Improving HEMI fuel Economy

boss_hoss · Post by **boss_hoss** » Wed Feb 25, 2004 9:26 pm

Anyone have any tips or suggestions on how to improve fuel economy on my 04 HEMI Ram 1500 2dr? Cold air intake? Freer flowing exhaust?
Thanks.

HappyKillMore · Post by **HappyKillMore** » Thu Feb 26, 2004 8:14 am

Pull out the 5.7L, sell it, and put in a 4.7L or a V6!

Probably the best thing to do to improve fuel economy is to get a lower final gear. Sure, you can get good acceleration and quarter-miles with the higher gears, but they keep the engine turning faster when you're cruising on the highway. That's this amateur's suggestion anyway!

mopar muscle 21 · Post by **mopar muscle 21** » Thu Feb 26, 2004 10:10 pm

Actually, I talked to a guy whom said his SC 4.7 got 13-14 mpg. That is pretty said..........for today's technology. Mopar needs to improve a bit on that aspect. If it wasnt for the hemi, i wouldnt have a dodge. I would have stayed with GM. My brother 94 z28 gets 22-23 mpg......um

HappyKillMore · Post by **HappyKillMore** » Fri Feb 27, 2004 8:12 am

Really? I would have expected the 4.7 to at least be better than the 5.7 in terms of mileage! Maybe not by a great deal, but at least by some. Of course it also depends on how the guy drives too. If he's always got his foot in it, then the mileage might be worse than the "average" driver.

I used to get low 20's on the '97 Z28 I traded in to get my Ram. For the first 25k miles or so, I was even getting high 20's on that car. On a road trip, I even once squeezed a 30 mpg leg out of that LT1! Not anymore...

Sam Makitra · Post by **Sam Makitra** » Fri Feb 27, 2004 6:03 pm

Gee, you sound like you would be a GM guy in MOPAR clothing. Why dont you go back to Generic Motors where you belong![quote="mopar muscle 21"]Actually, I talked to a guy whom said his SC 4.7 got 13-14 mpg. That is pretty said..........for today's technology. Mopar needs to improve a bit on that aspect. If it wasnt for the hemi, i wouldnt have a dodge. I would have stayed with GM. My brother 94 z28 gets 22-23 mpg......um[/quote]

mopar muscle 21 · Post by **mopar muscle 21** » Fri Feb 27, 2004 6:17 pm

Generic motors? What is so generic about the lt1,ls1, and the new lt2 (400 small block) Im just being honest on what I stated. If mopar didnt have the hemi.....i just dont see the reason in having one. Example- no hp, crappy mpg.

but.........im a hott rodder,and not a truck guy.Its nothing against mopar........lets face it.........their old Darts,SuperBees, Superbirds,Chargers,and exc. are worth more than any of ford or chevy's wonders.

mopartodd · Post by **mopartodd** » Tue Mar 09, 2004 2:45 pm

How on earth do you guys figure what an engine should be getting mileage wise? Why would you compare the mileage of a Z 28 (3200 lbs) to a truck (5000+ lbs)?

Common sense really seems to be in short supply. Damn.

5SpeedHemi · Post by **5SpeedHemi** » Tue Mar 09, 2004 7:25 pm

Thanks Mopartodd, I was wondering the same thing. How in hell can they compare my 6000+lb 2500 4X4 LB/QC Hemi Milage to a 3000 lb car.
commom sence is not to common unfortunatly. How much lumber can your brothers Z28 camaro haul or how many people can it pull out of the woods, should i go on I didnt buy the frickin thing for milage. if he did he should trade it in

HappyKillMore · Post by **HappyKillMore** » Wed Mar 10, 2004 8:37 am

I'm sorry, I forgot that the only factor in what mileage a vehicle will get is the weight of said vehicle. So if my 3500 lb Camaro used to get 20 and my 4800 lb Ram gets 14, then by extension a 6000 lb Ram gets 8.

Yes, I know all about the weight difference and the greatly increased air resistance-- trucks have to push a wall of air as they travel along. The biggest factor though, which you neglected to bring up, is gearing. My Z28 turned only 1700 RPMs at 70 mph, as opposed to the 2100-2200 that my Ram turns. Oh, wait, I can't say that because I have no common sense.

That being said, what I was remarking on before was the fact that in mostly city driving I used to be able to get 20, whereas now, with 95% highway driving, I get way less than that. I never meant to imply that I thought the Ram would get the same mileage as my Z28 did-- only that I thought the difference would have been smaller.

As for hauling lumber, etc.-- I was living in an apartment for the whole time I had a Z28. I bought a house last April and bought the Ram in July. So, when I started having a need to haul lumber, I bought a truck.

mopartodd · Post by **mopartodd** » Wed Mar 10, 2004 10:30 am

Just because you have a numerically lower gear, doesn't mean that mileage will improve. The gear selection wasn't considered since it isn't as big a factor as weight or areodynamics. The thing that wasn't mentioned was the fact that the HP ratings are different between the camaro and Ram. The Ram makes more HP than a Z28, it takes fuel to make power, more weight and wind resistance requires more power to move the object.
Your assuming that HP, gearing, and weight are proportional. They aren't.

Thus:

3500#camaro (275 HP) does not equal 5000#Ram (345 HP)

Sorry. Sometime physics sucks.

panic · Post by **panic** » Wed Mar 10, 2004 2:02 pm

WOODYSHEMI · Post by **WOODYSHEMI** » Wed Mar 10, 2004 6:42 pm

Looks like this could turn into another pissing contest............

HappyKillMore · Post by **HappyKillMore** » Wed Mar 10, 2004 8:10 pm

It could, but I'm not going to continue. Sure, there's more I could say, but it's a matter of opinion, and it doesn't make any difference in the long run. I just took exception to the "lack of common sense" comment and couldn't let the matter rest from there. I've gotten that off my chest, and am ready to get on with my life!

5SpeedHemi · Post by **5SpeedHemi** » Wed Mar 10, 2004 9:01 pm

We are all so relieved to here that ...LOL OK enough children
Be good and sleep tight nighty night

mopartodd · Post by **mopartodd** » Thu Mar 11, 2004 6:42 am

Happy. No offense was intended. I'm sorry if you were.

Yes, I wish my New Hemi Ram got better mileage, but it doesn't.

Have a good one.

HappyKillMore · Post by **HappyKillMore** » Thu Mar 11, 2004 4:00 pm

Apology accepted. I hope I didn't step on your toes with my response. If so, I'll apologize for that!

Torpedo · Post by **Torpedo** » Fri Mar 12, 2004 3:37 am

Well there are a few things you can do to help your fuel economy. But if you're a hot rodder than what I suggest won't be of much value. But I'll give it to you anyway. It's just common sense stuff. First off drive like there's an egg under the gas pedal. Instead of punching it, bring it up to speed more gradually. Stick to the speed limit and use your cruise control if you have one. Maintaining a constant speed will help and even a little fluxuation will cause diminished gas economy. Of course what the other guys said about weight and final gear is very true. When it comes down to it, there are 2 camps basically. The economy clan and then there's the petal to the metal bunch. It's either small and economical or big fast and a heavy drinker. If your a hot rodder than what's a few extra gallon when ya got the power. And even though the 5.7 isn't at the top of the heap yet, it will be soon. The aftermarket is working fast and furious to bring out the improved go fast goodies and will probably find ways to improve gas mileage as well. This new hemi has a great deal of potential. It just takes time for the go fast guru's to get their stuff to the market place. Course now what I'd like mopar to do, is to find a way to civilize the elephant (426 Hemi) and make it street worthy. But that's just me.

katron440 · Post by **katron440** » Sun Apr 18, 2004 11:32 pm

I currently drive a 2001 Ram 4x4 360 QC with 3.92 gears. my experience has been that with this particular engine in a truck that has such a large body to push thru the air, as well as weight, gearing is very important. Before I purchased this truck I drove a few with 3.55 gears and I felt that with the steep overdrive fourth gear, they were geared too tall. They kicked down way too easy, and mileage was not great, 17 mpg to the imperial gallon ( Canada ). My Ram's first tank netted 20.6 mpg in the Mountains. So it seemed that 3.92's were a better pick for this truck-engine combo. I actually felt that 4.10's would be even better as the rpm's would increase to around 2000 at 62 mph. 1700 rpm might be ok in a car that cuts the wind and weighs 3500 lbs, but not a truck. This winter I purchased 285-16's to replace the original 265's, big mistake, I lost the gearing advantage that I had over the 3.55's! I know that the Hemi has more torque that the 360, but it's only 40 ft lbs. In my opinion 3.92's would provide more overall driveability and better overall mileage than 3.55's, with my preference being 4.10's.

MEANGENE75 · Post by **MEANGENE75** » Tue Apr 20, 2004 9:44 pm

as a chrysler dealership employee and owner of a 2001 quad off road (4.10 ratio) with a 360, i can tell you you are the first person ive ever heard of getting better than 14 mpg. mine got 10, 11 with a cold air, msd, and gibson catback. only kept the truck 8 months for that sole reason. the only truck to ever consistantly get over 18 is the 1997-1999 cummins diesel. im not saying yours didnt, im just saying you are in a very elite group of maybe 2.

katron440 · Post by **katron440** » Fri May 21, 2004 10:36 pm

If you will notice in my posting I am from Canada and our "gallon" is considerably larger than the U.S. gallon ( 20% larger ) , so the 20.7 mpg that I mentioned is 16.5 mpg to the U.S. gallon. Something that you also have to remember is this is highway driving, not city driving.

GreenbeanZ28 · Post by **GreenbeanZ28** » Sat May 22, 2004 7:08 am

Lol, my 423 rwhp Z28 (with bad valvesprings I might add. I swear I'm not making excuses!) with 4.33 gears manages to get 19-20. With the 4.11's, I got 22 mpg on a 3 hour trip to Gatlinburg, Tenn for the Fall Rod Run this past September. It did get 31 mpg with the stock motor and just K&N and a catback. I'm managing to get 18.5 with my truck, which from what I read is damn good. I will admit though, I'm really really driving like a grandpa to get that 18.5.

Altar000Altar · Post by **Altar000Altar** » Wed May 26, 2004 11:42 am

From reading the stuff on the net and researching to bring my HP up I have discovered a couple things about the engine. It has a break in period which appears to be computer controlled. After about 10,000 miles, people have reported power gains and fuel economy gains. Of course this is just hersay.

If you drive an automatic, it is not recommended that you do a rear-end gear swap. Again, the damn pesky computer will not like it.

Well I hope that helps.

MidWest-RumbleBee · Post by **MidWest-RumbleBee** » Tue Jun 08, 2004 8:24 pm

2004 Rumble Bee 4x4 Here, 2000 miles. Just took a 500 mile trip 95% interstate at 70-75mph and averaged 18.0 MPG. Bucking major wind on the way back it got 16.6........ Right now it's 100% stock, cold air intake is on its way, we'll see what that does.

JR

Ant@Psi-FI · Post by **Ant@Psi-FI** » Wed Jun 09, 2004 1:14 pm

I have been datalogging the air fuel ratios of my Hemi and let me say that in the idle and partial throttle areas the Hem runs extremely trim 16:1 -15:1 a/f ratios. In wide open throttle I seen 11:1-12:1 which is on the rich side. I leaned out the WOT to 13:1 and the truck definately picked up.

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