When you launch your Viper in first gear from a dead stop and shift to second at moderate throttle do you feel the end starting to give? I was driving the other day and sensed this several times. I eased up on the gas and was able to more appropriately control the launch but....it was also kind of cold but not bone-chilling. Never drove the car in the summer but how big of a difference is there say at 40 degrees and degrees given the runcraps that are on the SRT 10?
When Launching....
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Cold temps and big torque do not mix. Dont try to drive your car at the limits at 40 and below, it wont act the same way it should when you are running it hard at 55 deg. and up. Have a little fun, but save the hero driving for another (warmer) day.
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what are the perfect rpm's between gears? for a stock car? anybody got good data?
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is warming up Ecsta's v700's beneficial?V10 MOJO said:
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Warming up any car tire is beneficial. Warm tires grip better. If you are worried about traction on cold days more than you care about tire life do a burn out...........It works for me.
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Not true for all tires...that's why I was asking about the ecsta's. the OEM Pilot sports are a rubber composite that harden with heat. Don't warm up the pilots, but ecsta's? I don't know. Not all tires are created equal :thumb:early93viper said:Warming up any car tire is beneficial. Warm tires grip better. If you are worried about traction on cold days more than you care about tire life do a burn out...........It works for me.
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Super Squirrel said:
My OEM pilots seem to do much better heated up. Never heard of a cold tire griping better. Do you have a link or a thread that explains this?
Speaking of pilots, here is the funny thing... all mustang / camero / 'vette owners are told that if you go to the drag races, do NOT do a burnout on street tires... just "clean them off" with a quick spin...
I used to always do this, but in Bradenton, I decided (during the street tire shootout) to be a little differnet. I did a smokey-ass burnout w/ Pilots, and smacked down a 1.6x 60 foot time! moral of the story: heat 'em up!
JD
I used to always do this, but in Bradenton, I decided (during the street tire shootout) to be a little differnet. I did a smokey-ass burnout w/ Pilots, and smacked down a 1.6x 60 foot time! moral of the story: heat 'em up!
JD
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early93viper said:
Not sure about the "gripping" part. I just stated that I have definitely read that heating pilots up "harden" them momentarily which generally reduces traction. I have tried both, and personally, I can't tell too much of a difference b/c I'm sure it's minimal. Not enough to make up for a few 1/10ths or anything :rofl: but a drag radial? well, those are certainly a different mechanism and those are "designed" to be heated.
I'll see if I can find the stuff that was written on it. I just remember reading that tire pressure has a more grandoise effect than heating up pilots. I wasn't trying to be controversial, just passing on stuff that I've learned while on the alley. I used to smoke my pilots too, but I refrain now. Which is more beneficial? I honestly don't know.
JID,
I can't explain that buddy. I don't know. I wouldn't exactly call that a "controlled" experiment :rofl: but hell, if it works, it works. Nice runs by the way, got a few of them on the DVD :thumb:
93, I'll see what I can dig up. :thumb:
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Gary,GARY JAVO said:
here's just a few articles (they're all over the place and I don't know the validity, but I do know there's been MULTIPLES written. I don't think it's an "old wives tale" anymore.
This is from domestic tunerz.com. Can go to the website and check it out for yourself.
Sup guys, figured this would be a good topic since this is probably the hardest part of the entire strip.
Street Tires:
As you may or may not have found out, street tires are probably the hardest to launch on effectively.
A few rules which should be followed regardless would be:
1 Do NOT go through the waterbox or do a burnout. Street tires are not made to be heated up, heating em up makes em quite greasy and they'll grab like your on ice.
2 Do NOT air down. Dropping maybe 5psi can be beneficial, but airing down to 20psi or lower is detrimental. Street tires ARE NOT WRINKLE WALLS. Airing down street tires will cause wheelhop at best, broken control arms, axles, sway bars etc at worst.
3 Do NOT launch in the groove. Line up at the outside of the track. Street tires and VHT do NOT get along. Launching in the groove will again, cause severe wheelhop, usually damaging, and will also really piss off the guys on drag radials/slicks as the rubber from the tires that gets left in the form of marbles on the strip makes it really hard for slicks to hook up and tends to be pretty detrimental to r compound tires.
Prepping street tires to launch is simple. Drive around the water box and scrub em a bit. A few rotations to get the marbles, any gravel or other debris and all that stuff off the tires is beneficial but dont overdo it.
The best way to launch on street tires that I have found is once you line up, put the engine up to a launch rpm(suggestions i'd make are around 3000-3500 depending on setup, but it will be different for everyone and tires will dramatically effect launch rpm) pull the ebrake up and let the clutch out just to the point of where it starts to grab. This "loading" of the driveline makes launching alot easier on the driveline, as well as cuts down wheelspin. You have effectively cut your chances of bogging in half, as the engine is under a slight load and should have bogged a bit when your clutch started grabbing, bringing the car back up to the launch rpm will basically get things ready to go if you will, and as I mentioned above, limits the shock load on the drivetrain making launches smoother and more consistent.
Once your moving, I avoid WOT till i'm in 2nd, as WOT in 1st causes massive wheelspin. Out of the groove is better traction for us, BUT is not as sticky as the rest of the track and as a result, traction is hindered pretty badly. Once your moving, gently move over to the groove. Once your moving the groove is your friend, traction is increased a bit, its easier to maintain control of the car, and wheelspin under shifts is dramatically reduced. Plus, if the unthinkable happens and you do loose it, you have a much better chance of getting the car back under control or down to a manageable speed if you end up in the wall. More on this later.
Drag Radials:
Drag Radials are the go between. They are an R Compound tire which means they react very well to burnouts, but they are also DOT legal which means they have water evacuation grooves and a somewhat stiff sidewall. They are also usually wrinklewalls to a point, which means airing down is helpful. I've found anything under 12psi is too much, but have had my best luck between 15-18psi. That will vary, as I am over a mile high and we are seriously down on power up here.
For drag radials, Burn em either in the box or out of it if you have the power to do so, but try to keep the heat even as that determines how much traction you'll have. A non contact thermometer can be helpful if you have someone helping you stage outside of the car, and play with pressures. Staggered pressures to compensate for your weight in the seat can have a dramatic effect on how the car handles under launch as well as top end stability which is again, very important.
Once your staged, and you DO want to line up in the groove on drag radials, I still like to load the drivetrain up on drag radials, but play with it. Depending on how well you heated up the drag radials, you might have better luck dumping the clutch and feathering the throttle a bit. Try to modulate the gas as your less likely to break an axle than modulating the clutch. The chances to break an axle on drag radials to double roughly, soo axle upgrades wouldn't be a bad idea now.
Figure on about 500-2000rpm more to launch on drag radials, depending on the tires and how hot they are. Once your moving, you can generally powershift all the way down the strip with some chirping in the 1-2 definately and usually a chirp on the 2-3, just try to feel what the car is doing. You can tell alot by how the car handles at the big end. If its pulling one way, that tire is probably stickier, try nudging over a bit to get the grip equal, but remember, keep the movements smooth and gradual. Sharp movements=bad things happening.
Slicks:
Slicks are all out race. Mushy sidewall, ultrasoft tread, and they are by NO means, streetable. Burn those babys at the stake. Roast and Roast and roast some more.
Seriously, you want slicks HOT HOT HOT. As hot as you can get em. Generally, I'll run slicks around 8-12psi(as low as 4-6psi with beadlocks), and once i'm out of the waterbox, i'll stop short of the timing beams and dump the clutch from a moderate rpm to see how it feels. This is helpful as it can let you know what to expect off the line and helps with where you stage. Once you pull up to the pre-stage beam, i'll generally put it on the 2-step here and nudge it forward till i break the staging beam. once that beam is broken, the clutch and gas are on the floor, as soon as the third yellow comes up, dump the clutch let off teh button and hang on.
Again you want to be in the groove, and you want to stay there for the entire run. Slicks Love heat and they also Love VHT. The stickier the better. The one exception to this is if the big boys(fuelers, prostocks etc) have been makin test passes in your lane, depending on your power, and the shape of your driveline you might have better luck out of the groove if your bogging out.
Keep in mind, these tires are made for going in a straight line. Dont turn hard on em, thats asking for problems. At this point, you should have upgraded axles in or 90% that your going to snap an axle like a twig. Slicks have stupid ammounts of grip and will probably hang on harder than your clutch and axles are capable of unless your running beefed up units.
At the tall end, same thing as the others, keep the steering inputs gradual and gentle. its generally easier to let the car drift a bit than it is to try to keep it perfectly straight. Its definately safer. At speed the tires will balloon a bit but they still have an incredibly soft sidewall which will deflect under major corrections.
As far as the unthinkable part of this sport, accidents. There are 2 kinds of accidents, ones you walk away from and ones you are rolled away from. I look at it like this, and I am being totally serious when i say this. If you come out of it alive, its a good accident. I dont say that to scare anyone off, but this is a dangerous sport we're involved in and safety needs to be the #1 priority for everyone involved.
At the line:If you break at the line and nothing is smoking, burning or getting ready to explode, SHUT THE IGNITION OFF. If you have an ignition kill, hit that, as well as turn the key off. A fuel pump and ignition cutoff switch is a good thing to install as a fuel pump shutoff can stop many problems from getting out of hand. Generally speaking, the EMS/Rescue crew will tow you out of the staging area and either pull you back to your pit space or if its a fixable problem, pull you out of the way to solve the problem and then get you back in at the end of the line.
Once your moving:
First thing to do is pull out of the groove if your able to. If the car dies or something breaks, pull it off to the outside of the lane as close to the wall as possible and secure the car. The reason for doing this is to keep oil, coolant and other debris out of the groove as much as possible. If something is burning, kill it, and get out as quickly and safely as you can. Dont try to put a fire out yourself, just get away from the car and let the EMS/Rescue guys do their jobs. They are there to keep you safe and they are very good at it.
If you hit the wall, ,kill the car, and assuming nothing is burning, sit tight. In any case where there is something burning, get out of the car and get to a safe location after shutting the fuel pump and ignition off.
Regardless of what you do, I can not stress enough, DO NOT ATTEMPT TO PUT OUT A FIRE ON YOUR OWN. If you have a halon system by all means, activate it, but dont stand around, get away from that vehicle.
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Here's another from a sportbike source.
Contrary to popular myth the main difference between DOT street tires & DOT race tires is not the rubber compound. It is the construction of the belting plies in the tire carcass.
The belting in street tires is designed to give more stability & better ride when the bike is upright whereas the belting in race tires is designed for better grip & stability at high lean angles.
We have all heard the stories about Ricky Racer crashing his bike cause he was running race tires on the street & couldn't keep them warm enough etc & while there is some validity to those stories because the rubber compounds are designed to work in certain heat ranges, the overall statement is false & usually nothing more than an excuse for rider error. Cold race tires still stick better than a cold street tire. Race rubber being a softer compound than street rubber will be inherently more grippy than a harder street compound. Now if you have just recently abused your race tire or have installed a race take off then you may have either not enough catalyst left in the tire to provide adequate grip or you may need to put in a little time to scrub off the dead layer of rubber to get to some fresh rubber with good catalyst in it.
"What the hell is catalyst you say?" Well what really gives a tire its grip is a chemical catalyst in the compound that when heated makes the tire adhere better to the road surface. The reason racers sell race take-off tires even though they have more than half the tread left is because they have burned the catalyst out of the tires through either too many heat cycles or simply too much heat was generated in the tire period & now the tire no longer functions to their satisfaction or required level of grip. The hardness of the tire compound is only one part in the factor on grip as is the temperature range they are designed to run in. Tires pushed beyond their temperature range for extended periods will start to delaminate (seperation of the rubber from the carcass). Now I don't know about who you hang out with, but I know only maybe a handful of guys that can actually overheat a tire during street use... Street riders as a general rule simply do not have to worry about getting any tire race or street into the proper operating temp range as a normal sport riding pace will bring the tire into a useable temp range. Racers on the other hand have to be concerned with selecting the proper temp range due to the fact that delamination can occur if the tire is subjected to sustained temps above it's operating range.
Another misconception is the idea that race tires are no good in the rain because of their lack of grooves in the tread. While it certainly is true that a tire needs grooves to channel water away to prevent hydroplaning, the real reason for lack of wet grip is again the compound. Street tires generally contain lots of silica in them to provide better heat dispersion (aids in consistent tire operating temps) & wet weather grip.
Contrary to popular myth the main difference between DOT street tires & DOT race tires is not the rubber compound. It is the construction of the belting plies in the tire carcass.
The belting in street tires is designed to give more stability & better ride when the bike is upright whereas the belting in race tires is designed for better grip & stability at high lean angles.
We have all heard the stories about Ricky Racer crashing his bike cause he was running race tires on the street & couldn't keep them warm enough etc & while there is some validity to those stories because the rubber compounds are designed to work in certain heat ranges, the overall statement is false & usually nothing more than an excuse for rider error. Cold race tires still stick better than a cold street tire. Race rubber being a softer compound than street rubber will be inherently more grippy than a harder street compound. Now if you have just recently abused your race tire or have installed a race take off then you may have either not enough catalyst left in the tire to provide adequate grip or you may need to put in a little time to scrub off the dead layer of rubber to get to some fresh rubber with good catalyst in it.
"What the hell is catalyst you say?" Well what really gives a tire its grip is a chemical catalyst in the compound that when heated makes the tire adhere better to the road surface. The reason racers sell race take-off tires even though they have more than half the tread left is because they have burned the catalyst out of the tires through either too many heat cycles or simply too much heat was generated in the tire period & now the tire no longer functions to their satisfaction or required level of grip. The hardness of the tire compound is only one part in the factor on grip as is the temperature range they are designed to run in. Tires pushed beyond their temperature range for extended periods will start to delaminate (seperation of the rubber from the carcass). Now I don't know about who you hang out with, but I know only maybe a handful of guys that can actually overheat a tire during street use... Street riders as a general rule simply do not have to worry about getting any tire race or street into the proper operating temp range as a normal sport riding pace will bring the tire into a useable temp range. Racers on the other hand have to be concerned with selecting the proper temp range due to the fact that delamination can occur if the tire is subjected to sustained temps above it's operating range.
Another misconception is the idea that race tires are no good in the rain because of their lack of grooves in the tread. While it certainly is true that a tire needs grooves to channel water away to prevent hydroplaning, the real reason for lack of wet grip is again the compound. Street tires generally contain lots of silica in them to provide better heat dispersion (aids in consistent tire operating temps) & wet weather grip.
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the link that was provided in past discussions was something else, I can't remember at this time, but I will try to jog my memory. I will post it when I can find it.
YOU BE THE JUDGE. I just don't know anymore.
YOU BE THE JUDGE. I just don't know anymore.
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