1999 Dodge Viper GTS/ACR
Color: Silver
Stripes: Blue
Interior: Black
Asking Price: $58,900 or best offer
-This is 1 of only 23 Silver/Blue Stripes ACR's
-521 HP
-569 FT/LBS TQ
-'99 was the last year with the strong
forged pistons and bigger cam.
-This ACR has A/C, black interior, factory Alpine stereo w/cd
-19" Forgeline VR1's with Michelin Pilot Sports -Full B&B stainless steel headers and 3" exhaust
system
-Aluminum flywheel
-VEC-1 air/fuel ratio controller.
-I have the original dealer window sticker showing the price of this car new at $84,835
-24k miles
1999 Dodge Viper GTS/ACR
Color: Silver
Stripes: Blue
Interior: Black
Asking Price: $58,900 or best offer
-This is 1 of only 23 Silver/Blue Stripes ACR's
-521 HP
-569 FT/LBS TQ
-'99 was the last year with the strong
forged pistons and bigger cam.
-This ACR has A/C, black interior, factory Alpine stereo w/cd
-19" Forgeline VR1's with Michelin Pilot Sports -Full B&B stainless steel headers and 3" exhaust
system
-Aluminum flywheel
-VEC-1 air/fuel ratio controller.
-I have the original dealer window sticker showing the price of this car new at $84,835
-24k miles
Headers, exhaust
VEC-1 air/fuel ratio controller
aluminum flywheel
the 521 is flywheel HP.
It spun the dyno rollers to 443.7 hp and 484.8 ft/lb tq
I used a 15% drivetrain loss to come to the 521 flywheel HP
At gainsville raceway I went 11.90 @ 122 mph on wore out 335 michelin pilot sports
I know exactly what you posted. And forgive me because it might just be me. I have been known to be wrong. And it has been a long time since I bought a 500 pkg. But I don’t see how you’re getting 521 HP with those mods. Look at the RSI 500 or the Venom 500 from Hennessey. Which both include respectively:
Headers
Exhaust
(2)K&N
70mm Throttle Bodies to match intake
Spark Plug Wires
Pulley w/ belt
With that pkg your only getting 510 HP, 460 RWHP. And 520 TQ, 488 RWTQ. Not trying to give you a hard time. Just trying to understand how you came up with 521 HP. Did you divide by .85 or multiply by 1.15?
[img]/images/graemlins/confused[/img]
I had an aluminum flywheel on my 1st Venom 500 so I know you don’t get more HP from that. Do you get more HP from a VEC-1 air/fuel ratio controller? Never had one but I didn’t think so.
A strong '99 plus headers/exhaust and fuel mgmt can easily pull 440 on the dyno. 440 / .85 = 521.
Where's the mystery?
Hey I have been known to be wrong. Just thought I'd ask. I sure didn't know that a Viper with headers & exhaust could pull 440 though. Of course I've never had a Viper with just headers & exhaust either. [img]/images/graemlins/laughing.gif[/img]
But Mark aren't you suppose to multiply by 1.15 and not / by .85?
And, our old 96 made 444 at the rear wheels with only tubes, filters, high flows, cat back and 98+ stock headers. Also made 504 RWTQ. My red, white and blue car last dyno'd at 435 RWHP with the same mods.
Earlier cars responded VERY WELL to freeing up the exhaust side of things.
If you can live without ABS, that's why those cars are so desirable, IMO. cheap HP increases.
A strong '99 plus headers/exhaust and fuel mgmt can easily pull 440 on the dyno. 440 / .85 = 521.
Where's the mystery?
Hey I have been known to be wrong. Just thought I'd ask. I sure didn't know that a Viper with headers & exhaust could pull 440 though. Of course I've never had a Viper with just headers & exhaust wither. [img]/images/graemlins/laughing.gif[/img]
But Mark aren't you suppose to multiply by 1.15 and not / by .85?
No. That would be generating 115% of the RWHP which is not correct. What you want is 85% of the flywheel HP to equal what is measured at the RW, or:
FWHP * 85% = RWHP
thus
FWHP = RWHP / .85
It is strong, but certainly doable. I've seen completely stock 97s lay down 420+ RWHP with not a single mod. Picking up another 20 from exhaust is pretty easy, especially with the air/fuel tuning thrown in.
A strong '99 plus headers/exhaust and fuel mgmt can easily pull 440 on the dyno. 440 / .85 = 521.
Where's the mystery?
Hey I have been known to be wrong. Just thought I'd ask. I sure didn't know that a Viper with headers & exhaust could pull 440 though. Of course I've never had a Viper with just headers & exhaust wither. [img]/images/graemlins/laughing.gif[/img]
But Mark aren't you suppose to multiply by 1.15 and not / by .85?
No. That would be generating 115% of the RWHP which is not correct. What you want is 85% of the flywheel HP to equal what is measured at the RW, or:
FWHP * 85% = RWHP
thus
FWHP = RWHP / .85
It is strong, but certainly doable. I've seen completely stock 97s lay down 420+ RWHP with not a single mod. Picking up another 20 from exhaust is pretty easy, especially with the air/fuel tuning thrown in.
Good enough for me. I was doing the calculation incorrectly thus getting a different number. Guess I got some bad info. Thanks Mark and Janni.
443.7 hp divided by .85 = 522 hp. i rounded down though.
Yes VEC-controllers can be worth as much as 35 hp at the tires (so I've heard). I only gained 27 hp.
Why wouldn't you think an air/fuel ratio conroller would pick up power. Most Vipers from the factory run very, very fat. Anytime you can adjust the air/fuel ratio and get the car as close as you can to "stoic" or even a little on the lean side (as long as EGT readings are in check) the car is going to pick up power.
From the factory my air/fuel ratio was 10.8:1 that is pig rich, leaving lots of power on the table. Made 416.8 hp
Anyways to make a long story short. After trying different settings with the VEC-1 the best pull was 443.7 that's a gain of 27 hp at the tires/ 31 at the flywheel.
"Lean is Mean"
They now have a VEC-2 wich adjusts air/fuel and timing.
