Nitrous

[randy ransome]

Here's an old article about Nitrous on a ZR-1

1991 Chevrolet Corvette ZR1 - Out Of Reach
Nobody Can Touch This 10-Second, Nitrous-Fed, ZR1 Monster

Kevin Shaw Apr 10, 2007 1 Comment(s) Share
Sorry to break the news to our Corvette Fever loyalists who didn't already know, but Corvettes weren't ever musclecars. Factory-built musclecars were a niche-market product aimed at the swelling baby-boomer, late-teen and early twenty-something demographic: a growing population of impulse buyers and consumers. frankly put, it was an advertiser and salesman's dream come true. Most commonly agreed upon by automotive journalists and historians, John Delorean's daydream turned reality-the GTO-paved the road for future musclecars: stripped-down, bare-bones sedans and coupes with minimal frills and lace, but with the most horsepower and punch each particular manufacturer dared to drop between the inner fenders. Most musclecars shared platforms and body panels with the more sedate family-geared people movers, distinguishing themselves from the masses with catchy badging and decals. By checking off a series of boxes on the order form, the Oldsmobile Cutlass suddenly became the menacing 4-4-2; the Buick Skylark transformed into the GS and the legendary GSX, a demure Plymouth Satellite erupted into a Hemi-powered Road Runner; the lowly Tempest roared to life as the GTO; and the austere Ford Galaxy would metamorphose into a R-Code 427.
Corvettes, on the other hand, weren't ever intended for teenagers or the artsy Greenwich Village crowd; the ad execs at General Motors slowly evolved the Corvette's image from America's answer to the European roadster to the standing example of U.S. sportscar machinery. the General retained the Corvette at the cusp of the performance edge with such equipment as independent rear suspension, four-wheel power disc brakes, fuel injection, the first American-produced vehicle with anti-lock brakes, and the first production vehicle with a dry-sump oiling system on the largest displacement factory small-block engine in history. Unlike its past musclecar brethren, the Corvette was expected to not only accelerate excellently, but to brake, corner, handle, and otherwise completely dominate its asphalt terrain with haughty superiority.
Benchmarks in performance litter the Corvette's long record; vehicles with cryptic names like Z06, L88, LT1, L89, and LS6 still ring loudly in the ears of enthusiasts, but one in particular rattles the halls of performance history still today-the ZR1.
We're not going to take the time to go over, yet again, the genesis of the legendary Mercury Marine-built, Lotus-designed, four-cam small-block. Rather, we're more interested in showing how Rod DeWild turned his already insane from-the-factory-floor ZR1 into one of the fastest, street and course-proven Vettes that Corvette Fever has ever dared to feature. Normally, power-adder-equipped, nitrous-fed, turbo-charged, super Vettes are the fodder of the more garage-thrasher friendly magazines.
Rod says getting to the point of ownership was the hardest part, "at that time, I never thought I would be able to own one. It seemed so far out of reach due to the high price tag [in 1990]. At the time, I was driving a $400 piece of junk Audi Fox." It took some time to warrant the monthly payment, but Rod gave in, drove to the dealership, asked to take this very same black ZR1 out for a spin, and quickly fell in love. He says, "The salesman didn't bother to go with me for the testdrive, so I took it to the interstate, turned the valet key on, and opened it up."
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Corp_0703_01_z 1991_corvette_ZR1 Front 2/13
Corp_0703_02_z 1991_corvette_ZR1 Engine_bay 3/13
Stroked
The plenum may read 415 ci, but in reality, this four-cammed beast boasts 421 cubes. This engine has been stroked and bumped up to 12.5:1 compression, and pressed with direct injection nitrous via a Nitrous Express system. Filled with Crower camshafts, it also boasts ported and polished performance-angle-cut cylinder heads.
Corp_0703_03_z 1991_corvette_ZR1 Badge 4/13
Tricky
These emblems tend to bend the truth to the casual street racer.
Corp_0703_05_z 1991_corvette_ZR1 Shifter 5/13
Monster
Only the master craftsmen at LPE dared to make such a conversion on a similar ZR1, but that particular monstrosity wielded twin turbos and considerably more funding. Rod says he just likes to have fun with his 600-horse ZR1 street machine. We can't blame him one bit.
Corp_0703_04_z 1991_corvette_ZR1 Trunk 6/13
Magic
Rod's magic in a bottle is hidden here between the rear braces of the DRM cage. Computers help to distribute the special sauce over the power band, making the most out of the direct-injection system.
It wasn't long after Rod drove the Corvette home that he began digging inside the quad-cammer's internals. The Lotus-designed heads were ported and milled by fellow craftsman Greg Van Deventer. Once returned, Rod personally tackled the task of cutting a competition valve job on the heads. The factory valves were retained but with back-cut stems. The block was bored out and built to total 368 ci, but that manifestation didn't last long. A Jerry Crews billet stroker crank replaced the factory unit, while the block was fitted with custom liners, torque plate honed and clearanced to accommodate the wide stroke made by the crank and rods. strong Oliver billet steel 5.850-inch rods mate to Bill Miller Engineering forged and dry film-coated 12.5:1 pistons with Childs and Albert Tool steel rings. Rod needed to replace the factory cams with new Crower hydraulic .465-lift bumpsticks. The final cubic inch tally was an impressive 421 cubes topped with a 63mm throttle body, a ported plenum and injector housing (crafted by Greg Van Deventer), a forced air intake, and a LPE Samco intake hose. A direct port Nitrous Express feeds the cold stuff into the chambers, pushing the pony count up to 600-plus horsepower whenever Rod so desires. Since this is all-new technology, a progressive nitrous control module, a wide-band O2 sensor with a data log, and a Doug Rippie customized computer controller with a personalized tune for Rod's combination were needed.
Though, the experience of rowing one's gears is unmatched in the sense of interconnectivity between the driver and machine, Rod knew there was much to be said for an automatic's prowess on the dragstrip. A GM 4L80E automatic with a Compushift "stand alone" computer took the place of the factory MN6 manual six-speed crash box. Rod documented his '91 ZR1 as the second to ever have undergone such a conversion, citing Lingenfelter Performance as the first when they married one to a twin turbo'd ZR1 years earlier. Controlled by a TCI shift kit with a 3,000-stall with a three-disc lock up, the 9-inch Precision Industries torque converter can nearly snap your neck when launched at full load. The telltale sign of the conversion is present in a B&M Mega Shifter poking out of the center console. A custom C-beam housing had to be created for the conversion. Instead of the factory IRS, DeWild Performance installed a Dana 44 rear with steep 4.11 Viper GTS gears and billet spindles. DRM coilovers and shocks at each wheel lowered the black ZR1 into the ground, while Rod skips between 15x311/42 skinnies and 18x911/42 HRE's up front when he's not racing and 15x11-inch Weld Racing rims and 18x12 street meats out back. Since the tech guys at any NHRA-certified track are sticklers for the necessary safety equipment, Rod installed a DRM rollbar and rear bracing.
Corp_0703_06_z 1991_corvette_ZR1 Interior 7/13
Shift
The B&M Mega Shifter is the only giveaway that this ZR1 is touting a heavily rebuilt 4L80E automatic transmission. The rest of the cabin is covered in factory dressings.
Rod and his father, Norm, are the DeWilds behind DeWild Performance in Henderson, Colorado. Dedicated to building some of the best performance engines in the Rockies, Rod has tinkered on several trick rods and street machines, including a custom '40 Ford with a 448ci small-block Chevy with Nextel Cup cylinder heads and plenty of plumbed nitrous, and a fearsome '92 GMC Typhoon with a stroked 383 pushing a stout shot of squeeze.
Rod laughs off inquiries about his ZR1's current streetability, saying he uses it as a daily driver when he's not at the drags. With the old 415 stroker, the inky-black Vette ate up the Beech Bend Raceway quarter-mile in 10.6-seconds at 131 mph. Official times haven't been made since the implantation of the 421ci quad-cam stroker, but with all the goodies-with or without adjusting for the nose-bleed altitude-it will happily smash that time with cold, mechanical enmity.
One thing is for sure, Rod DeWild's '91 ZR1 eats musclecars with a knife and fork.
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Corp 0703 Pl 1991 Corvette ZR1