Exhaust Drone Fixed! Spoiler Alert another 3.21 vs 3.92 discussion

[Bmags]

I live next door to the Rockies.If you know how to drive for milege,they'll shift into 8th with 3.21's with no issue.Hell the cars come with 3.07's behind most R/T Challengers and Chargers,and their tires aren't all that much smaller in diameter then alot of trucks with 3.21's. Any 1500 with the 17" wheel package comes with a 31" tall tire which isn't all that much taller then whats on alot of cars .My 300C has 2.82 gears in it,alot of hellcats have 2.62's,so claiming a truck with 3.21's won't pull 8th is a bunch of malarky,its people who don't know how to drive,not the truck.My driveways elevation is just under 3700ft,so hills are fairly common here

Sure, your 300c has 2.82 gears and weighs half of what my truck does, not to mention is way more aerodynamic. Good comparison.

Driving isn’t that hard, you press the gas pedal to match the speed you want and click the cruise button. Or you do this weird thing where you keep your foot on the pedal at the same position and the truck keeps moving at the same speed.

Glad to know your vehicles are fine. Thanks for clearing that up

For the record stock 20” wheels on the 1500 have a 33” tire.

 

[ThunderMug95]

My truck was the second one to have them Craig.I've had paddles in my truck since the fall of 2015,love them,lol.

SRT Steering wheel swap

$750.00 Canuck,or about 50 bucks US,lol:naughty:.The replacement factory shift button assembly and the aluminium AMG paddles are the biggest expense,they aren't cheap and make up the majority of the price.He has enough pieces on hand to build one more,after that I don't think he'll build...

www.ramforum.com

Well dang… If I wasn’t saving up for another major upgrade, I may have done that…

 

[Bmags]

The title and post don't seem to make all that much sense.

You removed last gear because of Done? But at same time, you posted it almost never goes in to 8th or goes in/out of 8th.

Then you posted you have HP Tuner and changed the Trans.

If you have HP Tuner, why you not just Tune it "correctly". In one of your posts, you mentioned to someone, you could tune their trans.
But you are posting you removed 8th gear in your own truck. If for some strange reason your truck is hunting 7-8 gear, correct it.

The truck hunts between 7th and 8th depending on the day. If I’m driving into wind for instance, 70mph, it won’t hold 8th gear well and has to downshift often.

8th gear, in addition to being lousy, also drones in my truck, so I was going to regear to 3.92… but since the final drive ratio between 7th in 3.21 is the same as 8th in 3.92 I figured I would just remove 8th gear for the time being.

Solves the drone issue and I don’t ever hunt gears anymore. Think they call that a win win.

Even if it would hold 8th gear (with 3.21 gears) I don’t want it for the drone…

 

[Wild one]

Sure, your 300c has 2.82 gears and weighs half of what my truck does, not to mention is way more aerodynamic. Good comparison.

Driving isn’t that hard, you press the gas pedal to match the speed you want and click the cruise button. Or you do this weird thing where you keep your foot on the pedal at the same position and the truck keeps moving at the same speed.

Glad to know your vehicles are fine. Thanks for clearing that up

By now you should have figured out cruise uses differant shift parameters then the gas pedal as far as the shift patterns go. It'll hunt for gears more when cruise is engaged then it does if you're using the gas pedal.Figured you'd be smart enough to have figured that out by now It's pretty common knowledge .Slightly stepping on the gas pedal just enough to over ride the cruise will promote it staying in 8th longer when approaching a grade

 

[Bmags]

By now you should have figured out cruise uses differant shift parameters then the gas pedal as far as the shift patterns go. It'll hunt for gears more when cruise is engaged then it does if you're using the gas pedal.Figured you'd be smart enough to have figured that out by now It's pretty common knowledge .Slightly stepping on the gas pedal just enough to over ride the cruise will promote it staying in 8th longer when approaching a grade

True… However this doesn’t help for the mouse farts though…

 

[CanRebel]

The truck hunts between 7th and 8th depending on the day. If I’m driving into wind for instance, 70mph, it won’t hold 8th gear well and has to downshift often.

8th gear, in addition to being lousy, also drones in my truck, so I was going to regear to 3.92… but since the final drive ratio between 7th in 3.21 is the same as 8th in 3.92 I figured I would just remove 8th gear for the time being.

Solves the drone issue and I don’t ever hunt gears anymore. Think they call that a win win.

Even if it would hold 8th gear (with 3.21 gears) I don’t want it for the drone…

It's your truck and if your happy that's all that matters.

Interesting... I'm going to have either drink or be high to understand the logical behind removing a gear to remove drone.

As far as I know, and not an expert. Drone is caused by engine and exhaust system vibrating at different frequencies. Don't see how removing 8th gear would correct that.
If your driving on the highway with 7th gear, or 8th gear. I don't see how it would effect anything related to engine or exhaust vibrating at same RPM/Speed.

Never heard anyone remove a gear cause of drone, if you hit same RPM , you should have drone, no matter the gear.

If you didn't want put stock back. Common thing I know people do is either wrap or j-pipe.

 

[GWillings]

I have the carven progressive and also started with the mufflex drone pipe. It didn’t make a big difference.

It’s really just a 1/4 wave resonator… and the issue is it’s designed for their exhaust.

So, you have to modify it such that its length coincides with the frequency of the done your exhaust has.

For me that meant shortening it considerably.

Now, 0 drone scientifically

I have the 2020 model, it had 2 resonators at the tail pipes, did the resonator delete and there is zero drone. As for the MDS jacking up your cams, a RAM Tech figured it out, hellcat oil pump has a higher pressure at idle, problem solved. I am tired of the bickering back and forth about things that have ALREDAY been covered, figured out and fixed. Which is one reason why I hardly EVER post on this site. To much childish BS.

 

[Wild one]

I agree with Sky on alot of his video's,but i don't agree that the hellcat or high volumne oil pumps are the be all / end all to the hemi's lifter issues.There is "no" pressurized oil fed to the cam lobe or lifter wheel and it's bearings,and the percentage of leak down oil past the lifter bores that actually makes it's way to the bearings in the wheel is a very small percentage of the oil that is needed to keep them alive.The majority of cam lobe/lifter roller lubrication is still from the oil flung off the crankshaft.Upping the idle rpm to 750 with the stock pump produces the same amount of oil flow if not more then the hellcat pump does at the stock 550/560 rpm,and provides more crank splash lubrication to the cam lobe,the hemi also needs to drove on the slightly aggressive side to provide more lubrication to the cam.Driving one like Grandpa is not doing the engine any good.

 

[Bmags]

It's your truck and if your happy that's all that matters.

Interesting... I'm going to have either drink or be high to understand the logical behind removing a gear to remove drone.

As far as I know, and not an expert. Drone is caused by engine and exhaust system vibrating at different frequencies. Don't see how removing 8th gear would correct that.
If your driving on the highway with 7th gear, or 8th gear. I don't see how it would effect anything related to engine or exhaust vibrating at same RPM/Speed.

Never heard anyone remove a gear cause of drone, if you hit same RPM , you should have drone, no matter the gear.

If you didn't want put stock back. Common thing I know people do is either wrap or j-pipe.

Don’t need to be high or drunk, just need to understand physics a little better.

Drone is typically associated with a specific engine RPM rather than at a specific vehicle speed. The common drone zone is around 1500rpm.

70mph down the highway in 8th gear had the truck running around 1500RPM, which (due to the lack of power at this engine speed) results in the engine drone.

In 7th gear, the RPMs at 70 are around 1900RPM, which is outside this zone resulting in the cab being whisper quiet even with the Carven muffler.

Drone is a product of engine speed and engine loading. That’s why I had mentioned about the engine lugging… try gear limiting your truck to 4th gear and go 1500rpm, you won’t hear the droning that you do at 1500RPM in 8th.

The overall point you are missing is that a 3.92 geared truck will not drone down the highway like a 3.21 geared truck does… which is what I am emulating by removing 8th gear.

If anyone out there has a loud exhaust and 3.92 gears would like to chime in about drone please share.

 

[Brapasorus Rex]

I am not so concerned with the drone as the ******* between 7th and 8th driving 90mph+ on the hilly interstates or when pulling my 35 foot camper…. As always you solved the problem for me as getting rid of 8th made the most sense compared to all other options. Of course we are probably smarter than most when it comes to finding cheap solid and reliable solutions! Braaaap!

 

[Bmags]

I am not so concerned with the drone as the ******* between 7th and 8th driving 90mph+ on the hilly interstates or when pulling my 35 foot camper…. As always you solved the problem for me as getting rid of 8th made the most sense compared to all other options. Of course we are probably smarter than most when it comes to finding cheap solid and reliable solutions! Braaaap!

Geez idk how smart it is going 90+ on the interstate… hope I’m not on the road at the same time you are haha.

Glad it worked though.

 

[kdoublep]

I am not so concerned with the drone as the ******* between 7th and 8th driving 90mph+ on the hilly interstates or when pulling my 35 foot camper…. As always you solved the problem for me as getting rid of 8th made the most sense compared to all other options. Of course we are probably smarter than most when it comes to finding cheap solid and reliable solutions! Braaaap!

You deleted 8th gear already?

 

[Wild one]

As for the MDS jacking up your cams, a RAM Tech figured it out, hellcat oil pump has a higher pressure at idle, problem solved. I am tired of the bickering back and forth about things that have ALREDAY been covered, figured out and fixed. Which is one reason why I hardly EVER post on this site. To much childish BS.

Don't know why your post isn't quotable,but seeing as how you think Sky's video on the Hellcat pump is the cure all for the cam/lifter issue,you might want to watch this video to. It points out alot of why the Hellcat pump isn't the end all / be all fix for the lifter/cam issue.

A Closer Look At The Mopar Gen 3 Hemi And It's Often Fatal Flaw

Our first video concerning Mopar's Gen 3 Hemi's notorious camshaft and lifter failure phenomenon caused a lot of discussion and controversy. It has nothing ...

www.youtube.com

 

[rvance]

I have a complete 3.92 setup I’d part with, rear axle and front carrier. PM if you’re interested.

Technically nothing needs to change in the PCM or TCM for the gear change. You can update the BCM value to anything you wanted… but it doesn’t effect anything. Speedo for instance isn’t based off the ratio setting.

The only caveat is adaptive cruise control uses it for some things, but if you don’t have that then it’s fine.

If you have the 8 speed tranny and wanted to change gears I would go 3.92 for sure. The others seem like a half measure.

I appreciate the offer. I've done the math and the 3.92 would be fine, but the shipping would probably be ridiculous. Plus, are you sure it will fit the 3.6 diff?

 

[Bmags]

The axle housing/hardware is the same for the trucks. With the cost of the gears alone buying something from your local salvage yard is likely the way to go. Then you just have to unbolt your setup and bolt in the new (used) assembly.

You'd be able to bolt in the 3.92 front carrier and rear axle without any issues. The frame/etc on the trucks are all the same regardless of the engine installed.

 

[rvance]

I don't think there's 3.73's available for the 1500's,that's more 2500 territory.
You must of been driving an oddball 5.7 if it wouldn't go into 8th with 3.21's,when i had 3.21's in my truck,it'd go into 8th at 50 mph no problem.I switched to 3.55's and in hindsight i wished i'd never made the switch,i prefered the 3.21's over the 3.55's.I made the switch for the dragstrip,and the truck never gained anything at the track.
If i didn't have a $h!tload of money invested in the rear diff with 3.55's in it,the 3.21's would be going back under the truck,as i still have my basically new 3.21 front and rear diffs sitting in my storage shed

I have already found the 3.73 gears. I have a 3.6 V6. No, with the 8 speed, it wouldn't make enough difference at the dragstrip unless it's your main use for the truck. I really don't understand your post I guess. I had Hemi Roadrunner racer that I drove on the street. I had 4.89, 3.92, and 3.55 gears. So I know something.

 

[Wild one]

I have already found the 3.73 gears. I have a 3.6 V6. No, with the 8 speed, it wouldn't make enough difference at the dragstrip unless it's your main use for the truck. I really don't understand your post I guess. I had Hemi Roadrunner racer that I drove on the street. I had 4.89, 3.92, and 3.55 gears. So I know something.

What's there that you don't understand? I switched to 3.55's and don't like them,not sure how hard that is to understand. I've ran 4.88's / 4.56's / 4.11's / 3.73's / 3.50's / 3.42's / 3.08's etc on the street with 3 speed auto's on 10 and 11 sec street cars,but i'm not sure how you figure they apply to this thread.
If you found 3.73's for a front and rear ZF diff,post up a link to them.
In your case with the little 3.6,they'll probably be a decent combo,but it might be easier to find a set of 3.92 diffs,probably be cheaper,as you can swap diffs pretty easy on a driveway.

 

[Bmags]

I have already found the 3.73 gears. I have a 3.6 V6. No, with the 8 speed, it wouldn't make enough difference at the dragstrip unless it's your main use for the truck. I really don't understand your post I guess. I had Hemi Roadrunner racer that I drove on the street. I had 4.89, 3.92, and 3.55 gears. So I know something.

Depending what you are looking to achieve, just removing 8th gear like I did might be a good option too. It wouldn't help with getting heavy loads moving any quicker... but it results in the same top end engine RPM/vehicle speed ratio as you'd get if you did the 3.92 swap.

 

[rvance]

Depending what you are looking to achieve, just removing 8th gear like I did might be a good option too. It wouldn't help with getting heavy loads moving any quicker... but it results in the same top end engine RPM/vehicle speed ratio as you'd get if you did the 3.92 swap.

Well, since it never gets into 8th gear. How would that help?. My issue is that, at the speeds I drive, it's just a touch below shifting into 8th. The 3:55 is just a better gear for these trucks. When you drive both, you can get a feel for it that can't be explained by numbers.

 

[huntergreen]

Just figured I’d throw this out there to the group.

BACKGROUND:
There are many reasons why folks love the 3.92 gears… (way lower 1st gear, lower reverse gear, better acceleration, etc) but for me I mainly was searching for ways to remove my highway drone from my Carven Competitor (which I love)!

Prior to this I had:
1) Solo Performane Mach 44 muffler (too quiet for me, and really the only loud sound was droning)

2) Carven Progressive (loud, but still not loud enough) with a fair amount of drone

3) Carven Competitor (louder still, and frankly the same drone as the Progressive)

In addition to (2) and (3) I also had installed the Mufflex Drone Supression pipe which made things a little better, but the truck was still frustrating to drive for more than 2-3 hours at a time.

I had heard good things about the Corsa Muffler, but it sounds more like a sports car than a V8 truck…

THE SOLUTION:
In general, 7th gear with a 3.21 runs at the same engine speed as 8th gear in the 3.92… which for me cruising at 65+ down the highway keeps my exhaust sounding loud and great with no drone!

What I ended up doing is reflashing my TCM to get rid of 8th gear, so now my truck only runs from 1-7th (giving me what amounts to be the same final gearing as I’d get with the 3.92).

Very happy with how things turned out, and I’m likely the only ZF7 in existence

Just curious, why not just use the gear selector to hold in 7 and instead of programmer ?