performance exaust, mpg increase?

[theholycow]

Originally Posted by dkjones96

I don't worry about the particles that get past these filters. You'd be amazed what can pass through an engine without damaging anything. I had a friend shatter a stock Chamion plug trying to pull it from his 3.9L Dakota(no idea why they torque the plugs at the factory so much) and he just started it and let the engine run until the ceramic insulator pieces and copper electrode passed out the exhaust and it runs great.

I had a Ford 460 that had to be replaced after that happened.

Actually, now that you remind me of it, I can't remember which came first...failing oil pressure (gauge needle flickered end-to-end so fast it was a blur) or the busted plug. I'll have to ask my dad if he remembers...

[Mayhim]

I had the same 8ppm of silicon with K&N filtration and Purolator filtration. Whether there was more airflow I couldn't say. I think any reduced filtration in the K&N has to do with operator error on the oiling.

But the K&N had a huge upfront cost and increased continued maintenance costs. I vote Purolator.

[dkjones96]

Headers came in but it isn't going to be a fair test. At the same time they go in I'm doing a lift and getting new tires...

[dkjones96]

Damn, you caught me.

I might actually get a fair test out of this yet. I decided this morning that I'm gonna replace the lower ball joints up front and relocate the sway bar mounts while doing the lift so I'll get a few weeks on the headers before it comes time to do any of the other stuff. That's at least a couple tanks.

[shatto]

My on the road experience. 98 Dakota V6.

Flowmaster Muffler
1 MPG improvement..........at 70 MPH (I-5, SF to LA)
At lower speeds it only made noise.

Modifying air intake.
Dirtier Air Filter. No detectable MPG change.

Gibson Headers
2 MPG increase, under normal driving.
Substantially better acceleration and pull when needed.

Headers were installed around 150,000 miles after the Flowmaster.



I have talked with other Dodge truck owners who dramatically increased their mileage, by installing thousands of dollars of intake, exhaust, manifolding, heads, roller-rockers, valve springs, pistons.......
You get the idea. You can radically modify the engine to achieve better power and MPG and maybe both, but the question has to be;

Is the purpose to get a MPG figure at any cost, or have a useful vehicle that gets good mileage?

[dkjones96]

Turns out I only got the header install done. We will see what it does, I topped off the tank after playing around and making my stainless headers turn a nice golden color.

I did notice my instant economy seemed better, that it wanted to pull off idle harder, and my top-end is like night and day. It was a drastic change from the manifold design which I posted earlier and an unbelievably annoying 6 hour install. That pipe that curves up and around to make the first and last cylinders equal length made them a total SOB.

Also remember when comparing these that most 4 cylinder cars already come with what you could call a header and won't see much of any increases in power or economy. The comparison is really only for engines with log style manifolds like pretty much every American V8 and V6 until about 2000.

[dkjones96]

I noticed this morning that cruising to the freeway I'm not giving enough throttle to lock the torque converter near the 40mph speed limit like I was, I had to speed to 48 to get it to stay locked.

On the freeway between 65-70 I'm not seeing any lower than 18 and it hovers between 23 and 27 depending on what the car in front of me is doing(stupid drivers). My average fuel economy is about 1.3mpg above normal as well so far. Its been right on so far when calculating at the pump.

[shatto]

Originally Posted by dkjones96

I noticed this morning that cruising to the freeway I'm not giving enough throttle to lock the torque converter near the 40mph speed limit like I was, I had to speed to 48 to get it to stay locked.

On the freeway between 65-70 I'm not seeing any lower than 18 and it hovers between 23 and 27 depending on what the car in front of me is doing(stupid drivers). My average fuel economy is about 1.3mpg above normal as well so far. Its been right on so far when calculating at the pump.

Disconnect the battery overnght. You'll want to let the computer learn the new settings.

[dkjones96]

I don't think it's a learning issue, there isn't much to learn. My TCM is programmed to unlock the converter somewhere around 4% throttle opening and I barely break that under normal circumstances. I datalogged today and I had to be going 45-50 to keep above that. I only average 8% throttle opening on the freeway at around 65-70.

Normal acceleration for me, which is faster than most people from a light, is only around 40%. I can easily drive around and never break 2500rpm.