NitroMustang65
Nitro Member
They get the revs up before the tree goes green, where as the Nitro cars just stomp the throttle from an idle. It sounds awesome though!
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Why do Top Alcohol FC and Dragsters do this?
- Thread starter NitroMustang65
- Start date
Nitrohaulic
Nitro Member
The alcohol cars are using a pedal clutch and three speed transmission, and are the hardest cars to launch in drag racing. The driver has to try to maintain a consistent launch RPM with a very "throttle touchy" blown car, hold the brake, watch the tree, then try to have just the right mixture of flooring it and releasing the clutch.
The nitro cars are using direct drive and a clutch that functions much like one in a go kart, so they leave the line without their foot on the pedal. The tuners are able to control the rate at which the clutch applies/tightens up as the car goes down the track. If you smoke the tires at a certain point, you can adjust for it. It's why you don't see the cars hooking back up after they smoke and when they try to pedal. The clutch is still locking up when they could actually use a little less at that point.
The nitro cars are using direct drive and a clutch that functions much like one in a go kart, so they leave the line without their foot on the pedal. The tuners are able to control the rate at which the clutch applies/tightens up as the car goes down the track. If you smoke the tires at a certain point, you can adjust for it. It's why you don't see the cars hooking back up after they smoke and when they try to pedal. The clutch is still locking up when they could actually use a little less at that point.
NitroMustang65
Nitro Member
Thanks for the great explanation, Ron. I appreciate it!
RAPID
Nitro Member
Re: Why do Top Alcohol FC and Dragster do this?
Mike,
That is when you put them on the high-side, or turn on the fuel pumps all the way. That way they have all the fuel they can get for the "Tug/Load" at the hit.
It sounds kinda cool on TV, in real life standing beside them, it sounds like you are trying to drown the poor thing! Especially on 85%.
Rapid
Mike,
That is when you put them on the high-side, or turn on the fuel pumps all the way. That way they have all the fuel they can get for the "Tug/Load" at the hit.
It sounds kinda cool on TV, in real life standing beside them, it sounds like you are trying to drown the poor thing! Especially on 85%.
Rapid
Outlaw Eric
Nitro Member
All of the above is correct, and another reason the blown alky cars rev up is to get their boost pressures up.
Thanks for the reply, which leads me to a follow-up post. I think I already know the answer, but I'll ask anyway.
Why not eliminate the burnout? Use heater wraps in the staging lanes to keep the tires at a precisely controlled temperature. Tires could be set at different temperatures, if so desired, to fine-tune for track conditions. Bypass the waterbox to keep debris and other contaminants off the tires. Fire the motor just prior to pre-stage. This reduces stress on parts, fuel consumption, and the probability of a catastrophic failure such as happened to Robert Hight at the 2006 October Vegas race that cost him the championship. No need for a reverse gear, the failure of which sunk Mike Ashley this year at Firebird.
My anticipated answer is that it's part of the tradition, expected by the fans, and provides more exposure for the sponsors, especially with a half-track burnout and slow backup.
If true, this reminds me of how NASA had the space shuttle designed. Because of its mass and available aerodynamic lift, landing it is very difficult. On-board flight computers can perform the task exceptionally well, far better than the best trained human pilot. But it's important for NASA PR that the crew riding in it have something relevant to do -- like landing it. To accommodate this, the orbiter had to be designed with extra reinforcing to the point where payload capacity and orbiting altitude were affected.
I know this comparison is a stretch. NHRA drag racing is a sport/spectacle, not government-sponsored research. But the cars are high-tech enough that crew chiefs must cringe at the notion that they are engineering for more than just getting down the track as quickly (and reasonably safe) as possible.
Why not eliminate the burnout? Use heater wraps in the staging lanes to keep the tires at a precisely controlled temperature. Tires could be set at different temperatures, if so desired, to fine-tune for track conditions. Bypass the waterbox to keep debris and other contaminants off the tires. Fire the motor just prior to pre-stage. This reduces stress on parts, fuel consumption, and the probability of a catastrophic failure such as happened to Robert Hight at the 2006 October Vegas race that cost him the championship. No need for a reverse gear, the failure of which sunk Mike Ashley this year at Firebird.
My anticipated answer is that it's part of the tradition, expected by the fans, and provides more exposure for the sponsors, especially with a half-track burnout and slow backup.
If true, this reminds me of how NASA had the space shuttle designed. Because of its mass and available aerodynamic lift, landing it is very difficult. On-board flight computers can perform the task exceptionally well, far better than the best trained human pilot. But it's important for NASA PR that the crew riding in it have something relevant to do -- like landing it. To accommodate this, the orbiter had to be designed with extra reinforcing to the point where payload capacity and orbiting altitude were affected.
I know this comparison is a stretch. NHRA drag racing is a sport/spectacle, not government-sponsored research. But the cars are high-tech enough that crew chiefs must cringe at the notion that they are engineering for more than just getting down the track as quickly (and reasonably safe) as possible.
Dougster
Nitro Member
As far as eliminating the burnout, while that would have a nice impact on less chance of breakage and speeding up the show a bit (personally I cringe when I see our nostalgia cars do 1000 ft burnouts) I think that a secondary benefit of the burnout comes from laying down some hot, sticky rubber on the track. Tire heaters would certainly help but there's no substitute for hot rubber-on-rubber contact.
Nitrohaulic
Nitro Member
Actually, I've heard many times that the purpose of a burnout is more to clean the tire than to heat it up. The heat also is also supposed to bring oils to the surface that help the tire to adhere. On my own bracket dragster, we've had many sets of tires "go away" (60 ft times start falling off) well before the wear holes are gone. I believe many pro stockers nowadays make passes just to put runs on tires, that they won't use new sets for qualifying or eliminations.
A nitro engine likes heat/load. Like Randy said, they do the burnout without the fuel all the way on. Running it leaner helps warm it up more and prevents cylinders from being flooded/put out. Just read a post from someone recently who crewed for Johnny West in which they said he had a dual fuel system, did his burnouts on alcohol, then switched to nitro just before staging.
Another interesting post or two by Frank Oglesby on classicfunnycarboard (in the sticky "tuneups" and "burned pistons" threads) talks about how he discovered years ago that many blown engines begin due to trying to do part throttle burnouts in lean conditions with barrel valves that are only made for idle or wide open use. I believe three of his posts on there are my all time favorites of any I've ever seen on message boards. They are:
#1 "The best line about backsiding I ever head came from Larry Fullerton--I said how is it going Larry?---He replied "Well on the last run I backsided everything except the f###ing weight bar and I haven't check it yet"
#2 "I don't want to give the impression I have all the answers as the B*tch Goddess of Nitro has ways of humbling all of us at times---As the ACE one time told me "When you are on nothing matters and when your off nothing helps"
#3 "....and as my buddy Rapid Roy Harris used to say "There is more than one way to skin a cat BUT the cat don't like none of them"---Frank"
My own interpretation of that last one is "There is more than one way to tune a nitro car BUT the car don't like none of them."
A nitro engine likes heat/load. Like Randy said, they do the burnout without the fuel all the way on. Running it leaner helps warm it up more and prevents cylinders from being flooded/put out. Just read a post from someone recently who crewed for Johnny West in which they said he had a dual fuel system, did his burnouts on alcohol, then switched to nitro just before staging.
Another interesting post or two by Frank Oglesby on classicfunnycarboard (in the sticky "tuneups" and "burned pistons" threads) talks about how he discovered years ago that many blown engines begin due to trying to do part throttle burnouts in lean conditions with barrel valves that are only made for idle or wide open use. I believe three of his posts on there are my all time favorites of any I've ever seen on message boards. They are:
#1 "The best line about backsiding I ever head came from Larry Fullerton--I said how is it going Larry?---He replied "Well on the last run I backsided everything except the f###ing weight bar and I haven't check it yet"
#2 "I don't want to give the impression I have all the answers as the B*tch Goddess of Nitro has ways of humbling all of us at times---As the ACE one time told me "When you are on nothing matters and when your off nothing helps"
#3 "....and as my buddy Rapid Roy Harris used to say "There is more than one way to skin a cat BUT the cat don't like none of them"---Frank"
My own interpretation of that last one is "There is more than one way to tune a nitro car BUT the car don't like none of them."
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Ron... you're pretty close on the 'oils' rising to the surface. but it's actually a sort of traction compound in the rubber. it is the compound that causes most of the smoking on the burn out. when it rises to the top it makes the tire tacky. a goodyear tech told me once that burn outs only need to be long enough to get the first whisps of smoke... meaning the tire temp is sufficent to get the compound to the surface.
as for running a motor on all alcohol to do the burn out... not sure how feasible that would really be. i warm mine on alcohol in the pits before letting the motor pick up the nitro to check out tune up. that transition from alcohol to nitro can be a pretty touchy. i know i wouldn't want to attempt it from the seat. i would think it would require two tanks... mutiple fuel shut-offs and/or another pump?
as for the purpose of the burn out... the biggest benefit is getting the engine/oil/trans/moving parts gently up to operating temps. most the clearances in a fuel motor are very dependent upon proper temps. and on a modern fueler... the clutch is very reactive to and affected by starting temps.
btw... really like the quote about more than one way to skin a cat. hahaha!! how freakin' true is that!? and it definitely applies to a nitro car. i know on 10 or 15% i was pretty brave about 'playin' with the tune up... but now that we're running nearly 90% i'm just happy to not be on fire when we get to the end. a little mistake goes a lllloooonnnnggg ways. and it doesn't go boom... it's more like KKAA-F-ING-BOOOM!
as for running a motor on all alcohol to do the burn out... not sure how feasible that would really be. i warm mine on alcohol in the pits before letting the motor pick up the nitro to check out tune up. that transition from alcohol to nitro can be a pretty touchy. i know i wouldn't want to attempt it from the seat. i would think it would require two tanks... mutiple fuel shut-offs and/or another pump?
as for the purpose of the burn out... the biggest benefit is getting the engine/oil/trans/moving parts gently up to operating temps. most the clearances in a fuel motor are very dependent upon proper temps. and on a modern fueler... the clutch is very reactive to and affected by starting temps.
btw... really like the quote about more than one way to skin a cat. hahaha!! how freakin' true is that!? and it definitely applies to a nitro car. i know on 10 or 15% i was pretty brave about 'playin' with the tune up... but now that we're running nearly 90% i'm just happy to not be on fire when we get to the end. a little mistake goes a lllloooonnnnggg ways. and it doesn't go boom... it's more like KKAA-F-ING-BOOOM!
FC Girl
Nitro Member
Hey Dave, to add to what Ron has said, the other style of alky car that you may hear at the line is one with a Lenco Glide, they actually pre stage and stage, then lock up much like a transbrake does, not many are using it, Mick Snyder has had the most success.
One other reason we come up on the RPM's is Wheel Speed, it's all about the wheel speed in the first 60 ft, not enough, you shake, to much, you shake, don't swap feet right, yep, you have shake unless you've slipped the clutch so much that it just drives through it.
One other reason we come up on the RPM's is Wheel Speed, it's all about the wheel speed in the first 60 ft, not enough, you shake, to much, you shake, don't swap feet right, yep, you have shake unless you've slipped the clutch so much that it just drives through it.
B
Buzzz Miller
You are allowed to run a single speed. However you are not allowed to run the fuel type clutch. The clutch management is not legal for either alcohol class. Without the clutch management, it is not much help. A-fuel cars run similar without the management.
So the limits of the clutch and the charactoristics of an alcohol engine really make you run the multi-speed transmissions. Also, alcohol engines don't like some of the things that the fuel engines like, so the effects would not be quite the same.
We do burnouts to heat the engine as much as we do heating the tires. Not to mention other items that need the heat before we give it full throttle and full load. Carbon brakes need to be heated up in the burnout so they work on the run. Other brakes not so much. Cleaning tires off is as important as the heat issue. But I guess the heated bags would keep the tire from picking up dust and rocks. I definitely don't want to buy some bags that heat my tires. Burnouts are the most fun part of driving.
Easy way to tell if your tires are shot, if they stop picking up rocks from the return road. If they pick up much less than they did when new, throw them. No matter what the depth gauge states.
Alcohol engines run off of fairly simple mechanical injection. They need to be cleaned out, basically getting any extra fuel out of the system, and put the system at par before achieving the proper RPM for the launch. Fuel engines have slide valves, timers, and a mass of stuff to manage the fuel everywhere from idle to pulling the chutes. Alcohol deals need to "Whap" the throttle to get everything to par, where fuel cars do that on a computer.
Nitro cars will drop in rpm and sound change right before they launch because they put the fuel pumps on full, but also they let out the clutch pedal and put the thing on load, then release the brake slightly to get into the second stage light. Both these happenings make that lower rpm, loaded sound.
So the limits of the clutch and the charactoristics of an alcohol engine really make you run the multi-speed transmissions. Also, alcohol engines don't like some of the things that the fuel engines like, so the effects would not be quite the same.
We do burnouts to heat the engine as much as we do heating the tires. Not to mention other items that need the heat before we give it full throttle and full load. Carbon brakes need to be heated up in the burnout so they work on the run. Other brakes not so much. Cleaning tires off is as important as the heat issue. But I guess the heated bags would keep the tire from picking up dust and rocks. I definitely don't want to buy some bags that heat my tires. Burnouts are the most fun part of driving.
Easy way to tell if your tires are shot, if they stop picking up rocks from the return road. If they pick up much less than they did when new, throw them. No matter what the depth gauge states.
Alcohol engines run off of fairly simple mechanical injection. They need to be cleaned out, basically getting any extra fuel out of the system, and put the system at par before achieving the proper RPM for the launch. Fuel engines have slide valves, timers, and a mass of stuff to manage the fuel everywhere from idle to pulling the chutes. Alcohol deals need to "Whap" the throttle to get everything to par, where fuel cars do that on a computer.
Nitro cars will drop in rpm and sound change right before they launch because they put the fuel pumps on full, but also they let out the clutch pedal and put the thing on load, then release the brake slightly to get into the second stage light. Both these happenings make that lower rpm, loaded sound.
Nitrohaulic
Nitro Member
I knew I was close, but that's why I preface everything I'm not 100% sure about with some kind of disclaimer language such as "I've heard" or "supposedly", LOL. I'm real picky about that in myself and in others. I did read "oils" one time years ago, but I knew that "oils" didn't sound quite right for traction, either, LOL.
Yeah, what I inserted about Johnny West really didn't belong where I put it. Wasn't really relevant, but I just saw it recently myself and thought it was pretty cool that he'd even think to do that, supposedly (see? LOL) to save a buck.
Yeah, that's what I like about classicfunnycarboard. This one's not bad, but there's a lot more technical stuff over there that's a better fit for my brain, even if much of the info is from a different era. Seems to me that more "human" quotes came from people when their customers were the people in the stands instead of the names on the sides of the cars, that maybe they were a little more relaxed and themselves.
Nitrohaulic
Nitro Member
Here's a nice example of an alcohol car as far as audio of the engine revving goes.
James Lackey Funny Car test pass - Google Video
James Lackey Funny Car test pass - Google Video
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