Flowmaster force II on Lt1 cars
02-24-2018, 09:07 AM
#22
Le Mans Master
...back pressure...is sometimes a very GOOD thing.
None of this should be taken as encouragement to remove your cats. They serve a purpose, and also help to reduce overall noise levels of the car. Good cats also aren't very restrictive at all. There are reasons to remove them, and reasons to keep them. But just understand that removing them won't reduce low-end power (or power at any other rpm range, either).
02-24-2018, 09:19 AM
#23
Against my better judgment, I'm going to point out that the above statements are not true. Back pressure is never, ever, a good thing for power/torque/BMEP/whatever, at any rpm or throttle opening. Especially once you're past the collector area, the best exhaust (for power/torque) is a non-existent one. That's not practical on most street cars, so you want the least restriction possible that still gets the sound and noise levels you want. I've hashed this out in a different thread on this site. That was a painful discussion, but it's worth reading if you can sift through all the noise.
None of this should be taken as encouragement to remove your cats. They serve a purpose, and also help to reduce overall noise levels of the car. Good cats also aren't very restrictive at all. There are reasons to remove them, and reasons to keep them. But just understand that removing them won't reduce low-end power (or power at any other rpm range, either).
None of this should be taken as encouragement to remove your cats. They serve a purpose, and also help to reduce overall noise levels of the car. Good cats also aren't very restrictive at all. There are reasons to remove them, and reasons to keep them. But just understand that removing them won't reduce low-end power (or power at any other rpm range, either).
That's what my education and experience has taught me.....I once lost my welds after the front y-pipe on my car and had to pull over and drop the rest of the exhaust to eliminate it from dragging the asphalt.
That was a large section of the exhaust of course. So I was running basically open long tube headers/no cats/no mufflers/no rear y pipe....
Sounded like a race car and it was FUN to drive.......
I did not dyno before and after and I have posted my rwhp on here several times with a full exhaust. I just needed to get the exhaust back on the car, that was my priority.
But let me tell you; I took a curious stab at my brother's 03 S/C Stang for ***** and grins on the way back to pick up the exhaust I left behind.....Let's just say the results were much better against that Cobra running open headers vs. full exhaust....a little better than the but o meter, but I can tell you for a fact it was REAL HAPPY with an open exhaust!!
Back pressure does nothing for my car except eliminate some SBC noise.......
Last edited by 856SPEED; 02-24-2018 at 09:20 AM.
02-24-2018, 09:27 AM
#24
Burning Brakes
Thread Starter
Against my better judgment, I'm going to point out that the above statements are not true. Back pressure is never, ever, a good thing for power/torque/BMEP/whatever, at any rpm or throttle opening. Especially once you're past the collector area, the best exhaust (for power/torque) is a non-existent one. That's not practical on most street cars, so you want the least restriction possible that still gets the sound and noise levels you want. I've hashed this out in a different thread on this site. That was a painful discussion, but it's worth reading if you can sift through all the noise.
None of this should be taken as encouragement to remove your cats. They serve a purpose, and also help to reduce overall noise levels of the car. Good cats also aren't very restrictive at all. There are reasons to remove them, and reasons to keep them. But just understand that removing them won't reduce low-end power (or power at any other rpm range, either).
None of this should be taken as encouragement to remove your cats. They serve a purpose, and also help to reduce overall noise levels of the car. Good cats also aren't very restrictive at all. There are reasons to remove them, and reasons to keep them. But just understand that removing them won't reduce low-end power (or power at any other rpm range, either).
02-24-2018, 09:49 AM
#25
Le Mans Master
I thought it was relevant to your topic, since you brought up removing the cats vs not removing them, in the context of losing low-end power if you remove them. So actually, you brought it up. The pain in that other thread wasn't caused by people like me bringing actual tech to a tech discussion. The painful part was when someone kept insisting that I was wrong, yet he kept repeating evidence that either didn't support or that directly contradicted his claims. I kept trying to point him in the direction of research and evidence so that he would learn what we were talking about, and he continually refused. The end result is a thread that has lots of useful info (from several people), but with a really poor signal-to-noise ratio. You have to sift through a lot of crap to find the useful stuff. That's unfortunate.
Anyway, you are free to ignore my replies here, of course.
02-24-2018, 11:01 AM
#26
Burning Brakes
Thread Starter
Well, I did disclaimer my reply by pointing out that it was against my better judgment.
I thought it was relevant to your topic, since you brought up removing the cats vs not removing them, in the context of losing low-end power if you remove them. So actually, you brought it up. The pain in that other thread wasn't caused by people like me bringing actual tech to a tech discussion. The painful part was when someone kept insisting that I was wrong, yet he kept repeating evidence that either didn't support or that directly contradicted his claims. I kept trying to point him in the direction of research and evidence so that he would learn what we were talking about, and he continually refused. The end result is a thread that has lots of useful info (from several people), but with a really poor signal-to-noise ratio. You have to sift through a lot of crap to find the useful stuff. That's unfortunate.
Anyway, you are free to ignore my replies here, of course.
I thought it was relevant to your topic, since you brought up removing the cats vs not removing them, in the context of losing low-end power if you remove them. So actually, you brought it up. The pain in that other thread wasn't caused by people like me bringing actual tech to a tech discussion. The painful part was when someone kept insisting that I was wrong, yet he kept repeating evidence that either didn't support or that directly contradicted his claims. I kept trying to point him in the direction of research and evidence so that he would learn what we were talking about, and he continually refused. The end result is a thread that has lots of useful info (from several people), but with a really poor signal-to-noise ratio. You have to sift through a lot of crap to find the useful stuff. That's unfortunate.
Anyway, you are free to ignore my replies here, of course.
Perhaps we could get back on track of this particular thread and not revisit painful threads.
Or pehaps we could just start a debate about oil viscosity.
Last edited by barchetta1; 02-24-2018 at 11:02 AM.
02-24-2018, 02:37 PM
#27
Drifting
I like the system and the solid feedback in this thread. But dang a brand new one is 1k!
02-24-2018, 04:49 PM
#28
Burning Brakes
Thread Starter
I ended up saying screw it.. went with NXT Step. Leaving all alone but the mufflers.. I just wanted a little increased volume. I didnt want to pay 8% of the value of my car for an exhaust.
Doing a full write up including before and after.
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