How much manifold pressure in a top fuel dragster?

[WATERWINGS]

I have asked this question to many and never got an answer.

OK, if it makes you feel better, how about in a top fuel BOAT?

I have heard of pulling tractors with 100 PSI, thats a quad turbo diesel, but thats probably nothing compared to a top fueler.

I had an old ('72) Capri V-6 with MSD, 4-barrel, alcohol injection after 4 PSI of boost, with no waste gate, I would let pump up to 20 PSI once in a while (also blew a head gasket somewhere around there)

Without a waste gate, you had to watch the boost guage instead of the tach to shift but it would pull it's ass off. (way faster than both of my stock Mustang GT's)

[WATERWINGS]

I even "Asked Geeves" He said I must have spelled something wrong!

[Capt.Insane-o]

:eek:

[WATERWINGS]

Is that all???

[WATERWINGS]

Also just saw Big Daddy Don run against Kenny bernstein's son, Brandon, Big just barely lost, due to hazing the tires.

Big is 71 years young now!!:) :D :cool:

Glad to see Big just back in the sport again!

Have his autograph/photo and have talked to him one on one twice, what a hero!

[Rickracer]

....it's mega volume. The injection setup is shooting the equivalent of 8 showerheads (not watersaver ones either) worth of fuel into ports you can literally just about stick your fist into.That's moving enough air to suck your typical hot air balloon flat in a matter of seconds. :cool:

[sho305]

Didn't the old cosworth V8s run something like 43psi at Indy?

Of course I remember reading an interview of a top fuel engine maker who said they hardly ever make a run to the end of the strip with all 8 cylinders. I think he said the rings blow out on 1-2 pistons every time. All in a few seconds or less.

Check this out: http://www.plr.nu/fabrication.htm

Now would that scoop be the bomb on top of an OB or what?:D :cool:

[pyro]

Hey guys, while we're on the topic, I went to cedar point yesterday and rode that new "Top Thrill Dragster" coaster ride, HOLY ****! zero to 120 in 3.5 seconds in a straight line, what a rush. hydraulic/cable driven, no electric motors. It goes straight up 420 feet, then straight back down the other side. Our group waited 5 hours to ride it, the park closes at 8, but once you're in line, they have to let you ride, we got off the ride at 10:30.

[Hydrovector]

Some interesting Top Fuel dragster facts:

One dragster's 500-inch Hemi makes more horsepower than the first 8 rows at

Daytona.

Under full throttle, a dragster engine consumes 1 1/2 gallons of nitro per

second, the same rate of fuel consumption as a fully loaded 747 but with 4

times the energy volume.

The supercharger takes more power to drive then a stock hemi makes.

Even with nearly 3000 CFM of air being rammed in by the supercharger on

overdrive, the fuel mixture is compressed into nearly-solid form before

ignition. Cylinders run on the verge of hydraulic lock.

Dual magnetos apply 44 amps to each spark plug. This is the output of an arc

welder in each cylinder.

At stoichiometric (exact) 1.7:1 air/fuel mixture (for nitro), the flame

front of nitro methane measures 7050 degrees F.

Nitro methane burns yellow. The spectacular white flame seen above the
stacks

at night is raw burning hydrogen, dissociated from atmospheric water vapor

by the searing exhaust gases.

Spark plug electrodes are totally consumed during a pass. After 1/2 way, the

engine is dieseling from compression-plus the glow of exhaust valves at 1400

degrees F. The engine can only be shut down by cutting off it's fuel flow.

If spark momentarily fails early in the run, unburned nitro builds up in

those cylinders and then explodes with a force that can blow cylinder heads

off the block in pieces, or blow the block in half.

Dragsters twist the crank (torsionally) so far (20 degrees in the big end of

the track) that sometimes cam lobes are ground offset from front to rear to

re-phase the valve timing somewhere closer to synchronization with the

pistons.

To exceed 300mph in 4.5 seconds dragsters must accelerate at an average of

over 4G's. But in reaching 200 mph well before 1/2 track, launch

acceleration is closer to 8G's.

If all the equipment is paid off, the crew worked for free, and for once

NOTHING BLOWS UP, each run costs $1000.00 per second.

Dragsters reach over 300 miles per hour before you have read this sentence.

[STV_Keith]

Originally posted by WATERWINGS
I have heard of pulling tractors with 100 PSI, thats a quad turbo diesel, but thats probably nothing compared to a top fueler.

BTW, diesel pulling tractors can exceed 200psi of boost. :)

[crazy horse]

The Unlimited aircraft DAGO RED ran 105 in. of boost in there Rolls-Royce powered P-51 when it set the worlds record of 517.079 mph.:D

[235spd liner]

a top alcoholic dragster will make 90-105 psi by the end of its run a fuel dragster will make 70-90 but the race is won with the cluch

[CRMERC]

the other thing that is weird is that they have no cooling system. The nitro does the cooling when it idleing and by the time its ready to melt the runs over. 2" inch fuel line very scary. Crazy horse I dont believe that is the same. That is in inches of mercury not pounds per square inch there is a better explanation but currently it exscapes me.

[mcollinstn]

100 inches (of mercury) is somewhere around 45 psi.

I have spoken to a supercharger guy who said Top Fuel runs in the neighborhood of 35 to 45 psi. Just passing along info I received - have no idea how right or wrong he was.

[sho305]

The Merlin V-12, they say under 3 atmospheres. Neat little 1 page writeup about racing P-51 engine here: http://www.enginehistory.org/rolls-royce.htm didn't know it was a 4 valve head...and 1650 cubic inches! In a hydroplane here at 4200rpm and 2500hp: http://www.lesliefield.com/other_history/roostertails_unlimited_chapter_5_the_power_plant.htm Too heavy and durable for drag racing I guess.:cool:

[Propster]

I don't' know about using more fuel than a 747. Maybe one engine or all 4 during cruise. A fully loaded 747 uses 4,000 gallons on taxi and take off. Each engine has a 1 1/2 inch fuel line going to it. Also, I can't imagine going over 45 psi in boost. The excessive heat would result in diminishing returns.

[ripperd2]

Originally posted by Propster
The excessive heat would result in diminishing returns.

Top fuelers have heat problems on the intake... Due to the vaporization of the nitro, it absorbs a tremendous amount of heat when it does that. After a run a top fuelie has frost on the intake....They spray special lubricants in the motors just before a run to keep things from frosting up and freezing, IIRC.

-Dean

[Mr Wobbly]

I was reading about the Merlin race engines the other day. The interesting thing is that for nearly 50 years after WW2 they were ignored as race engines because by Warbird standard the Merlin is a small engine at 'only'1750 cubic inches or 27 litres.

The big radials and the larger Rolls Royce Griffons ( 32 litres ) were more popular. Various people had tried to use Merlins, especially in the P51 Mustang because it is such a fantastically efficient airframe, but the Merlins did not like big revs and constantly threw rods out the side of the block.

The solution came when two engineers, who's name eludes me, noticed how similar the con-rods for the American Allison V12 were to the Merlin. The Allison rods were also much stronger and with some modification could be made to fit the Merlin.

This modification along with others allowed the Merlin to rev harder and thus produce more power. There are dozens of variations of Merlin engines and the builders found that by playing with Supercharger combinations ( they came with two and even three stage superchargers ) they could build upon the success of the engine mods used above.

It's also interesting to note that they also used the engine blocks from transport aircraft rather than fighters as these were made heavier and stronger to last longer and were better able to withstand the extra pressures involved in racing.

The Merlin originally developed about 960hp when first designed and was giving about 1030 during the battle of Britain. By the end of WW2 it was producing about 2050hp in the De Havilland Hornet fighter.

The P51D Mustang's Packard built Merlins produced about 1560hp giving the standard aircraft an optimal top speed of about 450mph. Interestingly the Mk 24 Spitfire needed the bigger 32 litre 2000 - 2300 hp Griffon engine to achieve similar performance, so you can see why the Mustang is a popular air-racer.

I love the sound of my V6 Merc, I love the sound of a good V8 car and I love the sound of a good V twin bike, but to my ears nothing beats the noise of those big Merlins.

Soory about the history lesson, but along with boats I love warbirds. As leats I can afford to own a boat ...lol!

Cheers all

Dayle

[sho305]

They are very impressive machines. One wonders why the technology often took so long to reach everyday cars/bikes/etc.

My father inlaw was telling me about when he was stationed in Germany and they had Chevy V8s in tanks there. They had superchargers on them and some of the guys sent them home when they left...brand new crate motors! 283s I think.

[chris_lacey]

Mr Wobbly, if you love warbirds you would have wet your pants at my last house. I lived adjacent to the Hamilton, John C. Monroe Airport in Hamilton, Canada. The airport is home of the Canadian Warplane Heritage Museum.

These guys fly their planes most weekends. The Sunday afternoons were often spent chasing each other around. It was very cool (and loud) to see a Mustang chasing a Corsair at about 1000' both flat out!

The loudest plane they have is their Lancaster. I believe it is the only one left flying in the world. When it was being restored the last of the 4 engines had to come from Australia. They only fly it a few times a year.
They lost their Spitfire in a fire a few years ago.
Cheers

[Mr Wobbly]

Hi Chris

Thanks for the reply.

Yes I probably would have wet my pants, however we are fotunate that a very small country like New Zealand has a world class warbirds museum in a small town called Wanaka in the alpine district of central Otago.

The Museum was started by Tim Wallis, now 'Sir Tim'. He made his money initially from the live captue of wild deer in the alps. These guys had to be seen to be believed, chasing deer at 0 feet in choppers, shooting them with net guns and then jumping out to hog tie them. The mortality rate in the industry was huge. To the Hunters, not the deer!

Anyway from memory, Sir Tim has a Corsair, 2 Spitfires, Several Russian Polikarpovs, a TBM Avenger Torpedo bomber, a Hawker Hurricane, a P40 Warhawk, A Texan/Harvard trainer conerted to look like a Jap Zero for the movie Tora Tora Tora and several other planes.

They have a bi-annual Airshow at Easter, ( next one is 2004 ) which regularaly attracts around, 100,000 people. At the same time down the road there is the Cardrona Hill Climb which is very much like Pikes Peak and often has some world class drivers and machinery attending.

It's petrol head heaven by our standards and well worth making the effort to see if your ever in NZ. Just a shame no boating events.

I'm happy to host or help any S&F members. Your just going to have to drink Kiwi Beer however!!! lol

The lakes around here are fantastic and the boating is great. the performance scene isn't as big, given out population only hit 4 mill last month, but there are still alot of nice boats around.

The gear is very expensive here because of our weaker dollar, ie a new performance merc can easily cost over 30 grand and a really nice rig will cost 50 grand plus. When the average wage is only about 27 grand per annum, a new boat is a dream to most people.

This is why I'm fitting a wiper to my PC moniter, to clear away the drool ( it is drool! ) after logging on to S&F.

Jet boating is really popular here with the amount of rivers we have which are braided and shallow. Jet Sprinting is also really popular and a sure crowd pleaser. There is no drag boating at all.
(sigh)

Anyway, better go.

Any replies welcome

Cheers

Dayle