What is everyone using / prefer as far as transmissions go? Im starting a build sheet for needs/wants and I have been looking at a clutch less set up. Sorry in advance if this has been asked. I looked but didn't really see this topic. Im going to be running C/mmp naturally aspirated. Just trying to get ideas and whats been a proven direction.
Many use Jerico, proven, lots of ratios, simple . . . Word of advice, less things break if you have less things to break . . .
Probably help to know an approximate weight and horsepower output. You don't always have to go top shelf, and there are a lot of really fast cars using transmissions rated well below what's being put through them at Bonneville.
Our old, reliable, reasonable Super T-10, bought brand new for a very reasonable rate, was good for seven records in very competitive classes. My mentor had the same setup 25 years ago and still has El Mirage and Bonneville records. The "secret" is to getting 3rd and 4th as close together as you can. The first three gears are just there to get you to 4th. {Your results may vary (especially at El Mirage -- virtually a drag race)} -- but we both still hold C records there -- his 25 years old.
G-Force 4 speed in Hooley's Stude. Many ratios for 1-2-3 and 3rd can be an overdrive (what we do). The G-force comes in clutch-less and what they call clutch assist I believe. We don't run the clutch-less model, but can shift without the clutch. Be careful about picking one that is clutch-less as you will be in and out of the gas at times and in that situation it might pop out of gear. It is great for the strip but not great for the salt in my opinion.
I have info on the G-Force here...
http://1fatgmc.com/car/car-other-1/G-Force%20101%20Info-1.html
Sumner
Thanks guys. Something to think about that I didn't as far as being in/out on the gas. Ive used clutchless setups on my drag cars but never on the salt.
Mike Strasburg at B&J may still have my old Owens 3 speed planetary he could make you a good deal on
Thank you all..... This is why I joined this forum was the knowledge of doing it vs. not...... Im still in the very EARLY stages and did not want to put a timeline on myself.
Important elements:
1. when it's traction limited, the torque rating becomes less important.
2. your target speed + how narrow your peak power range will determine how much RPM % drop you can stand on your shift into high gear. As Stan Back said, the other gears are to get there. A bad choice (high RPM power, 25% drop) means it will be faster in 3rd than 4th. Big MPH means load in high gear is mostly aero (in the lower gears it's inertia).
3. if you already have the axle + ratio, OD may be helpful but it uses more power (and higher internal temperature) than direct, and many add-on OD (Gear Vendors 78% recovery) have more drop than you might like. The BSA Gold Star had 92% recovery on the 3-4 shift 60 years ago.
4. if your top speed is really high, you need lots of "progression" (decreasing % drops in the upper gears) to have a useful 1st gear and still do the trick on the 3-4.