I'm not sure if this is the right section to put this in, but I'll give it a try.

I have an '05 GT, 14,800 miles, city driver and in addition to the SLP Loudmouth axle-back I already have installed, I'm looking to beef it up a little more by having SLP long tube headers (http://www.americanmuscle.com/slp-co...ders-2005.html), with the SLP catted X pipe (http://www.americanmuscle.com/slp-mu...pipe-2005.html) installed within the next month.

My question is, I see that some headers are 1 3/4" and some are 1 5/8" diameter. I plan to stay naturally aspirated, so which diameter should I go with? The ones in the link above are obviously 1 3/4", so is that the best diameter for my car? Does it even matter?

Hell, I don't even know if I'll end up getting headers. May just buy a hood, chin spoiler, and rear spoiler instead. I don't know if I want to spend $1,500 on something that might put out 20-30 horses maximum, which is a hell of a lot of money for a small gain.

Anyway, I digress. Any help would be appreciated.

 

Unless you are going to be really pushing the engine, 1-5/8" is the best since 1-3/4" will loose some power down low.

 

If you're going to be spending that much money go with American Racing Headers. They are way better quality and design.

 

Thank you for your replies.

I love my SLP Loudmouths. They look great, fit great and sound great. I'd like to go with a full SLP exhaust, but I may not be able to because I am unable to find 1 5/8" long tubes.

I went on YouTube and found a video of ARH 1 5/8" headers with a catted X pipe and SLP Loudmouths. I wasn't impressed at all. It literally sounded like a fat guy with diarrhea. Sounded like complete ****. I would not spend $1,400+ on something that sounded that horrible. I saw that ARH has an H pipe available with their headers, so could that possibly cure some of the fartiness of the X pipe... I don't want my baby to sound like a sonic fart.

Here is the video of the ARH 1 5/8" long tubes, catted X, SLP Loudmouths:
http://www.youtube.com/watch?v=O-MAKuAtOII


Here is the video of the full SLP exhaust, headers, X pipe, and Loudmouths:
http://www.youtube.com/watch?v=W7f7-...eature=related


The SLP makes the ARH sound like a sissy. The SLP Mustang sounds like it's a demon from hell and I love it.

I might go ahead and get the SLP 1 3/4" long tubes. I'd sacrifice a little power for a better sounding exhaust, as long as the 1 3/4" won't cause engine damage. I may also get a supercharger in about a year or so, still haven't made up my mind about that.

 

First of all you're comparing a car that is idleing with the camera several feet away, to a car that is reving with the camera right in the exhaust. Anything with an SLP catback is going to sound like ***. The ARH Mustang actually sounds aggressive at idle, and the SLP one sounds like a dump truck when reving.

 

Here are some much better non SLP catback clips:
http://www.youtube.com/watch?v=R8S5_sUu5K8
http://www.youtube.com/watch?v=3LivZ...eature=related

http://www.youtube.com/watch?v=EfdUA...eature=related
http://www.youtube.com/watch?v=r4uV2...eature=related

I have the ARH catted system with a Flowmaster catback and it sounds like ****! No rasp, no popping, just pure sex. Just like a Mustang should sound.

 

Headers don't contribute to sound and I hope you aren't basing your purchase based for that reason.

 

I disagree. But like they say, opinions are like ********, everybody has one.

Thank you for your videos, I listened to all of them. Alas, none of them do anything for me. I don't think 'wow' when I hear any of those cars. I think every one of us has a different opinion of what a Mustang should sound. I think a Mustang should sound like the devil himself is coming out of the tail pipes. As I have previously stated, I already have the SLP Loudmouth axle-back. I am very satisfied with it. I mainly tried to look at clips on YouTube that contained several different types of headers and midpipes with the SLP Loudmouths because I don't want to replace them and I'd like to stick with them.

@ Bassman97:
No, I am not basing my purchase solely on that reason. I know they won't increase the decibels of the exhaust, but the pipes surely do. I'd like to stick with one brand of exhaust and would like to gain some power and have an exhaust that sounds good to me, so SLP is the way for me to go. Also, ARH are a lot more expensive. I'd be willing to pay that much for the exhaust, but I just don't like how the ARH headers/pipe with the SLP Loudmouth combination sounds.

Anyway, to move on, I have another question. I know I'd get the maximum amount of power with a tune, but do I have to tune my car immediately afterwards? Can I just let it ride the way it is and tune it later?

 

I still amazes me how many people buy headers due to their sound. There are many variables that affect the exhaust tone, least of which are the minor differences in headers.

 

Don't know if that was directed towards me, but I assume it was. In case you didn't, please read my previous post. I'm not getting the headers mainly for sound. I want to push power out of my engine, but I know it is a combination of things that contribute to the sound of an exhaust; headers, cats, pipes, mufflers, straight throughs, etc.

Again, I'd like to know if I have to or if I should tune my engine. I'm not a gearhead and I'm not going to use 'I'm a girl' for an excuse. I damn sure don't know enough to not ask for input from others. That's why I joined this forum. I'd like to learn things. I want the maximum amount of power. I may just go ahead, pull the trigger on my bank account and purchase a tuner. Which one should I buy? Also, I already have a BBK CAI and I was thinking of selling it and buying a Steeda instead...

 

Yes, dump the BBK CAI and go for a JLT or Steeda piece.

The SLP 1 3/4 primary long tubes will work great and not kill any low end power.

As for the tune, exhaust mods don't affect the a/f ratio as much as changes to the inlet side of the motor. So, adding headers alone will not require a tune, but if you are done modding I suggest you have it tuned as the tune will maximize the power.

 

Yes you will need a tune. Just adding a cold air induction to a 05+ Mustang requires some sort of tuning whether mail order or dyno. That is why mostly everyone, including American Muscle, sells the JLT induction along with an Xcal 3 or Diablo for the new Mustangs. Just changing minor air flow details on the new Mustangs messes with the computer. A buddy of mine added a JLT RAI and Xcal 3 with a 93 octane mail order tune to his 07 GT, and dropped half a second in the quarter. I was at the track with him. The 3v respond very well to minor mods. Full exhaust, induction, and a custom tune should get a 3v really close to a 13.0 on street tires. Add some control arms, 4.10's, and drag radials and you have yourself a mid 12 second car.

 

I didn't tune my BBK and it has been just fine. I haven't had any problems at all. Car responded well, but I know it would respond better with a tune.

Can I tune my CAI and the new exhaust with this tuner http://www.americanmuscle.com/sct-x3...ash-tuner.html ?

Sorry for all the questions, guys. I just want to make sure everything goes correctly.

 

Dump the BBK and get a Steeda and an Xcal2.

Go with some 4.10 gears. Your a city driver so you'll probably benefit in MPG.

The headers don't contribute to sound. If i were you I'd get rid of the slp cat back. Sounds like crap. I absolutely agree with blownstang.

 

Yes, the Xcal 3 will work perfectly.

 

Can anyone tell me what ft/lbs i need to torque my BBK Shorty Headers Down at?
Thanks

 

I'm going to pull the trigger on the good ol' bank account and order the Steeda CAI with tuner, 4.10 Ford gears, and I'm ordering the SLP long tubes with the catted X pipe.

I have already stated that I know that headers don't contribute to sound. I like how my SLP Loudmouths sound, and don't really care what anyone else thinks. (No offense.) I'm keeping them because I love them.

I got quoted a massive amount of $700 to install gears and $916 to install the headers and pipe at the Ford dealership. I was quoted $550 at a specialty muffler place who did work on my other Mustang, so I'm going to take it there for the headers, but to the dealership for the gears because I want to make sure they're done right, so I'm willing to pay a little extra.

Now, for the tuner... Since I will be ordering the tuner and intake and putting the intake on last (after the headers, pipe, and gears are installed), should I have AM set my tuner up for 4.10 gears/headers/X pipe/Steeda CAI? Also, how in the hell do I tune for the headers and pipe? What kind of tune should I ask for those?

Sorry if I'm asking an ample amount of stupid questions, haha. You guys have been very helpful so far.

 

If you won't be putting the tune in until everything is done, then you can tell them to set it up for 4.10's, exhaust, and induction, or have them just do it for exhaust, and induction. You can set it up for 4.10's yourself. You won't be able to set it up for exhaust and induction. That is something they have to do. As far as the prices for those installs go, you are getting ripped off big time!!!! Never take your car to a dealership to have any performance part installed. Gears cost $350 to get installed, and headers $450.

 

My headers won't be getting installed at the stealership. They're going to a custom muffler shop and I have had work done by them in the past on my '93 'Stang, and I was very happy with them. I'm fine with paying $700 at the stealership for the gears, even if it is a rip. I want them done right and I want them done right the first time. Hell, if they're not done right, I can just bitch about how much I paid and tell them that since they were installed by Ford, they should have been done right.

Now, since I have to have them set it up for exhaust and induction, where would I put that at? Would that be in the section where you fill out your vehicle information? Should I click on that drop down box that says 'custom tune'?

Edit:
Would I fill it out like this?

• Year and Model of Car (2005 Mustang GT)
• Computer code (See Computer Code Tutorial) (Insert code here.)
• Octane of Gas (87,91,93,GT100,etc) (87 and 93)
• Rear Gear Ratio and Transmission (Automatic/Manual) (4.10, automatic)
• Cold Air Intake or Stock Intake (2005+ MUST Have Brand Name and Type) (Steeda CAI)
• MAF & Injector Size (What do I answer for this one?)
• Headers or Stock Manifolds (Headers)
• Mid Exhaust (Stock/H/X-Pipe Catalytic Converters or Not) (X-Pipe with catalytic converters)
• Mufflers or Straight-through/Glasspack Style Exhaust (Straight-through) (Since I have the Loudmouths, is that the right answer?)
• List of all other PERFORMANCE modifications (Including Non-Standard Tire/Wheel Sizes) 18x9 with 255/45-18, 18x10 with 285/40-18 wheels and tires.)

If anyone sees fit, please edit the above as necessary.

 

maf and injectors are stock so put that.

 

Thanks, Spike.

Okay... I ordered the headers, x-pipe, 4.10 FRPP gears, and Steeda CAI with SCT X3 tuner. Hopefully, the installs will all go well and I won't have to kill anyone.

Thanks, guys, for your answers. I really appreciate your help. This will be the end of the modding for quite a while... at least a year or two.