If I put headers and dual exhaust on my truck (1984 F-150) what about emissions testing? Do I have to have dual catalytic converters?

 

Technically, if you put headers on it, you are illegal. Dual convertors theoretically would work, but it still would be illegal. You cannot modify anything from the original catalytic convertor forward to the engine. There may be a few shorty style headers that are 50 state certified to be emissions legal, but they are for trucks newer than yours.

Will it pass emissions testing with headers? Possibly. More than likely yes if you messed with the tune of the engine a little bit.

Will it pass a visual test? No.

In the end, it depends on how hardcore your testing station people are. If they follow the letter of the law, the first paragraph in this reply stands.

 

if you check with Flow teck, I believe they make an "emission complient" pair or "tubeular exhaust manifolds" that will replacve your existing manifolds and be 50 state legal.

 

I put 50 state legal JBA headers on my 86 5.0. They were expensive ( about $600) but they are also titanium and ceramic coated. I love them.

Why are you going dual exhaust? I just fabricated my own Y pipe that runs into a 3" 2-1 tube then into a single 95000 series Magnaflow cat that takes the place of both of the old ones. Everything is 3", I am legal but still breathing.

Good Luck,

Lee

 

I dont know about texas but in Colorado you cant put any more or less than the origional number of cats, headers are legal here

 

I was going to twin exhaust to get better flow. No other reason. Same as for the headers. From what I just read - and thanks all for the answers - I need to question my decision to change at all. Can anyone tell me if there is any validity to better exhaust flow vs mileage and power? Is there any other reason for headers?

 

WIth my set up, I did notice a better gas milage boost. Horsepower increase didn't seem to change but it depends on how you do it. If you get too big, you can lose bottom end torque. I may have errored a bit on too large though I really haven't noticed too much of a loss on the bottom end as much as my tire change affected it. The only reason I say I may have gone too big is I seem to get better gas milage at high speed despite the aerodynamics of the truck being like a brick. If I cruise on the highway at 80 I do better than at 65-70 despite the wind resistance. I guess my flow to RPM ratio is best a bit higher than it should be. I do plan on regearing my truck though so hopefully it will get in line 15-20 miles an hour lower afterwards so I can cruise with the best milage at 65-70.

I think headers are worth it no matter what. The stock manifolds do not breath well at all. Just don't get too cheap on the headers you choose and get something that fits well, will hold up well and is legal.

As for the cats, I remembered wrong. They weren't 95000 series, they were 93500s with teh air tube ( second one down).....
http://www.car-sound.com/catalog/universal/935.aspx

On our trucks, they can take the place of both teh stock ones with just the one. No need to do this if your stock cats are still good. I only did the change over because I was changing my exhaust from the 2" to a 3" set up and was changing everything at once.

As for the dual exhaust, it is argued all the time. I chose single since my research seemed to point that single 3" breathed as good or better than dual exhaust and a single pipe is half the cost of dual pipes, dual mufflers, dual cats etc. I didn't want to lock myself into having to pay for double the costs on everything down the road.

Good Luck,

Lee

 

I always wanted to put duals on my truck, but the 4x4 is making it hard, especially with emissions. I think I'm just going to put a turbo muffler on the stock setup and call it a day.

 

That's just it; whats legal? I tell you, this emissions crap is really beginning to @#$% me off! I got a clean burning engine! I don't want to waste gas anymore than a green weenie wants me pumping unburned hydrocarbons into the air. What the hell is happening to this country?!?!?!?!?!

Sorry, I went off topic a little.

 

I think the manufacturers will tell you if you give them a call. Also, if it is legal in California, it is "usually" legal everywhere else since these idiots are stricter than most. If all else fails, I would imagine the DMV in Texas could tell you if it isn't already on the web somewhere.Headers should be legal as long as you can plug the O2 sensor in. Not much else on the stock manifolds. I would just be sure that the headers have the O2 threaded hole and that it is approximately the same distance away as the stock one so that it it able to heat up about the same as the stock setup. I have seen some guys try to mod thier vehicles using a relocation of the O2 at the rear of long tube headers or all the way back at the CAT and then the O2 sensor runs too cool and messes things up.

I agree on the hassles of the smog junk. I have a line on a nice engine to drop in but since I am currently stationed in California, I would have to modify the heck out of it to make it work according to their rules and then even if I am burning cleaner than now, would have to go through a referee station to get their blessing to drive it. My plan is to convert to a MAF setup instead of our MAS but with a larger block. I decided to just wait until I get orders and move again. I'll probably retire in an area where smog isn't even a concern. I will be burning cleaner and more efficient but won't have some state employee playing big brother.

Good Luck what ever you decide.

PS - Did you get my PM a few weeks back and were you able to get the parts you needed?

Lee

 

You can hone the exhaust manifold and gasket match them. The hone is were the send something through it to hone the inside of the manifold. I forget the proper name but it should increase flow. As for emission I live were there is no test so I can't help you there. Good luck.

 

http://www.dynomax.com/headers.stm

http://www.bassani.com/default.cfm?f...ainlessheaders

These are 50 state legal, and are a good quality part, as well. Give them a call, or search through their catalogs for your particular application.

For myself, I'd run a single 3" exhaust ofer dualies any day. One large diameter high flow cat, one pipe, one muffler.

Exhaust theory can get a bit long winded, but let's lay some basics down.

A single 3" pipe has the ability to flow more volume than dual 2 1/4" pipes combined. If you don't believe me, ask any plumber or pipe-fitter.

Added to that, headers will help increase "scavenging". Scavenging occurs when a cylinder is on exhaust stroke, and the push of the exhaust from that cylinder helps pull out spent exhaust gasses from other cylinders not currently on exhaust stroke. This in turn allows a greater volume of fresh fuel/air mixture to be allowed into the cylinder on it's next compression stroke. The more efficient your scavenging is, the more efficient your fuel delivery is. In the long run, this equals greater power and better mileage.

The length, as well as the tube diameter of a header will determine where it puts the power. Shorter tubes deliver more power in the upper rpm band, longer tubes deliver more power in the lower rpm band.

The same holds true for diameter. Small tube headers produce more power in mid to high rpm on small CID engines, where large tube headers react the same way on a larger displacement engine. If in doubt, use smaller.

 

The honing is called extrude honing.

 

The first poster said he had an 84. If it is a non-computerized engine, the headers will mess it up if it's completely stock. This is what I found out when I did this to mine.

I have a 79 351w, completely stock with all the emissions and the 2bbl carb in my 1980. After I put the full length headers on, it started pinging terribly. We of course are all quick to say that I am running leaner now with the headers. That is partly true, and I did go up 3 jet sizes in the 2bbl, and it made it run much better. But I still had a pinging problem.

That's when I discovered my EGR valve didn't seem to be working. So I got another one, and it didn't want to work either, even though I had good vacuum on it when the engine was warmed up and the rpms where up.

What I discovered is Ford used a little metal diaphram in the middle of the egr that uses backpressure from the exhaust to vary the amount of vacuum going to the egr diaphram. I had reduced the backpressure so much, the mechansim in the egr valve was bleeding all the vacuum away. You can confirm if you have this type of egr by looking underneath it after you unbolt it from the engine. It has a foam ring under it where the air gets filtered when the vacuum is redirected around the egr diaphram.

I ended up going to a cooler thermostat and cooler range plugs to cure the problem, along with the bigger main jets. I am eventually going to get a 4bbl manifold and holley 600 to get rid of most of my emissions stuff.

The factory tune on these engines seem to have a very delicate balance, that is easily messed up.

 

You guys need to move to western Kentucky, we have no emission laws here and we would love to have more Ford fans around.

This is where you can make the Fords chew up the asphalt.