What are the "realistic" gains or pro's and con's of having a throttle body spacer? Are they worth having?

 

From the research I have done, No one has actually provided any dyno proven gains. I had one on 3.0 VTEC and did not have any hp gains, but it did make a nice sound.

 

I have one on my Ram 360 and I love it, it makes a distinct whistle sound under slight to medium acceleration, but once you are at speed it is quiet again, I didn't dyno of course but, it may seem like a more steady power band, but not for sure[&:] I noticed about a half a gallon difference on the highway went from 14.1 to 14.8 ?? but who knows could be weather wind anything, I havent had it on the hwy again. Just makes a cool sound??

 

my intake kit from AEM came with a throttle body spacer because it made about 1hp more. i know the guys who designed the kits, that's how i know. w/ their kit for the 4.7 ram they don't include a TB spacer because it does not make any power

 

Taken from here: http://www.speedtweaks.ca/tipsandtricks.php

Throttle Body Spacers (Primarily the "Helix" style):

These spacers do not provide any gains in HP at all. They claim to increase TQ and MPG but we tested one and it gained nothing. The Dyno showed no gains in HP or TQ. We also had contacted one of the manufacturers for their comments on them and here's the direct quote (from email):

--------------------------------------------

From: AirAid Info
Subject: Re: AIRAID.COM Contact Form
Date: Fri, 09 Mar 2001 09:20:36 -0700

Dear Sir, thank you for your inquiry in our products. The spacer makes no HP on the Dyno. It makes all of it's power in torque in the low end. If you haven't noticed any power on the Dyno or the track then it's doing what it's supposed to. You would not see any gains down the 1/4 mile or increases on the Dyno. The idea of the spacer is to improve overall drivability and fuel mileage. In most cases when people install a bolt on part they expect better mileage and power, what happens is they are into the throttle a lot more than before trying to test performance and that's when the decrease in mileage happens.

Sincerely,

<Airaid Technician>
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Points to look at:

"The spacer makes no HP on the Dyno. It makes all of it's power in torque in the low end."
"If you haven't noticed any power on the Dyno or the track then it's doing what it's supposed to."
"The idea of the spacer is to improve overall drivability and fuel mileage."
So...it doesn't make any more HP, is not supposed to help in 1/4 mile performance (or on the Dyno), and is mainly for mileage and bottom end Torque. Well, Dyno's show TQ figures and there were no changes, mileage stayed the same, and 1/4 mile performance wasn't affected on the several others who have tried it (including us). They also are still not able to explain how the spacer keeps the swirl effect through the two turns (90 degree and 45 degree) in the intake plenum of the Dodge Ram/Dakota/Durango manifolds.

While the Throttle Body Spacer showed no gains on the 3.9/5.2/5.9L Magnum engines, the 4.7L engines have been reported to show noticeable gains from the spacer. Why? It's a much more efficient intake system with less restrictions than the Magnum engines. It may work just fine for the 4.7L crowd but we'll look into this at a later date for Dyno and long term MPG testing.


They work as good as fuel line magnets.

Bill,

 

I agree with SG. As I have said many times here already...the spacer is just left over tech from the carborator days. When the air/fuel was mixed in the carb the spacer would help mix the air and fuel better....now the fuel is shot right in the cylanders. The only thing the spacer will do is prevent you from being able to use most CAIs!!