I have a 99 PS (2/99) with 125K on it. I'm running a 60HP chip and original airbox. I want to go with the 4" exhaust but have some questions. Does anyone have comments on how difficult it will be to remove to stock downpipe? Does anyone know if it is a 3.5"?

 

On your truck, I'm not sure if your stock downpipe is a 3.5" or only a 3". On my older style truck, it was a flattened 3", but didn't flow like one. Removing the old downpipe is the hardest part of the job. It took some 6" blades on the Sawzall, and since the downpipe is stainless, it'll probably take more than one.

 

I was worried about rusted bolts. Is that what the sawzall is for or do I need to cut the pipe off? I've read here that I may be able to connect the 4" exhaust to a 3.5" downpipe. That sounds like a better option.

 

I haven't spent nearly as much time under the hood of a SuperDuty as I have an older truck like mine. My original downpipe was smashed flat by Ford, trying to get it to clear the firewall. If yours is also flat, replacing it with either a 3.5" or 4" would do you a lot of good. If yours is actually round, it's likely 3", and you'd need the Sawzall to cut through the old one, to get it off.
You disconnect the downpipe from the turbo by loosening the Marmon clamp that connects the two. A 7/16" deep socket will do the trick. I assume you're going to be replacing the entire exhaust system while you're at it, so just cut it up in manageable sized chunks.
I hope this helps.

 

Helps a lot, thanks for the replies.

 

micguyver

Your stock downpipe is a 3" round (non flattened) pipe. The rest of the stock exhaust is 3.5", all stainless.

You could get away with just upgrading the downpipe to a 3.5" piece if you were so inclined, and if you do upgrade the entire system I would recommend sticking with a 3.5" downpipe as you will keep a little better throttle response with a 60 horse tune.

Only two cuts are neccessary to remove the stock exhaust. The first is on the downpipe just in front of the tranny crossmember. The second is behind the muffler far enough back to get the tailpipe out over the axle.

I used a 4" angle grinder with a 1/8" cutting disk. Took about 10 minutes total to get the old exhaust out.

 

Is it necessary to cut the original downpipe or can it be removed in one piece? I have a Banks downpipe coming and prefer not to damage the original pipe if I don't have to.

 

Cookie88, thanks for the advice. This is the first truck I've owned that I have no intentions of getting rid of. I have decided to replace the entire exhaust with the 4" stainless and stick with a 3.5" DP. I have no problem spending the money for something that will last. I am still struggling with the intake though. I live in dusty conditions and have a hard time changing to the "open" type of filter system such as the Tymar. Probably will go with the AIS, assuming that the replacement filter cost will drop over time.

 

Micguyver

Hey good call replacing the entire exhaust. Your kit will come with a 3.5 in dp and a 4 in mandrel bent piping along with a straight pipe muffler. This will make a huge difference in letting your psd breathe. For you air cleaner look to the air raid intake and a K&N filter and do not over look the pre cleaner. It is an extra sleeve that goes over the K&N filter that makes cleaning so easy and keeps the bugs off the filter too. I live in phx Az and believe me you would be hard pressed to find many places dustier then here ( well other then San Angelo Tx). Good Luck!

Fire Rooster

 

I went with AIS due in some consideration of warranty issues. As far as K&N, most people on here curse them, according to everyone they don't seal well. Filter cost may go down on AIS but I doubt it, at least if you get the Donaldson, and not a knock off, filter made for it.

 

Thanks for all the comments. This certainly gives a lot to think about.

 

slc10844

You don't have to cut the stock downpipe, but in order to remove it from the truck un-cut you will have to get out the floor jack and remove the transmission crossmember.

micguyver

Being a performance oriented type of guy I'm not a huge fan of the AIS. It is probably the best filtering intake on the market, but the maximum flow rates suffer as a result. Replacement filters are also around $70 a pop. Whereas the Tymar type setups will support any current of future mods, and only lose a couple of thenths of a point in the filtering ability. Replacement filters run $19-$30 each depending on where you get them.

The only real downside of the Tymar is the warranty issue. As soon as a Ford tech pops the hood the jig is up.

 

cookie88
Warranty is not a problem. I have 125K on it.
Wouldn't the Tymar get dirty faster being wide open in the engine compartment?

 

Not really. The Tymar filter is an 8"x10" round filter, that is an enormous amount of surface area. The AIS filter has a similar (or slightly higher, can't remember now) surface area, but it is stacked.

What I mean is with the big Baldwin filter that comes with the Tymar the entire surface area of the filter is open for the engine to draw through. With the AIS the air must be pulled through layer after layer of material in order to utilize the entire surface area.

Both filters hold a similar volume, but the Tymar breathes easier doing it. Both of the filters are supposedly able to hold enough dirt that they only require annual changes.

 

Where's a good site to view/buy a Tymar?