Gutted Catalytic Converter?

[jdowens1]

I didn't do as much research as I would like on the cutouts but I remember many people said it would decrease performance. I do not remember why. Sorry to be so vague but that's all I got... ******* finals week this week sorry.

Older engines ran better with no back pressure and the less the better. Newer engines actually like having small ammount of back pressure so you might lose a little performance with cutout since your reducing backpressure. Years ago 1 psi back pressure was bad. With newer engines its normal to see 2-3psi at idle up to 8max psi at2500RPM. Someone else might have slightly different numbers since I'm going off Ford only.

 

[BigJ]

People say lots of thing that aint true

I think in this case, they're partially right. Like ISF and jd says, in theory cutouts will hurt low end torque, but help in high end horsepower when installed downstream of the cats.

I really love the sound of open pipes. I ran cutouts on my Mopar and it shook houses like an earthquake. No joke. But when it comes to the Raptor, for me its not worth giving up the low end torque, since thats the powerband mine lives in most of the time. Again, its the eye of the beholder thing again...

 

[ISFast]

I didn't do as much research as I would like on the cutouts but I remember many people said it would decrease performance. I do not remember why. Sorry to be so vague but that's all I got... ******* finals week this week sorry.

So glad I've been final free for a few years! The science finals were straight hell!

 

[Humvee21]

So glad I've been final free for a few years! The science finals were straight hell!

Dude, tell me about it!!! I'm taking Geology tomorrow. I thought this class was going to be a BREEZE. Evidently, NOT! For one of our exams we had to memorize the compounds, names, mineral type, texture, etc. of over 40 rocks. WTF!!!!!

I'm only taking this class to fulfill my 64 hour requirement....

 

[ISFast]

People say lots of thing that aint true

I think in this case, they're partially right. Like ISF and jd says, in theory cutouts will hurt low end torque, but help in high end horsepower when installed downstream of the cats.

I really love the sound of open pipes. I ran cutouts on my Mopar and it shook houses like an earthquake. No joke. But when it comes to the Raptor, for me its not worth giving up the low end torque, since thats the powerband mine lives in most of the time. Again, its the eye of the beholder thing again...

What I like about the cutouts on the raptor is a lot of the exhaust still goes through the muffler. This afternoon before going to work the exhaust was coming out the tail pipes while warming up meaning a fair amount goes both ways. Its pretty "quiet" while under no load or low rpm but when you get on it get ready to hold your ears!

But like J said depend on how you run your truck... I like to keep a fair amount of rpms in mine when playing but the 2010's only have the first 3 gears to lock out not like the select shift on the 2011 and newer. I've done both open and closed down the road and couldn't tell a drop of difference in MPG which to me meant nothing was really affected in the HP or TQ. I think there is enough back pressure by the time it gets to my cutout that it doesn't really matter other than sound. Exhaust manifolds, cats, y-pipe then the cutout. Maybe one of these days I'll dyno it open and close so people really know what it does on a raptor. My guess which is only a guess you may see a couple HP or TQ increase or decrease if that. But it sure sounds like its increasing 100 hp

---------- Post added at 11:33 PM ---------- Previous post was at 11:25 PM ----------

Dude, tell me about it!!! I'm taking Geology tomorrow. I thought this class was going to be a BREEZE. Evidently, NOT! For one of our exams we had to memorize the compounds, names, mineral type, texture, etc. of over 40 rocks. WTF!!!!!

I'm only taking this class to fulfill my 64 hour requirement....

40 rocks that's all I would have loved to have a test like that but I kinda like rocks... yeah i'm a nerd! Try like an anatomy class that they make you memorize everything but only ask a few questions on it. All the time to learn it in and out and then only get asked a fraction of what you had to learn. The biochem classes weren't that fun either but the hardest class i had was with 2 teachers in the same class one taught Tuesday the other taught Thursday each was 3 or 4 hrs a day. Then test time they would both give you a test of theirs on the same day over their stuff. NOT FUN!!! It was molecular biology. It was indepth conversations and over Scientific papers. You would go over a paper everyday usually over 10 pages of science BS then tell how they got the results they got and why,how, and whats it mean. Stupidly nuts

 

[SoSmoked]

As a general rule, a muffler swap alone will not, no. Maaayybe a few ponies at max RPM one way or another? But nothing that's not within the margin of error of the dyno anyway.

The setup I did made an incredible difference in engine performance. Gas mileage increase, better high end torque, low end is a sound distinguishable from 4 blocks away

Don't be fools

Just spend the dough and find the correct muffler guy to do what you want.

Took me probably 5-6 pipes before I found the sound I wanted. Also, out of magnaflow/flowmaster/spintech

The spintech was the ONLY one which I truely felt an engine performance change on.

Magnaflow was droney
Flowmaster needs to change their name to slow master due to the stupid loss in low end torque with their muffs
However spintech was the one true pipe(tried the pro street series single and loved it so much I went duel) which I actually felt that exhaust brake feeling going downhills and vice versa, smooth sound advancing uphill and zero drone with these bad boys. Its either straight throat or a slight rumble until you open her up

 

[BigJ]

Don't be fools? Ok... show me the dyno charts before and after. I appreciate your highly calibrated seat of the pants dyno tells ya its better, but I'm a numbers guy. Lets see the numbers, and end the debate.

 

[DynoDynge]

Being a self employed dyno operator, I can honestly tell you that gutting your exhaust or cutting your pipe off to reduce back pressure will do two things...... KILL the bottom end & annoy neighbors.
HP is simply a function of RPM X torque. Turning more RPM will raise your HP, but does not make you faster. Torque is the feeling of getting pushed back in your seat & generally speaking, open headers "feel" faster as a function of the lack of bottom end transitioning to upper RPM power band. If your motor is not mechanically timed to run the upper rpm range, then opening up the exhaust for better flow is a waste of time & effort.
If you are willing to spend the money & time, a good dyno shop can tune the exhaust to your particular motor. If not, just get the sound you like & drive it.

 

[Humvee21]

Flowmaster needs to change their name to slow master due to the stupid loss in low end torque with their muffs
However spintech was the one true pipe(tried the pro street series single and loved it so much I went duel) which I actually felt that exhaust brake feeling going downhills and vice versa, smooth sound advancing uphill and zero drone with these bad boys. Its either straight throat or a slight rumble until you open her up

Haha, you guys crack me up.

 

[BigJ]

Being a self employed dyno operator, I can honestly tell you that gutting your exhaust or cutting your pipe off to reduce back pressure will do two things...... KILL the bottom end & annoy neighbors.
HP is simply a function of RPM X torque. Turning more RPM will raise your HP, but does not make you faster. Torque is the feeling of getting pushed back in your seat & generally speaking, open headers "feel" faster as a function of the lack of bottom end transitioning to upper RPM power band. If your motor is not mechanically timed to run the upper rpm range, then opening up the exhaust for better flow is a waste of time & effort.
If you are willing to spend the money & time, a good dyno shop can tune the exhaust to your particular motor. If not, just get the sound you like & drive it.

What do you know? You're DynoJet guy.

Nah I kid. Actually I think you nailed it.

I'm no pro, but I've overseen well over 1000 pulls, 400 of which were on my car alone, and my experience agrees totally with what you said. I've seen that look of disappointment over and over again as the numbers roll in and the curves are revealed, and neither match what the butt dyno promised.