I know this has been covered before on here and had MANY different opinions, observations, etc. But I was hoping to get some clarification from some of you guys that have tried it and it worked......

91 F-150, AOD, 302, shorty headers currently with stock Y pipe (with the little crossover or "H" tube with the O2 sensor located between the y's before they go into the 1st cat) . I am fixing to replace the exhaust, and hoping to go w/ true duals on it. I have seen on here where some say to try to put the O2 sensor close to the motor, some say if you make a crossover pipe for the sensor & try to put in the same place, some say that it can be put on the passenger side header or just below the end of the header (for shortys), and some say it has to be in a crossover to read all cylinders...

What I'm looking to do is to put the O2 sensor in the new pipe just below where it connects to the header pipe on the passenger side (my headers don't have a place for an O2 sensor). This will be closer to the motor than the stock location but there won't be any crossover or exhaust from the drivers side for the sensor to read.

Will this work?

Thanks in advance.

 

My truck has been running for 8 years with a single O2 sensor in the passenger side longtube collector.. no crossover at all so it only reads 1 bank. This motor easily passes out local emissions sniffer tests, and runs beautifully. That pretty much says it all IMO.

 

Thanks Conanski. I'm still wondering which muffler to go with but leaning towards the flowmaster 40 series. I'll post when completed with results.

 

the BEST would be to put in a H, or Xtube anyways, and put it there, but realy... Your fine having the one on one bank IMHO. Thats what I have for now. I may put a bung in the collector of the Ypipe Im building, but I may just leave it in the header where it is now.

 

I have tried both the 40 and 50 series, and to be honest there isn't much difference between them. They are both loud and crack when you go up through the rpms, the 50 is just a touch quieter. Both of the mufflers I have are 3" in and out so there can't be a lot of restriction in there.

 

1995 F-150 4x4 Accel 300+ign, and wires,cap,rotor,K&N breather system I am running a 70 series flowmaster muffler and 21/2 pipes and it works good for me.I know this is going to be more restrivite than a 40 or 50 series. Just remember exhaust has a lot to do with fuel input. I have found out if it is too easy out it can go lean, but usually the computer takes up the slack.

 

I'm finally getting around to getting the exhaust done on friday. One more quick question..Should I reconnect the tube (I guess it's either the EGR tube or goes to the air pump) to the new exhaust or just cut it off, or plug it? What are the consequences to just cutting it off and leaving it open or should I plug it?

I can get it welded back in since it's in pretty good shape.

What do you guys think?

 

I plugged mine off, no idea weather this is a no-no or not, so far mine does OK. I would like to take that noisy smog pump off, but I don't know if I can get by with that or not.

 

I removed my air tube and had no problems. The system is designed to inject some air into the exhaust on cold starts to help the cat get up to temp and burn off excess hydrocarbons. Once the motor is at operating temperature the system dumps all the air to atmosphere, so you're just hauling around extra plumbing for nothing most of the time. I plan to completely remove my pump and the remaining plumbing this spring.

 

too large a pipe diameter can cause its own restrictions by allowing turbulence, you may have 11/2 primary's and 3" collectors but as the xhaust cools it requires less space so 21/4-21/2 is plenty for duals on most street engines..if you do a search I'm sure there will be plenty of formulas on the net to figure out your optimum pipe size

 

Actually too large a pipe doesn't induce backpressure, but it does inhibit scavenging, which causes the same problem.

 

never said it does...in those words.....I said it can cause turbulence, but maybe we can start a thread on word games, lot of that going on

 

I was planning on going with 2.5" pipes, hi flo cats, flowmaster 40 series, and based on what you guys stated I'll just plug the air tube.

I wasn't sure if that tube was the EGR (and hadn't taken the time to trace it yet) or just to the air pump and didn't want to upset the EGR.

 

It's the air pump, on the 302 the EGR gases are sourced from the lower intake and make the short journey to the EGR valve with a tube that runs under the upper intake on the pasenger side.