High flo cats vs. no cats difference
High flo cats vs. no cats difference how much of a difference will there be between high flo cats vs. no cats when it comes to performance and sound. i'm thinking about sounding my ecu chip in for a tune but i'm not sure if i wanna have cats put on or not with my new headers.
If you don't use the cats, it will be really fu*king loud! With a decent amount of rasp. I like that sound myself but other don't. Performance wise.....look at it this way...if you got LT headers and no cats and a straight through muffler, then you got pretty much NO BACKPRESSURE. And you actually have to have a certain amount of backpressure to operate normally. You may loose some torque on the bottom.
search metal cats,cost you about 5hp,they are the best.oh yea before i forget,if somebody tells you you need backpresure,stick him right in the jaw hard as u can,cause he is giving you misinformation!!!!
Originally Posted by chadnol10
I'm gonna let the muffler shop use his supposed high flo cats i'm told for the most part they are all the same. does that sound ok?
they are not all the same you get what you pay for!!
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Originally Posted by caviness
search metal cats,cost you about 5hp,they are the best.oh yea before i forget,if somebody tells you you need backpresure,stick him right in the jaw hard as u can,cause he is giving you misinformation!!!!
Last edited by Ragtop 99; Feb 21, 2007 at 11:26 AM. Reason: flame bait
Originally Posted by Torque_Wrench
Hey I hate to burst your bubble....but you ain't "stick" ing me right in the jaw. I do this for a living! You have to have a certain amount of backpressure to run at optimal performance levels. No backprerssure = loss of low end torque. Trust me on this because I've been to classes from general Motors since 1998 and I've taken the calsses and listened to the instructors for GM tell me that you HAVE to have a certain amount to preform correctly. So do you suppose the General Motors and all their vast knowledge just made that up?
It's not back pressure it's well I'll give you a hint the letter V and speed.
I see General Motors classes are about as worthwhile as investing in their stock lmfao.
Last edited by Ragtop 99; Feb 21, 2007 at 11:26 AM. Reason: flame bait quote edited
Originally Posted by Ace$nyper
You never said you passed those classes.
It's not back pressure it's well I'll give you a hint the letter V and speed.
I see General Motors classes are about as worthwhile as investing in their stock lmfao.
It's not back pressure it's well I'll give you a hint the letter V and speed.
I see General Motors classes are about as worthwhile as investing in their stock lmfao.
If so, then you're as useless as the other guy.
Originally Posted by Torque_Wrench
Hey I hate to burst your bubble....but you ain't "stick" ing me right in the jaw. I do this for a living! You have to have a certain amount of backpressure to run at optimal performance levels. No backprerssure = loss of low end torque. Trust me on this because I've been to classes from general Motors since 1998 and I've taken the calsses and listened to the instructors for GM tell me that you HAVE to have a certain amount to preform correctly. So do you suppose the General Motors and all their vast knowledge just made that up?
I don't think GM is wrong, I think you misheard or misunderstood. Backpressure doesn't increase low end torque. Exhaust gas velocity and pulse timing do. The problem is that it is tough to build an emission compliant system with no backpressure. GM engineers tune the car around that fact. If the backpressure is removed as part of the exhaust work and then one changes the tuning. Without changing the tune, performance can be negatively impacted in some cases.
Loss of low end torque on some header systems is due to loss of exhaust gas velocity, not failure to acheive back pressure. In fact many headers for these car show gains in the low end.
Last edited by Ragtop 99; Feb 21, 2007 at 11:31 AM.
Originally Posted by Torque_Wrench
So in all your wiseness, you think that no backpressure will not hurt your low end torque?
If so, then you're as useless as the other guy.
If so, then you're as useless as the other guy.
I happen to have a top of the line header maker in my phone, he's a dear friend. Possibly have picked a trick or 2 up from him.
It won't if you propperly setup your exhaust back pressure is always bad, no if ands or buts.
Where this rumor that if you arn't lying GM foolishly pushed to you, started is many exhausts when you lose backpressure *thats a good thing* You also lose exhaust volcity and the bigger part of the puzzle scavanging.
Scavanging is why a car with headers will make more power then one thats open blocked. Esp in the whole band instead of just peak and top of the RPM band when the gases move faster due to engine speed.
So what is it, GM offers that poor a level of classes to tech or are you lieing online for crediblity? Either way it's kinda sad.
Originally Posted by Ragtop 99
I don't think GM is wrong, I think you misheard or misunderstood. When you say you do this for a living, do you mean design exhaust systems?
Backpressure doesn't increase low end torque. Exhaust gas velocity and pulse timing do. The problem is that it is tough to build an emission compliant system with no backpressure. GM engineers tune the car around that fact.
Loss of low end torque on some header systems is due to loss of exhaust gas velocity, not failure to acheive back pressure. In fact many headers for these car show gains in the low end.
Backpressure doesn't increase low end torque. Exhaust gas velocity and pulse timing do. The problem is that it is tough to build an emission compliant system with no backpressure. GM engineers tune the car around that fact.
Loss of low end torque on some header systems is due to loss of exhaust gas velocity, not failure to acheive back pressure. In fact many headers for these car show gains in the low end.
As for what I do for a living is, I am the Service and Parts manager at a GM Dealership. And we do exhaust also.
So keeping that in mind, we put headers (LT's) on a 2001 Camaro and used 3 inch pipe and a Loudmout muffler. The car actually ran worse. We went back and replaced the 3 inch pipe with 2 1/4 and the car ran suprisingly better.
Originally Posted by Ace$nyper
I never said I was loaded with wiseness, just your blatent misunderstanding and chest beating does seem to put me miles ahead of you as far as simple understanding on exhaust theorys.
I happen to have a top of the line header maker in my phone, he's a dear friend. Possibly have picked a trick or 2 up from him.
It won't if you propperly setup your exhaust back pressure is always bad, no if ands or buts.
Where this rumor that if you arn't lying GM foolishly pushed to you, started is many exhausts when you lose backpressure *thats a good thing* You also lose exhaust volcity and the bigger part of the puzzle scavanging.
Scavanging is why a car with headers will make more power then one thats open blocked. Esp in the whole band instead of just peak and top of the RPM band when the gases move faster due to engine speed.
So what is it, GM offers that poor a level of classes to tech or are you lieing online for crediblity? Either way it's kinda sad.
I happen to have a top of the line header maker in my phone, he's a dear friend. Possibly have picked a trick or 2 up from him.
It won't if you propperly setup your exhaust back pressure is always bad, no if ands or buts.
Where this rumor that if you arn't lying GM foolishly pushed to you, started is many exhausts when you lose backpressure *thats a good thing* You also lose exhaust volcity and the bigger part of the puzzle scavanging.
Scavanging is why a car with headers will make more power then one thats open blocked. Esp in the whole band instead of just peak and top of the RPM band when the gases move faster due to engine speed.
So what is it, GM offers that poor a level of classes to tech or are you lieing online for crediblity? Either way it's kinda sad.
The 2.25" pipe might have increased gas velocity on the low end. some headers with 2.5" collectors instead of 3" show better low end gains, but some of it was from lack of tuning.
Originally Posted by Torque_Wrench
Simple friend....I'm not lying for credibility (who would do that?)....the simple mistake is....the class didn't go in depth about the theroy of scavanging or exhaust gas pulsation. The Instructors remark was stated earlier (i won't write it down again)....and I take his word for it.
There by spreading misinformation.
These cars are large motors and move a good deal of air, I'm not quite sure why a simple setup of long tubes and a mostly 3" straigh setup would hurt the car. Unless the ECU was being picking as long as the headers were of a good make and I can't off hand name a poor Long tube for these cars it should have helped the whole band.
2.25 piping would probbly be too small for a motor of this size, stock is 2.7 from what one of the stickies on this site said, and the most "choking" part is the muffler.
Originally Posted by Ragtop 99
The 2.25" pipe might have increased gas velocity on the low end. some headers with 2.5" collectors instead of 3" show better low end gains, but some of it was from lack of tuning.
I also noticed on my own truck.....I put LT headers on it and fabbed my own cat-less Y and wnet into a Dynatech muffler and I also noticed I lost considerably on the low end torque. So days later I got my PCM re-tuned for a catted Y and I re-installed my 2 cats with the same header and muffler set up, and I noticed a definite increase in the low end torque and power.
These examples are what I'm basing my responses from.
I'm not trying to call names or **** in anyone's face, but it seems everytime a person posts some advice stating their personal experiance on here, then some one like "Ace Snyper" or "Caviness" responds by calling you a liar or saying that your "stupid" or your ideas "suck". Why even post on LS1Tech if others are going to go right off and call you a liar? That's what I don't like about guys like that. Why not listen to others experiance and offer your insight into it instead of tryin to make someone look like a dick?
Originally Posted by Torque_Wrench
So keeping that in mind, we put headers (LT's) on a 2001 Camaro and used 3 inch pipe and a Loudmout muffler. The car actually ran worse. We went back and replaced the 3 inch pipe with 2 1/4 and the car ran suprisingly better.
