Can't wait to get started

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Re: Can't wait to get started

Postby Itsturpintime » Tue Mar 25, 2014 9:55 am

Dreher race cars , yes I have a trans brake not sure if it's only for low I'll have to find out and get back to u, and for the tires I have some 14 staggered supper scoops but I'm not sure if ther 32. Or 34. I think 32. But I'll check to night. thanks
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Re: Can't wait to get started

Postby Itsturpintime » Tue Mar 25, 2014 2:28 pm

Yea the brake only works in low gear. And the tires are a staggered 14 paddle supper scoop 32" tall. Thanks !
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Re: Can't wait to get started

Postby Hot Stuff » Tue Mar 25, 2014 6:10 pm

Dreher Race cars wrote:
Hot Stuff wrote:Not a real good comparison, but im at 2500# with driver, a little 269" small block chevy, with a th350, with 5.38 gears in the rear, 4.88 up front. I launch at 6000 rpm in 1st, and shift into 2nd almost immediately after releasing the brake, then shift into 3rd at 8200 rpm and trap at 8200 rpm in 300'. All in high range. Seems the key to a 3 speed is getting it out of 1st gear ASAP. I have a custom planetary with a 2.23 first gear, 1.42 second, and 1:1 third. It's better than the stock 2.52, 1.52, 1:1. I like it. But if I ever redo the drivetrain setup, it'll be a glide. I only went with the th350 because I had it, and I run a tcase. No way to hook the glide to a tcase in my super short wheelbase.

:shock: I really have a hard time believing this, a 269ci 2500 lbs that can pull a 5.38 gear and cross the finish line at 8200RPM even your second gear is 7.63 you would be lucky to shift out of second before crossing the finish line. You better check your transfer case shifter you have to be in LOW range not HIGH range as stated above.


What's so hard to believe? You've seen me run at gravel. It's a Dana 20 case. It's not in low range. It's geared so low in low range it would never be able to make a 300' pass. It runs 5.0's all day long.
Cast iron head, under .500" lift, flat tops, and a good 7" converter. The little 3" stroke is just a screamer.
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Re: Can't wait to get started

Postby Dreher Race cars » Tue Mar 25, 2014 10:29 pm

What's so hard to believe? You've seen me run at gravel. It's a Dana 20 case. It's not in low range. It's geared so low in low range it would never be able to make a 300' pass. It runs 5.0's all day long.
Cast iron head, under .500" lift, flat tops, and a good 7" converter. The little 3" stroke is just a screamer.[/quote]
What is your top speed in 300' ? What RPM does your converter hit wide open on trans brake ? And your telling me that you run 8200 crossing the finish line in high gear? For comparison I had a modified 6cyl with a standard dana 20 ( 2 to 1 ratio) with 4.56 gears, ran 2nd to 3rd with a manual trans in low side 9.12 final drive. It would turn about 7600 and run 5.0s to low 5.1s. Also the takeoff ratio your claiming 2.23 x 5.38 =11.99 is very close to a powerglide setup 1.76 x 6.5 =11.44 our NA car with this setup and 800 HP/ 1920 lbs with driver runs out to half track , before it shifts at 7800 ,the same gear ratio in heavier cars around 2300lbs with less power say 650 HP (and there are many) will run to about 200 ft. Yet you claim you shift out of this ratio as soon as you let go of the trans brake!! The ratio we shift to 6.5 which is lower than your final we only turn 7200 to 7400 crossing the finish line while turning 3.6s. And one more thought the calculated tire speed for 5.38 at 8200 RPM with your tire height is 138 MPH even if you deuct 20% for converter slippage and possible tire spin thats still 111MPH. SO YES IT'S HARD TO BELIEVE!!
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Re: Can't wait to get started

Postby Dreher Race cars » Wed Mar 26, 2014 1:35 am

Itsturpintime, Sorry for straying from the original question. If you have the standard ratio 400 2.48,1.48, 1to1 and you have a 9in Ford rear. My opinion would be to start with 4.86 and plan on only running 1st and 2nd this would be 12.05 takeoff and 7.19 final in 2nd. Or if you plan on running nitrous all the time and for sure over 1000hp and 2500lb or under, maybe 4.56 which is real close to the glide setup at 11.30 takeoff and 6.75 final. I agree with Tony on your tech answer that you will most likely run faster only using 2 gears if you gear the car for 3 speeds the low gear for high horsepower is usually too low and will result in tirespin and time lost. Again my opinion , wait a while if possible ,someone may chime in with a setup real close to yours and say what they are running and what RPM they turn.
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Re: Can't wait to get started

Postby Hot Stuff » Wed Mar 26, 2014 6:18 pm

So educate me on what the numbers should be if it were in low range. I'm curious. 16.50 rear tires.
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Re: Can't wait to get started

Postby Dreher Race cars » Wed Mar 26, 2014 6:48 pm

Hot Stuff , gear ratios going by what you say your transmission ratio are LOW SIDE in transfer 1st 23.99 this gear is really too low for takeoff and would cause you to have to shift immediately within the first 20 or 30 ft. 2nd 15.27 would be close to a good takeoff gear for you and depending on your HP should run out to about 120 to140 ft in comparison my takeoff ratio on my 6cyl in 2nd was15.96 and would run out to shift at about 90 ft. 3rd 10.76 final this would be buzzin the motor at the finish line but not a ridiculous gear for your setup 10.76 at 8200 RPM calculated tire speed with your tire height is 70 MPH, which i imagine is very close to what you run!! If your converter is 6000 to 6500 stall it should be pretty locked up so i would think your actual speed might be somewhere between 64 and 68 MPH, and most likely slower at gravel than it would be on a good dirt track.
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