E350 post Grocery getter re-gear or not

[Seattle E350]

I drove the E350 with a 5.4L on a 400 miles round trip last weekend. I am planning on installing trutrac in the rear axle and I'm wondering if I should change the gearing. There was some mild hills on I-5 where the transmission dropped down gear to maintain 70mph. A lot of the places I plan to travel have 75-80mph speed limits. I think once I'm done insulating and loaded up for a trip my total van weight will be around 7500lbs. I know I won't be winning any races with a fully loaded and lifted one ton van. A tad more power would be cool though.

Couple questions:
1. Is there any mild motor mods like intake or exhaust stuff that will bump power a tad? I saw someone using a SuperChips tuner. Anyone use those?
2. If I re-gear for hwy speeds do I lose bottom end power? Also, what gear ratio should I be looking at? I'll post a pic of the rear axle later to see if what I currently have can be identified.

 

[Paddy]

First you need to verify that your engine is working at its proper best. Then you need to pick your tire size. If you’re keeping your current tires, and it’s downshifting to maintain speed at 70 then you wouldn’t be regearing for hwy speeds (gearing up, or lower number ratios) that would only make it worse.
Not sure about power ups on your engine but there generally isn’t much to be had on modern gas engines. Little bigger exhaust pipe and a free flowing cat is about it. Don’t fall for any cold air intake baloney.
True track is a great idea, they rule.

 

[Seattle E350]

First you need to verify that your engine is working at its proper best. Then you need to pick your tire size. If you’re keeping your current tires, and it’s downshifting to maintain speed at 70 then you wouldn’t be regearing for hwy speeds (gearing up, or lower number ratios) that would only make it worse.
Not sure about power ups on your engine but there generally isn’t much to be had on modern gas engines. Little bigger exhaust pipe and a free flowing cat is about it. Don’t fall for any cold air intake baloney.
True track is a great idea, they rule.

Ok, so I got the terminology incorrect as I am new. Hence the questions. Gearing? Gear change or not? The motor is running fine and I’ve decided these are the tires I’m using since they’re brand new and rule. Also, hence the “post Grocery Getter” thread title.


I see a ton of people on the Sportsmobile forum claiming the 5.4L is great after a 5 Start tune.

 

[brp]

You can check your door jamb sticker and see what axle you have, easier than crawling under the van.
To answer one of your questions...yes, you do either lose cruising speed/efficiency or low end grunt when selecting gears for your axles. Finding the right balance is the goal.

https://www.blueovaltrucks.com/tech...y-your-ford-truck-axle-from-the-door-sticker/

I've got about 33.5" tires on my E-350 Quigley, with a 5.4, and I have 4.10 gears. I am happy with that ratio. In most cases, my top end cruising speed is limited by the vehicle size/handling, not power. If you tow, or live at high altitude, you may want to go with more low-end grunt (a higher gear number, I think 4.56 is next). Let us know what tire size you have though, that is a big factor.

 

[Explorerinil]

Give nitro axle a gear a call about your gearing question, they will go over it with you and give you good advice.

 

[ujoint]

Divide the old tire size diameter into the new size and then multiply by the stock gear ratio. That will tell you what gears it should have with the new tires/lift.

 

[luthj]

In general the stock final drive ratio (tires x gears) is best. Moving that around does not add/remove power, but sets your powerband/rpm when crusing in various gears. Unless you made a significant change to your vehicles gross weight or horsepower, I would not change much from the factory final drive.

 

[Seattle E350]

Thanks everyone!

Here’s my rear axle and door sticker pics. I’ll have to look at the stock tires to check what size they were. I never really looked at them because I knew I was changing them anyway.

 

[luthj]

Per your door sticker stock tires are 245/75R16. That is about 662 revs per mile. Per your door sticker, the axle is option 39, so your axle s 3.55:1. So your driveshaft rotates 2,305 times per mile. I would try to stay close to that with your tire/gear combo. Assuming that I am reading your axle plate correctly.

You could go maybe 5-7% higher than that, to say 2,400-2,500 rotations per mile.

 

[Seattle E350]

Here’s my rear axle and door sticker pics. I’ll have to look at the stock tires to check what size they were. I never really looked at them because I knew I was changing them anyway.

You can check your door jamb sticker and see what axle you have, easier than crawling under the van.
To answer one of your questions...yes, you do either lose cruising speed/efficiency or low end grunt when selecting gears for your axles. Finding the right balance is the goal.

https://www.blueovaltrucks.com/tech...y-your-ford-truck-axle-from-the-door-sticker/

I've got about 33.5" tires on my E-350 Quigley, with a 5.4, and I have 4.10 gears. I am happy with that ratio. In most cases, my top end cruising speed is limited by the vehicle size/handling, not power. If you tow, or live at high altitude, you may want to go with more low-end grunt (a higher gear number, I think 4.56 is next). Let us know what tire size you have though, that is a big factor.

Damn, the door tag and rear axle are showing it to be a 3.55

 

[Seattle E350]

Per your door sticker stock tires are 245/75R16. That is about 662 revs per mile. Per your door sticker, the axle is option 39, so your axle s 3.55:1. So your driveshaft rotates 2,305 times per mile. I would try to stay close to that with your tire/gear combo. Assuming that I am reading your axle plate correctly.

You could go maybe 5-7% higher than that, to say 2,400-2,500 rotations per mile.

I’m running 285’s now after the lift

 

[luthj]

285 what? 285/75R16? Those have 612 revs per mile. So an equivalent gear ratio would be 3.73:1. Though if you are running really heavy, and drive mountains much, you might consider 4.10:1.

Ideally you want your engine to have enough power at cruising RPM in top gear, so that you aren't needing to downshift for modest hills. For heavy vehicles shifting the cruising RPM up (higher gear ratio) provides more of max engine power at a given speed in top gear.

 

[Seattle E350]

285 what? 285/75R16? Those have 612 revs per mile. So an equivalent gear ratio would be 3.73:1. Though if you are running really heavy, and drive mountains much, you might consider 4.10:1.

Ideally you want your engine to have enough power at cruising RPM in top gear, so that you aren't needing to downshift for modest hills. For heavy vehicles shifting the cruising RPM up (higher gear ratio) provides more of max engine power at a given speed in top gear.

Oops, yeah new tires are 285/70R17

 

[Caustic]

Before I started my diy u joint conversion, my van was as follows
-2012 E350 5.4 3.73 gear ratio
-K and N intake
-Flowmaster 40 (would not recommend)
-5 star tuned
- leveled front end running 265/70r17's
I live in Colorado and occasionally pull my rock crawler with the van. As far as gear changes if you have 3.55's I would say with out a doubt you should go lower (numerically higher). The tough decision is to what? Going to 3.73's isn't worth the time/ cost and it would still be a bit doggy. So that puts you between 4.10-4.56. If you do significant interstate driving then 4.56's might be a little too far. With the 5.4 though that doesn't mind humming along at 3k rpm... my final 2cents would be go up to 4.56.

 

[Seattle E350]

Before I started my diy u joint conversion, my van was as follows
-2012 E350 5.4 3.73 gear ratio
-K and N intake
-Flowmaster 40 (would not recommend)
-5 star tuned
- leveled front end running 265/70r17's
I live in Colorado and occasionally pull my rock crawler with the van. As far as gear changes if you have 3.55's I would say with out a doubt you should go lower (numerically higher). The tough decision is to what? Going to 3.73's isn't worth the time/ cost and it would still be a bit doggy. So that puts you between 4.10-4.56. If you do significant interstate driving then 4.56's might be a little too far. With the 5.4 though that doesn't mind humming along at 3k rpm... my final 2cents would be go up to 4.56.

Thanks