Thread: i need some TF info for school please

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Top Fuel
Reserved for supercharged, fuel-burning dragsters, built specifically for all-out drag racing competition. Minimum weight at conclusion of run, 2,300 lbs including driver.

Engine: Reciprocating 90 degree V8 automotive-type engine. Single camshaft. Multi-valve and/or overhead camshaft engines prohibited. Maximum 500 cubic inches. Minimum 490 cubic inches. Maximum bore center spacing 4.800 inches. Maximum two valves per cylinder. Only one cylinder head design (hemispherical chamber) is acceptable: Intake valve angle 35 degrees +/- 1 degree, Exhaust valve angle 21 degrees +/- 1 degree. Engine block must be forged aluminum.

Dry-sump oil system.
Valve covers vented via minimum 1 1/4" I.D. hoses to rear 8 qt. baffled catch tank. No vents below valve covers. Unless constructed of titanium, SFI 14.4 ballistic valve cover restraints required.
SFI 7.1 lower engine ballistic restraint device (flexible ballistic material shaped to cover the bottom of the motor from header to header and from crank hub to rear motor plate to catch shrapnel. Non-flammable material liner to absorb oil. (oil absorbent material new for 2008).
Flange or lip must be fashioned to prevent intake to block gasket from extruding out.

Supercharger: Limited to Roots type. Rotor helix angle may not exceed that of standard 71 series GM-type rotor. (High-helix rotors are twisted at 6.5 degrees of twist per inch of length). Maximum size 14-71. 22 1/4" case length, 11 1/4" case width, 19" rotor length, 5.840" max rotor diameter including fixed stripping (teflon strips imbedded into grooves in the rotors to help seal rotor to rotor and rotor to case). (white strips seal rotor to rotor and orange strips seal rotor to case). Case must be one-piece with removeable front and rear bearing end plates. Spacer or components between supercharger and injector "hat" constructed of aluminum or composite material only, 2 1/2" maximum thickness. Variable speed/multi-speed devices prohibited. SFI 14.3 restraint system mandatory (ballistic bag covering entire blower and four straps anchored to pins at the headers, all fire-proof material). SFI 23.1 burst panel(s). Single panel must meet or exceed 10 sq. in. rupture disc area. Two or more panels must equal or exceed 12 sq. in. rupture disc area. Aluminum blower to manifold studs mandatory. Maximum blower overdrive 1.50:1. (the blower jams about 50 psi pressure into the motor and it takes about 800 hp just to turn the blower)

Maximum fuel injector hat air inlet opening 65 sq. in. Max height from crank centerline to top of hat 46.00". No electric or electronically controlled fuel injection. Fuel limited to 90% nitromethane/10% methanol. Maximum two fuel pumps
Don Garlits said years ago that the amount of fuel being blown into the motor would be about equal to the amout of water from 5 shower heads at once. I figured up the mileage with the help of one of the crew members at the last event.......1 mile per 55 gallons. Well, they're making 1,000 hp per cylinder now, so that's the amount of fuel it takes to do it.

Heads are billet, no water passages. Two spark plugs per chamber. Two magnetos (22 amps each). (Yep, you could weld thin material with 'em) They tell me though, that the motor is runnin' like a glow-plug motor when she gets wound up and doesn't really need the magnetos. They also tell me that the motor is takin' in so much fuel that it is just short of hydraulicing itself. At (I think) around 350 degrees, nitromethane changes chemically and releases its own oxygen and that's what allows such a fat mixture. (or lack of mixture )
I've heard two explanations for the zoomie flames at night:
1. nitro burns slowly and is still burning out the pipes
2. it's the air burning (or some component in the air...water vapor maybe?)
I don't know which is the correct explanation.

I asked one of the crew chiefs what the over-the-nose spring pressure was on the valve springs.....650 lbs.

What I wrote here is specific to NHRA Top Fuel cars. Other venues such as Nostalgia Top Fuel have different specifics (for instance, they are limited to one fuel pump and one magneto). They can also use the open face helmet with mask. NHRA requires a full face helmet with shield.