backpressure question on exhaust
 

ok so i just installed my new exhaust system. sounds great and i love it, i can deff tell a difference with it too. but now that its done and i have the time to think about it, how can i check to see if its ok and gettin enough back pressure or not? im runnin the setup below in the image, its obx racing longtubes with resinators and mids. also with a flowmaster 50series muffler. the flow is amazing thru the system, but i was wonderin if its gettin backpressure since im running no cats in the system at all. any ideas?

https://www.f150online.com/galleries...767&anum=15315

If you're running a 50 series Flowmaster, you are getting more backpressure than most of the rest of us with aftermarket exhausts. Don't worry about it.

anyone else with imput?

There is no advantage to "back pressure" in the exhaust system.

The general objective in an internal combustion engine is to get as much fresh air/fuel mixture into the combustion chamber as quickly as possible - compress it - ignite it and utilize it's energy to perform work on the piston - and exhaust the spent combustion chamber gases as quickly and thouroughly as possible. Back pressure (and you can't totally eliminate it all at all times) just means you're not getting spent exhaust gases out. The more exhaust gases you're leaving in the combustion chamber, the more you dilute the incoming air/fuel mixture and results in somewhat less, to a great deal less power output produced. It also can elevate the temp of the incoming air/fuel mix which can result in other problems in the combustion chamber. However, it can also help reduce harmful emissions.

im just worried bout burnin up the valves or something to that effect, i kno sometimes they can no seat or start to burn up with low to no backpressure (or so ive heard from others with that happening to them) so i wanted to take the precaution of being careful with it lol. i dont wanna be buyin new internals or engines yet!

your going to want a little back pressure but with your system your fine. MANY people have LT's with no cats and a cat back

thats what i figured, thanks for the info, feels much better to get into the throttle when goin places :thumbsup:

I'm not an engineer but the guy said you never want back-pressure in the exhaust is way off unless there are special circumstances AA Fueler etc.

If I were you I'd get more opinions on the subject

Exhaust Operation and the Back Pressure Myth

I didn't write this, but it'll answer your questions.

If the volume of the pipe is too large the pressure drop behind each pulse will not be as likely to help in the scavenging effect of the next cylinder. The same principle goes if the pipe is too short. The short pipe does not allow enough time for proper scavenging and leaves the system before it can occur. *** Scavenging is the correct consideration not back-pressure - good article

Your tuner should how much back pressure
 

I Would think you would have to have some if its a Lightning:usa: