Y pipe/ cat question

vetterdog · Mar 13, 2018

My 99 3.0 has had its y-pipe swapped out for and earlier one without the cats on it, but now that y pipe is rusting out, so it's time to replace it. Beside the obvious issue of price, ($80 vs $400) what difference in performance, gas mileage etc., would going back to four cats (vs two, which is what I have now) make, and what are your opinions about which way to jump. I also have a NJ state inspection coming up. All they check is emissions/codes via the OBD scan. Thanks to all!
-Dave

cbxer55 · Mar 13, 2018

And since the truck is a 99, you're allowed a certain amount of Monitors to be Incomplete? So technically you might be able to continue not using the cats? In Oklahoma, we have the advantage of no inspections. A lot of guys here with Lightning's eliminate the EGR and the cats. That's an upcoming mod for mine. Also planning on getting rid of both on my Ranger as well.

adsm08 · Mar 13, 2018

cbxer55 said:
And since the truck is a 99, you're allowed a certain amount of Monitors to be Incomplete? So technically you might be able to continue not using the cats? In Oklahoma, we have the advantage of no inspections. A lot of guys here with Lightning's eliminate the EGR and the cats. That's an upcoming mod for mine. Also planning on getting rid of both on my Ranger as well.

Thank you much for admitting to the planned commission of a federal felony. Several federal felonies at that. :icon_thumby:

vetterdog · Mar 14, 2018

The state of NJ doesn't make any allowances for vehicles made after 1995, inspection-wise. I guess what I'm trying to figure out, is what the original configuration should be, since this exhaust system isn't stock as it is right now, and what my best options are going forward. I just want the truck to pass the inspection, run properly (it runs fine as is) and to avoid federal offenses! Since there are two cats on it now, inline behind the y-pipe, is it necessary/required to have two more? And how will the addition of two more cats affect how the truck runs, gas mileage etc., if at all? Thanks again for any and all input.

adsm08 · Mar 14, 2018

It looks like there were two configurations for the rear cat. A single bed, and a dual bed.

I suspect, that the addition of the two stock front cats will not affect anything significantly, if at all. In a properly tuned exhaust a cat will not affect flow. The reason is that the cat's casing is much larger than the rest of the pipe. This allows for the cat to have the same flow area as the rest of the pipes even with the matrix in place.

They caused issues in the 70s and early 80s because the exhaust sizes weren't tuned properly, and because carbs don't adjust the same way EFI does, and so it would roast them with raw fuel. Unfortunately some people have not gotten their heads out of the 70s and still think that cats cause flow restrictions when they are not falling apart.

cbxer55 · Mar 14, 2018

If cats don't cause any restrictions, why are vehicles louder without them? I mean, my Ranger has no muffler at all. There is a Y welded directly to the cat, and two pipes sticking out in front of the right rear tire. The cats are the only muffler, and it is not unnecessarily loud.

Every Lightning I've heard with the cats removed, from even the stock exhaust, is WAY louder than it is with them. If there existence is enough to make the vehicle quieter, they're adding resistance.

And the things I'd like to do, versus the things that get done, is quite large. In order to remove cats and egr valve and keep the check engine light off, one needs a proper handheld tuner for each vehicle, to turn off the items in the tune. I don't have one for either vehicle. May never. My Lightning runs mighty fine as it is. The only reason anyone removes the egr valve on Lightning's is it makes plug changes easier. It's in the way of two plugs and a PITA to get around.

adsm08 · Mar 14, 2018

cbxer55 said:
If cats don't cause any restrictions, why are vehicles louder without them? I mean, my Ranger has no muffler at all. There is a Y welded directly to the cat, and two pipes sticking out in front of the right rear tire. The cats are the only muffler, and it is not unnecessarily loud.

Every Lightning I've heard with the cats removed, from even the stock exhaust, is WAY louder than it is with them. If there existence is enough to make the vehicle quieter, they're adding resistance.

And the things I'd like to do, versus the things that get done, is quite large. In order to remove cats and egr valve and keep the check engine light off, one needs a proper handheld tuner for each vehicle, to turn off the items in the tune. I don't have one for either vehicle. May never. My Lightning runs mighty fine as it is. The only reason anyone removes the egr valve on Lightning's is it makes plug changes easier. It's in the way of two plugs and a PITA to get around.

There are more factors to sound than just restriction of flow. A longer tube will not restrict flow, but will change the sound. A thicker pipe wall will dampen noise and vibration and not cause a restriction.

Are you trying to tell me that a glass pack muffler is a restriction to exhaust flow? It makes the exhaust quieter than no muffler at all.

I am also well aware of the clearance issues of the EGR on the 2V triton engines, owning one myself, and having worked on multiple dozens of them over the years, including a number of Lightnings. Frankly I find the placement of the fuel pressure regulator, directly above #7 far more inconvenient.

cbxer55 · Mar 14, 2018

Yeah, and a lot of Lightning owners have fixed that fuel pressure regulator issue as well. And also I have a bracket which relocates the ps pump to the fan cowl, getting it out of the way of plugs. Also a heater hose cleanup kit which puts substantially shorter heater hoses on, and gets those out of the way of some plugs.

But, on a Lightning, it's far easier and less time consuming, to just pull the blower. Takes 15 to 20 minutes. Then the plugs are a breeze to change. While the blower is off, clean the ic (they get a lot of oil on them), put it all back together.

Yes, most of us have oil separators on our Lightning's, which eliminates the oil on the ic altogether.

vetterdog · Mar 15, 2018

Ok, I'm going to replace it as it is now, without the two extra cats, saving myself a bunch of loot. Thanks for the info!
-Dave

adsm08 · Mar 15, 2018

vetterdog said:
Ok, I'm going to replace it as it is now, without the two extra cats, saving myself a bunch of loot. Thanks for the info!
-Dave

That should be fine. Especially if NJ inspections are the same as they used to be last time I knew the rules there and there is no check engine light.

vetterdog · Mar 16, 2018

One more question, I have no idea what the actual pipe on there now is, but it looks to be what is on the 93-94 Rangers. I find a part #93102, but it's listed as being for the 4.0, while I have the 3.0. Is this an issue/will it bolt up? Just wanna be sure. Thanks.

vetterdog · Mar 26, 2018

Got the y pipe I ordered and it is NOT compatible with my setup. SO< for reference, a 94 y pipe wont bolt up to a 99 motor. S**t.

Y pipe/ cat question

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