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Callaway Intake and Exhaust Bolt-Ons

First-Year Fortification: Intake and exhaust bolt-ons from Callaway yield 20 rwhp on a 2001 Z06

Chris Werner Jan 11, 2013

Perhaps the concept of trickle-down economics isn’t all that far-fetched. Case in point: your author (or more correctly, his old man) recently picked up this virtually flawless, 52,000-mile C5 Z06 for just $19,000 – a full thirty grand less than it went for new. Yes, the world-class supercar we know as the Z06 has finally dropped into the econocar price bracket, and should the Corvette divinities see fit for the C6 versions to one day near this level of affordability, it will surely be the best of all possible worlds.

Ghtp 1301 01 Callaway Intake And Exhaust Bolt Ons 2001 Chevrolet Corvette 2/22
Ghtp 1301 02 Callaway Intake And Exhaust Bolt Ons Callaway Double D 3/22

01. Let’s start with Callaway’s so-called Double-D Exhaust System, easily the most highly polished cat-back I’ve ever installed. Constructed of T304 stainless steel, Callaway says its design promotes maximum flow and the highest possible horsepower, along with a deep, powerful tone that’s “excitingly pleasing for the driver, not raucous for the bystander.” Carrying PN 208.50.4800, this particular system fits all 1997-2004 Corvettes; MSRP is $1,395.00.

Such a good find naturally opens up some spare change for upgrades. The fact that this is a first-year Z06 means its 385-hp LS6 is slightly down on power compared to the ‘02-’04 model years (which received upgrades in the form of a bumpier cam and complementary lighter valves, improved airbox and MAF, and a less-restrictive catalytic converter setup, adding 20 hp to the advertised SAE figure). On the Dynojet at Heintz Racing (Mooresville, NC), a baseline pull resulted in 330.5 hp and 329 lb-ft, which equates to roughly 389 horsepower at the flywheel if you assume 15% drivetrain loss - about right, considering this car already had an aftermarket air filter. According to the Heintz crew (full-service specialists in late-model GM, Ford, and Chryslers), later C5 Z06’s normally put about 345 ponies to the tires…. could this deficiency be made up by simple swaps of an intake and cat-back?

Ghtp 1301 04 Callaway Intake And Exhaust Bolt Ons Stock Z06 4/22

It sure can. Beyond our dyno-proven increases, real-world performance shot up as well. Before-and-after HPDE track events at Virginia International Raceway proved the added underhood potency, as 140 mph was easily eclipsed on the back straight (the car was just able to touch that figure before). In addition, your Bondurant-trained author felt no discernible difference in handling due to the added mass of exhaust hanging behind the rear axle.

Ghtp 1301 10 Callaway Intake And Exhaust Bolt Ons Callaway Exhaust 11/22

09. Back on the dyno, both horsepower and torque figures jumped by 8.5, bringing totals to 338.9 hp and 337.6 lb-ft. I don’t know about you, but I haven’t seen that much of a gain from a cat-back on an otherwise-stock car in a long time (possibly since the LT1 era). Callaway wasn’t kidding – this exhaust really flows! (Its sound is a bit on the quiet side, but it’s a nice tone that has gotten a bit louder as the miles have gone by.)

Ghtp 1301 14 Callaway Intake And Exhaust Bolt Ons Painters 15/22

13. Now fully assembled, the Honker is attached to the throttle body and upper radiator cover and pre-fit atop the radiator shroud. Painters’ tape is used to mark the edges of where it needs to sit.

Ghtp 1301 21 Callaway Intake And Exhaust Bolt Ons Dyno 22/22

20. Final dyno values increased to 350.5 hp and 344.3 lb-ft, an increase of 11.5 hp and over 6.5 lb-ft with the Honker – and that’s at a standstill. With speed on the road, the Honker should add even more power, plus it adds a badass intake growl. All said and done, the Callaway parts gave us 20 rwhp and over 15 rwtq with absolutely no tuning (note how AFR change is negligible between runs, proving gains are a result of flow and not an artifact of leaning out), bumping us to 412 hp at the flywheel and beyond stock power levels of later C5 Z06s!


Heintz Racing
Callaway Cars Inc
Old Lyme, CT 06371



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