2015 Pentastar V6 Towing [SUPERCHARGER SUCCESS!]

[Robeffy]

LOL, there is a bar in downtown North Bay called the Fraser, I hear that's the PLACE!

 

[engineering]

Sprintex tells my the supercharger kit should ship next week sometime. Hopefully, Diablo Sport has the ECU boxes in-stock right now.

Fingers crossed.

 

[Lucy Girl]

I will let my wife know that Lucy Girl told me to just buy a new truck.
Also, I will be signing up for internet dating immediately after.

Hey I just moved to Germany. Probably safe from your wife there. LOL

 

[VernDiesel]

I don't think the cooling system or the transmission is going to like the supercharger especially towing the TT.

Peak torque at 4,175 the motor would be comfortable towing at 4,000 rpms all day if needed. So would the transmission and the cooling system because below peak torque the engine isn't being overworked where it generates excessive heat. But it won't need that for this TT with the right gear and the 8 speed.

Instead of working its **** off screaming through the first 3 gears and staying at the top of 3rd to run 60 or 65 mph with the 3.21. Break the work load down for the engine, cooling system, and transmission, by dividing the work load (accelerating 0 to 65 mph) by 6 small steps (gears) instead of 3 by using a 4.11/4.56 rear end gear. Not sure what the gear ratio is in 3rd off the top of my head with the 3.21 gear but the ratio in 6th with say the 4.11 is 4.11 as its a 1 to 1 ratio.

Being only a 2wd perhaps makes this cost effective where it would not with 4wd. Being that you have two overdrives means it will still be very live able probably even more fun to drive without trailer on the highway. Final drive ratio comes out to about 2.75 (67% of 4.11) so while you will use a little extra fuel you won't be spinning that lil 3.6 hard by any means. I believe it to be far and away a better compromise for this situation than say adding the supercharger. Well with the exception of what Crash mentioned earlier being swapping in a whole call it wheel to wheel rear end from a new take out or salvage yard unit with a 3.92. Less involved and risks in doing it this way.

https://www.americantrucks.com/ram-gears-2009.html?utm_source=bing&utm_medium=cpc&utm_term=+ram++gears&utm_campaign=Drivetrain+-+Gears+(R)&T5_Var1=(R)+-+Gear+-+Generic+-+General+(BMM)&T5_Var3=Red&T5_Var2=search&dialogtech=ppc&&msclkid=60879b05a0d91b21d42ffb00122c3cea&utm_source=bing&utm_medium=cpc&utm_campaign=Drivetrain - Gears (R)&utm_term=+ram +gears&utm_content=(R) - Gear - Generic - General (BMM)&gclid=60879b05a0d91b21d42ffb00122c3cea&gclsrc=3p.ds

 

[ramffml]

I don't think the cooling system or the transmission is going to like the supercharger especially towing the TT.

Peak torque at 4,175 the motor would be comfortable towing at 4,000 rpms all day if needed. So would the transmission and the cooling system because below peak torque the engine isn't being overworked to generate excessive heat. But it won't need that for this TT with the right gear and the 8 speed.

Instead of working its **** off screaming through the first 3rd gears and staying at the top of 3rd to run 60 or 65 mph with the 3.21. Break the work load down for the engine, cooling system, and transmission, by dividing the work load by 6 gears instead of 3 by using a 4.30 rear end gear. Not sure what the gear ratio is in 3rd off the top of my head with the 3.21 gear but the ratio in 6th with the 4.30 is 4.30 as its there at a 1 to 1 ratio.

Being only a 2wd makes this cost effective. Being that you have two overdrives means it will still be very live able even more enjoyable to drive without trailer on the highway. Final drive ratio comes out to about 3.05 so while you will use a little extra fuel you won't be spinning that lil 3.6 hard by any means. I believe it to be far and away the best compromise for this situation.

https://www.americantrucks.com/ram-gears-2009.html?utm_source=bing&utm_medium=cpc&utm_term=+ram++gears&utm_campaign=Drivetrain+-+Gears+(R)&T5_Var1=(R)+-+Gear+-+Generic+-+General+(BMM)&T5_Var3=Red&T5_Var2=search&dialogtech=ppc&&msclkid=60879b05a0d91b21d42ffb00122c3cea&utm_source=bing&utm_medium=cpc&utm_campaign=Drivetrain - Gears (R)&utm_term=+ram +gears&utm_content=(R) - Gear - Generic - General (BMM)&gclid=60879b05a0d91b21d42ffb00122c3cea&gclsrc=3p.ds

I always hate to argue with a master at towing, but man, I would not encourage running the 3.6 and 4000 rpms all day. I've seen testing of these engines, and like the 5.7 it will heat up very quickly and get very hot at those rpms, regardless of the theory.

 

[VernDiesel]

Certainly I'm not encouraging high rpm towing. In fact the opposite using the lower rear end gear allows the motor to use more of the transmission gears so it won't need to run as many rpms as long or stay in 3rd because it can't make the jump to 4th. I just didn't want him to think as many do that he has to tow low at say 2,000 rpm. It will take more rpms to get it moving with peak torque at 4,175 than say 2,000 like the ED. Ao it will have to use more of those rpms more often than say the Hemi or the ED accelerating up and hold 65 mph.

BTW discussion questions asking someone to explain or back up their logic is all good. Nobody is perfect plus I still learn new stuff all the time especially as technology keeps on marching.

 

[engineering]

Certainly I'm not encouraging high rpm towing. In fact the opposite using the lower rear end gear and more gears he won't have to run as many rpms as often or long. Just don't want him to think as many do that you have to tow low at say 2,000 rpm. It will take more rpms to get it moving with peak torque at 4,175. And it will have to use more of those rpms more often than say the Hemi or the ED accelerating up and even at cruise.

Thank you for joining the discussion....I appreciate the opinions of those that know more than I do.

On the concept of the supercharger, I don't expect 6L Diesel RPM's. I only expect an improvement over the stock normally aspirated condition. The biggest improvement a supercharger offers in this scenario is that it builds torque much earlier and the peak is moved to a much lower RPM. At 2k RPM it is about 100ft/lb above the stock engine.

It is hard to anticipate exactly how that will impact the RPM's on any given stretch of road. I am guessing it will keep the engine at a much lower RPM number on average and reduce the rapid-fire gear shifting as the ECU hunts for a survivable gear. It is constantly shifting right now at the slightest change in grade.

Cooling? To be determined. The boost pressure is rather modest and the driving itself is not crazy so we shall see. The engine, oil, and trans temps hardly change at all from unloaded to full-loaded configurations. Long stretches uphill, the trans temp rises a little although the supercharger will not change that.

 

[VernDiesel]

Agreed except that the supercharger enabling the engine to do more work will put some extra load on the cooling system for both radiator and transmission. But I doubt that it will be excessive unless heavy pedaling it up a long grade with TT in tow. Does anyone make a transmission tune specific for the Zf & Pentastar? Might be worth looking into for transmission benefits in a couple areas. Looking forward to reading about your results.

 

[engineering]

I wish I had any understanding of how much headroom has been designed into the cooling system.
Clearly more heat will be generated, but perhaps the thermostat still has a lot of room to open up in order to compensate?

I suspect that in mild temperatures it will be reasonable, but not so confident about Death Valley mid-summer which is 120F+ along with serious hill climbs.

In general, we try to avoid ridiculous temperatures for our own comfort but at some point we will violate that rule. I am prepared to upgrade the fans and/or radiator if needed. That does not cost much (I already have all the fab toys). The engine bay in the V6 is comically empty too which makes a mod like that rather simple.

 

[ramffml]

Can't you just drop in a hemi? I mean a super charger ain't cheap either, especially new.

 

[engineering]

Can't you just drop in a hemi? I mean a super charger ain't cheap either, especially new.

I did consider the option of 'dropping in a HEMI'
After looking around a bit - it was apparent that I would be on my own and need considerable help from professionals. Almost anyone with the V6 that wanted a HEMI would simply sell their V6 and buy a HEMI. It would cost less and have a better result - you get a bone-stock HEMI without all the hacks, learning, and mistakes with a full engine swap.

The supercharger, while expensive, is a rather simple bolt-on mod that is easily reversed if needed. A single day of my time and no need to get a shop involved.

HEMI swap = expensive, complicated, lots of potential for unexpected challenges.
Supercharger = expensive, easy, predicable result, reversible.

 

[ramffml]

I did consider the option of 'dropping in a HEMI'
After looking around a bit - it was apparent that I would be on my own and need considerable help from professionals. Almost anyone with the V6 that wanted a HEMI would simply sell their V6 and buy a HEMI. It would cost less and have a better result - you get a bone-stock HEMI without all the hacks, learning, and mistakes with a full engine swap.

The supercharger, while expensive, is a rather simple bolt-on mod that is easily reversed if needed. A single day of my time and no need to get a shop involved.

HEMI swap = expensive, complicated, lots of potential for unexpected challenges.
Supercharger = expensive, easy, predicable result, reversible.

Fair enough. I thought you might be able to source a Hemi from a junkyard but yes the installation is quite a bit different vs supercharger!

 

[RLJ10X]

I did not read all 10 pages, so if this has been said before, please forgive me.

You putting more power in front of a V6 transmission, will be nothing but trouble, transmission wise.

Your engine makes decent power. It just has no leverage to work with. You'd be pleasantly surprised with 4.10 gears. I have 4.10s in my 545RFE, which supposedly has the same top gear ratio as your tranny. At 70 mph, your engine will be spinning about 2000 rpm, I think.

It's a 6. Do 4.10s. Let that engine spin.

 

[engineering]

I did not read all 10 pages, so if this has been said before, please forgive me.

You putting more power in front of a V6 transmission, will be nothing but trouble, transmission wise.

Your engine makes decent power. It just has no leverage to work with. You'd be pleasantly surprised with 4.10 gears. I have 4.10s in my 545RFE, which supposedly has the same top gear ratio as your tranny. At 70 mph, your engine will be spinning about 2000 rpm, I think.

It's a 6. Do 4.10s. Let that engine spin.

Gear change is not off the table, but as an additional modification to reduce the load on the transmission from the additional torque developed from the supercharger.

I got a quote to do the 4.10 for around $800 or so. Doubtful that I would attempt to do that on my own - it needs a professional with the proper tools.

If I go that route (3.92 or 4.10 rear gear), this should be about as capable as a Pentastar RAM 1500 could be in terms of towing while maintaining most of the reliability, drivability, and without being dragster loud.

 

[ramffml]

I did not read all 10 pages, so if this has been said before, please forgive me.

You putting more power in front of a V6 transmission, will be nothing but trouble, transmission wise.

Your engine makes decent power. It just has no leverage to work with. You'd be pleasantly surprised with 4.10 gears. I have 4.10s in my 545RFE, which supposedly has the same top gear ratio as your tranny. At 70 mph, your engine will be spinning about 2000 rpm, I think.

It's a 6. Do 4.10s. Let that engine spin.

His issue is pulling power while running on the highway. Changing physical gear ratio is just a complicated, expensive, and unnecessary way to press "downshift" on his gear limiter.

 

[engineering]

His issue is pulling power while running on the highway. Changing physical gear ratio is just a complicated, expensive, and unnecessary way to press "downshift" on his gear limiter.

Indeed. The topic of gear changes now that the project is getting a supercharger is more related to reducing the load on the transmission.
Not sure it is needed at this point, but still on the table if it becomes an concern.

With the help of others on this thread, I learned that gears alone would not achieve the goal.

 

[RLJ10X]

Gears alone will go a long way towards rectifying your issue.

Do gears first. Then you tell us.....

 

[engineering]

Gears alone will go a long way towards rectifying your issue.

Do gears first. Then you tell us.....

ISSUE: Maintain 60-65mph highway speeds in hilly/mountainous areas while pulling a travel trailer with huge coefficient of drag.

After quite a bit of consideration - I figured that gears alone could offer some help, but not enough. I don't need to crawl over rocks, bog out of a mud hole, beat a Challenger in a drag race......I just want to be able to get through Death Valley's long 11%+ grades without having to drop down to 30mph and/or some RPM above 4000.

Adding torque is the only practical way to solve the problem of not having enough torque. There is a certain amount of torque that must be delivered to the contact patch to maintain a given speed. The computer in the truck just keeps downshifting (more RPM) until it gets the torque to the wheel satisfied. If I add 100ft/lbs of torque output at the engine, there is less downshifting and lower RPM.

 

[VernDiesel]

ramffml, Not to offend. "His issue is pulling power while running on the highway. Changing physical gear ratio is just a complicated, expensive, and unnecessary way to press "downshift" on his gear limiter." While there is a grain of truth in it.. its the wrong conclusion and misses the point and the value. I believe this is why RLJ10X followed you and made post 97.

"Gears alone will go a long way towards rectifying your issue.

Do gears first. Then you tell us....."

I believe you did not understand my first two posts. Again not trying to offend just re read it as I've tried to make it more clear then think it through.



Engineering said " I was disappointed with how it handled very slight grades. There were a lot of stretches where 60mph pushed it into 3rd gear which is about 4300 RPM @ 60mph. For brief stretches, maybe that is ok but seems excessive for long periods.
A trip we took to Death Valley was really dramatic going through the mountains, we were going very slow and still something like 4k+ RPM for a long time."

And here is where he started out on the right track or IMO. "Initially, I just thought that I would change the rear-end form 3.21 to 3.92 which gets me about 22% more torque."

IMO Engineering would be far better served to do the gear swap 3.92/4.11/4.56 and possibly adding a TCM tune (transmission control module) first if available and then possibly adding the supercharger later. Only using 3 gears to accelerate climb or in some cases hold speed means he is working that engine & cooling system real hard and leaving lots of the benefit of torque multiplication and that transmission on the table.

Adding the supercharger will put more load on the motor cooling system and transmission as it adds engine torque. The gear swap multiplies existing engine torque making it easier on the motor cooling system & transmission. While the supercharger will potentially make the truck able to tow more at least if and until something breaks slips or overheats so its generally better used for making the truck fast.

 

[engineering]

And here is where he started out on the right track or IMO. "Initially, I just thought that I would change the rear-end form 3.21 to 3.92 which gets me about 22% more torque."

IMO Engineering would be far better served to do the gear swap 3.92/4.11/4.56 and possibly adding a TCM tune (transmission control module) first if available and then possibly adding the supercharger later. Only using 3 gears to accelerate climb or in some cases hold speed means he is working that engine & cooling system real hard and leaving lots of the benefit of that transmission on the table.

It seems that rear-gears will change the transmission gears but in the end - the RPM's will need to be really high for the steep grades. Gears exchange RPM for torque, right?

To get the extra torque required for an uphill run - the RPM has to go up. My Death Valley example was the most extreme so far - I had to go really slow and was still needing big RPM's to get that.

Will gearing really help at highway speeds (with big drag) and hills? Different transmission gears, but still 4-5k RPM?