so I just got my truck back from the exhaust shop, and you could say I'm like a fat kid after the candy shop! A while ago I posted asking about my truck, it was running like a dog, not revving out as it should, horrid gas mileage. I had heard from a few people that it might be the CATS plugged up, so I figured hell, why not kill two birds with one stone? I already had a single 3 inch flowmaster exhaust from the cat's back, but I wanted more...Louder...So I bought a flowmaster super 40, took the truck down to a local exhaust hobbiest and told him what was up. In less than 24 hours, I now have 2 and a half(or maybe 2, not sure) inch pipes off the y-pipe, collecting into a single 3 inch and removed the cats(o2 sensor was taken care of with an eliminator). The guy told me that basicly, the first cat puked it's guts into the second one, which would be where my problem was. Needless to say, I have hedman shorty headers, into the 3 inch exhaust, and it sounds pretty damn good! And holy poop did I notice a difference in performance, revs out way more and gets there a lot faster. Just thought I'd share, I'm just a broke high school student that is excited about not spending more money!

 

sounds like you got one hell of a deal with that exhaust system.. I need a better exhaust system for my truck.. seems like she's got the power, i just need to free it up.. how did you eliminate the o2 sensor? It is a very important part of the EEC/EFI system.. without it, the ECC won't know how much fuel to feed the engine

 

Well, my exhuast was quite the screw around, I was going to get a shop to do it, they "ordered" me a super 40, so I take the truck down and leave it there and I said "would you like my number so you can call if it is not going to be done by noon?" and the guy tells me, "no no, it will be done". I go down to pick it up "oh, yeah I didn't get your muffler in" when the day before he told me it was in the back...So after that and some other screw arounds with the same guy, I told him to F**k his hat, and left. So now I ordered my own damn super 40 for $30 less, then changed my mind and bought a flowmaster cat-back kit, installed that and just wasn't happy. So finally I got it all done yesterday, in the end it all cost me around $700 canadian, when I could have just got it done for $300 the first time...Live and learn!

So, to actually answer your question, BBK performance sells a pair of "o2 eliminators". These little buggers(I only needed one on my truck) just plug inbetween your wiring harness, and your o2 sensor, pretty damn easy and pretty damn slick. The sensor does need to go back into the exhuast though, because it still senses heat and air flow. Those set me back $85 canadian.

http://www.bbkperformance.com/products/exhaust.shtml
Second picture down, the kit on the left.

 

The O2 sensor simulator/eliminators are only for the after-cat O2 sensor, not for the primary sensor(s)...

 

If you put headers on your truck, you just stick the sensors back in and they are fine. On my truck, the downstream o2 sensor was between the 2 cats.

 

Hate to bust your bubble there. But the performance gain you likely grabbed was from fixing the clogged cats. The hedman shorty headers (with 1 1/2" primaries) show little to any gains over stock manifolds.

A truck driving around with a clogged cat is like you trying to run a mile with a hand over your mouth and your nose plugged. The truck can't breathe. Probably feels a whole lot quicker in comparison, but now you have it running the way it should normally.

The flowmaster 40 sounds good too. If you'd like to really open up that motor, you could pick up some steel long tubes (sell your hedmans on ebay or craigslist) and the exhaust man could build you a cheap Y pipe to run into the flowmaster super. The stock Y pipe on our trucks is a horrid performance bottleneck as well.

Longtubes are generally much cheaper than shorties and show real gains.

$700 canadian??? Wow!! For that price you could have picked up some decent heads. Not to mention a full flowing true exhaust. Not just a cat back loud exhaust.

FlowTech/Hooker LongTubes with a flowmaster super 40- $200
Custom Y pipe work - $150
header install (optional- if you can't do it) - $175

There you would have seen some legitimate low end and mid range HP and TQ gains.

I guess you do live and learn!! Get rid of those shorty headers and that stock Y pipe. Your 5.0 needs all the low end torque it can get.

 

I know what the truck ran like before the clogged cat, and taking the cat's out and freeing up the exhaust made a huge difference. Right now, it is more just a daily driver. I am not about to tear the headers off it because I didn't have fun the first time I did it, and probably won't the second time either. The only possible upgrades this truck might see is a tune and gears, other than that I am on the lookout for an old truck I would like to make into a street truck.