Talk:Top Fuel

Valve angle

Not sure where the "a 90-degree valve stem angle" came from in the article, but it's not even close to correct. Perhaps the seat valve angle of 45 degree was confused with the valve inclination angle. The included valve stem angle, intake to exhaust was 58 degrees in the 426 Hemi engine. There have been several deviations to the stock valve angles, depending on manufacturer and model of the head. source: http://www.stagev.com/drawings/StdValveHead.jpg — Preceding unsigned comment added by 97.113.239.250 (talk) 05:23, 18 April 2022 (UTC)

Engine idle

I would know why the idle of the engine has a non rythmical sound when the nitromethane kicks in--Saludacymbals (talk) 20:09, 15 August 2012 (UTC)

Nitromethane does not "kick in", the engine is always running on it. You have it confused with Nitrous Oxide which is just an oxidizer, and sometimes referred to by Fuelers as "The Baby Bottle". The non-rhythmical sound you hear is due to a 270+ degree overlap racing camshaft, sometimes referred to as a "lope" or a "rump". AE7EC (talk) 00:38, 5 August 2017 (UTC)

-- Nitro cars are started with gasoline or alcohol, then switched to nitro, hence the sound change. The reason this is done is because there is so much nitro takes some heat to get it started burning. When you spin the motor, is can't get up to the 1800 or 2000 RPM with heat to start the amount of Nitro that is being fed into the combustion chamber. That is whey you here them start the motor, then it quickly switches to nitro and starts cackling. To understand that, you need to know the properties of nitro, it is basically exploding in the chamber, not burning. You can cut nitro to produce more power though I am not sure they do it these days. They use to cut it with acetone or propylene oxide.A Tope Fuel car can handle up to 98% nitro but NHRA regulates it to 90% nitro. Also, running 98% is something failry recent, due to better magento and ignition systems. — Preceding unsigned comment added by Spdge70 (talk • contribs) 17:01, 29 March 2018 (UTC)

1000 ft vs 1/4 mile

The wording of the article indicates that 1000 foot is the normal, and that running 1/4 mile is the exception. The is an extremely US-centric view, when 1/4 mile has always been the distance run all over the world. It really should be added almost as a footnote that America alone made run 1000", and that this is not that traditional or internationally accepted distance for the event. —Preceding unsigned comment added by 58.173.132.226 (talk) 04:43, 12 July 2009 (UTC)

I'm pretty sure that parts of this article have been lifted from a widely distributed article which has been claimed to have factual errors. One of example is that of the "dieseling"; I remember someone saying that this only happens occasionally, but the article gives the impression that this is normal.

Can anyone with more expertise please clarify this?

The 1000' change was made by the NHRA after the death of Scott Kalitta, due to the extreme speeds Top Fuel Funny Cars & Dragsters were attaining over the 1/4 mile races. It was deemed that 1000 foot would allow for a safely lower speed, and more shut-down time. It otherwise would have made it a mess if tracks with shorter shutdown areas were set to 1000', and longer tracks like Bandimere were allowed 1/4 mile runs. Not only would this cause extreme favoritism of the longer strips, but it would have made a mess out of records. All other classes, including Top Alcohol still run 1/4 mile, as far as I know. Scott's final run can be seen here: https://www.youtube.com/watch?v=cfdDBq4POh4 AE7EC (talk) 00:49, 5 August 2017 (UTC)

Picture

a much closer night time shot might be a better choice

moving photo of top alcohol dragster to Top Alcohol article. Cdh1984 06:53, 2 May 2006 (UTC)

Clutch and Tires

These dragsters wouldn't be performing at this level without the innovations in slipper clutch design..... as well as tire innovation and manufacture

Please help The only fellow mentioned in this article is one who died. In a clutch section, Big Daddy Don Garlits should be mentioned as the innovator who tried manually slipping a manual clutch--before this, the cars smoked the tires for nearly the entire distance!

Grammar

I took care of some of this today....

The section titled "The Top Fuel Engine" has quite a few grammar errors - many are subject/verb disagreement. I'd fix it but sometimes one has to know the implied meaning in order to achieve the correct explicit meaning when repairing grammatical errors. Can someone who is familiar with the subject and the English language fix this? human 19:10, 12 August 2006 (UTC)

Too specific?

See my additions re the engine design......Yes, they are ALL the same, at present 500 cubic inch limit Other designs have been tried, but the cost of production for such a low volume deal is prohibitive....the sport is already at the limits of costs, as each run costs in the thousands of dollars. Also note that the fuel classes, funny car, alcohol dragster, and alcohol funny car use the same engine with variation for the application--the mechanicals remain fundamentally the same. Pro stock has a great deal of variety, but the 500 inch rule still applies

Much of the engine description appears to apply to a single engine, as opposed to top fuel engines in general. Is it really the case that every top fuel car uses the exact same engine? IE, no one's ever put the exhaust out four pipes?

Maury 12:37, 29 August 2006 (UTC)

Other layouts are occasionally attempted. The McGee brothers tried an OHC design (around 1990). I believe their engine had a hemispherical combustion chamber in a pent-roof configuration with four valves, but the pushrod layout has endured. Rainbow-five (talk) 17:58, 6 August 2015 (UTC)

The Fuel

Hello... Interesting article for those of us who know nothing about drag cars. One key point of this article must beto explain just why these cars use nitromethane rather than gasoline (or any other fuel)... and that point isn't really that clear from the section "The Fuel".

Now looking at the wikipedia article on nitromethane, it says:

"14.6 kg of air are required to burn one kg of gasoline, but only 1.7 kg of air for one kg of nitromethane. Since an engine’s cylinder can only contain a limited amount of air on each stroke, 8.7 times more nitromethane than gasoline can be burned in one stroke. However, nitromethane has a lower energy density. Gasoline provides about 42-44 MJ/kg, nitromethane provides only 11.3 MJ/kg. This analysis indicates that nitromethane generates about 2.3 times the power of gasoline when combined with a given amount of oxygen."

That seems much clearer. I'm not sure if that agrees what it says in this Top Fuel article. "Nitromethane has a stoichiometric air fuel ratio of about 1.7:1 and its energy content is about 11.2 MJ/kg. This suggest a very high specific energy at stoichiometric, about 6.6 compared to about 2.9 for gasoline. " is a pretty opaque explanation unless you have a degree in chemistry. Any chance someone who understands (not me!) could explain it better please? The stuff up above about less oxygen being needed by nitromethane, so fuel can be burned more quickly, is much easier to understand. Thanks! Chrisw404 15:03, 13 October 2006 (UTC)

The reason they use nitromethane ..

Every one knows that to make something explote ore fire you need air. the nitro methane allows to put more air in the engine than the gasoline ore other fuel does. that would say that its explote ore burn more than gasoline does. then if you can puth more air into the engine you can puth more fuel in. as more fuel and air you can puth in the engine as more horsepower you get —Preceding unsigned comment added by 80.160.127.128 (talk) 12:03, 24 August 2008 (UTC)

There is a huge difference between simply burning nitromethane stoiciometrically with air and the monofuel reaction of detonating nitromethane through concussive force. —Preceding unsigned comment added by 216.139.21.100 (talk) 04:00, 2 October 2008 (UTC)

I'm too tired to rewrite and footnote tonight, but the article says "In a typical run the engine can consume as much as 22.75 Gallons (103 Liters) of fuel during warmup, burnout, staging, and the quarter-mile run.". Now that number of 22.75 gallons is quoted from Wikipedia all over the Internet. However, the NHRA gives a very different number: "NHRA Top Fuel dragsters and Funny Cars use between 10 and 12 gallons of fuel for a complete pass, including the burnout, backup to the starting line, and quarter-mile run" (http://www.nhra.net/streetlegal/funfacts.html). TDHofstetter (talk) 02:10, 27 July 2014 (UTC)

In 2022, I'd say typically the fuel tank capacity is around 17 U.S. gallons. 193.166.112.29 (talk) 21:02, 10 August 2022 (UTC)

Which is faster?

Top fuel or funny cars? I'm not sure where the answer should be put..this article or the other one.--Hooperbloob 01:28, 6 December 2006 (UTC)

While both cars have the same amount of power, Top Fuel cars are lighter which allows them to accelerate faster and produce lower ET's. However, Funny Cars are more aerodynamic giving them a higher top speed. I suppose it matters how you define "faster".Mustang6172 (talk) 05:46, 6 February 2008 (UTC)

funny cars aint faster than the topfuel dragster. the topfuel dragster is mutch more thin and lower than the funnycar that would say you dont have so mutch air pres on the buddy. a funnycar need 500 horsepower more than the topfuel dragster to run as fast as they run. —Preceding unsigned comment added by 80.160.127.128 (talk) 12:05, 24 August 2008 (UTC)

Capitalization and hyphenation

Is it Top Fuel dragster, Top-Fuel dragster, or top fuel dragster? They're all used in this article. 23 February 2007 (UTC)

Ignition and supercharge

Fine page ! I'm one of those who didn't know much about dragsters before to read this page . So, I'm not sure to have caught up the aim of the following procedure : "Directly after launch the timing is typically decreased by about 25 degrees for a short time as this gives the tires time to reach their correct shape."
I can't figure out what can happen if this is not done: should this burn the tires, should make the thing uncontrollable, or... what if not, please ? I can just suppose that the goal is to temporarily reduce the power, right ? So what speed is supposed to be attained at this point when the tires are correctly shaped, and how long is the timing let that few degrees advanced ?

Also, what do they measure the exhaust temperature for ? Is it to regulate something ?
About the air surpercharger, I bet that only a few people know what General Motors scavenging-air blowers do look like. At least I don't, so I can't see why it seems to fit particularly well the design of top fuel engines.
--82.243.41.112 23:48, 4 March 2007 (UTC)

Torque equation

could the equation used to reckon the torque be furnished? —The preceding unsigned comment was added by 69.178.134.34 (talk) 00:34, 23 April 2007 (UTC).

Rewrite/split articles?

There is a lot of good information in this article. I think we could make "Top Fuel" more concise and more clear. I also think we could create "Top Fuel Engines" as a separate article with whatever interesting but more esoteric data we can actually source. Any thoughts? Gfloner 11:45, 5 July 2007 (UTC)

Speed of sound

would these cars be able to break the speed of sound given enough distance?76.27.107.181 03:36, 2 September 2007 (UTC)

You might want to ask at the science reference desk, as I'm not sure how watched this talk page is. Someguy1221 03:41, 2 September 2007 (UTC)

They have only about a tenth the power of the only land vehicle to have done so, the ThrustSSC.--Father Goose (talk) 06:04, 6 February 2008 (UTC)

They also weight about a tenth as much as ThrustSCC. (GTD 26 Nov 2008 21:14 UTC )

At low speeds weight matters, because initial acceleration is dominated by weight (mass, really -- Force = Mass * Acceleration). At the speeds ThrustSSC is going, aerodynamic drag becomes a huge force, and the greater torque that comes from a higher horsepower engine (assuming RPMs are equal -- horsepower is directly related to torque and RPMs) is needed to overcome drag. The maths get pretty complex, pretty fast, but the short answer is that torque is the force moving the vehicle forward, and mass times acceleration plus aerodynamic drag are the forces counteracting that. At a standing start, drag is 0 and all of the force (torque) goes into initial acceleration. Eventually torque divided by wheel diameter equals drag and top speed is reached and acceleration is 0. Note that weight doesn't appear in that equation, except to insure that the tires don't slip. Tall Girl (talk) 04:14, 30 September 2013 (UTC)

Nitro percentage

Stating a maximum of 85% is not entirely correct, at present NHRA rules dictate 85%, but in europe the maximum is 90%, and NHRA are going to go back to 90% soon.

79.73.154.251 15:53, 2 November 2007 (UTC)

They reverted to 90% in the US beginning in 2008.

[GTD 21:14, 26 November 2008] —Preceding unsigned comment added by 158.145.224.34 (talk)

Speed data

Are there are data sets available that measures the position/speed/acceleration vs. time? (Of course, any one of them can be used to derive the other two.) If a typical run burns 103 L of fuel then that's 117 kg of fuel (assuming 100% nitromethane) which is not insignificant which means acceleration is not constant (weight loss, among other things). Cburnett (talk) 01:23, 12 February 2008 (UTC)

That acceleration is not constant is guaranteed. Air resistance and traction surely vary enormously over the course of the quarter mile, and gearshifts probably introduce a noticeable sawtooth into the acceleration profile as well. It would be interesting to see a graph presenting the data you mention. I'm sure the teams collect it on every single run. But getting one's hands on such data... that's another matter.--Father Goose (talk) 06:29, 12 February 2008 (UTC)

father goose.. top fuel and funny cars dont have gears. —Preceding unsigned comment added by 80.160.127.128 (talk) 12:08, 24 August 2008 (UTC)

Octane rating?

Is there an octane rating to top fuel? What about raw nitromethane, or hydrazine?68.231.189.108 (talk) 23:31, 6 December 2009 (UTC)

NHRA Top Fuel Champions (1974-2009)

This was removed from the main article. It does not belong here. If it can be used elsewhere, copy and paste it into another article, then delete this section. I like to saw logs! (talk) 06:40, 18 December 2009 (UTC)

• 1974 - Gary Beck,
• 1975 - Don Garlits,
• 1976 - Richard Tharp,
• 1977 - Shirley Muldowney,
• 1978 - Kelly Brown,
• 1979 - Rob Bruins,
• 1980 - Shirley Muldowney,
• 1981 - Jeb Allen,
• 1982 - Shirley Muldowney,
• 1983 - Gary Beck,
• 1984 - Joe Amato,
• 1985 - Don Garlits,
• 1986 - Don Garlits,
• 1987 - Dick LaHaie,
• 1988 - Joe Amato,
• 1989 - Gary Ormsby,
• 1990 - Joe Amato,
• 1991 - Joe Amato,
• 1992 - Joe Amato,
• 1993 - Eddie Hill,
• 1994 - Scott Kalitta,
• 1995 - Scott Kalitta,
• 1996 - Kenny Bernstien,
• 1997 - Gary Scelzi,
• 1998 - Gary Scelzi,
• 1999 - Tony Schumacher,
• 2000 - Gary Scelzi,
• 2001 - Kenny Bernstien,
• 2002 - Larry Dixon,
• 2003 - Larry Dixon,
• 2004 - Tony Schumacher,
• 2005 - Tony Schumacher,
• 2006 - Tony Schumacher,
• 2007 - Tony Schumacher,
• 2008 - Tony Schumacher,
• 2009 - Tony Schumacher

Confusing Introduction

I found these two sentences rather confusing: "They are the fastest such category, with the fastest cars reaching the end of the 1/4 mile in less than 4.0* seconds at speeds up to 337 mph (530 km/h)*Times below 4.0 seconds have not yet been achieved on the 1/4 Mile this time relates to the shorter 1000 feet distance,while the 337 mph is only achieved on the 1/4 mile (all as at Aug 2009)"

I think that this means "They are the fastest such category, with some cars reaching the end of the 1000 feet in less than 4.0 seconds, and reaching speeds of up to 337 mph (530 km/h) on the 1/4 mile event." Can anyone confirm? Jamesscottbrown (talk) 11:43, 24 December 2009 (UTC)

Copyediting

It's sad that such a good article is so poorly referenced.....anyway, I've started copy editing it. However, I'm going to have to take some stuff out due to lack of citations.Bddmagic (talk) 16:50, 21 September 2010 (UTC)

copyediting done.Bddmagic (talk) 16:57, 21 September 2010 (UTC)

esza

I think the engine detail misses bearing information detail. I'm more into boat drags, but teams are lucky to have an engine last through one race. Most blown engines are due to high rpm, noted in rear axle ratio limit to keep speed down. Drags are more about acceleration than speed. Anyway there are turbines that spin 40,000 rpm so how do we get car to do that. I'm confused as to engine fuel, we are using a manifold? Air compressed (blown) ahead of the fuel injection? The manifold may not be hot enough to detonate high octane gasoline (isooctane) and air, but Nitromethane only needs the pressure to be too high or a shock wave to detonate. Industrial grade Nitromethane (has Methyl Nitrite and Nitrate) is more likely to explode than pure Lab grade and there's been explosions just boiling pure Nitromethane. (If you have lived in a hot climate and had an older engine, it will sometimes "diesel". The cylinder is so hot that even when spark is turned off it still burns the fuel air mixture it draws in. High octane aviation gas starts burning at 536 °F, low octane gas at less than 470°F, diesel at below 410 °F.) Power comes from gases expanding from cylinder top stroke to full stroke. Gases expand because the reaction produces more volume and because gases at higher temperature have a higher volume. Compression of air/fuel increases the base temperature of reaction. Normal engine has top stroke temp of 300°F exhausting at full stroke at 1400°F; Compressor heats air up, a hot manifold will give a higher temperature at top of stroke giving lower Engine efficiency. (Aircraft often cool the supercharger output before it reaches the engine.) The gasoline oxygen calculation is wrong. Ignore the tiny volume of gasoline used, and rem air is only 21% oxygen (Nitrous Oxide is 35% oxygen + extra energy) burning gas only gives 2 times the original oxygen volume in exhaust gases, it takes of about 900 Liters of air to burn .115 Liter of gasoline. ( This is so rich you see smoke, previous calculation in wiki is where gas is completely burned up to Carbon Dioxide, since 85% of the energy comes from burning to Carbon Monoxide anyway we optimize power based air the cylinder can aspirate by running rich.) Nitromethane with no air generates 2 1/2 volumes of gases. Aircraft piston and turbine engines (and jets), like those used in fighters and drag boats, can get a boost of energy by using water and/or alcohol injection. Hence I don't think lowering the Nitro percentage has as much effect on power, in fact replacing some of the alcohol with water might be beneficial. Perhaps additives like in Otto Fuel II torpedo fuel that increase burning rate would be allowed? Or eliminate the blower and use a Nitrous cylinder? If lots of unburned fuel is wasted, why aren't the exhaust pointed upwards instead of backwards for more thrust? And the note about tires, the "burning" of the tires at the start is to heat up the tires, as the rubber is "stickier" when its hot giving more traction. Shjacks45 (talk) 16:00, 5 March 2011 (UTC)

that is about 6 Kg Air per 1 Kg gasoline but volume calculation makes more sense. Considering Nitromethane is a monopropellant (it needs no air in rocket and torpedo motors) why not use a two stroke engine and get twice the power per cycle. — Preceding unsigned comment added by Shjacks45 (talk • contribs) 16:28, 5 March 2011 (UTC)

Acceleration

To reach 280 mph in 660 ft requires an "a" of 3.99G; this is 1st semester physics.Es330td (talk) 00:52, 8 June 2011 (UTC)

Yes and no. First, that's assuming constant acceleration. Second, traction in dragsters changes over the period of the race as the wings produce additional down-force. As you'll remember from 1st semester physics, F = m * a, but also friction limits the amount of force. At a standing start, the traction is limited to the weight of the vehicle plus initial exhaust down-force, times the coefficient of friction of the tires. At speed, wing down-force increases the effective weight of the vehicle for the friction calculation, so acceleration can further increase, subject to increases in drag caused by increases in speed. Long story short, acceleration isn't a constant. Tall Girl (talk) 04:23, 30 September 2013 (UTC)

Some rewriting needed

Article currently [1] reads in part Billet steel crankshafts are used; they all have a cross plane a.k.a. 90 degree configuration... Not really; crossplane V8 engines are all 90 degree Vs, but flatplane V8s can be any angle and 90 degrees is one of the two most common angles (the other being 60 degrees). Andrewa (talk) 21:53, 26 May 2012 (UTC)

Just a comment to clarify, after several years with no comments from anybody:

The text refers to the angle separating the crank planes, not the V angle of the engine block. In that sense, it is fully correct.

Out of memory, at least once in a time (in the 70's?) there was a rule that required the engine geometry be based on an existing American passenger car engine design, and all the V8's used to have 90 degree angle (and a 90 degree cross-plane crankshaft). In practice, the reference engine came to be the second-generation Chrysler Hemi https://en.wikipedia.org/wiki/Chrysler_Hemi_engine#Second_Generation:_426.

In 2012, the NHRA rules were like this. No mention about American, so you could have entered a Rolls-Royce based engine, too, or a Russian ZIL, or GAZ, but not much else? And it must be NHRA-accepted, too:

"ENGINE Any NHRA-accepted, reciprocating, 90-degree V-8, single camshaft, automotive-type engine permitted. Multi-valve and/or overhead-cam engines prohibited. Maximum 500 cid, minimum 490 cid; maximum bore center spacing 4.800 inches; maximum cam centerline 5.400 inches, maximum two valves per cylinder. Only one cylinder-head design is acceptable: Intake valve angle of 35 degrees, + or - 1 degree Exhaust valve angle of 21 degrees, + or - 1 degree Engine block must be forged aluminum and NHRA-accepted."

So, pretty restrictive rules, probably due to concerns of excessive speed and cost. I do not know of any other V angle than 90 degrees being used as the between-cylinder-banks angle in a top fuel engine during the past 40 - 50 years or so. I assume this is the combined effect of rules and tradition. Salmhe02 (talk) 17:22, 8 November 2018 (UTC)

References

Transmission?

How is this article not mentioning that these cars don't even have a transmission? Is this supposed to be common knowledge? Certainly not for someone who is googling Top Fuel. 2A02:8070:1CD:9000:221:5DFF:FEB4:C5E0 (talk) 23:37, 2 March 2015 (UTC)

Top Fuel Motorcycle Information Should be Added

Top Fuel is also a motorcycle class, but no mention is made of it in the article. Perhaps if this omission is intentional the title of the article should be changed. The Motorcycle Drag Racing article has a link to this article. — Preceding unsigned comment added by 24.22.76.12 (talk) 17:14, 18 December 2015 (UTC)

Adding fuellers to the fire

The first line says "Top Fuel dragsters", as if nothing else can be, or is, a TF car. That's obviously wrong, & needs fixing...but I don't want to blindly tamper with a settled lead section. TREKphiler ^{any time you're ready, Uhura} 16:23, 13 April 2018 (UTC)

Link problem

(Note: I would do this myself but I'm not sure if I should, so I'm putting this here.) Under the fuel section and in the third paragraph, there is a link that say "pre-ignition." Now when I click on it, it takes me to something about knocking. But when I go down this page, it says it is not to be confused with pre-ignition. So I wondering if I should relink it. Thanks, Ramesty. Ramesty (talk) 06:41, 19 October 2019 (UTC)

The math here is wrong...

From start to finish the engine will turn 240 revolutions. Including start up, burnout, staging and the race, the engine must survive just 500 revolutions before being rebuilt.[citation needed] This calculation assumes an average racing engine speed of roughly 3800 revolutions per minute over a period of 3.8 seconds.

The 240 number is accurately 3800 RPM for 3.8 seconds, but the narrative clearly states "Including start up, burnout, staging and the race" which is far longer than 3.8 seconds. Additionally, it has to be assumed that the engine will turn far more than 3800 RPM during the race itself. 184.83.70.31 (talk) 13:30, 15 November 2023 (UTC)