We came loaded for bear with a big box of goodies from Lethal Performance. Many of you familiar with the 2011+ Mustang market are likely aware of Lethal’s offerings in the exhaust department. They came storming onto the scene early with both off-road X and H mid-pipes. Knowing that it’s long been a heated topic of discussion as to which is the better choice, we decided to try shedding a little light on the issue by testing them both on theSVTP 2012 Mustang GT project car. We have sounds clips, personal impressions (aka opinions), and dyno numbers for styles of mid-pipe. All the data was gathered the same day, with only hours separating the testing of each pipe.
The first thing I want to say about both pipes is that they fit fantastically. The installation is simple and straightforward. It’s really as easy as unbolting the stock pipes and bolting on the Lethal parts. Both the aluminized Lethal pipes bolt on exactly as they should without any drama. The most difficult part of the installation was removal of one nut on passenger side collector flange. To remove it we had to use an estimated 32 feet of extensions and 17 swivels while accessing it through the engine bay. It was no fun at all.
Fortunately, after all the hand tool acrobatics we were nearly ready to spin the rollers on the dyno. When making the switch to an off-road style exhaust it is necessary to tune the ECM. To go along with its exhaust fixtures Lethal sent us a custom tune from Jon Lund. If you haven’t heard of Jon Lund before perhaps you should consider extricating yourself from beneath the bolder under which you appear to be residing. Mr. Lund has been tuning Coyote powered Mustangs from the very beginning, and you can purchase tunes created by him through Lethal Performance. In order to obtain consistent results, all runs made with Lethal’s off-road pipes were ran with the same Lund tune. So with our SCT X-Cal III filled with Lund’s hexadecimal trickery we set out in the pursuit of performance.
During our baseline run the SVTP GT put down 362.0 RWHP and 349.7 RWTQ.
Our first combination to test was the Lethal X-pipe with the stock intake and the required Lund tune. This produced 381.6 RWHP and 369.1 RWTQ.
With just the addition of the Lethal X-Pipe and a Lund tune we picked up 19.6 hp and 19.4 lb/ft of torque.
After that, we bolted on our Airaid MXP Intake and gave it another run. That maxed us out at 387.5 RWHP and 374.3 RWTQ.
The Airaid intake helped us tack on 5.9 HP and 5.2 lb/ft of torque compared to the stock intake.
This brings our total to 25.5 HP and 24.6 lb/ft over our baseline.
Next up was the Lethal Off-Road H-Pipe. The swap from the X-pipe to the H-pipe was exceedingly simple. Like before, unbolt the old and bolt on the new.
Our first H-pipe test was with the stock intake, and that netted us 380.1 RWHP and 368.2 RWTQ.
That represents a gain of 18.1 HP and 18.5 lb/ft over stock.
However, it is a loss of 1.5 HP and 0.9 lb/ft versus the X-pipe with the stock intake.
Lastly, it was time to try out the Lethal H-pipe with the Airaid intake. That combination rewarded us with 384.5 RWHP and 369.7 RWTQ.
Second grade level mathematics tells us that this is an increase of 22.5 HP and 20.0 lb/ft over stock.
The addition of the Airaid intake gave us an extra 5.5 HP and 1.8 lb/ft over the stock intake.
However, this is 3.0 HP and 4.6 lb/ft less than the X-pipe and Airaid combo.
Now that we’ve safely navigated today’s math lesson, we can get down to the issue of sound. This is the place where you’re going to find a real difference between the designs. Let’s face it, when you’re dealing with a 3,600 pound car you’re not really going to feel a three horsepower difference. So when you’re trying to decide on which style of mid-pipe to purchase for your Mustang the idea of a minuscule power difference should be secondary. What I’m sure most of you will be after is a change in exhaust tone, and these two pipes certainly have differing personalities.
The X-pipe brings with it a raspy note with a hint of exotic flavor. It sounds almost European in nature. If you’re a fan of the higher toned, more tinny, sound of a V8 from across the pond the X-pipe is the choice for you. If you’re more of an American V8 rumble traditionalist the H-pipe is the mid-pipe for you. It produces a much lower and deeper tone than the X-pipe, sounds more like what most people would expect from a muscle car. The H-pipe provides a well defined growl as the RPMs rise, whereas the X-pipe roars.
But it's one thing to talk about how something sounds, and it's another to listen for yourself.
And it wouldn't be an SVTPerformance.com article if we didn't include a small memory card full of pictures. Enjoy.
Ubiquitous glory shot.
An example of the work we preformed at Arrington earlier in the day.
Strapped down and ready to go.
This car looks powerful just sitting on the dyno.
SVTP version of "The Spin Cycle."
Time to get our hands dirty.
Install Instructions: Bolt this under that.
This should give you an idea about the wall thickness of the Lethal Mid-Pipes.
For ease of installation the X-Pipe comes in two pieces.
The enemy within.
One of these is not like the other. (Hint: It weighs less than two tons.)
A sound insulated dyno control room is a nice thing to have if you value your hearing.
I believe I spot a NASCAR engine.
The stock components are very high quality, but they need to go.
If you look over the stock piping you'll find many bends, crimps, and reductions that can impede exhaust flow.
The stock band clamps are good quality and are reused with the Lethal kits.
A necked down section of pipe is clearly visible here.
Having access to a lift makes a mid-pipe install much simpler.
Have to get the oxygen sensors swapped over to the new pipes.
The stock cats bolt directly to the factory tubular headers.
Here you can see how flange connection methods differ on the stock (studs) and Lethal (bolts) pipes.
Getting the X-pipe into place.
The Lethal X-Pipe installed.
The Lethal parts install cleanly and without any unexpected drama.
The Lethal H-Pipe is up next.
All cinched up. It's a very clean install.
The Lethal Pipes mate nicely to the stock band clamps.
That rusty chunk of steel driveshaft will be addressed sometime in the future.
Using bolts instead of studs to connect the flanges to the headers makes installing the Lethal pipes much easier than removing the stock parts.
I think the SVTP GT needs the tranny cooling scoop from the Boss 302.
The Lethal H-Pipe looks right at home.
The H-pipe crossover slips together and is held in place with u-bolt style exhaust clamp.
Strapped down and ready to make some power.
An FRPP differential girdle would look great here.
Dyno time.
I think we're running about 300 MPH here.
I need to install a dyno cell like this at my house.
so basically it comes down to a matter of sound preference.... looks like you ended up keeping the H on...
____________________________________
Quote:
Originally Posted by Mustang Husband vs Wife
If you make fun out the mustang forums one more time, I will yank out my baby powder and smack the shit out of your mustang hating ass, all we need to do is keep modding the mustang
i have had the x pipe for a long time and the fitment is great and the quality is awesome! i think the more mods you add the bigger the gap will get!,,,,,,my .02
Thanks for the amazing writeup and the video...i can finally decide which one i will go with!
Quote:
Originally Posted by 5spd07gt
Nice write up as always. So I have to ask, which setup did you prefer and leave on the car? X or H?
I prefer the sound of H-pipe, so that's what stayed on the car.
Quote:
Originally Posted by ViciousJay
so basically it comes down to a matter of sound preference.... looks like you ended up keeping the H on...
Yep.
Quote:
Originally Posted by WHITEMACH
i have had the x pipe for a long time and the fitment is great and the quality is awesome! i think the more mods you add the bigger the gap will get!,,,,,,my .02
So an H pipe with let's say pype bomb muffler delete exhaust would sound good? I'm looking for something loud, If I don't end up getting headers. Would the x pipe be louder but raspier?
The lady who runs the apartment office asked me today if I could park a little farther from my apartment because my 90 year old neighbor downstairs apparently gets extremely frightened in the morning when I leave to go to work.
____________________________________
2011 Sterling Gray Metallic
6 speed/Brembo/3.55
Roush AB-Intake/Lethal OR H-Pipe/Lund Tuned
27% tint all around, RTR Wheels
The lady who runs the apartment office asked me today if I could park a little farther from my apartment because my 90 year old neighbor downstairs apparently gets extremely frightened in the morning when I leave to go to work.
H-pipe here. If I heard that peelin around a corner I would probably guess a different car. Alot of 4.6 noise is all I hear. I like hearing a 4.6 with full exhaust.
____________________________________ 2.93 upper | Billetflow idlers | K&N filter | Accel coils | Magnaflow x & Mac 3" catback | Pro 5.0 | Fiore quadrant & FW adjuster | Fidanza 4.3 | Liberty 26 spline IS| LP retainer sleeve | LDC Freeplay mod | Billetflow IRS brace | MM Aluminum SR Bushings | Rotorpros dimpled & slotted rotors| 315 555's| LP 3/8" spacers| ARP studs | cut springs | 445/450
A true hotrodder wouldnt be content until he had created a car so violent, so totally sick that the act of dropping the hammer would result in instant death. anything less would result in the need to go faster -Tony Defeo
Quote:
Originally Posted by StrokeMe
Apocalypse = No government = No Chevrolet
"He came in dukes of hazzard, gettin it, diggin like that like Dale Junior and then hooked up and shot forward. And when he hooked up and shot forward that’s when he came and hit"
o/r H and flowmasters here. never anything different.
____________________________________ If you cant fix it with a hammer, you've got an electrical problem.
2001 Black Convertible
K&N cai, Mac o/r H-pipe, Flowmaster Delta 40's
Centerforce Dual Friction Clutch Kit, Ford Racing Adjustible Clutch Cable & FR dual hook Quadrant
MM CC Plates, Eibach Pro kit -less rear iso's and front lower iso's
18x9 front 18x10 rear Chrome Deep Dish Bullit's, 265x35 and 285x35 Sumitomo HTR Z II
Cobra R 2.5" cowl hood, 03/04 rear bumper
Inc mods: 3.73 FR gears, Spec flywheel, Accufab twin 60 TB, Mac LT's
Great write up. Does the clamp on the H seem tight or does it need to be welded?
Check out my install how to. I ended up using a stainless band clamp since it will be there for the long haul. With the band clamp there is no noticeable leakage at the slip fit connection.
Awesome article Travis!! The pics, video and write-up came out great. Definitely gotta give a shout out to Stacy as well as I'm sure she played a big part of those pics coming out so nice. :-)
You did an awesome job. This clears up a lot of questions we seem to get all of the time about the sound and power difference between the X and H. Just like you said no one is going to notice a 3hp difference however the sound is definitely what separates one from the other.
We're glad you chose us to be a part of your build and thank you for making us a part of the SVTperformance family. It's been about 6 years since we hooked up with you and the love we get from the community just keeps on growing.
Thanks again!!
Jared and the entire crew at Lethal Performance, Inc.
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