My experience with open Long tube headers on an ls1
#1
TECH Fanatic
Thread Starter
iTrader: (27)
Join Date: Apr 2008
Location: Dayton, NV
Posts: 1,203
Likes: 0
Received 0 Likes
on
0 Posts
My experience with open Long tube headers on an ls1
The reason im making this thread is because lately i have seen some threads popping up on how the car would run with open LT headers.. so i thought i would share
So lately i have decided to modify my 98 trans am. Its an automatic with 2.73 gears, nothing special with descent pick up from the factory...
Anyway, im on a budget so ive decided to keep it simple. LT headers, Catted Y, stock catback with cutout, and a 3400 stall converter with 3.73 in the future. I have personally never done this before so i wanted to experiment a bit
So far i have Volant intake, ptb, and open cutout. Good start.
This sunday, my long tube headers have arrived and me and a couple of friends decided to install them, but since welding was required to install my cats, and Y pipe to the catback, i have decided to keep open headers with no O2 sensors (reason for no front O2's is because i have to order my extentions)... So I ended up driving my car back with just open headers home for about 25 miles
And let me tell this, for the ones who want to run their car with just open headers... dont! For the following reasons:
First: its terribly loud even on an ls1 with stock camshaft even at idle, loud enough to set off some car alarms. Under WOT, its waaaaaay louder. Example: As i was driving on the interstate, i see a rider on the Harley with loud pipes, as i goosed my car a little next to him he literally flinched... yes im a douchebag for doing this
When i was driving on the highway, the drone was pretty intense... enough to make coins in my cupholder jingle lol.
Second: Your car will not feel faster... but rather noticeably slower. Its all noise and no go, which makes sense since there is absolutely no backpressure
Third: If you drive past a cop, you will get pulled over and since i was driving late at night, i have not encountered any, thank god.
In conclusion, my car idles fine, but just unuseable on the street with no performance gains.
Later this week i will complete my exhaust set up as well as a stall following by a nice dyno tune, once i get my funds together.
Well, that was just my opinion, if you still wanna do it, noone is stopping you.
So lately i have decided to modify my 98 trans am. Its an automatic with 2.73 gears, nothing special with descent pick up from the factory...
Anyway, im on a budget so ive decided to keep it simple. LT headers, Catted Y, stock catback with cutout, and a 3400 stall converter with 3.73 in the future. I have personally never done this before so i wanted to experiment a bit
So far i have Volant intake, ptb, and open cutout. Good start.
This sunday, my long tube headers have arrived and me and a couple of friends decided to install them, but since welding was required to install my cats, and Y pipe to the catback, i have decided to keep open headers with no O2 sensors (reason for no front O2's is because i have to order my extentions)... So I ended up driving my car back with just open headers home for about 25 miles
And let me tell this, for the ones who want to run their car with just open headers... dont! For the following reasons:
First: its terribly loud even on an ls1 with stock camshaft even at idle, loud enough to set off some car alarms. Under WOT, its waaaaaay louder. Example: As i was driving on the interstate, i see a rider on the Harley with loud pipes, as i goosed my car a little next to him he literally flinched... yes im a douchebag for doing this
When i was driving on the highway, the drone was pretty intense... enough to make coins in my cupholder jingle lol.
Second: Your car will not feel faster... but rather noticeably slower. Its all noise and no go, which makes sense since there is absolutely no backpressure
Third: If you drive past a cop, you will get pulled over and since i was driving late at night, i have not encountered any, thank god.
In conclusion, my car idles fine, but just unuseable on the street with no performance gains.
Later this week i will complete my exhaust set up as well as a stall following by a nice dyno tune, once i get my funds together.
Well, that was just my opinion, if you still wanna do it, noone is stopping you.
#2
http://www.hondacivicforum.com/forum...ts-wrong-3064/
http://my.prostreetonline.com/forums...php?t-1639.htm
http://mechdb.com/index.php/Exhaust_back_pressure_myth
http://www.dsmtuners.com/forums/freq...kpressure.html
http://www.rx8club.com/showthread.php?t=28945
http://www.fullsizechevy.com/forum/g...sure-myth.html
http://my350z.com/forum/intake-exhau...k-for-n-a.html (the long post about half way down the page)
http://www.miata.net/garage/KnowYourCar/S4_Back.html
Last edited by nissan 570sx; 05-23-2011 at 08:26 AM.
#4
http://picardfacepalm.com/picard-facepalm.jpg
http://www.hondacivicforum.com/forum...ts-wrong-3064/
http://my.prostreetonline.com/forums...php?t-1639.htm
http://mechdb.com/index.php/Exhaust_back_pressure_myth
http://www.dsmtuners.com/forums/freq...kpressure.html
http://www.rx8club.com/showthread.php?t=28945
http://www.fullsizechevy.com/forum/g...sure-myth.html
http://my350z.com/forum/intake-exhau...k-for-n-a.html (the long post about half way down the page)
http://www.miata.net/garage/KnowYourCar/S4_Back.html
http://www.hondacivicforum.com/forum...ts-wrong-3064/
http://my.prostreetonline.com/forums...php?t-1639.htm
http://mechdb.com/index.php/Exhaust_back_pressure_myth
http://www.dsmtuners.com/forums/freq...kpressure.html
http://www.rx8club.com/showthread.php?t=28945
http://www.fullsizechevy.com/forum/g...sure-myth.html
http://my350z.com/forum/intake-exhau...k-for-n-a.html (the long post about half way down the page)
http://www.miata.net/garage/KnowYourCar/S4_Back.html
#5
TECH Fanatic
iTrader: (6)
http://picardfacepalm.com/picard-facepalm.jpg
http://www.hondacivicforum.com/forum...ts-wrong-3064/
http://my.prostreetonline.com/forums...php?t-1639.htm
http://mechdb.com/index.php/Exhaust_back_pressure_myth
http://www.dsmtuners.com/forums/freq...kpressure.html
http://www.rx8club.com/showthread.php?t=28945
http://www.fullsizechevy.com/forum/g...sure-myth.html
http://my350z.com/forum/intake-exhau...k-for-n-a.html (the long post about half way down the page)
http://www.miata.net/garage/KnowYourCar/S4_Back.html
http://www.hondacivicforum.com/forum...ts-wrong-3064/
http://my.prostreetonline.com/forums...php?t-1639.htm
http://mechdb.com/index.php/Exhaust_back_pressure_myth
http://www.dsmtuners.com/forums/freq...kpressure.html
http://www.rx8club.com/showthread.php?t=28945
http://www.fullsizechevy.com/forum/g...sure-myth.html
http://my350z.com/forum/intake-exhau...k-for-n-a.html (the long post about half way down the page)
http://www.miata.net/garage/KnowYourCar/S4_Back.html
#6
LS1Tech Administrator
iTrader: (3)
Join Date: Nov 2001
Location: Schiller Park, IL Member: #317
Posts: 32,362
Likes: 0
Received 1,794 Likes
on
1,278 Posts
Where is it that some people have gotten this crazy idea that backpressure makes power?
If you are down on power it's because you don't have front O2s yet, or any sort of tuning for the headers.
Trending Topics
#10
11 Second Club
iTrader: (18)
It's more noise throwing off perception than anything.
I can open my cutouts and swear the car is running like crap, but up until a week ago when I removed the tail pipes over the axle (made the car extremely quiet) it would pick up a tenth and a half and over 1 mph at the track.
But yeah anyone running open headers on a street car is a moron. And anyone running nothing but pipe with no muffler or resonator has no tastes and must just like being loud for no reason.
I can open my cutouts and swear the car is running like crap, but up until a week ago when I removed the tail pipes over the axle (made the car extremely quiet) it would pick up a tenth and a half and over 1 mph at the track.
But yeah anyone running open headers on a street car is a moron. And anyone running nothing but pipe with no muffler or resonator has no tastes and must just like being loud for no reason.
#11
TECH Fanatic
iTrader: (6)
sooo, whats the perfect combo?
Lt's, ory, catback?
Lt's, highflow cat, catback?
or some other combo?
Sorry, but i get way too many conflicting stories
https://ls1tech.com/forums/drag-raci...ss-pics-9.html
this guy uses open headers for the track, & a sweet setup an runs low 11's
Lt's, ory, catback?
Lt's, highflow cat, catback?
or some other combo?
Sorry, but i get way too many conflicting stories
https://ls1tech.com/forums/drag-raci...ss-pics-9.html
this guy uses open headers for the track, & a sweet setup an runs low 11's
#13
12 Second Club
iTrader: (49)
back pressure means your engine has to work harder to expel the exhaust gasses, thus making your car FEEL faster because it is working harder. ever wonder why your exhaust sounds mildly different under a large load than free revving at idle?
when i installed headers, and ran them open up and down the road a few times just for ***** and grins...i noticed i had lost low end TQ, but gained a bunch of power up top. that is just the characteristics of the exhaust being moved faster due to no back pressure, your engine can breathe more at higher RPM's.
#18
Front O2's control the fuel ratios so if you didn't have those in that would be the main reason it ran like crap. People unplug the back ones because those just control the CEL light to make sure the cats are working, but you HAVE to have the front ones hooked up for it to run decent
#19
bingo...
back pressure means your engine has to work harder to expel the exhaust gasses, thus making your car FEEL faster because it is working harder. ever wonder why your exhaust sounds mildly different under a large load than free revving at idle?
when i installed headers, and ran them open up and down the road a few times just for ***** and grins...i noticed i had lost low end TQ, but gained a bunch of power up top. that is just the characteristics of the exhaust being moved faster due to no back pressure, your engine can breathe more at higher RPM's.
back pressure means your engine has to work harder to expel the exhaust gasses, thus making your car FEEL faster because it is working harder. ever wonder why your exhaust sounds mildly different under a large load than free revving at idle?
when i installed headers, and ran them open up and down the road a few times just for ***** and grins...i noticed i had lost low end TQ, but gained a bunch of power up top. that is just the characteristics of the exhaust being moved faster due to no back pressure, your engine can breathe more at higher RPM's.
If you really wanted to see evidence, bolt a plate on a set of header collectors with a 1.5" or so hole in it. You'll get a ton of back pressure from doing that but your exhaust velocity and flow are going to be killed and you're going to lose a bunch of horsepower.
back pressure = bad
#20
LS1Tech Administrator
iTrader: (3)
Join Date: Nov 2001
Location: Schiller Park, IL Member: #317
Posts: 32,362
Likes: 0
Received 1,794 Likes
on
1,278 Posts