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TB and spacer

894 Views 11 Replies 8 Participants Last post by  08 Shifter
What does everyone think of getting a bigger throttle body and throttle body spacer on a stock bullitt? Is it true the spacer will give better fuel economy? Just wondering if anyone as added these mods.
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Me thinks if a $1 piece of aluminum would increase fuel economy, it would have come with one from the factory.
i am not sure of that. Ford leaves out alot of things that can help the car.
j0eyabs said:
i am not sure of that. Ford leaves out alot of things that can help the car.
Such as? In the fuel economy $1 part category.

I don't think a larger throttle body, which will also require a tune, will help better fuel economy. It may or may not make it worse.

I'm not sure what spacer you are referring to. I've seen a few on eBay that claim to improve fuel economy by creating a vortex of the incoming air etc. I have my doubts about the claims.
Steeda sells a TB spacer on their site that claims to add Hp and better fuel economy.
I have never had to retune a car when adding a TB. When I upgraded my SVT Focus to a 67mm TB it did only add 3 hp peak but i did get an extra 7-10 miles per tank and had a better throttle response with no tune. I was just wondering if the Mustang has the same effects.
If you don't go too big with a throttle body you might get away not having a retune, but I think it's still recommended to do so.

It might be expensive to just try. If Steeda guarantees results with the spacer and will give a refund if it doesn't match their claims, give it a try.
good idea. I will call them and see what they say.
j0eyabs said:
good idea. I will call them and see what they say.
Wish I could offer some Additional Insight here but No-Can-Do.

I think I'd have to verify the throttle body size first to make sure the spacer is a perfect match. Did I read somewhere that the Bullitt's throttle body is slightly larger than the one in the 08 GT?
Throttle body spacers are pure bunk. ALways have and will be. A larger throttle body will not always help, either.
Somebody please enlighten me as to exactly HOW increasing the plenum-volume by adding a spacer after the throttle-body on a DRY INTAKE MANIFOLD is supposed to increase HP and MPG? As there is a tuned-length to each runner, and the plenum itself is tuned, I can see MOVING the power around the rpm-range a bit (but not much!), but no increases due to just a simple 1" deep by whatever dimensions of opening the spacer happens to be.

This works a bit-better on a carbureted engine - but even a single-plane carb'd intake has comparatively small plenum-volume compared to most any modern dry-type EFI intake. Mostly, it also just mostly moves the powerband up the rpm-range too, and "adds" little to no power (with a major caveat being phenolic spacers that actually help to keep the carb and the fuel contained in the float bowl "cooler").

And, putting one on a carb'd engine DOESN'T automagically work wonders - I've seen engines actually LOSE a bit of power and driveability by doing this, so we pulled the spacer back off and tossed it in the corner...........
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Spacer=No!Larger throttle body,is it really worth a few hundred bucks for a claimed few HP.Put the money in the tank or feed the pig.Only justification for a larger throttle body is an increasee in demand for air.So..............
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