AFE’s Silver Bullet Throttle Body Spacer, Fact or Fiction?

A few weeks ago I got a comment from a reader asking my opinion on Throttle Body Spacers (TBS).  Quite frankly, despite a lot of reading over many years I’ve never used a TBS myself.  If you search for dyno results, the folks doing the testing always lump in the TBS with a bunch of other mods so it’s hard to tell which mod produces which result.  Well, I had a little time on my hands and I’ve always been curious about the TBS’.  Does that little piece of metal actually do anything?  Let’s find out!

Opening up the box and looking at the parts… My initial reaction is Hell-to-tha-no!  Think about it, if this little chunk of metal made a noticeable difference, wouldn’t OEM engineers put them in all our engines to sell us more power from the factory?  AFE claims up to 10 HP & 14 lb-ft of torque for this little gizmo, so let’s see what all the excitement is about.AFE-SilverBullet-TBS

I consider myself a man of science, so I’ve hunted down a dyno and booked some time to get to the bottom of this.  First things first, let’s get a base run with my existing set up: 3.6L Pentastar V6, AFE 49-46218 Hi-Tuck Exhaust, Volant’s 17636 PowerCore® Intake System, & SuperChips Flashpaq 3872 set to the 87 tune program.





Dyno Results Before

As you can see in the image above, the Dyno shows 231.0 max HP at 6,400 rpm & 210.0 max torque at 2,600 rpm.  Not to shabby for this fat bottomed girl to scoot around on.  Now, let’s toss on the TBS.

To install the TBS, all you do is pop off the engine cover, remove the intake tube and pull 4 8mm screws holding on the throttle body, slip the TBS & gasket in place, then reassemble using the factory hardware.

Silver Bullet before and after

Just in case you blinked and missed it, here’s another picture of the TBS installed.

Silver Bullet Installed
With the engine cooled off and all the parts bolted up, let’s go for another run.


Dyno Results After
After installing the TBS, the new max torque is 210.7 (gain of 0.7 ft-lbs) and 236.8 hp (gain of 5.8 hp).  The torque gain, less than 1 ft-lb at the wheels, is pretty negligible and the new peak power, at the very tippy top of the red line, isn’t something I’ll use, but let’s overlay the before/after runs to see if there’s more to this story.

Dyno Results Combined

Looking at the overlay, the excitement is actually in the difference in the before/after torque curves.  Like I said earlier, 0.7 ft-lb isn’t all that exciting, but having close to your max torque earlier in the tach, well that’s a difference you can feel using the Butt Dyno.  I have no intention of taching out my Jeep for that extra 5 hp at the top end, however look back at the rest of the graph.  Just like the torque curve, you can see that you have access to more HP through out the entire power band.  Not a lot, but every little bit helps scooting around all that armor and tire weight.

I went into this test thinking I was going to send the TBS back because It doesn’t do crap.  Well, here’s scientific evidence that proved me wrong.  Sure it doesn’t make the 10 hp/14 ft-lbs it claims to on the box, but access to more of your engine torque earlier in the power band helps get the most out of this engine.  And between you and me, I still can’t believe that little part actually does anything at all.


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