Computer Reprogramming Is This The Place?
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Computer Reprogramming Is This The Place?
I have spent the last hour trying to find any type of post that resembles my question but have been unable to do so. If this question is in the wrong area would someone please direct me to the appropriate place?
My stats:
2005 Dodge Quad Cab
5.9 Litre Cummins Diesel (obvously)
3.73 rear end gears
6 speed manual trans.
2 wheel drive
No power accessories at all (plain Jane)
(This is the truth as I have hand calculated for the last 2 years) (no electronic mileage gauge)
Highway driving average 24 mpg at 68 mph, about 1950 to 1975 rpm
City driving average 18 to 19
This is my question for those of you here who know about the computers in these trucks.
I was told that I could have my computer "reprogramed" so that I could run at a higher speed but that my "rpm's" would be lower enabling me to still retain my current fuel mileage. Right now my speed and rpm's read as follows:
Current:
68 mph = (about) 1900 to 1950 rpm's
75 to 78 = 2300 to 2400 rpm's (somewhere in that range)
Desired goal:
75 to 78 mph = 1900 to 1975 rpm's
The info that I was told is that this is possible but obviously I do not know if this is the truth thus, I am asking this to those of you with the knowledge. If I keep my rpm's "just below" 2000 I am at my optimum peak in mpg but once I hit 2000 or more, my mpg starts to decline.
I have looked into the Gear Vendors "Over/Under" unit but at the moment it is to pricey for me. I have also heard about these "Plug and Play" units (for lack of a better term) but I am also unsure of them and I really am not concerned for the "power" aspect as I use my truck to pull a trailer occasionally but use it daily to commute to work and I have an hour drive each way.
I'm sorry to take you the long way around the mountain here guy's but I figure if you have as much info as possible it makes it easier on you as I am looking to you for an answer as to whether what I was told is correct or not or if there is another alternative.
I thank you all for your patience in reading my "mini novel" and any help is most greatly appreciated
The Lord Bless You
hizson
My stats:
2005 Dodge Quad Cab
5.9 Litre Cummins Diesel (obvously)
3.73 rear end gears
6 speed manual trans.
2 wheel drive
No power accessories at all (plain Jane)
(This is the truth as I have hand calculated for the last 2 years) (no electronic mileage gauge)
Highway driving average 24 mpg at 68 mph, about 1950 to 1975 rpm
City driving average 18 to 19
This is my question for those of you here who know about the computers in these trucks.
I was told that I could have my computer "reprogramed" so that I could run at a higher speed but that my "rpm's" would be lower enabling me to still retain my current fuel mileage. Right now my speed and rpm's read as follows:
Current:
68 mph = (about) 1900 to 1950 rpm's
75 to 78 = 2300 to 2400 rpm's (somewhere in that range)
Desired goal:
75 to 78 mph = 1900 to 1975 rpm's
The info that I was told is that this is possible but obviously I do not know if this is the truth thus, I am asking this to those of you with the knowledge. If I keep my rpm's "just below" 2000 I am at my optimum peak in mpg but once I hit 2000 or more, my mpg starts to decline.
I have looked into the Gear Vendors "Over/Under" unit but at the moment it is to pricey for me. I have also heard about these "Plug and Play" units (for lack of a better term) but I am also unsure of them and I really am not concerned for the "power" aspect as I use my truck to pull a trailer occasionally but use it daily to commute to work and I have an hour drive each way.
I'm sorry to take you the long way around the mountain here guy's but I figure if you have as much info as possible it makes it easier on you as I am looking to you for an answer as to whether what I was told is correct or not or if there is another alternative.
I thank you all for your patience in reading my "mini novel" and any help is most greatly appreciated
The Lord Bless You
hizson
Administrator/Jarhead
Joined: Jun 2006
Posts: 14,965
Likes: 19
From: Jacksonville, NC
Hi, Hizson, welcome to the DTR.
You cannot reprogram the computer to change RPM's at a certain speed and get true results... I could reprogram your speedo to read faster than what you are going, and your RPM's would be impressive at a set speed...
The only way to truly do that is to get taller tires, or change the rear end raito, you have 3.73's now, you can go to 3.55's, and I think that there is another raito, but I don't know it off the top of my head. The gear vendors is another route, but you said that's too much $$$.
If you are looking for fuel milage, you can do a few things.
First, proper maintence is key. Fluid changes, air filter being clean, and tire pressure are important things to start. If you want to go further, you can run synthetics, but how much that helps is not really proven... It does help a little. Keep your truck clean, and cleaned out. A cleaner body keeps down on drag, and keeping all the extra weight out reduces the load on the engine.
If you want to go further, look into aftermarket air filters, exhaust, then maybe a mild programmer, such as the smarty jr.
Even if you keep the RPM's down, the faster you go, the more drag you produce... I'd stay just under 70 for good results, and at 65 probably for the best results.
Where do you live?
I hope this helps a little.
Ask questions on anything you like.
You cannot reprogram the computer to change RPM's at a certain speed and get true results... I could reprogram your speedo to read faster than what you are going, and your RPM's would be impressive at a set speed...
The only way to truly do that is to get taller tires, or change the rear end raito, you have 3.73's now, you can go to 3.55's, and I think that there is another raito, but I don't know it off the top of my head. The gear vendors is another route, but you said that's too much $$$.
If you are looking for fuel milage, you can do a few things.
First, proper maintence is key. Fluid changes, air filter being clean, and tire pressure are important things to start. If you want to go further, you can run synthetics, but how much that helps is not really proven... It does help a little. Keep your truck clean, and cleaned out. A cleaner body keeps down on drag, and keeping all the extra weight out reduces the load on the engine.
If you want to go further, look into aftermarket air filters, exhaust, then maybe a mild programmer, such as the smarty jr.
Even if you keep the RPM's down, the faster you go, the more drag you produce... I'd stay just under 70 for good results, and at 65 probably for the best results.
Where do you live?
I hope this helps a little.
Ask questions on anything you like.
Thread Starter
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Joined: Sep 2008
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Thank you.
I was kind if figuring that the gear vendors was going to be my only real option to actually change anything. Their brake down shows that with the 3.73 rear end the change goes to a 2.72 in 6th gear. I change my fluids on a regular basis so that's not a problem.
Maybe finding out how low I could go on a rear end gear change is an option but then wouldn't I have to have the computer reprogramed for the gear change?
I was kind if figuring that the gear vendors was going to be my only real option to actually change anything. Their brake down shows that with the 3.73 rear end the change goes to a 2.72 in 6th gear. I change my fluids on a regular basis so that's not a problem.
Maybe finding out how low I could go on a rear end gear change is an option but then wouldn't I have to have the computer reprogramed for the gear change?
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I live in Las Vegas so there isn't a lot of hill climbing on the freeway. The trailer I pull isn't that heavy when I pull it. My kids race go-karts so I have 3 karts, tools, fuel, water. and misc. items. My trailer empty weighs more that all of the stuff I put in it. I can run up Cajon Pass coming out of San Bernardino at 80 mph "EASY" if I wanted to. I bought this truck specifically for taking my kids racing but I had always wanted the Dodge Cummins. I drive truck for a living and knew about their dependability.
I had an 88 Chevy Crew Cab with the 6.2 diesel it did the job but just didn't have what I wanted. I considered putting a Banks Turbo on it but when a fully loaded Ready Mix truck passed my wife and I on one of the few steep grades in our city she told me I couldn't take my kids out of town with the Chevy anymore and told me to go look at the truck I had been looking at for sometime. I wanted to kiss that Mixer Truck so bad so here I am.
Dodge Cummins owner and happy with my purchase. This has been one of the best vehicles I have ever owned. many don't like Dodges but at the end of the day 24 mph in a 1 ton pickup.
I had an 88 Chevy Crew Cab with the 6.2 diesel it did the job but just didn't have what I wanted. I considered putting a Banks Turbo on it but when a fully loaded Ready Mix truck passed my wife and I on one of the few steep grades in our city she told me I couldn't take my kids out of town with the Chevy anymore and told me to go look at the truck I had been looking at for sometime. I wanted to kiss that Mixer Truck so bad so here I am.
Dodge Cummins owner and happy with my purchase. This has been one of the best vehicles I have ever owned. many don't like Dodges but at the end of the day 24 mph in a 1 ton pickup.
Last edited by hizson; Nov 7, 2008 at 08:51 AM. Reason: end is messy
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Administrator/Jarhead
Joined: Jun 2006
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From: Jacksonville, NC
I took it out for you...
Yes, I have not done it, but a few members here have... use the search function and search for 'rear end swap' or '3.55'... it may take a little, but the info is here.
If you strike out on that, start a thread in the 3rd gen engine and drive train section...
Yes, I have not done it, but a few members here have... use the search function and search for 'rear end swap' or '3.55'... it may take a little, but the info is here.
If you strike out on that, start a thread in the 3rd gen engine and drive train section...
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I really appreciate all of your help MH. I am obviously trying to do this with as little "out of pocket cost" as possible but I know there will be some type of expense and with the current economy and who knows what will happen during this next administration I want to hold on to as much of my paycheck as I possibly can.
You have been helpful though and it is greatly appreciated
The Lord Bless You
hizson
You have been helpful though and it is greatly appreciated
The Lord Bless You
hizson
I understand the $$$ thing... Let us know if you need any more help...
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sorry for the caps probably your cheapest option in reality
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From: Tulare, CA
Minimum Brake Specific Fuel Consumption occurs when engine RPMs are at (or VERY NEAR) Peak Torque. Our peak TQ numbers occur at approx 1600 RPM. So with Stock tires, 3.73 Gears and a .70 Overdrive (I think that is our OD ratio). Minimum BSFC (or maximum MPG) should occur at or near 57.6MPH
The only real way to change that number is to increase effective gear ratio.
to put the engine at approx 1600RPM at 70MPH without changing the Rearend ratio you would have to go to 38.38" tires.
NOW that said, this is obviously for only cruising speeds, so if you were to do alot of highway driving it might be beneficial.
The only real way to change that number is to increase effective gear ratio.
to put the engine at approx 1600RPM at 70MPH without changing the Rearend ratio you would have to go to 38.38" tires.
NOW that said, this is obviously for only cruising speeds, so if you were to do alot of highway driving it might be beneficial.