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## RE: Transmissions

 To: Beth Butters , RE: Transmissions Beth Butters Fri, 23 Apr 1999 21:45:49 -0700
 ``` I really do understand what you are saying if E.T.s made a difference for trap speed but really they don't, of course that's what drag racing is all about. You can take any given car and it will run just so fast in the quarter mile assuming it didn't top out early because of being geared to low. Without touching the engine it is usually easy enough to lower the E.Ts with tires gearing traction aids ect. But without changing the tuneup, the trap speed is still a function of the cars weight and the power to move it and it won't change but a couple of %. If at the drag strip the race was won or lost with trap speed 60 foot times wouldn't mean a thing. Sure if your car isn't capable of over powering the track surface, put lot's of gears in it and run it as if it were an Austin Mini. But most of the cars I see run on the flats are perfectly capable of braking traction when they enter the torque band in all the lower gears, so you have to ease into each gear which waists much of the mechanical advantage you have available to you. Maybe I can explain speed verses distance the way I understand it , your engine produces a given amount of total torque in the time it takes to go a distance and obtain a certain speed , weather it takes 20 sec. To do this or 25 it makes no difference it's the same area under the acceleration curve, which is the total torque used to accomplish the task. That is why the to tall geared , short geared car will match the trap speed of an identical car with optimum gearing in the quarter mile. So to my way of thinking that as long as your car is geared so it will pull smoothly at W.O.T. with the gears you have available , your going to be going the speed the car will go at the 2 1/4 mile. Dos this only make sense to me or what? We'll knowing all the different ideas I come up with that is probably the case, I've only thought about this for 35 years and have rarely found anyone who could comprehend what I was talking about. None of this is t can at the 2 1/4 and still be geared tall enough to make your target speed isn't how you do it, atleast with a 5 mile track. Good Luck Guys, Kvach ---------- From: Dave Dahlgren[SMTP:dahlgren@uconect.net] Sent: Friday, April 23, 1999 6:47 AM To: Beth Butters Cc: Land-speed@autox.team.net Subject: Re: Transmissions The real problem is that you run out of race track to play with. Your old 55 would go faster than 80 I hope. Mine did. The whole key point is to keep the engine in the power curve . If yours is 5000 rpm wide and flat then fine. Most are not. My years of experience tell me that the power curve of most engines is 2200 rpm wide where things really happen. The engine we run has am much smaller one than that. peak torque is at 8800 and peak power at 9900. When you are not there you are just burning off the track distance. The faster you go the quicker you burn up the distance waiting to get to peak power. In my humble opinion you ought to be at 90 to 95 percent of what the car is capable of at the 1/4 and use the rest to get the last few percent. It has worked for me every time. I do not even like the push off as it burns off at least a 1/4 mile that i could have used. To me this is a drag race with a very long timing trap. But only my opinion . I have tested this and every time I am faster at the 1/4 I am faster at the end. The only thing you may not like is the amount of time that the car is not accelerating at the end of the course. if your car is accelerating at the 4 mile marker you have left a bunch of speed in the trailer so to speak. Remember it is an average speed the faster you go in to the measured mile the faster your average. The only thing in favor of you way of doing it is that now to my knowledge all the passes are in the same direction. When it was the same physical mile had to be really going early on so that when you run in the other direction you do not get to the same physical spot too soon going too slow. Anyway I guess it is "po tay toes" and "po taa toes"... i spend a day or too with the dyno sheet from the engine and the computer figuring out the power available and the power required to go a certain speed. correct all for the weather and altitude. If the car does not break and slippage is in the range calculated car will go within 1 or 2 mph of what we expect off the trailer. Have never made a 'warm up' or 'test pass' since the first one when car was new .. that one was 179 on a 162 record... Told Goodman to just leg it out through second gear and shut it off on the short course so we could look it over before we run it out the back door. Now it is off the trailer, pull the trigger, go for it. you have to love the EFI the tune up is done when the engine starts, the gearing is done before we leave, and if the computer says we will not break a record we work on the car until it says we will, then we haul the car out to make a pass or two. Just my way of doing i am sure there are many that work, this one has never failed though. Regards, Dave Dahlgren ```
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