ok, i'm always looking for "cheap" little things i can do to my truck to make it more powerful, if i ran a shorter belt on my truck and bypassed the smog pump would i see a gain in my HP or my MPG? either one and i would do it, also will the y-pipe and cat assembly off of an 83 F-150 w/351w fit on my 89 f-150 w/302?? thanks in advance, Justin.

 

I do not think that the y-pipe from an 351 will fit on a 302. 351 is wider and taller at the heads. I would check with an auto parts store. Just ask them for the part number for both and see if they match.

As far as the air pump, I still have my air pump on, but I removed all of the lines that connect to it, so basically it is blowing air around the inside of my engine compartment. I'll have to look at the belt routing to see if you can route around it.

If you do take the smog stuff off, save it. You may need to put it back on someday.

 

smae here I just pulled all the plumbing off of the air pump. so now it is just blowing air with no back pressure on it.
however, this may just be a coinsidence, but when I pull the engine codes, I get a code about the air pump.

 

I removed the air pump on my 1990 & 1991 F150 by using a 88.0" six rib belt (880K6). It eliminated the pump and a bunch of potential vacuum leaks (which I was chasing in the first place). The crap I eliminated was a good 15-20 lbs and isn't as important to us as our Mustang friends but in my opinion good none the less. In my 1990 Bronco the pump was on the verge of freezing up and really made a difference as far as acceleration and MPG the F-150 was operating fine but I want to say from the ole buttometer it seemed to make a differenceas far as acceleration. I can tell you more on MPG in a week or so. Hope that's the info you needed. Regards.

 

Redneckerson, do you still have the convertor on the truck without using the airpump? I have true duals on my 1989 F-150 and last fall the truck sat quite awhile and the pump locked up. I removed the pump and blocked all lines. I DID notice a difference rightaway. My 1993 is completely factory before the muffler, I want to get the convertor hollowed, but haven't found the time or anyone to do it for me. I think the pump is needed for the convertor to operate fully, but not too sure.





'93 F-150 loaded and modified!
Check my Gallery

 

You need the air pump to inject air into the cat in order to burn up hydrocarbons. without the pump the cat will not heat up enough to do its job and may fail. Big bucks!!! And it won't pass smog!!

 

well if they work together, i guess i'll just have to take off both... i live in texas, no smog checks

 

Pastmaster: I still have the cat at this point but will soon "lose" it when the Flowmaster exhaust comes in. In the mean time I did the ole "smash and crimp" by the cat. After further investigation I noticed a type of valve by the heads which only let air into the cat but won't let exhaust travel the other way. I'm sure yours has this valve since mine was stock before I molested it (that doesn't sound good does it). I live in a no emissions area so the cat was as good as gone to start with. regards.

 

I did the same as Redneckerson, and completely removed my pump with a shorter belt and threw the locked up pump away. After a while the check valve on the tube that goes between the heads in back of the engine rusted and made a bad exhaust leak. I ran down to the local hardware store with the tube in hand and found a pipe cap to fit. It fit perfectly to a black steel pipe cap like they use for running natural gas in homes. I think it was a 3/4" cap. I have also heard that those holes in the rear of the head are threaded and a coarse thread 5/8" bolt plugs them off nicely. I haven't yet taken the time to try it. If anyone does, let me know!

 

I just pulled the pulley off of my pump so I could leave all of the plumbing alone, just need the shorter belt.

 

The F150 I bought a few months back had the air pump hose cut right at the pump, but the cats (2) are still in place. So what I am learning here says that while the air pump is not taking as much power from the belt, the cats are not getting the proper air flow and plugging up? This would be bad 'cause the net gain would be negative, due to the cats fouling and restricting the exhaust flow big time. Should I bust out the cats? Keep in mind this is a work truck, used on my farm and not registered or smog checked or anything.....

 

You won't hurt anythign by running cats without the air pump. The pump is what initially helps to heat up the cats upon intiial start -- by heating them from both sides per se. They will still get plenty hot and pass emissions fine without the air pump. I've been running Mustangs like that for years without any problems.