sensors, which are fine) with 703 injectors, bored TB and a Spectre CAI. Car wants to bite every time I touch the throttle. Once I add the free-flow exhaust, it will be perfect.

I don't care what people say, the engine runs smoother with very fast response. CAI is very loud when you apply throttle, but gets better once you cruise...

The instructions provided above for ECU reset, are correct.

 

[bzauche]

Go for it. I just did it (except the O2 sensors, which are fine) with 703 injectors, bored TB and a Spectre CAI. Car wants to bite every time I touch the throttle. Once I add the free-flow exhaust, it will be perfect.

I don't care what people say, the engine runs smoother with very fast response. CAI is very loud when you apply throttle, but gets better once you cruise...

The instructions provided above for ECU reset, are correct.

I think I'm going to man. (same guy from CF)

Will a free flowing muffler do the trick or do I need upgraded headers, etc...?

 

[GordoSmasho]

...And you must be traveling on flat ground with no wind resistance

And that was commuting with about 700lbs of tools and a ladder up top. 410s ax15. Correct speedo. 15mpg. Sometimes more. If your getting less something isn't up to spec. I've had 5xjs in various heights and tire sizes and 15 was the worst I ever got when everything is up to spec.

 

[yaromb]

I think I'm going to man. (same guy from CF)

Will a free flowing muffler do the trick or do I need upgraded headers, etc...?

Well, people in the know seem to say that if you increase the air intake, you need to increase the exhaust to make the whole process flow better. Actually makes sense.

I have yet to hear about anyone installing one of these free flows and complaining he was robbed of engine performance...

 

[SanDiegoXJ]

I think I'm going to man. (same guy from CF)

Will a free flowing muffler do the trick or do I need upgraded headers, etc...?

heh, just take a look at the stock header....comes direct from the factory with a dent in it to clear the front DS but really works as an airflow restriction.

IMHO, if you want the Jeep to breath better, header should be your first move....all the air in the world going in the engine isn't gonna help if it can't get out. And the free flow muffler idea, along with a high flow cat, is a great idea...

But I did a $400 Borla cat back and got nothing more than essentially a stock tailpipe and Borla muffler. Would much rather have a Detroit locker for the money at this point as I really saw no improvement in performance, just sounds a little throatier.