Need to 'cheat' on Economy run
Ya, I actually tried drafting some big rigs... but I had to be about 12 inches off their tail to make it work. I wonder if anyone would notice a big rig leading me in the event??? 
Put your runflat tires on. It make 2-3 mpg difference at sustained highway speeds. How far are you going to run, when/where do you fill up, is it highway only or combined roads.
If you are going to make the run at noon, fill up early in the morning and squeeze that last ounce into the tank. Then just before everyone fills up to start, do it again. Make sure you have the column lock turned off and when possible shut off the engine and coast in neutral when possible. If it is going to be a highway run, try and have an hour run with cruise control at 60 and let the PCM lean out naturally before you get to the start.
If you are going to make the run at noon, fill up early in the morning and squeeze that last ounce into the tank. Then just before everyone fills up to start, do it again. Make sure you have the column lock turned off and when possible shut off the engine and coast in neutral when possible. If it is going to be a highway run, try and have an hour run with cruise control at 60 and let the PCM lean out naturally before you get to the start.
Maximum safe inflation of all tires seems like a logical idea. Also, in your attempt to find a fuel cell, don't forget about the front mounted windshield wiper reservoir and maybe a little blue food coloring.
Ben T.
Ben T.
don't know exactly how far we're going, or the roads to travel. We're going to get filled up at one location, all by the same person. Then drive a distance and the same person will top us off again. I don't have more details than that.
I figured on inflating the heck out of the tires.. with nitrogen, and was even thinking of removing 2 or 3 of the brake calipars (put a block of wood between pads and hang the calipar off the rotor for less drag).
The added fuel resevoir would be good, but I'd have to measure the amount I'm putting in... might look a little suspicious if I come up with 150mpg!!!
I figured on inflating the heck out of the tires.. with nitrogen, and was even thinking of removing 2 or 3 of the brake calipars (put a block of wood between pads and hang the calipar off the rotor for less drag).
The added fuel resevoir would be good, but I'd have to measure the amount I'm putting in... might look a little suspicious if I come up with 150mpg!!!
i got it.. put a relay switch in your car to kill the power to four of your injectors while cruseing..
i say kill the injectors b\c just killing the coil packs still means fuel is still flowing but killing the injectors will actually cause something like the gm dod setup also you can flip it back afterwards so it dosent seem cheezy.. finally you can program the car to ignore the 02sensors so it wont try and compensate for the bad 02 readings
i say kill the injectors b\c just killing the coil packs still means fuel is still flowing but killing the injectors will actually cause something like the gm dod setup also you can flip it back afterwards so it dosent seem cheezy.. finally you can program the car to ignore the 02sensors so it wont try and compensate for the bad 02 readings
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TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
Be careful with that... the engine isn't decided for DoD, and if you don't do it right, you're going to have cylinders firing throwing off the balance of the engine ....
Also keep in mind by hacking up the factory wiring harness you're inviting future electrical problems (unless you seal everything up very well)
Also I wouldn't personally try this at cruising speeds or under any load... decel already has DFCO so you could try adjusting that more aggressively... I honestly don't think cutting off 1/2 the injectors for short periods of time will help a whole lot though... the conditions under which you could do it safely are generally conditions where the injector pulsewidth is very short
Also if it's off for too long those 4 cylinders will have cooled down (DoD also prevents the valves from opening so it keeps the hot exhaust gas in there thus keeping the cylinders relatively warm and the same temp as the rest) ... could cause some running or hesitation issues after switching back on (just a guess as I've never tried it myself)
Also keep in mind by hacking up the factory wiring harness you're inviting future electrical problems (unless you seal everything up very well)
Also I wouldn't personally try this at cruising speeds or under any load... decel already has DFCO so you could try adjusting that more aggressively... I honestly don't think cutting off 1/2 the injectors for short periods of time will help a whole lot though... the conditions under which you could do it safely are generally conditions where the injector pulsewidth is very short
Also if it's off for too long those 4 cylinders will have cooled down (DoD also prevents the valves from opening so it keeps the hot exhaust gas in there thus keeping the cylinders relatively warm and the same temp as the rest) ... could cause some running or hesitation issues after switching back on (just a guess as I've never tried it myself)
Teching In
Joined: Nov 2006
Posts: 2
Likes: 0
You have HPTuners right? Bring your laptop along, scan the whole time and bring up the window (its a button near the DTC button, it looks like an engine) where you can change your timing and idle speed (real time, not the data tables) I drive my 98Z28 everyday like this and once i get on the highway, i set my commanded AFR to 17:1 and watch my O2 (stock narrow band) sensors max out lean. I get about 34MPG (highway)this way.
Like horist said, you should have aggressive DFCO settings so your fuel is cut off the instant you close the throttle. Also (this may be more tricky with an auto) reduce or zero out your throttle cracker because it usually lets unwanted airflow by the throttle, like during throttle lifts and decel. If you will spend any significant amount of time idling, lower your idle rpm and crank the spark up. Even if the pulsewidth doesn't change your injectors are firing less often. Try to improve the aerodynamics of your car. Skinnier tires, lower the stance if there's an easy way to do that, tape off body gaps, etc.
