Do throttle body spacers really work?

[TerryMason]

I've heard alot about throttle body spacers over the years, but I'm not sure I understand or believe alot of it.

Unless the factory installed a spacer in there that was purposley restricting airflow I don't see how raising the trottle body up 1/2 inch would help. The "cyclone" thing just sounds like marketing talk to me.

Am I way off? Would a throttle body spacer do anything for my 4.0?

[Dry suit diver]

I've heard alot about throttle body spacers over the years, but I'm not sure I understand or believe alot of it.

Unless the factory installed a spacer in there that was purposley restricting airflow I don't see how raising the trottle body up 1/2 inch would help. The "cyclone" thing just sounds like marketing talk to me.

Am I way off? Would a throttle body spacer do anything for my 4.0?

some 4 litre owners over here have reported better oomph when accelerating but that may be the placebo effect. the only true way to test is get it on a dyno.


or write to myth busters

[Bounty__Hunter]

I think they work, and most are 1" tall.

The biggest improvement is from 62mm throttle bodies, which I happen to sell, cheap. I use one on my 2.5L in conjunction with a 62mm spacer.

[jeepster357]

I use the Airaid cold air intake along with the Throttle body spacer, I cant quote you numbers but judging from my seat dyno (seat of my pants) my 4.0 does seem to have more oomph. I have noticed haveing to down shift less on steep grades and I did gain around 1-2 mpg's. And there is a added bonus of a little bit of a "growl" that comes from the air intake. cool.

[Heydace]

They do work, you may feel a slight difference (or not). The theory behind them is that they atomize fuel molecules better than the stock t-bore and intake. I would opt for a larger t-bore and air intake system (K&N or similiar) then open up the exhaust to allow for the increase in air intake. You want a smooth flow of air in and exhaust out.

[TerryMason]

I can understand a cold air intake making a difference, but I haven't bought into the spacer yet.

For $5 Chrysler could make these parts themselves. If they really did give a 1 mpg fuel savings, that would be a 7% fuel savings - why wouldn't Chrysler want this?

I'm gonna go ahead and buy one and put my money where my mouth is. I've kept great milage records to date, so I'll let everyone know what I find out.

[jeepster357]

When I installed my TBS it was in conjunction with the new intake so I cannot vouche for the TBS as a stand alone upgrade. I do know my mileage and performance has increased slightly over stock though.

[PA-XJ2]

hey, i think they work i had one on my 90 XJ (renix motor) and i could def notice a difference on take off.
-Ant

[Bounty__Hunter]

Terry, any update?

[TerryMason]

I've got the spacer, but with all this good fishing weather, I haven't had time to install it.

[Bounty__Hunter]

Keep in mind that power and mileage may improve over the course of a week or two after install, giving the computer time to adjust to the change.

[CyberJeepEric]

We sell the Airaid Throttle Body Spacers, usually along with an intake. Most of our customers agree that there is a noticable increase in torque from the combination. However, we have also received the feedback that after a while, a month or two, that the computer actually re-adjusts itself to compensate for the aftermarket products. At which time both the power and mileage gains are lost, in theory anyway. I have heard that disconnecting the negative post of the battery overnight will reset the computer and get the improvements back again. I stress that this is all in theory. In our 2007 Wrangler Unlimited Rubicon, the improvements have never seemed to diminish. However, we don't drive it a whole lot and with 37's who is checking gas mileage?

[ursman]

hey, i think they work i had one on my 90 XJ (renix motor) and i could def notice a difference on take off.
-Ant

Just curious as to where you were able to find a TBS for a Renix system. To the best of my searching, I've been unable to find one.

[03_Rubicon]

I bought the Air Raid 1" spacer for my 03 rubicon, and I immediatly noticed an increase in HP while accelerating. For what it costs....I would recommend it, and it is a snap to install.

[Bounty__Hunter]

Just curious as to where you were able to find a TBS for a Renix system. To the best of my searching, I've been unable to find one.

Hesco Inc. - High Performance Engine Service has the 62mm throttle bodies, plus adapters to use newer HO TB's on the Renix intake. Another option is to use a HO intake and TB, and just modify the TPS. While you're at it, use a HO head for the best gains, along with a '99+ intake with equal length runners.

[ursman]

Hesco Inc. - High Performance Engine Service has the 62mm throttle bodies, plus adapters to use newer HO TB's on the Renix intake. Another option is to use a HO intake and TB, and just modify the TPS. While you're at it, use a HO head for the best gains, along with a '99+ intake with equal length runners.

That's good info to know. Thanks!

[avan]

Personally I think that there will be no added advantage of a TBS. By increasing the distance from the fuel/air mixture from reaching the combustion chambers you are actually creating a mirco-second lag to a trottle response. If any affect is to be felt the increase of air verlosity should be before the carb, i.e a turbo-charger

My 2 cents worth

[ursman]

Personally I think that there will be no added advantage of a TBS. By increasing the distance from the fuel/air mixture from reaching the combustion chambers you are actually creating a mirco-second lag to a trottle response. If any affect is to be felt the increase of air verlosity should be before the carb, i.e a turbo-charger

My 2 cents worth

I have no idea where you've seen evidence that adding a TBS will cause "micro-second" lag. Simple physics shows that adding volume, in this case air/fuel increases power. There isn't any lag. Even if there was, we're talking about Jeeps not race cars.

[avan]

A "quote" from another "car forum" from a group at an engineering college

I" can't stress this enough: under *controlled* circumstances with a 350 cid Chev motor producing 180 hp and every engineering student submitting a design. NO measurable hp or fuel economy gains were recorded at under approximately 1 meter. This was using an assortment of aftermarket products as well as the shop designs. It did lead however to massive throttle lag.
A long straight tube on the air side of the carb or TB with no vanes, few bends, no internal sources of turbulence, a cold air source and a large, quality paper element returned the best HP and fuel economy gains without modifying the mechanics of the engine."

PS we have both turbo-charged and super-charged Jeeps in our 4x4 club

[avan]

And yet another 4x4 forum quote:


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

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>
-------------------------------------------
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"