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CUMMINS' Performance
#1
I have noticed that quite a few of AO members have Cummins powered tow rigs/daily drivers, including myself. I was hoping to get some basic knowledge of what mods have been done, what myths have been unraveled, and discoveries about anything to do with performance regarding your Cummins.
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#2
Leave it be is my best advice. It is more than fine for towing in its stock form. I can talk with you sometime to keep you from making mistakes many others have if you really wish to modify it. Get some gauges regardless though.
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#3
I am running 3.73 gears. Havent ran through a full tank of fuel though. might be around 13-16 mpg
Ive heard running taller skinny(12.5 or thinner) will improve the ratio and keep RPMs down in the sweet spot on highway driving.
I got amazing mileage in my old 12 valve cummins, 20-22 mpg stock. the 24 valve cummins sure gobbles up fuel.

what are you running Mel?[COLOR="Silver"]

---------- Post added at 12:49 am ---------- Previous post was at 12:49 am ----------

[/COLOR](the 12 valve had 3.55 gears in it)
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#4
Dude something must be going on. I have 3.73 gears and I average over 25mpg usually in the 27mpg range. I easily get 18mpg plus towing the jeep down for M&G. I would check your tire pressure first and the air filter. You should be getting much better than that. And how long are you letting it sit and idle? I did add a super chips flashpaq and it wasn't worth it. Of course I got it for free so no money lost.

If you are going to do any performance mods I highly suggest you get a pyrometer gauge, trans temp gauge, and fuel pressure gauge at a minimum. A few things also to know and think about. Most performance mods no matter what they advertise are not going to increase your mileage like you think if at all. Trust me I've been through this many times and done a lot research on the matter. Also if you do any kind of prgrammer be sure that you get one that changes timing, ie pulse width, and such. Stay away from any like Edge that do fuel pressure. You will be asking for trouble late down the road. Unless you dump more money into the motor for things like injectors, stud the head, fire ring the head, new boost tubes, new lift pump, and a few other things. Also don't buy into getting a bigger exhaust. These things come with a 4" turbo back exhaust there is no need to upgrade except maybe a better muffler. But that really isn't needed either. also remember black smoke is just wasted fuel. Banks is one of the best. They pride themselves on minimal black smoke (wasted fuel).

Unless you plan on doing some racing, sled pulling or the like most of the upgrades just aren't worth the money for what you potentially give up.
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#5
Well said Mel.
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#6
The truck came with an edge tune. Been running it on the stock or mileage setting. Idling it for maybe 10 minutes. The tires are not super wide but definitely stick out past the body a little. The prior owner put in a 5 inch exhaust system too.
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#7
10 minutes idling every morning will kill mpg quick.
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#8
Yes it will. And todays diesels aren't quite like the old ones. My papa used to say don't move it until the temps come up and the air is up. Well you will be waiting till summer for the temps to come up. The edge will use more fuel. Why? Because it takes more fuel to create more fuel pressure. The 5" exhaust is a waste but if it is there it's not going to hurt anything. Slightly wider tires aren't going to hurt your MPG like that.
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#9
Thankfully I can turn off the performance tuning with a button or two
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#10
Mel got most of it on the head, number one upgrade is gauges pyro tranny and boost are what i run keep an eye on the tranny temp in these dodges they got hot quick which ultimatly leads to tranny failure. Secondly ditch the edge, they are nothin but problems on cummins engines ive had one and would always throw codes display always messed up it was at edge products more than it was in my truck, I run a Smarty programmer by MADs electronics by far the best programmer for the 3rd Gen cummins IMO. on 04.5 and earlier keep an eye on the lift pump that is next to the fuel filter housing it WILL fail if you have the in tank version no worries, if not i would suggest an aftermarket lift pump such as AirDog or FASS. I personally have an AirDog 150 and use fleatgaurd filters on it havent had a problem yet. exhaust: stock on 04.5 + is 4" not sure about the earlier 03s, 4 inch is plenty though unless your after more sound, I have a turbo back 5" MBRP no cat and it is loud when towing (almost annoying). keep the air filter clean on these trucks as they tend to suck ALOT of air, if you are gonna run an aftermarket intake the AFE pro gaurd 7 is my filter of choice as it traps more dirt then the others stock being the best though. best place to get info on these trucks is Dieseltruckresource.com

hope all that helps a lil, if i were to do it all over again i would leave it stock and just drive it but i cant leave anything alone lol
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#11
hmm.. I can look into pulling the edge tuner when I get caught up on projects. Until then I will just keep it at stock. The Edge tuner does have some other settings like torque converter lock up and tire size adjustments. This is just my daily driver, it just might see some camping trails.
Maybe an upgraded suspension/leveling kit and some taller tires (2-3 inches) in the far future. Im going to enjoy just driving this one and not tinker with it until its time to replace parts.
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#12
One other thing I forgot. The biggest issue with the transmission is the torque converter. The rest is actually pretty good. They run these transmissions in race trucks with only swapping the TQ converter. they are single a single disc paper weight. I'm sure the o3 has a 4" exhaust but since you got a 5" one now it doesn't matter.

I am a paying member on Dieseltruckresource.com Those guys are great there and you can get some deals. I'm also a member of turbo diesel regisrty (TDR) and there is more knowledge and info there than you could ever need.

As for filters and such I used ot order my from genos garage. You can get kits that have enough oil filters, air filters, fuel filters and belts for 4 services all in a nice plastic tote. And they are fleet guard filters. The cummins place down on vanhorn will order you some but you have to talk them into it. If a few folks get together we may be able to have them do a bulk order a little easier.

The lift pump is an issue. The biggest issue is if they fail it wont allow the cp3 pump to get enough fuel and allow it to cool and lube properly which can result in about $2000 repair bill with you doing the work.

Courtney I like your thinking. Leave it stock. I haven't done all the mods I thought I would due to what I use mine for. USing it as a dd and tow rig you don't need all the extra crap and it can cause you some issues down the road you aren't prepared for sometimes. And I'll stress again guages are very important.
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#13
I have some kind of air box in it. It is a Volant Cold Intake air box. I have never heard of it before.
http://www.autoanything.com/air-intakes/...10422.aspx

there is a link to what it looks like
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#14
Mel- I am interested in a filter/belt service package from Cummins. Count me in[COLOR="Silver"]

---------- Post added at 10:35 pm ---------- Previous post was at 10:32 pm ----------

[/COLOR]LIFT PUMP. So how do I know when it is dying or dead? Do I bother replacing before it goes?

Also- I posted a link to the Volant air box just to show what I have in the truck ... but it needs to be approved by a moderator. never had that issue before.
Anyway, please approve the post Big Grin[COLOR="Silver"]

---------- Post added at 10:52 pm ---------- Previous post was at 10:35 pm ----------

[/COLOR]hey, where did the post go?
http://www.autoanything.com/air-intakes/...10422.aspx
there is it again.. try #2
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#15
The gauges sound simple enough , I just need to find a nice little cluster to make everything look professional and nice. I read up on the torque converter issue and I plan on swapping it out when I have some money
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#16
ATS torque converter review:
http://www.pirate4x4.com/productreviews/ats/tranny/
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#17
I personally don't like theirs. ATS that is.

http://www.goerend.com/torqueconverters.php It is best to call them and talk to them. Gorend is the best choice.
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#18
well.. along with a tranny rebuild too (ATS diesel link)
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#19
i get 25-27 mpg all day long empty and 19 towing my flatbed .

ive burnt 3 trannys now all related to the tourque convertor coming undone .. today my power steering quit ..now waiting on gene's ..this wont end well ....
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#20
Petey I would contact Gorend for any transmission stuff. If you just want to buy parts and have someone rebuild that is ok but don't let anyone around here order the parts. I know you may be good friends or such with born again but they are going to order oe equivelant stuff. I've talked to them before about rebuilding mine and what they were going to order they told me was "performance" parts wasn't even close. Another good source for trans parts is suncoast.
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#21
Just tried to call and got an annoying automated message. Didn't get anywhere Sad
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#22
called Georend and they had the secretary call me back after i left em a message. She was not able to answer my questions, so the tech will call me tomorrow.
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#23
akram Wrote:Petey I would contact Gorend for any transmission stuff. If you just want to buy parts and have someone rebuild that is ok but don't let anyone around here order the parts. I know you may be good friends or such with born again but they are going to order oe equivelant stuff. I've talked to them before about rebuilding mine and what they were going to order they told me was "performance" parts wasn't even close. Another good source for trans parts is suncoast.


X2 on this, Goerand is the way to go. Il be going that route when my trans takes a dump. stay away from ATS heard nothing but bad. Also that Volant intake is ok but not the best I have my original airbox if you wanna buy it.

as far as the lift pump goes if your truck has the small black round pump next to the fuel filter canister i would replace it soon or it will leave you stranded
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#24
There are fuel pressure warning light setups that will let you know when your pump craps out.
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#25
Zukman Wrote:There are fuel pressure warning light setups that will let you know when your pump craps out.

only problem with this setup is by the time the light comes on the pump is pretty much done and you will be doing damage to the CP3. A gauge will let you see a trend in dropping pressure JMO
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#26
and that is why I always suggest one of the gauges be a fuel pressure gauge. Even if you do put an aftermarket lift pump on.

Peter it may be worth a try to get the dealership to replace the external one with an in tank one. they were doing this at one point. That is why the later 2003 models usually have the in tank one. They recognized the problem. But there is no official recall for it. Some dealers replaced it under the engines 100k mile warranty. But as you know don't hold you breath for Genes to do it.
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