AFE Intake, Borla Catback, and Superchips Review for 2018 5.3

INTJ · May 30, 2019

I have had my 2018 Double Cab Std Bed Max Tow 4x4 for year and have about 13,700 miles on it. This past weekend I added a CARB legal AFE Magnum Force Stage 2, a Borla Touring Cat Back, and a Superchips Performance Tune.

Install:

Removing the factory exhaust took two hours on my garage floor. I could do it in half the time now. To get the factory unit out in one piece requires jacking up the rear right side frame to get adequate clearance between the axle and body. The Borla install was very easy and took about an hour going slowly. It is a high quality kit. The specs call for 35 ft lbs on all the clamps but the bolts felt a little stretchy so I stopped at 30. I took the factory clamp that is reused to about 25. I’ll retorque in a week or so.

Removing the factory intake and installing the AFE took about an hour.

The Superchips didn’t update correctly so I had to call Superchips the next day to have them fix the update. After that it was easy.

I got to drive it for a day with just the intake and exhaust, and it seemed to make a difference in acceleration. I wasn’t interested in making any more noise, but the Borla Touring has a nice low pitched rumble. At freeway speeds you can just hear it on a quiet asphalt and on noisier asphalt or concrete the road noise overwhelms the exhaust. When AFM kicks in you can hear a very mild helicopter sound on a quiet road but in a noisier road it too can’t be heard. Over all, cruising is quieter than any of the three Duramaxes I have owned. My wife says the Borla sounds nice and is very quiet when I back into the garage. Of course, when I accelerate it is significantly louder, especially when you get the throttle valve open.

Superchips customer service was very responsive and got me going very soon on Tuesday. The Performance tune, along with the intake and exhaust has really made the engine happy. It is much more responsive and pulls harder. Superchips said the Performance tune with the intake and exhaust should add about 30 HP, which seems about right to this former hobbiest drag racer. That wouldn’t likely take more than .3 off a 1/4 mile ET, but the way the power is now makes it a real pleasure to drive.

Overall I am very pleased.

Edited May 30, 2019 by INTJ

All Terrain · May 30, 2019

Do you have to use premium fuel with the performance tune?

INTJ · May 30, 2019

Yes. Around here Premium costs me $4-5 more per fillip. I don’t think the other canned tunes require Premium.

Pivot · May 30, 2019

Nice upgrades. I have the Borla Atak and S&B Cold Air Intake. Love both. I just received the Bilstein 6112 struts and coils and 5100 for the rear. As soon as I do the level and get new rims and bigger tires, I plan on doing a tune to recalibrate the speedo , but really want to disable the silly AFM and Governor. I'm leaning towards a custom Diablew Tune. It's a little over $100 more when packaged with the hand held unit.

Can you shed any light on why you went with Superchips? ? I don't hear many people talk about Superchips. 30 hp sounds like a lot, but you could be close. I have the 6.2L and man when I pulled all the restrictive baffles and hardware on stock air cleaner, bolted in the S&B CAI and then added the Borla, wow , it really woke things up. Truck eagerly lurches forward when i hit the gas and brings a smile to my face every time.

INTJ · May 31, 2019

oI added the Roadmaster Active Suspension last year and am very impressed with the increase in stability. It lifted the back of my truck an inch so i added an inch lift the the front. I like his height—easy to get heavy loads—like my lathe and milling machine—in an out of the bed.

I went with the Superchips because I need to have a CARB compliant tune for the state I live in. Also, I did’t want to fuss with all the tuning. I have had three Duramaxes and ran tunes in all three and I wanted a hassle free tune install.

Superchips told me the Performance tune with the intake and cat back would add about 30 HP. That seems reasonable to me. I think to get much more I’d need a cam and headers. Maybe a Whipple.....

silveradosid · May 31, 2019

have you towed anything with the performance tune, just wondering if it makes a difference

INTJ · May 31, 2019

I haven’t towed or even hauled anything yet, but Superchips says not to tow on the Performance tune. They do have a canned tow tune as well. I would expect the tow tune to help a little but nowhere near what a tow tune does for a turbo diesel.

INTJ · June 11, 2019

Looks like the combination of intake, exhaust, and tune has improved my freeway mpg by about 2.5. That is based on DIC readings over the same route, driven about three weeks apart. My DIC is something like 7% rosey, but it is consistent. When I correct for all that it puts my freeway mpg before at about 19 mpg at around 72 mph to 21.5 mpg at the same speed. Actually, I had heavier traffic on the trip after the mods.

Now if I really wanted to have reliable figures I would run several trips and track both hand calculated and DIC mpgs both with and without mods. I could even test to see how each mod impacted mpg, starting with premium fuel, then adding intake, then adding exhaust, then tune. I could do the same with dyno readings for HP gains.

I am not interested in all that. I am happy that my truck runs betters, accelerates better, and gives me a couple mpg better; all while staying emissions legal. There is one shift point I’d like to change. It’s slow to downshift under hard acceleration from 30-40 mph. The TCM might learn that out. If it keeps bothering me I’ll just add a supercharger and be done with it.

Mileguru · June 12, 2019

11 hours ago, INTJ said:

There is one shift point I’d like to change. It’s slow to downshift under hard acceleration from 30-40 mph. The TCM might learn that out. If it keeps bothering me I’ll just add a supercharger and be done with it.

Even with a supercharger the 8-speed is slow to downshift. Are you 6 or 8 speed? The whole TCM is funny; after you do a mod or a new tune, it runs/shifts much better and then it learns itself back to the crap shifting. Mine started shifting better after I tied the exhaust flapper open. I'm going to buy a new muffler and delete the flapper soon in hopes that I free up some airflow and get improved shifting (which makes no sense, I know...improved shifting with exhaust, but my HARD CLUNK from 1-2 and 2-1 has almost disappeared after I tied the flapper open).

BTW, if I had to do the supercharger purchase over again, I'd probably buy a Whipple instead of a Magnuson. One of the factors that people don't know/think about is that Whipple includes a handheld to install their tune and Magnuson does not. This of course is if you are buying the tune that comes with the SC. There are other issues like pulley sizes and stuff, but I've pretty much got my truck running perfectly now. The biggest drawback with these trucks is the torque based system and how it dictates the transmission. There's not a whole lot you can do to get around it. Even if you unlock the 8-speed TCM, top notch tuners say not to mess with the trans tune all that much.

INTJ · June 12, 2019

41 minutes ago, Mileguru said:

Even with a supercharger the 8-speed is slow to downshift. Are you 6 or 8 speed? The whole TCM is funny; after you do a mod or a new tune, it runs/shifts much better and then it learns itself back to the crap shifting. Mine started shifting better after I tied the exhaust flapper open. I'm going to buy a new muffler and delete the flapper soon in hopes that I free up some airflow and get improved shifting (which makes no sense, I know...improved shifting with exhaust, but my HARD CLUNK from 1-2 and 2-1 has almost disappeared after I tied the flapper open).

BTW, if I had to do the supercharger purchase over again, I'd probably buy a Whipple instead of a Magnuson. One of the factors that people don't know/think about is that Whipple includes a handheld to install their tune and Magnuson does not. This of course is if you are buying the tune that comes with the SC. There are other issues like pulley sizes and stuff, but I've pretty much got my truck running perfectly now. The biggest drawback with these trucks is the torque based system and how it dictates the transmission. There's not a whole lot you can do to get around it. Even if you unlock the 8-speed TCM, top notch tuners say not to mess with the trans tune all that much.

Interesting. I have the six speed, and I will get a Whipple it and when I supercharge. My thought was the Supercharger would have enough power to a accelerate well in the higher gear, kind of like my tuned DMaxes. Thoughts?

Edited June 12, 2019 by INTJ

Mileguru · June 12, 2019

9 hours ago, INTJ said:

Interesting. I have the six speed, and I will get a Whipple it and when I supercharge. My thought was the Supercharger would have enough power to a accelerate well in the higher gear, kind of like my tuned DMaxes. Thoughts?

For the most part that is true. It's absolutely amazing off the line 0-60mph, but has a couple "boggy" spots due to the poor shifting. The shifting issue is how it slides into gear slowly and cuts power a bit (part of the torque management I assume) and how it doesn't downshift quickly (you sometimes have to almost floor the accelerator for it to say, "Ok fine, I'll downshift a gear." Something else that accompanies the lack of downshift is how the truck will not give you the power you're asking for when you're already 30-40mph+ and hit the accelerator...it'll spin the rpms up but pull back on the power (torque management again, I assume). Something that helps a little bit is turning off traction control. Despite this, it does accelerate pretty well in a higher gear like you're saying, but you don't get the "boost" feeling and that's what frustrates me at times.

My comparison is to my '06 mentioned in my sig. 4-speed trans and 4.10 gears, so much more pull in the high gears. However, my old truck didn't like going over 75-80mph whereas this truck easily cruises at that speed and feels more "luxury" if you will.

INTJ · June 12, 2019

The early DMaxes would defuel so bad it felt like you had a manual, came off the accelerator, and put the clutch in. Speaking of speed, I too have noticed that it’s way to accelerate well to about 80, but to accelerate hard above that we need a lot more power.