PhoenixGTS
Enthusiast
Would I need a whole two miles of runway/road to give the car a proper chance to show what it can do from a standing start to top speed?
In bolt-on car, how much distance would I need to make a top speed run?
- Thread starter PhoenixGTS
- Start date
DEVILDOG
VCA Member North TX
With your mods and gearing I think you should be able to top out within 1.5 miles.
Fast Freddy
Enthusiast
with the mods you have such as the custom trans with that .64 6th gear ratio and the 3.55 rear gear you should be able to hit your top speed in 6th gear within 2.0 miles. i see that you also have more aggresive gearing in 5th gear as well as 6th gear too so if am guessing at 6,000 rpm's you car is gonna be limited to a top speed of about 170 mph in 5th gear with that .80 gear ratio you have in your trans. the stock 3.07 gear which i am currently running will take you to 202 mph in 5th gear at 6,000 rpm's, that is if you have enough power to pull it.
it took me 2 miles to hit my top speed of 198 mph from a dead stop. i stayed in it for another 1 mile after that trying to get more speed out of it but there was just nothing left. i made my run on a flat road though with no tailwind. if i had a downhill or a good tailwind i would have got 200 mph out of it. my speedo was reading 200 mph though. but my GPS told the real truth, it was only 198 mph.
my vettes rear gear ratio is a 3.42 with a .75 ratio in 5th gear in the trans. at 6,500 rpm's my vette gps'd 176 mph. it took me 2 miles to hit that top speed on the same stretch of road that my viper went 198 mph on. so as you can see with less rev's available to you in your viper and more aggresive gearing than even a year 2004 Z06 vette you are only gonna be able to go faster than 170 mph if your car has the power to pull 6th gear. since your custom trans has a .64 6th gear ratio versus the stock viper or vettes .50 ratio. i think you just might be able to pull 6th gear. the question is how far can you pull it? i am guessin 190 mph mph.
it took me 2 miles to hit my top speed of 198 mph from a dead stop. i stayed in it for another 1 mile after that trying to get more speed out of it but there was just nothing left. i made my run on a flat road though with no tailwind. if i had a downhill or a good tailwind i would have got 200 mph out of it. my speedo was reading 200 mph though. but my GPS told the real truth, it was only 198 mph.
my vettes rear gear ratio is a 3.42 with a .75 ratio in 5th gear in the trans. at 6,500 rpm's my vette gps'd 176 mph. it took me 2 miles to hit that top speed on the same stretch of road that my viper went 198 mph on. so as you can see with less rev's available to you in your viper and more aggresive gearing than even a year 2004 Z06 vette you are only gonna be able to go faster than 170 mph if your car has the power to pull 6th gear. since your custom trans has a .64 6th gear ratio versus the stock viper or vettes .50 ratio. i think you just might be able to pull 6th gear. the question is how far can you pull it? i am guessin 190 mph mph.
OP
OP
PhoenixGTS
Enthusiast
For me 6th @ 6,000 rpm = right at 200 mph which, of course, my car would never do, but the sweet spot around 5,250 is in the high 170s range in 6th so the car will definitely go faster in 6th than 5th (and with an extra gear to help I am guessing it would get there sooner than with stock gearing).
Fast Freddy
Enthusiast
[/QUOTE]
For me 6th @ 6,000 rpm = right at 200 mph which, of course, my car would never do, but the sweet spot around 5,250 is in the high 170s range in 6th so the car will definitely go faster in 6th than 5th (and with an extra gear to help I am guessing it would get there sooner than with stock gearing).
[/QUOTE]
i don't have a gearing calculator in front of me but if indeed your modified trans gearing coupled with your 3.55 gear outback hits 200 mph in 6th gear at 6,000 rpm's then you might just be able to get close to 195 mph. your cars engine probably only makes peak hp at 5,250 rpm's though and as you go past 190 mph you will be past your peak hp curve and lose momentum. this will limit you to a max speed of 190-195 mph depending upon if the road you are running on has a downhill or tailwind.
that said my viper makes peak power at 5,450 rpm's with the camshaft i currently have in it. if i had a camshaft with more duration in my engine that made peak power at say 5,800 rpm's i would have probably hit 200 mph on gps.
For me 6th @ 6,000 rpm = right at 200 mph which, of course, my car would never do, but the sweet spot around 5,250 is in the high 170s range in 6th so the car will definitely go faster in 6th than 5th (and with an extra gear to help I am guessing it would get there sooner than with stock gearing).
[/QUOTE]
i don't have a gearing calculator in front of me but if indeed your modified trans gearing coupled with your 3.55 gear outback hits 200 mph in 6th gear at 6,000 rpm's then you might just be able to get close to 195 mph. your cars engine probably only makes peak hp at 5,250 rpm's though and as you go past 190 mph you will be past your peak hp curve and lose momentum. this will limit you to a max speed of 190-195 mph depending upon if the road you are running on has a downhill or tailwind.
that said my viper makes peak power at 5,450 rpm's with the camshaft i currently have in it. if i had a camshaft with more duration in my engine that made peak power at say 5,800 rpm's i would have probably hit 200 mph on gps.
OP
OP
PhoenixGTS
Enthusiast
From what I hear other folks can do I cannot picture 195 (remember you probably have 100 more hp than I do). All I would really like to do is tell people I have done 300 kph in the car (186 mph).
Fast Freddy
Enthusiast
186 mph should be a peice of cake in your car. but again i think you could get 190 mph out of it on the road i throw down on. with a BIG tailwind you might even get close to 195 mph. in my viper back when it was bone stock i got 180 mph out of it on GPS so again 190 mph should be more realistic for your car with the aggresive gearing you got. one thing is for sure you will never know until you get out there and try it. the viper was made for just this kind of thing. your engine will make more power in the winter time than in the summer time and the winds are at their calmest early in the morning so there would be an advantage for you to wait until the winter time. but if you are like me > you won't be able to wait that long and you will have to try it now. besides its good practice, lol
just remember to bring a GPS along to record your results. speedo's are notoriously innacurate at these speeds. my vipers speedo is off by 2 mph at speed and my vettes is off 4 mph. if you do bust 190 mph then i for sure wanna race you, lol
here is a pic of my GPS max speed recording the day i maxed out my viper. this pic was taken just 5 minutes after i made my run. sorry about the poor quality of the photo but my hands were kinda shakin when i took this pic, lol
just remember to bring a GPS along to record your results. speedo's are notoriously innacurate at these speeds. my vipers speedo is off by 2 mph at speed and my vettes is off 4 mph. if you do bust 190 mph then i for sure wanna race you, lol
here is a pic of my GPS max speed recording the day i maxed out my viper. this pic was taken just 5 minutes after i made my run. sorry about the poor quality of the photo but my hands were kinda shakin when i took this pic, lol
joe117
Enthusiast
"with a BIG tailwind you might even get close to 195 mph."
Wouldn't a tailwind add whatever the wind speed was to your car speed?
I say that because the aero drag is about the only thing you are fighting to get top speed.
So a 10 mph wind from direcly behind should give you 10 mph higher top speed.
Right?
Wouldn't a tailwind add whatever the wind speed was to your car speed?
I say that because the aero drag is about the only thing you are fighting to get top speed.
So a 10 mph wind from direcly behind should give you 10 mph higher top speed.
Right?
Fast Freddy
Enthusiast
joe - wind speed has diminishing returns on a vehicles performance. i have run my turbocharged drag bike at the drag strip one time with a 20 mph tail wind and i only picked up 5 mph in the trap. now water is a different story. i have run my boat down a river where the current was moving along at 2.4 mph and my boats top speed went up from 84.6 mph to 86.8 mph according to my GPS.
From mecanical point of view the Viper has no difficulty to reach 200mph. You just need the right conditions.
However you must be carefull running above 150mph on highway. You need a lot of space, good tires, perfect road surface, no wind and no traffic.
- At 150mph you hit 1 mi in 24 seconds
- It is creazy quick and you only realize it when you have a deer or a Toyota Prius in front of you.
- You need to see perfectly what is ahead of you on at least 1/2 mi. This is the minimal distance that you will need to safely stop your car.
- There should be no traffic. Approching a 65mph running car at 150mph is dangerous. Best is to do a such run around 5AM Saturday or Sunday morning.
- Road surface must be perfect. There should be no rocks or small holes. They can burst your tires easily.
- Wind is something to be carefull about. It can be your friend or enemy. If the wind's direction changes suddenly you can end up on the top of the trees like a Cessna that missed its take off. I prefer to run without wind.
- If you have a wing remove it. Above 150mph you don't need it. Just keep the vertical elements to stabilize your Viper. Above 200mph vertical stabilizer are vital.
- Check your tires and your suspensions before the run. The pressure will be tremendous on them above 200mph. These two elements are critical. If they fail you are dead.
However you must be carefull running above 150mph on highway. You need a lot of space, good tires, perfect road surface, no wind and no traffic.
- At 150mph you hit 1 mi in 24 seconds
- It is creazy quick and you only realize it when you have a deer or a Toyota Prius in front of you.
- You need to see perfectly what is ahead of you on at least 1/2 mi. This is the minimal distance that you will need to safely stop your car.
- There should be no traffic. Approching a 65mph running car at 150mph is dangerous. Best is to do a such run around 5AM Saturday or Sunday morning.
- Road surface must be perfect. There should be no rocks or small holes. They can burst your tires easily.
- Wind is something to be carefull about. It can be your friend or enemy. If the wind's direction changes suddenly you can end up on the top of the trees like a Cessna that missed its take off. I prefer to run without wind.
- If you have a wing remove it. Above 150mph you don't need it. Just keep the vertical elements to stabilize your Viper. Above 200mph vertical stabilizer are vital.
- Check your tires and your suspensions before the run. The pressure will be tremendous on them above 200mph. These two elements are critical. If they fail you are dead.
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