Headers - Shorties or Long Tube?

[SleeperGT]

Now that my car has been stabalized from the last round of upgrades, car is actually running GREAT, I'm ready to cause trouble again and I think I want the next upgrade to be headers, provided everyone agrees. I currently have 2 1/2 "exhaust (x-pipes) from manifold back with Magna Flow mufflers and dual high flow cats.

With my current setup I'm thinking I should go with Long Tube headers which should give me the most hp gain. If you have had direct experience with this upgrade on a 4.6 GT with a S/C please comment, the good, the bad and the ugly are apreiciated. Also, what have peoples experiences with Shorties been? My other questions are as follows;

1. I've heard long tubes can cause a clearance issue, how far do these things hang down, can you actually see them in the profile of the car hanging beneath the front of the car?

2. What kind of HP gaines can I expect? I'm guessing I'm running about 370 hp at the rear wheels right now. What should I expect to gain?

3. Who makes the "best" set of long tubes, by this I mean quality and performance. I was thinking of going with a set from Ford Racing.

4. Will adding them cause any issue with my current tune, and will I have to get the computer reprogrammed? My biggest concern is causing detonation. Extra hp is great, but if I get detonation or other issues than it's not.

5. What should I expect to pay for a good set?

6. How difficult is the installation?

All input is greatly appreciated!!

[Technick]

At this point, with the level of mods to the car, and considering the hassel of installing headers, get it over with and install the long tubes. If you have a tubular K-member, so much the better. If not, if you can afford it install a tubular K-member at the same time. I have found that the fastest way to install headers on the 4.6, be they long tubes or shorty's is to drop the K-member out of the way. That means having to support the engine from above, but it makes installing the headers a breeze, especially if you have access to air tools and a side post lift. The major up-side is the fact that you should never have to up-grade the exhaust system again despite any future mods you may do outside a full on purpose built drag car. For the effort required the shorty's just do not provide the bang for the buck, 10-20 H.P. tops. I have installed BBK long tubes on both Cobra and GT 4.6 engines and they have great ground clearance and fit rather nicely. Unless you try to install them with the K-member in place then they are a real pain. I have also installed JBA shorty and Ford Motorsport shorty headers on Cobra and GT 4.6 Mustangs and they are everybit as much a pain in the butt as the long tubes.
By far the worst set to install, even with the K-member out was a set of Sean Hyland long tubes, plug the ground clearance was nil. This was 5 years ago and I hear Sean Hyland has changed suppliers since then. They were by far the BEST sounding headers I have ever heard! But it was a lot of pain and suffering just for the sound quality.

[SleeperGT]

Thanks for the advice Technick. What type of hp gaines could I expect from Long Tubes. Would you expect it be in the 10 - 20 range, 20-30 range or 40-50 range. I'd guess 20 to 30?

[Technick]

Not knowing what H.P. level the car has now (any dyno runs yet?) then 25-35 is not out of the question. With a high flow cat X-pipe, you should still be emission legal. The cats on aftermarket X or H pipe will only cost you about 5 H.P. on a 450 rwhp car compared to no cats at all! Above 500 rwhp then the cats are more of a liability. I have seen increases of over 60 h.p. with a well tuned car when changing from shorty headers to long tubes. Any supercharged or Nitrous equiped engine will respond much better than a N/A engine to long tubes. If you are cramming more air in you have got to let it out! Remember the engine is just a air pump, pump it in, pump it out! The more efffecient the pump the more H.P. The engine will only produce power to the level of its largest restriction, be that inlet or outlet.

[SleeperGT]

After the stock Vortech install the car dyno'd at 313 rwhp and 370 rwtrq. Car ran a best of 106 mph at 13.0. I had a custom Diablo chip (not dyno tuned) and Anderson Powerpipe installed and the car ran 111 mph @ 12.6. I didn't have it dyno'd since these latest upgrades so the question is how much hp is 5 mph worth? I'm guessing I am currently running about 360 rwhp or so.

Could long tubes introduce any sort of detonation issue on the car (I just went through a lot of back and forth getting my chip set right for the car....clean up major driveability and detonation issues) and I really don't want to go through that again if adding long tubes could would require a new chip program.

[Technick]

Typically long tubes will require more fuel as the exhaust scanvages much better amd lets the engine breath better. Try putting the 02 sensors as close the exhaust port as possible as the quicker the 02 sensor heats up the better it responds, and more accutate it is. The 02 should be able to tell the ECU to deliver more fuel.

[jmjett01]

Longtubes. Clearance will be a little bit of a problem. You can expect minor exhaust leaks from the driver side as well. Being that you have a centrifugal charger, the longetubes with off-road h pipe would be beneficial. I have used BBK, Hooker, and Cooks longtubes. Hooker tubes is by far better quality, 700+ dollars, and support. Currently I run a 11.41 @124mph. I have the BBK Lontubes (500$+149$) and matching H pipe with Spintech and turn downs. JBA's catforward will run you the same price but the outcome is by far better with longtubes. Dyno tune your car and find out for your self. Tune it per cylinder and watch for detonation...in your weakest cylinder. Expect to purchase rods, pistons, etc. Look at Probe! What psi are you running at peak power and are you intercooled? 30 pds squirters with what fuel system(aeromotive)? I "highly" recommend you look into steeda and what they are doing wiht supercharged programs that they now distribute. Look under tech comments and you will get a rough idea as to why they have the step on some others. I have used mid lengths before to prevent ground clearance especially when you are lowered by 1.5 to 2in. Replacing K member is highly recommendable. Try D&D Motorsports, if im not mistaken, they have a very creditable rep and special on there K member. Noise and vibration will be high and the heat under your feet as well.
Take care my friend...and eat up every bowtie you can...

John