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Considering switching to Diesel, need basics...

Old 01-07-2012, 03:23 PM
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Considering switching to Diesel, need basics...

I currently have a major gas guzzling truck, a 2006 Dodge Ram SRT10. I want to continue to drive a truck, for how practical and useful they are, but I want something that gets better than 9mpg city and 12mpg highway. I just switched jobs where I will have to travel about 100 miles per day, so I really need much better mileage.

I also want to be able to keep the performance I have too, which is why I probably wouldn't switch to a Hemi Ram, because I won't get 500+ hp out of that very easily.

I've been researching the 6.7 Cummins a good bit, and I'm disappointed in how hard it is to find good mileage information. I almost wish the EPA rated 2500/2500 trucks (okay I won't go that far).

So here are my questions:
1) I've heard people mention that diesels have higher maintenance expenses. I don't quite understand, what do you have to maintain on a diesel engine that you don't on a gas? Aren't the oil changes less frequent with a diesel?

2) If I buy a 2007-2009 model 6.7 Cummins 2500 truck with only a quad cab (not mega) can I likely tune it for 15 city and 19 highway? I'm doing a cost analysis to see how much I would save making the switch from my current ride.

3) Could I make it about as powerful/quick as my current truck (525hp and 525 lbft torque) fairly easily? What would it take to do this? With the added weight of the 2500 frame and 4x4, it would probably need to be more like 500hp and 700-800 lb ft of torque to feel similar.

4) Anything else I need to know before making a switch? Maintenance, other costs, etc? I've seen some 2007-2009 models in my truck's trade in value range, so I could almost make a swap, so initial price increase of a diesel plant isn't a big deal for me.

Thanks!
Old 01-07-2012, 04:16 PM
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Originally Posted by TROTTMAN
I will have to travel about 100 miles per day, so I really need much better mileage.
I commute 200 miles rt, all highway, so I drive a car @ 30 mpg and it just passed 345,000 miles with the original engine. I put about 8-10,000 miles on the trk/yr.
Old 01-07-2012, 06:52 PM
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Originally Posted by TROTTMAN
I currently have a major gas guzzling truck, a 2006 Dodge Ram SRT10. I want to continue to drive a truck, for how practical and useful they are, but I want something that gets better than 9mpg city and 12mpg highway. I just switched jobs where I will have to travel about 100 miles per day, so I really need much better mileage.

I also want to be able to keep the performance I have too, which is why I probably wouldn't switch to a Hemi Ram, because I won't get 500+ hp out of that very easily.

I've been researching the 6.7 Cummins a good bit, and I'm disappointed in how hard it is to find good mileage information. I almost wish the EPA rated 2500/2500 trucks (okay I won't go that far).

So here are my questions:
1) I've heard people mention that diesels have higher maintenance expenses. I don't quite understand, what do you have to maintain on a diesel engine that you don't on a gas? Aren't the oil changes less frequent with a diesel?

2) If I buy a 2007-2009 model 6.7 Cummins 2500 truck with only a quad cab (not mega) can I likely tune it for 15 city and 19 highway? I'm doing a cost analysis to see how much I would save making the switch from my current ride.

3) Could I make it about as powerful/quick as my current truck (525hp and 525 lbft torque) fairly easily? What would it take to do this? With the added weight of the 2500 frame and 4x4, it would probably need to be more like 500hp and 700-800 lb ft of torque to feel similar.

4) Anything else I need to know before making a switch? Maintenance, other costs, etc? I've seen some 2007-2009 models in my truck's trade in value range, so I could almost make a swap, so initial price increase of a diesel plant isn't a big deal for me.

Thanks!
1) Diesels take more oil than a conventional gas engine, plus there is a fuel filter to change out. Thats where the added costs come from.

2) A 3rd gen 6.7 like you mentioned can easily get the mpg you're after. It'll require full emissions deletes and a tuner. From what I've read and seen, H&S is your best bet

3) It could be made into that but it's gonna get spendy. That kind of horsepower you're looking at a bigger turbo or twins, fueling mods, trans or clutch upgrades and engine upgrades

4) If you're gonna get a 6.7, delete the emissions and enjoy. Also stick around here and you'll learn tons
Old 01-07-2012, 08:03 PM
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I think you'll find that you don't need all that horse power with the normal torque of a diesel. They will tow practically anything out there in stock form. If you want to drag race keep the gasser. Diesels are slow to wind up but they are great to drive. I was flying down the road today and didn't even realize I running 85 with tons of pedal left in my '99 , and it will run like that from coast to coast at 20mpg's.
Old 01-07-2012, 08:11 PM
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I think you need to look into a commuter car and keep the SRT. If you don't tow or haul anything that needs a diesel, then you would be better off with a daily driver that was very fuel efficient.

Or, you could get a diesel and do this:

Old 01-08-2012, 03:21 AM
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I don't get the picture...

How much are the tuners? What are the performance gains?
Old 01-08-2012, 08:15 AM
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I love that vid madhat...I had to watch it a few times. I dont mean to hijack, but what tranny are you running?
Old 01-08-2012, 08:15 AM
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Click the picture, it's a video and is the answer you're looking for.



-Kris
Old 01-08-2012, 10:21 AM
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Oh haha, thanks... I probably should have been able to figure that out.

So back to programmers, if I only used a programmer, what kind of hp/tq gains could I see?
Old 01-08-2012, 10:34 AM
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Hi, Welcome to the forum.
Some of your questions were answered and some were not so here is my response to them. I have placed them under your questions in red. I have also provided a link to a downloadable pdf book that may provide more information to make an intelligent decision on a diesel truck.
http://www.turbodieselregister.com/m...ersguide.phtml


Originally Posted by TROTTMAN
I currently have a major gas guzzling truck, a 2006 Dodge Ram SRT10. I want to continue to drive a truck, for how practical and useful they are, but I want something that gets better than 9mpg city and 12mpg highway. I just switched jobs where I will have to travel about 100 miles per day, so I really need much better mileage.

I also want to be able to keep the performance I have too, which is why I probably wouldn't switch to a Hemi Ram, because I won't get 500+ hp out of that very easily.

I've been researching the 6.7 Cummins a good bit, and I'm disappointed in how hard it is to find good mileage information. I almost wish the EPA rated 2500/2500 trucks (okay I won't go that far).

So here are my questions:
1) I've heard people mention that diesels have higher maintenance expenses. I don't quite understand, what do you have to maintain on a diesel engine that you don't on a gas? Aren't the oil changes less frequent with a diesel?
Like the one poster above as mention above. Diesel engines in a truck will hold more oil. A Cummins uses 3 gallons and filter at every change. A Fleetguard oil filter will cost about $12.95 and about $35.00 for oil. With a 6.7L stock engine will be every 4K to 7.5K miles depending on driving conditions. A deleted truck will be a minimum of 7.5K miles.

2) If I buy a 2007-2009 model 6.7 Cummins 2500 truck with only a quad cab (not mega) can I likely tune it for 15 city and 19 highway? I'm doing a cost analysis to see how much I would save making the switch from my current ride. Yes, you can easily do this but the truck will need to be deleted and you will need either a Smarty or H&S programmer. You will need to add the cost of deleting this will be around $1200 to $1500 US depending on how you do the deletes.

3) Could I make it about as powerful/quick as my current truck (525hp and 525 lbft torque) fairly easily? What would it take to do this? With the added weight of the 2500 frame and 4x4, it would probably need to be more like 500hp and 700-800 lb ft of torque to feel similar. I am using the Smarty on level 3 which is safe for the 6 spd auto transmission and engine. Smarty claims that they add 60HP to the rear wheels and 120 lb-ft torque also. The stock motor produces 350 HP at 3,000 RPM and 650 lb-ft torque at 1,500 RPM. So with a 20% loss due to efficiency in the drive train (this is a guess no dyno) my RWHP is 340 and the torque is 640 lb-ft.

4) Anything else I need to know before making a switch? Maintenance, other costs, etc? I've seen some 2007-2009 models in my truck's trade in value range, so I could almost make a swap, so initial price increase of a diesel plant isn't a big deal for me. I believe gages are in order such as EGT, Transmission and Boost. This information could come from analog gages or a programmer like the H&S Blackmax. If you go above the 450 to 500 hp range at the engine, than you will need to add head studs and beef up the auto transmission.
My sons 5.9L is making more than 700HP and is street drivable but this cost him $$$ to do.


Thanks!
Jim W.
Old 01-08-2012, 10:39 AM
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So would I be better off just buying a 2006 or 2007 with the 5.9 since I won't have to do the delete? Do the 5.9s see similar performance improvements from either of those two programmers? Sounds like the delete is fairly expensive to do... I've heard the 5.9s seem to get better mileage anyway...
Old 01-08-2012, 11:00 AM
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Diesels have a lot of advantages over gassers, but they also have some disadvantages.

They're very slow to heat up. A gas truck can idle for about 8 minutes and be up to operating temp. A diesel takes forever. If you live in a cold climate, that's a disadvantage.

Because they're turbocharged, they make essentially the same power at 10,000' as they do at sea level.

Torqe is what gets a vehicle moving off the line. A diesel makes a ton of torque. Stomp on the pedal, and you'll be amazed at what happens.

If you're lucky, carefull, and do the right mods, you can get 18-20mpg on the highway. They're very speed sensative, and as the speed climbs the mileage drops. cruising at 78mph with no severe head wind, I get about 18.

Diesel is now the most expensive fuel available. Diesel trucks are more expensive to buy and maintain, and fuel mileage isn't what you think it should be.

Unless you really need a diesel for towing, probably not your best choice. Sure are fun to drive, though.
Old 01-08-2012, 11:06 AM
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Originally Posted by TROTTMAN
So would I be better off just buying a 2006 or 2007 with the 5.9 since I won't have to do the delete? Do the 5.9s see similar performance improvements from either of those two programmers? Sounds like the delete is fairly expensive to do... I've heard the 5.9s seem to get better mileage anyway...
Yes and No. How is that for an answer? The 5.9L does not have the same stock hp and torque ratings. So when a programmer is added the hp and torque improvement will not be as great as on the 6.7L engine. The 4 spd auto that is used with the 5.9L is a little weaker than the 6 spd auto with the 6.7L engine.
The 4 sp 48RE auto transmission was rated for 325 HP and 610 Lb-ft for the 06 and 07 trucks. You will need to beef up the 48RE sooner than the 68RFE auto on the 6.7L truck to achieve more hp and torque.
More programmers are available for the 5.9L and there are more options also but these all take $$$ to do. Just remember speed and torque cost $$$ to do.
Jim W.
Old 01-08-2012, 11:50 AM
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Just a thought.

If you are commuting 100 miles each day, keep your truck, get a small car that gets good fuel economy, and pocket the savings over buying a diesel truck. Your want of having a truck for practicality is a good one. Your need for a diesel, really isn't there.

Fuel economy numbers are a crapshoot. Although the numbers are high, I see a LOT of them that are terribly inflated.

You are using twice as much oil per oil change, air filters need to be changed more regularly, fuel filters on a regular basis, and fuel is more expensive than gas. Parts for the 2500/3500 series trucks are in the ballpark compared to a 1500, but cack a couple of injectors on your new diesel, and you'll wish you kept with the gassers for sure.

All I am saying, is do a whole bunch of research into actual ownership and maintenance costs, before you jump in to one of these things.


Good luck with your choices.
Old 01-08-2012, 02:27 PM
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I thought the 5.9s had a 5 speed auto in some years... is that not the case?

I've thought about owning two cars, but that carries quite a cost - two car payments, two insurance payments. I figured once do-all vehicle would be a better option.

But it's starting to sound like just buying a truck with a smaller V8 with a cylinder deactivation system might be a better call. I've always wanted to buy a diesel truck though, not for towing but for performance.

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