2020 Isata 5 30FW Gear Ratio - Page 2

**bclemens** · 02-13-2019, 04:32 PM

OK, I was just sent the Ford 2019 brochure. It shows 330 hp at 2600RPMs and 750 ft lbs @ 2,000 RPMS.

The 2019 Cummins is showing 360 @ 2800 and 800 ft-lb @ 1800 rpms.

So for max torque, it looks like the Ram will already spin lower. I think the '18 is still 750 at 1700.

George71 · 02-13-2019, 05:27 PM

Quote:

Originally Posted by bclemens

OK, I was just sent the Ford 2019 brochure. It shows 330 hp at 2600RPMs and 750 ft lbs @ 2,000 RPMS.

The 2019 Cummins is showing 360 @ 2800 and 800 ft-lb @ 1800 rpms.

So for max torque, it looks like the Ram will already spin lower. I think the '18 is still 750 at 1700.

Thanks for looking into it, they are going to spin at whatever the gearing makes them spin at. As you can see the Ram gets more torque at lower RPM so it will work better if geared that way. That's one of several reasons I like the cummins better. I'm not saying it wouldn't be great at slightly higher RPM, just better at or near the peak torque RPM unless you are near max capability of the motor witch this setup is not. You are right about the Aisin everything I hear is that it is a great trans. Met a guy that hauled RV's for a living who got almost 500k out of his and only died because the fluid pump went out. I would love to test drive one but there are none in Fl. to drive that I know of.

**bclemens** · 02-13-2019, 05:31 PM

Yes, unfortunately, the only two heading to Lazydays soon, are already sold.

caseymyers · 02-13-2019, 05:35 PM

[QUOTE=bclemens;2024677]I would test drive one first. I found the rpm's at 70 to be outstanding. I think in my live-through video I mentioned that I didn't even feel like the engine ran any higher. At 55-60-70 there was very little noticeable change un my mind. Take off was great.

I would also look at what they are rated at and where. I can't seem to find it like I used to for the Ford E450....but it would give you peak torque spec @ XXX RPMS. I would see where the Ford and Ram show their peak specs (HP and Torque). We dp upgrade to the Aisin tranny, which seems to be thought of very highly.

Actually I found "some" charts.

It appears the 6.7l Cummins seems to range from 1500-1700 rpms for peak torque (The highest torque numbers noted as only on the Aisin tranny).

For the F550, it appears their peak torque numbers range from 1600-1800.

So in a quick glance, 4 out of 5 dentists would say the Ram should run about 100 rpm's lower with current gearing.

Agree, this RAM is a very nice drive, plenty of power and the fuel milage is not all that bad for a heavy motor home.

Not to take you off subject but I was looking at that RAM Media site and it looks like they are sticking to previous years options rules, to get the Laramie and many of the upper end options you need a crew cab, not avail in the Chassis Cab. Here is an example...

Uconnect 8.4 AM/FM with 8.4-inch Touch-Screen Display, Media Hub
(USB, Auxiliary), Navigation, Uconnect with Bluetooth, SiriusXM Satellite Radio, HD Radio, (Package with Laramie) (SLT option is Crew only)

I5PhilGa · 02-13-2019, 06:39 PM

Quote:

Originally Posted by George71

I can't say I'm sure of the increase MPG either but it's a high probability. I'm also after lower RPM at highway speed because it makes for a nicer quieter driving experience. I currently have a 4x4 f550 based RV with a 4.88 and it spins more than I like although it's a little worse because the ford trans. is geared different. Diesel engines in general and especially the Cummins in line 6 don't like to spin at high RPM. Peak torque is at 1800 RPM, a good place to be cruising near. I am looking at the 30fw so I'm sure with 800 lbs. of torque and the 4.44 it will still slam the dishes to the back of the cabinet more than I would want to. Only time will tell how FCA will let them be equipped. Just curious at what highway speed do you average 10 MPG and is it a 4x4?

I have consistently averaged 10mpg towing a small Jeep Cherokee (numerous trips between Georgia, Iowa and Indiana) and 10.2 not towing anything running 62-65mph which seems to be it's sweet spot. Yes it is a 4x4.

mjbenedict · 02-13-2019, 06:59 PM

deleted/

George71 · 02-13-2019, 08:27 PM

Quote:

Originally Posted by I5PhilGa

I have consistently averaged 10mpg towing a small Jeep Cherokee (numerous trips between Georgia, Iowa and Indiana) and 10.2 not towing anything running 62-65mph which seems to be it's sweet spot. Yes it is a 4x4.

Thanks for the info.

jdebevec · 02-16-2019, 08:56 AM

Quote:

Originally Posted by I5PhilGa

I have consistently averaged 10mpg towing a small Jeep Cherokee (numerous trips between Georgia, Iowa and Indiana) and 10.2 not towing anything running 62-65mph which seems to be it's sweet spot. Yes it is a 4x4.

I agree, get about the same mpg with our 2018 I-5. Running at 72 mph the mileage drops off to about 9.5 mpg. but that's because the engine is running at 2400 rpm. Gear ratio is good for a happy medium because at highway speeds the trans rarely has to downshift for anything but the steepest hills... the Cummins just works a little harder without even breaking a sweat. But running at higher rpm's while just cruising just uses more fuel, so it would benefit from a taller overdrive gear.

I5PhilGa · 02-16-2019, 09:26 AM

Quote:

Originally Posted by jdebevec

I agree, get about the same mpg with our 2018 I-5. Running at 72 mph the mileage drops off to about 9.5 mpg. but that's because the engine is running at 2400 rpm. Gear ratio is good for a happy medium because at highway speeds the trans rarely has to downshift for anything but the steepest hills... the Cummins just works a little harder without even breaking a sweat. But running at higher rpm's while just cruising just uses more fuel, so it would benefit from a taller overdrive gear.

Totally agree with you. When I was still working I traveled at 70-72 mph because vacation time was precious. Now I've got all the time I need. It would be interesting to see someone change out their differentials to the 4.44 ratio to actually compare mpg, torque range, towing, etc.

George71 · 02-18-2019, 03:57 PM

Quote:

Originally Posted by I5PhilGa

Totally agree with you. When I was still working I traveled at 70-72 mph because vacation time was precious. Now I've got all the time I need. It would be interesting to see someone change out their differentials to the 4.44 ratio to actually compare mpg, torque range, towing, etc.

If Bclemens will let me order one that way I will be the test case. I'm sure MPG and engine noise will be better with still way more acceleration and hill climbing ability than needed

caseymyers · 02-18-2019, 04:08 PM

Quote:

Originally Posted by George71

If Bclemens will let me order one that way I will be the test case. I'm sure MPG and engine noise will be better with still way more acceleration and hill climbing ability than needed

I read on here somewhere that Dynamax has a standing order for chassis from their dealer, and in the past you couldn't custom order the chassis other than 4x4 or not. I wanted the Laramie package and RAM won't even ship you one unless you buy a crew cab.

**bclemens** · 02-18-2019, 04:45 PM

I wouldn't count on that...he's mean. Just ask his kids.

George71 · 02-19-2019, 11:03 AM

Quote:

Originally Posted by bclemens

I wouldn't count on that...he's mean. Just ask his kids.

I doubt you're that mean, plus there's time before the chassis are out so hopefully those kids will soften you up by then and maybe make a good coach even better.

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