What is the main reason for the sluggish feel?

[HSKR R/T]

Ttou said you have adjusted the computer for the larger tires. you definitely need to do that as it will effect shifting for sure.

 

[John Kloehr]

Adjust computer for tire size just to get shifting and the speedometer right. The extra diameter will hurt felt torque a bit (can calculate that), the extra weight is harder to judge but accelerating a heavier wheel and tire combo will hurt felt torque (will feel sluggish).

From the other direction, once purchased a used Mercedes with very light wheels and tires (Mercedes spec but dealer add-on for first owner fitted after manufacture). Did not realize what a difference they made until after it got totaled. The identical replacement car with stock rims and tires was just not as peppy, especially as speeds increased. Both felt about identical off the line, but 25 to 50 mph was a night and day difference. Rotating mass makes a big difference.

 

[akostaac]

Have also seen lots of reports here that after a large tire diameter change like you have done the transmission shift points are off enough to materially degrade performance.
You can get it recalibrated at a dealer for your tire size potentially, or I believe you can do it yourself if you purchase a Tazer device or maybe it was through Alpha OBD itself .

This is why it is so important to recalibrate your speedo so your transmission shift points are where they need to be. I learned this with my 4th gen lifted and 35in tires. I drove away from the shop that installed the lift and tires and by the time I got home I was googling why the transmission or truck rode differently than before. First thing I found was, Did you recalibrate your speedometer? I recalibrated the speedometer right away and the truck was back to normal. Don’t get me wrong, you will feel the weight of the tires but it will shift smoothly and you will not feel sluggish. I have calibrated all my trucks ever since if I increase the tire size.

 

[RHO]

Hi, I have a Ram Rebel 2021 and I just recently performed several mods really close together and I can't figure out what exact mod is what is contributing the most to feeling very very slow. (also, 2mpg less)
1) Cold Air Intake (S&B) - is it worst than stock on extremely hot environments like Phx AZ? Currently at 110 degrees.
2) 3 inch leveling kit?
3) slightly slightly bigger tires than stock. Went with 285/75/18 (10-15 lbs heavier than the stock tires)
4) Installed a Carven Muffler R 3 inch.

I know everything is playing a factor on my sluggish feel, maybe not the muffler, but I really hate how it feels now. I will be disconnecting the battery to see if the computer resets itself on the exhaust flow as it is the last mod I performed, but i don't think will do anything.

Feeling pretty sad on the performance to be honest, might need to go for some headers to add some more punch, I don't know.
Thanks everyone

you might not have the gearing in the diff to turn those bigger tires properly,A guy i worked with year's back Had a gmc yukon blazer up graded the tires and you could tell the difference right sluggish like you said.

 

[John Kloehr]

you might not have the gearing in the diff to turn those bigger tires properly,A guy i worked with year's back Had a gmc yukon blazer up graded the tires and you could tell the difference right sluggish like you said.

The Rebel package includes plenty of axle gearing.

 

[mikeru82]

Yeah, I just didn't know with the extreme heat here in Arizona if it was actually hurting me more to have the side vent open and actually hurting the performance by pulling hot air. I've closed it too but feels worse.

If you suspect the aftermarket intake is causing at least some of this why not stick the stock intake back on and see if there is a difference in how it feels to you? The stock intake is a factory CAI. If you are pulling in air from the hot engine bay you are doing nothing to help the engine breathe better.

 

[RHO]

The Rebel package includes plenty of axle gearing.

yes you are correct ,

 

[KichoRebel]

If you suspect the aftermarket intake is causing at least some of this why not stick the stock intake back on and see if there is a difference in how it feels to you? The stock intake is a factory CAI. If you are pulling in air from the hot engine bay you are doing nothing to help the engine breathe better.

Sad after spending close to $400, Yes after spending more days with the mods, it does have to do a little bit with the hot air I think. Some days when it is not extremely hot , the truck's response feels better.

 

[KichoRebel]

This is why it is so important to recalibrate your speedo so your transmission shift points are where they need to be. I learned this with my 4th gen lifted and 35in tires. I drove away from the shop that installed the lift and tires and by the time I got home I was googling why the transmission or truck rode differently than before. First thing I found was, Did you recalibrate your speedometer? I recalibrated the speedometer right away and the truck was back to normal. Don’t get me wrong, you will feel the weight of the tires but it will shift smoothly and you will not feel sluggish. I have calibrated all my trucks ever since if I increase the tire size.

I haven't not yet, looking at Pulsar and other plug in Tuners that could do the recalibration and maybe some hp gains...
What do you recommend, how did you recalibrate yours?
Thanks

 

[akostaac]

I haven't not yet, looking at Pulsar and other plug in Tuners that could do the recalibration and maybe some hp gains...
What do you recommend, how did you recalibrate yours?
Thanks

Alfaobd will do it if you have one and if not I suggest you get it because you will be able to do few changes to the truck for free that otherwise you may need to pay for someone else to program it in your truck.

 

[CHeYeNNe71]

I haven't not yet, looking at Pulsar and other plug in Tuners that could do the recalibration and maybe some hp gains...
What do you recommend, how did you recalibrate yours?
Thanks

Ok a few things you can do. First recalibrate your throttlebody, yes this helps.

Next I'm running 3" lift with almost 35's and MOPAR CAI and Carven full exhaust, plus the Pedal Commander ( throttle controller ) and Edge Pulsar which does add power, plus Plug n play. I don't have a warranty to worry about, but ran on my 4th Gen w/ 6" and 37's.

I also have a topper to add more weight, oh and 3.21

 

[KichoRebel]

Ok a few things you can do. First recalibrate your throttlebody, yes this helps.

Next I'm running 3" lift with almost 35's and MOPAR CAI and Carven full exhaust, plus the Pedal Commander ( throttle controller ) and Edge Pulsar which does add power, plus Plug n play. I don't have a warranty to worry about, but ran on my 4th Gen w/ 6" and 37's.

I also have a topper to add more weight, oh and 3.21

View attachment 204207

Beautiful truck! Looks great.
Thanks for the tip on the throttle calibration. I will try that today.
I like the the plug in Pulsar, I think I will def end up buying it, I just didn't have it in my budget so quick haha.

Do you mind sharing if it is really worth it, you did see the difference when putting the performance setting?
Thanks

 

[CHeYeNNe71]

Beautiful truck! Looks great.
Thanks for the tip on the throttle calibration. I will try that today.
I like the the plug in Pulsar, I think I will def end up buying it, I just didn't have it in my budget so quick haha.

Do you mind sharing if it is really worth it, you did see the difference when putting the performance setting?
Thanks

Considering I ran it on my 4th Gen and bought again for the 5Th Gen. I think it's worth it and if you can find used for a good price, even better. I bought both of mine used. Look on FB Marketplace.

Just make sure to run proper fuel for the tune you choose to use. I like the ease of changing tune on the fly, Shuts off MDS and not having to run premium 24/7 if you don't want to.