There's a general misconception in hot rodding that louder is better-but most of us know that's nonsense. Some "back-pressure" in the exhaust system is good for scavenging and exhaust velocity, which helps make more power. An oversized exhaust system will actually be less effective than a smaller, more accurately sized one, plus while the dumps we had been running for a while were cool, we've grown old of the excess noise produced by our commuter.
We could go on about how louder does not always equal better, but the real reason for this story is simple-your author was sick of driving 60 miles everyday feeling like the exhaust system was riding shotgun. I'd take a passenger anywhere and have to holler just to communicate, and that gets old. Of course, I didn't want to lose the rumbling Mustang sound. The solution: a new exhaust system with tail pipes-but would that require a sacrifice in performance? We'd soon find out.
The Pypes polished stainless...
Editor's Note: If you read "The Strip Performer" last month, you know that we recently installed an Edelbrock Performer RPM II intake manifold on our resident '93 LX coupe. So there's no confusion, this installation and test was performed prior to, and completely independent of, that story.
Since we wanted to maintain a budget-friendly theme, we called Latemodel Restoration Supply for some advice. Our contact there recommended components from Pypes. Pypes offers a full line of performance exhaust for late-model Mustangs-from headers to tailpipes. Not only are all the components made of stainless steel, but are priced to not break the bank.
Parts on hand, we strapped the coupe to our in-house Dynojet chassis dyno for a baseline, which resulted in 265 rwhp and just short of 292 lb-ft of torque. Then, we unbolted the old components, which consisted of 15/8-inch shorty headers, off-road H-pipe, and some older race-style mufflers with dumps.
The Pypes components were easy to install, and cleared our AOD with no problems. On the Dynojet, the new pypes (pun intended) did not disappoint. Power output increased from 4,000 to 5,500 rpm, though peak horsepower stayed the same at 265. Torque output, however, is where the new components shined. Torque was increased from 4,000 to 5,500 rpm as well, and peaked at 297-a 5-lb-ft increase.
How about the noise, you ask? Well, we tested that as well. Thanks to a handy decibel meter we borrowed from our friends at Modified Mustangs & Fords, we recorded noise output of the old and new exhaust from inside the vehicle with the windows up. This test would best represent what we're experiencing in real-world conditions.
The header tubes are welded...
The header tubes are welded to one single flange...
... which makes installation...
... which makes installation easier.
The midpipe (PN PYP-XFM10)...
The midpipe (PN PYP-XFM10) costs $169.99. It features an X-style crossover, which promotes scavenging.
It comes with all the hardware...
It comes with all the hardware necessary for installation.
The Pypes stainless steel...
The Pypes stainless steel after-cat (PN PYP-SFM13VS) retails for $439.99. It will bolt to most midpipes, including stock.
Our system came with polished...
Our system came with polished Violator mufflers from Pypes. For $100 less, you can get the non-polished mufflers (PN PYP-SFM13V; $339.99).
We opted for the 2-1/2-inch...
We opted for the 2-1/2-inch polished tip for a stock look. However, you can opt for the kit with polished slip-on, 3-inch tips for $419.99 (PN PYP-SFM16V).
First, we unbolted the after-cat...
First, we unbolted the after-cat from the midpipe.
We then removed the H-pipe...
We then removed the H-pipe from the flange on the headers.
We then unbolted the headers...
We then unbolted the headers from the cylinder heads...
... and removed them from...
... and removed them from the top.
The Pypes headers come with...
The Pypes headers come with new header bolts and gaskets.
Then, we installed our O2...
Then, we installed our O2 sensors.
Since the downpipes are separate,...
Since the downpipes are separate, installation is much easier.
After the hardware is in place...
After the hardware is in place on both downpipes, we installed the X-style crossover (clamps included in kit).
We supported the X-style crossover...
We supported the X-style crossover with a pole jack, and installed the lead pipes and mufflers...
... then we removed the rear...
... then we removed the rear wheels...
and installed the tailpipes...
and installed the tailpipes using the stock hangers.
Once everything is lined up,...
Once everything is lined up, you can tighten all the bolts and clamps.
Don't forget to reattach the...
Don't forget to reattach the O2 sensors to the harness.
| Stock ECM |
| Adaptive On 14 Deg Base Spark |
| RPMx1,000 | HP | FT-LB |
| 3.80 | 188.73 | 260.84 |
| 3.90 | 204.87 | 275.89 |
| 4.00 | 216.03 | 283.65 |
| 4.10 | 225.09 | 288.35 |
| 4.20 | 232.28 | 290.47 |
| 4.30 | 238.28 | 291.04 |
| 4.40 | 243.97 | 291.22 |
| 4.50 | 248.61 | 290.17 |
| 4.60 | 250.91 | 286.48 |
| 4.70 | 251.59 | 281.15 |
| 4.80 | 253.55 | 277.43 |
| 4.90 | 256.68 | 275.13 |
| 5.00 | 258.42 | 271.46 |
| 5.10 | 260.92 | 268.71 |
| 5.20 | 263.12 | 265.76 |
| 5.30 | 263.76 | 261.38 |
| 5.40 | 264.44 | 257.20 |
| 5.50 | 265.00 | 253.06 |
| 5.60 | 263.66 | 247.28 |
| 5.70 | 260.22 | 239.77 |
| Max | 265.00 | 291.22 |
| Stock ECM W/Pypes |
| RPMx1,000 | HP | FT-LB |
| 3.80 | 191.32 | 264.35 |
| 3.90 | 205.50 | 276.75 |
| 4.00 | 217.30 | 285.31 |
| 4.10 | 226.28 | 289.86 |
| 4.20 | 235.17 | 294.08 |
| 4.30 | 242.30 | 295.95 |
| 4.40 | 248.75 | 296.92 |
| 4.50 | 252.38 | 294.56 |
| 4.60 | 254.13 | 290.16 |
| 4.70 | 256.19 | 286.28 |
| 4.80 | 254.57 | 278.55 |
| 4.90 | 258.70 | 277.29 |
| 5.00 | 258.68 | 271.72 |
| 5.10 | 261.60 | 269.41 |
| 5.20 | 263.65 | 266.30 |
| 5.30 | 265.07 | 262.67 |
| 5.40 | 265.81 | 258.53 |
| 5.50 | 264.53 | 252.61 |
| 5.60 | 262.66 | 246.34 |
| 5.70 | 258.67 | 238.35 |
| Max | 265.81 | 296.92 |
| Old Stuff | Pypes |
| Idling | 78 dB | 70 dB |
| WOT acceleration | 92 dB | 88 dB |
| Cruise 55 mph | 81 dB | 75 dB |
| Cruise 80 mph | 83 dB | 78 dB |
Though it doesn't seem like much, it should be noted that just a few decibels make a big difference. The Pypes system is 4-8 decibels quieter (from inside the car) than our old system with dumps; since we traded our old H-pipe for an X-style midpipe, we picked up some torque, too-the best of both worlds. Now that's music to my ears.
As you can see in the chart, horsepower was up by 4 at 4,500 rpm, though peak remained the same. Torque, however was up by 5 lb-ft at peak.