[1slo5.0]

Long tube headers will always make more power across the entire RPM range. I've seen it on dynos and at the track on my own vehicles. They make useable power that you want for street driving. Long tube headers scavage the cylinders better than shorties. Aftermarket shorties aren't worth the price because you usually don't gain anything. If you are going to buy long tube headers don't look for the best price or you will run into steering shaft issues and starter issues. I don't understand the hot floorboard issue that Ryan mentioned since the exhaust pipes run in the same location as the long tube headers if you were running shorty headers. I guess I've never experienced a hot floorboard and I've driven some of my cars for up to 21 hours non stop at a time. I guess it goes back to buying good headers versus cheap headers. I have never seen an engine bay get hotter either. In reality the engine bay should be cooler because long tube headers move exhaust gasses faster than shorty headers. Its the same theory as dual versus single exhaust. A dual exhaust system runs cooler because it moves the gasses quicker than a single exhaust system but the draw back is the dual exhaust system rusts out quicker because it doesn't get as hot. If heat is that big of an issue get ceramic coated headers.

[Onemanzu]

i agree with darrell on the floor board thing, i have not had a problem with mine, but i have ceramic coated, they rub on the floor pan... and they were kinda cheap... about the same price as shorties

[ryans88gt]

The exhaust is cooler, which means the heat went somewhere (i.e. the engine bay/ floor board).

Long tube headers have about 3 times the surface area as shorties, which means they have about 3 -times the heat exchanging area. Ceramic does help a lot.

[Arctic Fox]

Originally Posted by Onemanzu do tell

I'm not good at explaining this stuff, so read these first:

The truth about exhaust backpressure and torque

Exhaust Backpressure

http://www.veryuseful.com/mustang/te...Scavenging.pdf

More can be found with google

[ryans88gt]

Originally Posted by Darrell Long tube headers will always make more power across the entire RPM range. I've seen it on dynos and at the track on my own vehicles. They make useable power that you want for street driving. Long tube headers scavage the cylinders better than shorties. Aftermarket shorties aren't worth the price because you usually don't gain anything. If you are going to buy long tube headers don't look for the best price or you will run into steering shaft issues and starter issues. I don't understand the hot floorboard issue that Ryan mentioned since the exhaust pipes run in the same location as the long tube headers if you were running shorty headers. I guess I've never experienced a hot floorboard and I've driven some of my cars for up to 21 hours non stop at a time. I guess it goes back to buying good headers versus cheap headers. I have never seen an engine bay get hotter either. In reality the engine bay should be cooler because long tube headers move exhaust gasses faster than shorty headers. Its the same theory as dual versus single exhaust. A dual exhaust system runs cooler because it moves the gasses quicker than a single exhaust system but the draw back is the dual exhaust system rusts out quicker because it doesn't get as hot. If heat is that big of an issue get ceramic coated headers.

Well, way up there in the north... don't you leave your heat on year around...lol. I drive my 88 2 hours at 75 mph sometimes during the summer when it is 90 degrees and 100 % humidity. The floor boards get hot enough to cook an egg on. Since the collectors are 3 1/2 inch, they are right up against the floor pan and have a lot more surface area. As far as long tubes being better power wise, for carbed cars I agree. For other cars, it really really depends on the car. On an EFI car, I have seen long tube swaps cause repeated problems due to poor O2 sensor location. The O2 sensor is spaced a certain distance from motor such that the cycle times read between exhaust pulses. Moving the O2 sensor 1 inch from the motor can cause serious problems with driveability (also the sensor doesn't get hot enough sometimes. Also any car with a knock sensor and be seriously impaired by a long tube swap.

[1slo5.0]

Originally Posted by ryans88gt The exhaust is cooler, which means the heat went somewhere (i.e. the engine bay/ floor board). Long tube headers have about 3 times the surface area as shorties, which means they have about 3 -times the heat exchanging area. Ceramic does help a lot.

The reason for it to run cooler is because it is spread out more through a bigger area, like single to dual exhaust. Its not that more heat is escaping thru the pipe walls, the heat is flowing faster thru a larger area and not moving slow like in a single exhaust pipe. Its like moving your hand thru fire. If you move it slow it gets hot. If you move it fast you don't feel a thing. Like myself and others have said, I've never had any heat issues with any of my Mustangs and they've eventually all had long tube headers. I drove my 91 GT non stop to Las vegas which was a 21 hour, 1800 mile one way trip. No hot floor boards.

[1slo5.0]

Originally Posted by ryans88gt Well, way up there in the north... don't you leave your heat on year around...lol. I drive my 88 2 hours at 75 mph sometimes during the summer when it is 90 degrees and 100 % humidity. The floor boards get hot enough to cook an egg on. Since the collectors are 3 1/2 inch, they are right up against the floor pan and have a lot more surface area. As far as long tubes being better power wise, for carbed cars I agree. For other cars, it really really depends on the car. On an EFI car, I have seen long tube swaps cause repeated problems due to poor O2 sensor location. The O2 sensor is spaced a certain distance from motor such that the cycle times read between exhaust pulses. Moving the O2 sensor 1 inch from the motor can cause serious problems with driveability (also the sensor doesn't get hot enough sometimes. Also any car with a knock sensor and be seriously impaired by a long tube swap.

I'm not that far up north! I'm only 120 miles north of Chicago. I have the same weather here that you northern FIBs have.

The 3 1/2 collectors could be an issue since I was referring to 2 1/2 and 3 inch that I've used on most of my street beaters. I did have 3 1/2 inch collectors and exhaust on my black car and never had any issues with hot floor boards on that car but my collectors and exhaust were not tight to the floor. I guess I would try some different headers if I were you because you seriously shouldn't be getting hot floor boards like that.


Exhaust pules do not matter with 02 sensors. They read the gas, not the pulse. If the pulse matter then it would matter if you had the sensor on an individual port or down in the exhaust pipe which it doesn't matter. I've seen them mounted in various locations on various cars. Where you run into problems is on OBD2 and up cars with no cats.

[ryans88gt]

Directly from TMOSS

"A word of caution to those who install long tube headers. In order for the O2 sensors to operate properly, they must be at, and stay at, a minimum temperature. If you place the HEGO O2 sensors farther away from the head than the stock location, you may have the sensor too far away to keep it hot enough to read correctly due to the cooled exhaust gases. This causes the EEC to enrich mixture and may cause plug fowling. Ceramic heat coating the headers will help maintain exhaust gas temperature. The EEC has a timing table used to time the sampling of the O2 sensors to coincide with the arrival of the latest cylinder exhaust pulse from each bank. Moving the HEGO sensor further away (or closer for that matter) may result in an ill-timed sample, which could also cause improper air/fuel mixtures to occur due to the O2 sensor not sampling when the pulse passes the sensor. One way to compensate for the additional time needed due to adding length in the Long tube headers is to change the timing table with an EEC-Tunerâ or TwEECerâ ."

[91cobra5.0]

Originally Posted by ryans88gt Directly from TMOSS "A word of caution to those who install long tube headers. In order for the O2 sensors to operate properly, they must be at, and stay at, a minimum temperature. If you place the HEGO O2 sensors farther away from the head than the stock location, you may have the sensor too far away to keep it hot enough to read correctly due to the cooled exhaust gases. This causes the EEC to enrich mixture and may cause plug fowling. Ceramic heat coating the headers will help maintain exhaust gas temperature. The EEC has a timing table used to time the sampling of the O2 sensors to coincide with the arrival of the latest cylinder exhaust pulse from each bank. Moving the HEGO sensor further away (or closer for that matter) may result in an ill-timed sample, which could also cause improper air/fuel mixtures to occur due to the O2 sensor not sampling when the pulse passes the sensor. One way to compensate for the additional time needed due to adding length in the Long tube headers is to change the timing table with an EEC-Tunerâ or TwEECerâ ."

your saying that o2 sensors gettting a bad reading will cause the car to run crappy? what if my tune is already way out of wack being near 6000 ft and no oxygen in the air?

[1slo5.0]

Originally Posted by ryans88gt Directly from TMOSS "A word of caution to those who install long tube headers. In order for the O2 sensors to operate properly, they must be at, and stay at, a minimum temperature. If you place the HEGO O2 sensors farther away from the head than the stock location, you may have the sensor too far away to keep it hot enough to read correctly due to the cooled exhaust gases. This causes the EEC to enrich mixture and may cause plug fowling. Ceramic heat coating the headers will help maintain exhaust gas temperature. The EEC has a timing table used to time the sampling of the O2 sensors to coincide with the arrival of the latest cylinder exhaust pulse from each bank. Moving the HEGO sensor further away (or closer for that matter) may result in an ill-timed sample, which could also cause improper air/fuel mixtures to occur due to the O2 sensor not sampling when the pulse passes the sensor. One way to compensate for the additional time needed due to adding length in the Long tube headers is to change the timing table with an EEC-Tunerâ or TwEECerâ ."

I don't agree with some of that and have proven otherwise with my own work but like always, its your car you can do what ever you want to it. If you don't want long tube headers, don't buy them. Its that simple. Everything I build always runs efficiently so I'm not going to change anything I do.

[ryans88gt]

Originally Posted by Darrell I don't agree with some of that and have proven otherwise with my own work but like always, its your car you can do what ever you want to it. If you don't want long tube headers, don't buy them. Its that simple. Everything I build always runs efficiently so I'm not going to change anything I do.

I assume TMOSS knows what he is talking about since he has gone to soo much trouble figuring out everything electrical about these cars. How often do you see people tune for driveability under closed loop conditions?
I agree long tubes work well on carb cars and work great for a lot of people on EFI, but I just wanted to share some of the down side of longtubes, since there are some disadvantages (don't forget about starter heat soak). I saw a LS1 camaro loose 45 hp by doing a long tube swap on the dyno...that was funny (timing retard due to knock sensor).

[91cobra5.0]

Originally Posted by ryans88gt I assume TMOSS knows what he is talking about since he has gone to soo much trouble figuring out everything electrical about these cars. How often do you see people tune for driveability under closed loop conditions? I agree long tubes work well on carb cars and work great for a lot of people on EFI, but I just wanted to share some of the down side of longtubes, since there are some disadvantages (don't forget about starter heat soak). I saw a LS1 camaro loose 45 hp by doing a long tube swap on the dyno...that was funny (timing retard due to knock sensor).

since he got a timing retard due to the sensor couldnt he just advance the timing more to make up for what the comp changed?

or just get some simulators?

[1slo5.0]

Originally Posted by ryans88gt I assume TMOSS knows what he is talking about since he has gone to soo much trouble figuring out everything electrical about these cars. How often do you see people tune for driveability under closed loop conditions? I agree long tubes work well on carb cars and work great for a lot of people on EFI, but I just wanted to share some of the down side of longtubes, since there are some disadvantages (don't forget about starter heat soak). I saw a LS1 camaro loose 45 hp by doing a long tube swap on the dyno...that was funny (timing retard due to knock sensor).

Like I said, I don't agree with all of it. I'm not going to get into a pissing match about who knows what they are talking about or who is better. I'm confident in my abilities and I've never experienced any of the issues he refers to in the 15 or so years I've been building these cars.

As far as heat soak goes, that goes back to quality versus cheap.

[1slo5.0]

Originally Posted by 91cobra5.0 since he got a timing retard due to the sensor couldnt he just advance the timing more to make up for what the comp changed? or just get some simulators?

No, it doesn't work that way. The computer will keep pulling timing until the knock is gone no matter where your initial timing is set.