Quote Originally Posted by Carbon View Post
Unforgiven, I have a couple of questions about Top Fuel engines in cars if you can answer. First question, when the crew starts the engine after rebuild sometimes they do it on alchohol and others they start on alchohol and switch to Nitro, why is this?
Second question, when the car is staged you can hear a noticeable pull-down in the engine right before they launch, can you explain?
Carbon, I'll tell you how we did it and why..not saying everyone does it the same way..so here it goes..In the pits when we do our our first start we squirt into the injectors with Alcohol (gas if it's cold out) and we have an alcohol bottle tied into the fuel system with fuel pump off..We fire off the motor and let it build heat and verify all holes are firing, while this is going on we also look for oil leaks..While this is going on, the driver will let out the clutch and tires are spinning, he pushed in clutch and puts the car in reverse (this is done on the stands) then pushes clutch back in and goes forward. ( this verifies we can shift the car forward- reverse, make sure it all works)this all happens within 1st minutes of starting car. Once the tuner and i agree all is well..we signal to driver to engage the pump..as the motor starts to pick up the Nitro we kill the alcohol..the pump is only feeding part of the fuel to the motor at this time..(now I'm looking for leaks in the fuel system) once all is looking good (remember the tires are still spinning) I'll signal to the driver to engage the pump fully and pull the brake...the brake will load the engine and thats where the Nitro starts going nuts (without the load you'll see raw fuel out the pipes..) we'll do that twice make sure there's no leaks and signal to the drive to kill the pump..the motor starts to clear up, then starts to idle up then we kill the mags.. .thats out initial start....now we do a quick lookover. clear out any nitro thats in the fuel systen (pump is shut off and system drained of fuel) pull plugs, run valves, adjust clutch and put it back together..we're ready to head to staging lanes. On the starting line: the car has plenty of temp on it so when we start start it on Alcohol..look over to the car in the other lane..we get the nod they are ready, I signal the driver to start engaging the pump, (partial only) motor is running on Nitro and quick lookover i have driver come into the water box for a burnout..he does his thing..Now here''s where a-fuel is different that in a blown car.. being injected we have alot of compression in the motor on once the car stages, the driver will engage the pump full and this thing starts getting violent..Nitro like to see a load....Now on a top fuel car...when it first stages, it's also only on partial pump once it get's to ready to stage the driver will fully engage the pump..ALOT of fuel is running thru the motor. On a A-fuel deal we hit the motor with 21-22 gallons of fuel running thru the system (like i said others will hit it with more or less)Top fuel is going to be twice as much if not more...