I need a build powerglide that has a second gear more like an OD where it is something more like .67 instead of a 1 to 1. Does anyone know if there are even parts available to do that? Changing rear end is not an option before someone suggests that path forward.
Not really possible. The GM 2 speed powerglide, like the 3 speed Turbohydro350/400, Mopar 904/727, and Ford C4/C6 tansmissions are simple planetaries that have 2 or 3 ratios utilizing low gear(s) then lock up everything spinning together to give 1:1 ratio. Later trans cases had the ability to grab a different part of the planetary gearset, achieving an overdrive ratio. A powerglide does not have that capability. If you did- you'd have only 1st gear and Overdrive, which is a tall order for most street cars to push through. Why is a rear ratio change not an option? (I know you said it wasn't, but you didn't say why). If it was, you could always use a more suitable rear ratio and there are millions of people making low 1st gear planetary gear sets for powerglides- that way you wouldn't lose the low speed acceleration.
I am not trying to be evasive, but I need to keep things at a high level and not get into a deeper discussion on the whole project. Let me ask this question to rule in or out the possibility of a rear end change. To accomplish what I need from a top speed stand point with a 1 to 1, I need a rear end ration in my ford 9" that is as close to 2.00 as possible. When I ordered my Strange rear end the tallest gears they offer is 3.00. I have seen discussions about a ford gear that was 2.49 years ago, that is it. Am I wrong. Can I get a super tall rear gear that can handle serious HP and torque?
You can add an overdrive to it http://www.gearvendors.com/hrgm3s.html it would make more sense to swap it for an overdrive transmission, or learn to deal with the high rpm operation. Didn't used to be a problem in the old days. 9" gears are available used in 2.47 ratio. I have a set I got on ebay for about $50 edit: I don't know how much torque they can handle, but I ran the 2.47s in my 55 behind a blown big block for a few months. I've run used 2.75 gears in the car for years, no problems.
Here are my constraints and capabilities. Tire size can't exceed 26-27 inches and top RPM is 5000. I do have ridiculous amounts of low RPM torque available. I thought about gear vendors and might end up doing that, but I am trying to explore all options. I have access to a drag rated powerglide that has some specific modifications I need which is why I was looking at modifying a powerglide is it were possible, I could also look at a more modern transmission with OD, but not ready yet to stop looking at other options.
Isky dreamwheel comes out...fiddle, fiddle, fiddle...27" tire...5,000 RPM...you're talking fairly close to 200 MPH there! Isn't an automatic going to be subtracting out some RPM unless you move up to something that locks anyway? Wouldn't some sort of OD manual trans be a good idea? If you are up to something strange and specialized (land speed record for cement mixers??) I think you need some sort of carefully chosen transmission here, not an extremely limited and designed for entirely different purpose PG that you happen to "have access to." And/or a different rear...you are looking for a range that gets lots of people thinking quickchange.
I must be doing my math wrong because at 5000PM with a 26" wheel and a 1 to 1 drive I only get 128.9 MPH. Am I doing something wrong?
I would be done if there were the case and the 2:00 existed!. When I run the numbers with a gear vendors which has a .78 final, I only get 165. Not enough. I need close to 180.
You're gonna need to change somethin fer sure. I see someone already beat me to the Gearvendors or a quickchange. Both are GREAT ideas. As to the idea of strength in a lower (numerically) ratio- the longer geared the ratio is, the stronger the pinion. The ring gear doesn't change diameter-it just moves to the side to make room for bigger/smaller pinion gears. -rick
.78 x 2.47 = 1.92 so if you run 2.47 gears and the GV overdrive, you have what you need, right? btw having a close ratio transmission is helpful for LSR, although if you're running something that has way too much torque at midrange, it's not so much of an issue.
Ok a friend suggested something really crazy so I thought I would throw it out and see the reaction. Assume that I can set the engine up to rotate in either direction and I don't need a torque converter, he suggested that I turn the powerglide around backwards, spin the engine oppose and flip the rear end over 180 degrees. He believes that the Powerglide L1 would now act as a .57 top gear the L2 would now be a 1 to 1 first gear which is OK. So if you shift manually, L2 is L1 at 1-1 and L1 is L2 at .57. Reverse would be very tall and park should still be park. This just sounds like there would have to be something really wrong it.
This would do it, except that I would have to junk yard crawl to find a 2.47 and I am not sure it would handle real large HP and torque. I don't mind the crawl, but will it hold up.... I think they were used in Lincoln town cars.
It would be challenging to "turn the PG around". Maybe you could do it? Does he have some ideas of how to make it work? pump, shafts, etc
The gears should be strong enough, as mentioned there is less load on the pinion teeth on the low numerical ratio gears. I found some on ebay for fifty bucks, they're not something you have to crawl around in the mud to find.
Electric pump and he assumes that he could work out the shaft coupling. My first thought was that the transmission is designed to have the "load" flow through front to rear and that trying to spin the "little end" off the motor and the front facing the drive shaft would cause part failure, but no ones knows I guess because I don't think it has ever been done.
If the GV or HoneODrive dont give you the ratio you need- you could build your own OD box- but i think the GV+ gear swap would do it- I'd personally do a GV + quick change- Winters has a new quickie out now that's a monster for the salt- i think its the Xtremeliner model or something else clever like that.
I have to show my ignorance. I am loosely familiar with the GV and what it does, but I do not know anything about a quick change and the Xtremeliner. Can you point me to some links to educate me?
The old Halibrand QC rear allows ratios down to something like 1.8...but if you install them backwards, you get like 8.50 and you will overrev and destroy your engine while backing out of the garage...
The price of a GV and the power robbing of one you would be better off with a quick change and the glide but you would also be better off with a clutch trans... Then maybe a Lenco too
there are things called one way clutches in automatic transmissions. I don't see how you could turn it around without a bunch of custom parts. Seems like a GV would end up being the cheaper solution.
That's what I was thinking about turning around a P/G it would take some major to get a input (now output) shaft to hold up to said? torque.
I'll be the first admit that I know little about the inner workings of automatic transmissions or gearing calculations, but just a thought: what about an OD transmission AND a GV unit? One of the number crunchers would have to get on this. I think GV makes a double overdrive, and if you put that behind, say, a 4L80E, you might be in business. Posted using the Full Custom H.A.M.B. App!
So what would be wrong with using a TH200-4R? They have a .67 OD that would work with 3.00 gears. They can be beefed up (not cheap, but then neather are any of the combos that have been kicked around) to take around 600 HP and have a lower low gear than a PG to get you moving. I've always heard a numerically high gear set will stand more HP than a low geared set, because the pinion gear has more teeth/larger diameter.
So you want help with something that has no existence? Nore are you willing to listen! Good luck. As far as flip'n a PG end for end. A 3 speed manual trans with 1st removed and flipped is possible.
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