VIPERnXr4ti
Enthusiast
well the 2001 ACR won Sport Compact Car's Ultimate Street Car Challenge, the Cars were as follows
1996 Mitsubishi 3000GT VR4 Spyder-slightly modded
1993 Mitsubishi Eclipse GSX-heavily modified
1972 Datsun 510-heavily modified
2001 GTS ACR "mildly" modified engine mostly suspension work
2001 Acura Integra Type R- hevily modified(turbo)
1994 Toyota Supra- heavily modded
2000 Toyota MR2-heavily modded
2002 Laminar SRX-7-kit car with turbo RX-7 motor
2001 Subaru WRX- heavily modded
1998 Nissan Skyline GT-R R33-mild modifications
Here is what was said about the Viper......
"Pushrods"
By Dave Coleman
Photography: Jared Holstein
Thanks. We spend all year mocking the arcane, imprecise, Iron Age technology of the pushrod, and every year you, our faithful but apparently inattentive reader, vote some pushrod monster into the Ultimate Street Car Challenge. Last year it was Geoff Bennett's supercharged 4.9-liter 5.0 Mustang, a car that took the bizarre honor of being the most powerful single-engine car on the dyno. But the Mustang only had 16 pushrods, and being a dedicated drag racer, it was never a threat for overall victory.
But you had to vote this thing in. Twenty pushrods in all, 10 of them opening massive 2-inch intake valves, feeding an engine more than twice the size of the next biggest powerplant in the group. Not only does this beast pack the displacement for which we've been told there's no replacement, it packs steamroller Hoosier rubber and a suspension and chassis tuned for the track. This thing is a ringer for the dynosaur team.
This particular Viper started life as an ACR model, which is factory rated at 460 hp, 10 ponies more than a Viper GTS. But when Paul Mumford of Yorba Linda, Calif., first brought it to the dyno, he found it to be 25 hp weaker than his previous plain, old pedestrian street Viper. That pissed him off. His solution? Send the whole car to EMI Racing.
There, Eric Messley oversaw a transformation that should give every other USCC competitor cold sweats. First the engine came out and went to Caldwell Development (CDI). John Caldwell's engine-building resume stretches from building the giant-killing BRE Datsun engines 30 years ago, to crafting the thundering Viper V10s that took Le Mans in 1998 and 1999.
Anticipating the sustained high revs (that's a relative term in the Viper world) of the track, Caldwell ripped out the whole reciprocating assembly, dropping in a stronger forged crank and rods, and adding forged pistons with a modest 10:1 compression ratio. Displacement remained the same.
A new camshaft--that's singular, as in one camshaft for the intake and exhaust valves--was ground to Caldwell's specs to give seriously high rpm breathing ability without losing that legendary Viper torque. It opens staggeringly large valves through 20 pushrods and 20 1.7:1 roller rockers.
The heads were ported by CDI, and the intake manifold was Extrude Honed. Gorgeous CDI headers, like stainless-steel snake pits, adorn either side of the engine, feeding exhausts by Bondio Fabrication that knock a few decibels off before belching the hot, spent gases onto the ankles of unsuspecting pedestrians. You've gotta love side pipes. With all the breathing work done, the stock ECU was re-tuned by the Viper shop to make it all work.
So far this is just another pushrod story of gratuitous horsepower and abundant displacement. Now it gets good. EMI Racing tore out ACR's Koni race shocks, and replaced them with triple-adjustable Penskes. EMI also installed 600 lb/in. springs up front and 850s in the rear. The motion ratio of the Viper's double-wishbone suspension makes these spring rates far more reasonable than they may first appear.
Then all the stock rubber was replaced with mono-balls at the end of all the A-arms. For tires, Mumford runs 305/30ZR-18 Hoosiers on the front. On the front! And 335/35ZR-17s go in the back. Ponder that for a second. If you lined up all that rubber side by side, you'd have more than four feet of Indiana gummy. That's just silly.
Brakes, a notorious Viper weak point, are addressed with 14-inch Stoptechs in front and 13-inch Stoptechs out back. Repeat. Thirteen-inch Stoptech brakes in the back. There is a lot of car to stop.
OK, so this is a fast Viper. It has stupid horsepower, huge brakes, and an embarrassment of rubber. It still takes a very talented driver to milk the potential from any Viper, and Paul Mumford packs credentials. Mumford is a regular at Viper track days, Porsche Owners Club track days, Touring Car Club track days... Pretty much if there's a track and a day, Mumford and his Viper will be there.
Most recently at this summer's Open Track Challenge, where drivers race at seven different tracks in seven days, Mumford not only took first in Touring 1, the fastest class to require the cars to be driven from track to track, but placed second overall in a field littered with dedicated track cars. And for that event, he had plain old Michelin Pilot Sport street tires.
Our advice to the other nine drivers: Turn that boost knob just a little bit more.
2001 Viper ACR
ENGINE
Engine Type: V10, aluminum block and heads
Internal Modifications: Engine built by Caldwell Development (CDI) with forged crank, forged rods, 10.0:1 forged pistons, CDI camshaft, 1.7:1 roller rockers, CDI ported heads
External Modifications: Extrude Honed intake manifold, CDI Headers, CDI baffled oil pan, Bondio Fabrication exhaust
Engine Management Modifications: Viper Shop tuned ECU
DRIVETRAIN
Layout: Front engine, rear-wheel drive
Drivetrain Modifications: Unitrax axles, True-Track limited slip differential, 3.55:1 final drive
SUSPENSION
Front: EMI Racing suspension with Penske triple-adjustable shocks, 600 lb/in springs and mono-ball A-arms
Rear: EMI Racing suspension with Penske triple-adjustable shocks, 850 lb/in springs and mono-ball A-arms
BRAKES
Front: 14-in. vented Stoptech rotors with Stoptech four-piston calipers, EMI Racing brake lines
Rear: 13-in. vented Stoptech rotors with Stoptech four-piston calipers, EMI Racing brake lines
EXTERNAL
Wheels: 18x12-in. front and 17x13-in. rear Complete Custom aluminum wheels
Tires: 305/30ZR-18 front and 335/35ZR-17 rear Hoosier R3S03
The Viper put down 541 HP(TQ#'s not given)
got 20.2mpg(woohoo)
ripped apart the Competition on the 1.45mi track on the infeild of the California speedway by posting a 1:15:67 (the next closest car was the Nissan Skyline with a 1:21:96
the Viper pulled 1.076g on the skidpad and stopped from 60 in only 107.7ft
now here is where i was a little dissapointed it ran throught the 1/4 in 12.22 seconds @124.86mph and ran 0-60 in 4.6 seconds, the car is setup for the track and the temp was 100* but i was expecting better times...
1996 Mitsubishi 3000GT VR4 Spyder-slightly modded
1993 Mitsubishi Eclipse GSX-heavily modified
1972 Datsun 510-heavily modified
2001 GTS ACR "mildly" modified engine mostly suspension work
2001 Acura Integra Type R- hevily modified(turbo)
1994 Toyota Supra- heavily modded
2000 Toyota MR2-heavily modded
2002 Laminar SRX-7-kit car with turbo RX-7 motor
2001 Subaru WRX- heavily modded
1998 Nissan Skyline GT-R R33-mild modifications
Here is what was said about the Viper......
"Pushrods"
By Dave Coleman
Photography: Jared Holstein
Thanks. We spend all year mocking the arcane, imprecise, Iron Age technology of the pushrod, and every year you, our faithful but apparently inattentive reader, vote some pushrod monster into the Ultimate Street Car Challenge. Last year it was Geoff Bennett's supercharged 4.9-liter 5.0 Mustang, a car that took the bizarre honor of being the most powerful single-engine car on the dyno. But the Mustang only had 16 pushrods, and being a dedicated drag racer, it was never a threat for overall victory.
But you had to vote this thing in. Twenty pushrods in all, 10 of them opening massive 2-inch intake valves, feeding an engine more than twice the size of the next biggest powerplant in the group. Not only does this beast pack the displacement for which we've been told there's no replacement, it packs steamroller Hoosier rubber and a suspension and chassis tuned for the track. This thing is a ringer for the dynosaur team.
This particular Viper started life as an ACR model, which is factory rated at 460 hp, 10 ponies more than a Viper GTS. But when Paul Mumford of Yorba Linda, Calif., first brought it to the dyno, he found it to be 25 hp weaker than his previous plain, old pedestrian street Viper. That pissed him off. His solution? Send the whole car to EMI Racing.
There, Eric Messley oversaw a transformation that should give every other USCC competitor cold sweats. First the engine came out and went to Caldwell Development (CDI). John Caldwell's engine-building resume stretches from building the giant-killing BRE Datsun engines 30 years ago, to crafting the thundering Viper V10s that took Le Mans in 1998 and 1999.
Anticipating the sustained high revs (that's a relative term in the Viper world) of the track, Caldwell ripped out the whole reciprocating assembly, dropping in a stronger forged crank and rods, and adding forged pistons with a modest 10:1 compression ratio. Displacement remained the same.
A new camshaft--that's singular, as in one camshaft for the intake and exhaust valves--was ground to Caldwell's specs to give seriously high rpm breathing ability without losing that legendary Viper torque. It opens staggeringly large valves through 20 pushrods and 20 1.7:1 roller rockers.
The heads were ported by CDI, and the intake manifold was Extrude Honed. Gorgeous CDI headers, like stainless-steel snake pits, adorn either side of the engine, feeding exhausts by Bondio Fabrication that knock a few decibels off before belching the hot, spent gases onto the ankles of unsuspecting pedestrians. You've gotta love side pipes. With all the breathing work done, the stock ECU was re-tuned by the Viper shop to make it all work.
So far this is just another pushrod story of gratuitous horsepower and abundant displacement. Now it gets good. EMI Racing tore out ACR's Koni race shocks, and replaced them with triple-adjustable Penskes. EMI also installed 600 lb/in. springs up front and 850s in the rear. The motion ratio of the Viper's double-wishbone suspension makes these spring rates far more reasonable than they may first appear.
Then all the stock rubber was replaced with mono-balls at the end of all the A-arms. For tires, Mumford runs 305/30ZR-18 Hoosiers on the front. On the front! And 335/35ZR-17s go in the back. Ponder that for a second. If you lined up all that rubber side by side, you'd have more than four feet of Indiana gummy. That's just silly.
Brakes, a notorious Viper weak point, are addressed with 14-inch Stoptechs in front and 13-inch Stoptechs out back. Repeat. Thirteen-inch Stoptech brakes in the back. There is a lot of car to stop.
OK, so this is a fast Viper. It has stupid horsepower, huge brakes, and an embarrassment of rubber. It still takes a very talented driver to milk the potential from any Viper, and Paul Mumford packs credentials. Mumford is a regular at Viper track days, Porsche Owners Club track days, Touring Car Club track days... Pretty much if there's a track and a day, Mumford and his Viper will be there.
Most recently at this summer's Open Track Challenge, where drivers race at seven different tracks in seven days, Mumford not only took first in Touring 1, the fastest class to require the cars to be driven from track to track, but placed second overall in a field littered with dedicated track cars. And for that event, he had plain old Michelin Pilot Sport street tires.
Our advice to the other nine drivers: Turn that boost knob just a little bit more.
2001 Viper ACR
ENGINE
Engine Type: V10, aluminum block and heads
Internal Modifications: Engine built by Caldwell Development (CDI) with forged crank, forged rods, 10.0:1 forged pistons, CDI camshaft, 1.7:1 roller rockers, CDI ported heads
External Modifications: Extrude Honed intake manifold, CDI Headers, CDI baffled oil pan, Bondio Fabrication exhaust
Engine Management Modifications: Viper Shop tuned ECU
DRIVETRAIN
Layout: Front engine, rear-wheel drive
Drivetrain Modifications: Unitrax axles, True-Track limited slip differential, 3.55:1 final drive
SUSPENSION
Front: EMI Racing suspension with Penske triple-adjustable shocks, 600 lb/in springs and mono-ball A-arms
Rear: EMI Racing suspension with Penske triple-adjustable shocks, 850 lb/in springs and mono-ball A-arms
BRAKES
Front: 14-in. vented Stoptech rotors with Stoptech four-piston calipers, EMI Racing brake lines
Rear: 13-in. vented Stoptech rotors with Stoptech four-piston calipers, EMI Racing brake lines
EXTERNAL
Wheels: 18x12-in. front and 17x13-in. rear Complete Custom aluminum wheels
Tires: 305/30ZR-18 front and 335/35ZR-17 rear Hoosier R3S03
The Viper put down 541 HP(TQ#'s not given)
got 20.2mpg(woohoo)
ripped apart the Competition on the 1.45mi track on the infeild of the California speedway by posting a 1:15:67 (the next closest car was the Nissan Skyline with a 1:21:96
the Viper pulled 1.076g on the skidpad and stopped from 60 in only 107.7ft
now here is where i was a little dissapointed it ran throught the 1/4 in 12.22 seconds @124.86mph and ran 0-60 in 4.6 seconds, the car is setup for the track and the temp was 100* but i was expecting better times...
