For all of the men out there who love that inline 6 torque monster, here's another goody you can add to make it even better. I contacted AirRaid (www.airraid.com) and found out they sell a throttle body spacer for the Ford inline 6. Part# is 400-593 and they're selling it for $109. From what research I have done a spacer helps out in gas mileage and added horsepower. I don't think it will add to torque however. Every little bit of horsepower helps with this engine. Hell I'm getting one! Good luck!

 

Not to sound too skeptical, but could we un-educated type get a few more specs on these before we dive in. Sounds good, but their site has no information or proof on their claims.

Karl Knox 95 F150XL 2WD Ext Cab 4.9L I6 EFI E40D

 

I'm thinking about one of these for my car. the ones avaible for my car range in size from 1/2 to 1 1/2". This troubles me a bit, because no one can tell me what the correct size is. I'm under the impression that the bigger the better, but I'm not for sure about that. Also they make an injector spacer which does the same as the throttle body spacer only to the injectors. Well if I find out any more info on these. I'll let you know. By the way, you can make your own if you can fabricate a little. All you need is one of those hard plastic cutting boards, and your gasket as a template, and just cut it to the height you want. I know some people with homemade ones and they work as good as the $110 you are considering buying, but for a whole lot less.

Dave

 

From what I have been able to find by browsing the web is most throttle body spacers are any where from 1/2" to 1 1/2" sizes or thickness. Generally most manufacturers claim a 8-10 horsepower increase and about a 10-15 lbs torque increase. Another individual replied that manufacturing your own would be cheaper. I agree with this. The only problem I have found in trying to do this is finding a piece of aluminum (without paying $100 for the aluminum)to work with and someone who has the drill bits big enough to drill the holes I need! I'm not to sure about using plastic unless its made to handle high temperatures.
Most companies claim your getting extra power from their unique helix bore that spins the incoming air charge. Yeah right and a donkey's butt don't stink! Mechanics I have talked to say an engine gets the extra power by allowing the engine to suck on the air for a while longer after it has passed the carburetor or throttle body. From my point of view a spacer acts somewhat like a "mini,mini" supercharger!?
Its a sound way of getting a little more power but it would definitely be cheaper to make your own if you can find the stuff you need. Any other questions?

 

The plastic that I was refering to is very thick, and it really isn't that hot at the throttle body, so melting I don't think would be a factor. Another guy mentioned making one out of Corian, the table top stuff. I can't make stuff like that, so I have to purchase mine, just want to get the apropriate size.

 

The basic thinking behind the long, long intake tract on the 4.9L (as opposed to the carbureted 300) is torque; way, way low down torque. I think Ford went all out to make this engine a tractor motor.
The same thinking applies to the throttle bore sizing--smaller diameter, faster air speed, faster throttle response lower in the curve.
That is why I am so curious about your 56mm T/B; to see if it enhances seat-of-the-pants performance.
As far as a throttle bore spacer goes, go through your Yellow Pages under "Metal--Suppliers". There is a "Rose Steel Supply" here in Houston that handles (believe it or not) used steel and aluminum. Find some plate material in 1/8, 1/4, 1/2, 1-in.--what have you--and stack 'em; experiment with different stacking thicknesses and see if you can feel anything.
T/B holes? Well, stock is 43mm...just a tad smaller than 1-3/4-inches, a common hole saw size.
Go to Home Depot and buy one; also an arbor, and drill the holes yourself.
Have to cut the plate down? While you're at Home Depot, pick up a 7-1/4 inch diameter metal cutting plate and put in on your table saw or circular saw.
Pick up a carbide bur to wallow, er, "finish grind" the T/B holes to size.
Can't afford all those gaskets? Use gasket in a tube.
Want to make your own "...internal precision helix..." (or whatever Airaid is calling it)? Move that bur in and out as you are finishing grinding those bores, like finish-honing a cylinder bore.
I surely don't understand how inducing turbulence at the beginning of that long intake tract is going to affect the air flow down- stream, at the intake port, where the fuel is injected--not mixed way earlier, like a carburetor or TBI system.
Eddie

 

Looking through my "Jeg's" catalog just now, I noticed two things in the carburetor spacer section.
Note, these are spacers for 4-bbls. on V-8s, not our 4.9L EFI six, but...one is made of *wood*, another of phenolic, which if I remember correctly, is used for backer boards in electronics. That is probably the "plastic" you were wondering about elsewhere. If so, I bet an electronics supply house would or plastics supply house would have sheets of the stuff.
Jeg's makes haste to point out that this wood they are using for carb spacers is laminated.
Any racers out there seen this stuff?
Ed

 

Ford went to great effort to tune the intake and exhaust on the EFI 300I6 for maximum low end torque. I find it hard to believe that adding 1/2 to 1&1/2 inch spacer between the throttle body and the plenum is going to do anything. In addition you will have trouble with your air box connection as the tubes will be too long. Anyone have dyno numbers? Then I will believe it. (It is possible that greater power could have been acheived but that Ford had to back it off for emissions or fuel economy purposes.)

 

Hey all, this article is getting good exposure, I have emailed the guys at www.airaid.com to read our thread and give us their professional opinion and help us with the specs. Lets see if they join in.

Karl Knox 95 F150XL 2WD Ext Cab 4.9L I6 EFI E40D

 

I have to agree with what all of you are saying. Ford did make the intake for this engine very long which would definitely add to low end power. This intake is made to produce power from damn near idle to 3800 rpms. But like most of us I'm going hog wild in trying to find other ways to give this engine a little more umph! Adding a 1 inch space between the T/B and the intake has to do something in relation to engine performance, it seems for the better in other applications I have read about. However I am a little sceptical about paying a $110 for a piece of 1" aluminum with holes in it, when I could do the same thing for half the price if not less. Old Timer has a good idea when he says its better just to make your own. I strongly agree. Just grab a T/B gasket, map it out on a piece of strong plastic or aluminum(my choice) and drill that sucker out. According to Airaid the spacer is emissions compliant.

 

from what i understand about carb spacers, they make power in 2 differant ways.

1. they help to insulate the carb from the intake. so the heat from our exhaust will not be transmitted as easily to our carbs.

2. it allows the air/fuel mixture to mix a little more before turning and going through the intake tract.

David
85 F-150 300 I6

 

Just to throw my two cents in.I have a poweraid 1 1/2" throttlebody spacer on my 4.9 and here is what I have found.Very little power increase but better throttle response and definitly better gas milage about 6mpg better. Hope this helps.

 

Total overall increased runner length. Phenolic plastic is a composite made of fiber and plastic - "natural" almost looks like wood, and it stinks when you mill / cut it.

 

Guys, I went to the Airaid web site and looked at the spacer pictures there and it seems that the swirl effect they get is from the spacer being internally threaded with a very course thread of around 6 threads per inch. There is a picture that shows a cross section of one of the spacers. Any one with access to a lathe could reproduce this thread with no problem. As far as the swirl action getting down the runners and to the injectors and still be swirling, I doubt it. If one wants to try to make one, make it out of maple from home depot and see if it works to deliver any gains.

Bob / stractor

 

Just my two cents worth-
I had a 1" adapter plate I made using AutoCAD and had it burned out of 1" steel plate (Really not that heavy if that's what your thinking- It mated my Clifford intake to my Edelbrock 600) just messing around I added a alum. 1" spacer for a total of two inches. I ran this way all summer- Throttle response was great and so was mileage. (15-18mpg) Well in the cooler mornings near fall- Throttle response was very poor until the ambient temp outside got warmer. I literally found a carb heat plate in a friends junk pile (I believe it's a GM model and it is slanted from front to back- about 1" on onside and 1-1/2 on the other) Any ways, I removed the 1" alum spacer and installed this heat plate. Ran my heater intake hose to it. Early morning throttle response is back to normal and runs great when it's hot out. It also leveled the carb out to horizontal, since the engine sits at a slope. Also last winter when it was really cold out, the carb would ice up to a big ball and choke out. I'm sure that this heat plate will cure this problem. So guys, my recommendation is to hit the junk and buy ANY $5 4bbl heat plate and make it work.