Moparts
Why not use 727 like a glide
Posted By: Dart451
Why not use 727 like a glide - 02/25/10 07:35 PM
Was running some numbers around and was wondering why not use the first two gears on a 727 like a glide then third will be overdrive.
The 727
1st 2.45
2nd 1.45
so 2.45/1.45=1.69
a glide is 1.76 first to second ratio
I understand the extra drag on internal components and needed to get the convertor set up right.
[image]https://board.moparts.org/ubbthreads/upload2/5829790-Glidevs727.tif[/image]
Posted By: Bob_Coomer
Re: Why not use 727 like a glide - 02/25/10 07:46 PM
Quote:
Was running some numbers around and was wondering why not use the first two gears on a 727 like a glide then third will be overdrive.
The 727
1st 2.45
2nd 1.45
so 2.45/1.45=1.69
a glide is 1.76 first to second ratio
I understand the extra drag on internal components and needed to get the convertor set up right.
[image]https://board.moparts.org/ubbthreads/upload2/5829790-Glidevs727.tif[/image]
The whole idea of going to a glide is to get away from the low 1st gear.
Im not following you on the OD thing.
The only two gears between them that are actually the same is the ones your not wanting to use LOL..
High and 3rd are the same. 
Both are a 1:1
Posted By: Dart451
Re: Why not use 727 like a glide - 02/25/10 07:51 PM
I want to use a 3.23 or 2.76 rear gear and run 1/4 using first and second only. So I will finish at the strip in second.
Posted By: dOoC
Re: Why not use 727 like a glide - 02/25/10 07:59 PM
Quote:
I want to use a 3.23 or 2.76 rear gear and run 1/4 using first and second only. So I will finish at the strip in second.
THERE 'ya go ! ... 
... been doin' THIS furr years !
Posted By: Big B
Re: Why not use 727 like a glide - 02/25/10 08:35 PM
Joe at Tranzact sells a 2 speed 727. This would be much cheaper then converting over to a PG, if your car already has a 727
Posted By: Dart451
Re: Why not use 727 like a glide - 02/25/10 08:46 PM
Not about wanting a two speed as wanting to drive the car down the highway. I already have a well built 727, so if the convertor is redone, and change the rear gears it would be alot cheaper then a overdrive.
Looking for why this would be a bad idea?
Posted By: Dodgem
Re: Why not use 727 like a glide - 02/25/10 09:05 PM
Why not?? It will work.
Posted By: maximum entropy
Re: Why not use 727 like a glide - 02/25/10 09:16 PM
why not? with the right converter, you prolly wouldn't lose much. i do it in the eighth.
Posted By: Dart451
Re: Why not use 727 like a glide - 02/26/10 12:54 AM
Never seen much posted about it, so figured I was missing something.
Think I will start looking for a new rear gear.
Posted By: John_Kunkel
Re: Why not use 727 like a glide - 02/26/10 01:25 AM
Back in the early seventies some nitro funny cars used 1st and 2nd gear in the 727 with 2.76 rear end gears. Top gear was close to the 3.91's everybody was running then.
Posted By: RADAMX
Re: Why not use 727 like a glide - 02/26/10 03:40 PM
I would think the glide would have a lot less drag and would weigh less.
so in a light car the glide would be better at the strip.
I still have a heavy car so I need the lower first gear of the 727.
I run a 3.89 gear and 28 inch tall tires
been thinking about going with 3.55's in a attempt to use the torque of the nitrous motor..
Posted By: moparacer
Re: Why not use 727 like a glide - 02/26/10 04:13 PM
It wont be "like a glide" because you will be using the planetary in 1st and 2nd gear.
Wont have the true 1:1 ratio.
Posted By: maximum entropy
Re: Why not use 727 like a glide - 02/26/10 04:20 PM
i don't think the op is worried about absolute maximum efficiency, and neither am i. these are street cars, and after a long weekend of racing, NOTHING is finer than hitting the highway home and snicking that baby into "top cog". too bad i have a dana 60, or i'd put 2.71's in it!
Posted By: MR_P_BODY
Re: Why not use 727 like a glide - 02/26/10 05:03 PM
One problem would be that you wouldnt have a trans
brake.... if you use one
Posted By: Dart451
Re: Why not use 727 like a glide - 02/26/10 07:29 PM
I already have a trans brake why couldn't i use it?
Posted By: maximum entropy
Re: Why not use 727 like a glide - 02/26/10 07:31 PM
i would.
Posted By: Bob_Coomer
Re: Why not use 727 like a glide - 02/26/10 08:20 PM
Quote:
i don't think the op is worried about absolute maximum efficiency, and neither am i. these are street cars, and after a long weekend of racing, NOTHING is finer than hitting the highway home and snicking that baby into "top cog". too bad i have a dana 60, or i'd put 2.71's in it!
Thats what i dont under stand with the OP... neither the the 727 or the PG has is OverDriven in 3rd? Were is the OD you guys keep talking about? They both have a final drive a 1:1
In this case a A518 would be optional..
Posted By: maximum entropy
Re: Why not use 727 like a glide - 02/26/10 08:39 PM
Quote:
Quote:
i don't think the op is worried about absolute maximum efficiency, and neither am i. these are street cars, and after a long weekend of racing, NOTHING is finer than hitting the highway home and snicking that baby into "top cog". too bad i have a dana 60, or i'd put 2.71's in it!
Thats what i dont under stand with the OP... neither the the 727 or the PG has is OverDriven in 3rd? Were is the OD you guys keep talking about? They both have a final drive a 1:1
In this case a A518 would be optional..
no, it would not "actually" be overdrive, but the overall ratio would be as if it were overdriven, capice? yer making a very simple concept into something complicated. 
Posted By: rebel
Re: Why not use 727 like a glide - 02/26/10 08:48 PM
Quote:
I want to use a 3.23 or 2.76 rear gear and run 1/4 using first and second only. So I will finish at the strip in second.
when i first got into racing with my 'cuda, with the 3.23 gears & tweaked stock converter, i'd be changing into 3rd as i crossed the stripe. i think i ran 275x60 quicktimes with that combo. isn't this where you want to be?
Posted By: dizuster
Re: Why not use 727 like a glide - 02/26/10 09:26 PM
Uhhhh...can I sprinkle in a little common sense?
Anyone ever run a stock'ish gear (3.23), and then put more gear in the car (4.56)?
Remember how much quicker the 4.56 gear was?...lol...
Also, loose converter with a gear like that will absolutely sucks for drivability on the street... (ever taken off from 2nd or 3rd on accident, it's terrible)
So why couldn't you do it? Oh you can, it will just be A LOT slower...
My Dad ran his blown small block car from 2nd gear this year (so he could run the Sportsman class). It's heavy, and has ~5200 stall converter. As I remember the car was about 6~7 tenths slow!
Posted By: W7_Scamp
Re: Why not use 727 like a glide - 02/26/10 09:39 PM
[?
Anyone ever run a stock'ish gear (3.23), and then put more gear in the car (4.56)?
Remember how much quicker the 4.56 gear was?...lol...
Also, loose converter with a gear like that will absolutely sucks for drivability on the street... (ever taken off from 2nd or 3rd on accident, it's terrible)
So why couldn't you do it? Oh you can, it will just be A LOT slower...
My Dad ran his blown small block car from 2nd gear this year (so he could run the Sportsman class). It's heavy, and has ~5200 stall converter. As I remember the car was about 6~7 tenths slow!
I run 3:23 gears in my valiant. Stock 440 shortblock, 509 cam, factory heads 3800 trans specialty's converter (runs great on the street) at the track I shift at 5500 and trap 5300.
P.S. If you do a burnout and leave in 2nd on the street it dead hooks. the car runs 11.70's thru the exhaust and is a street car not a race car.
I'm trying to convince myself to change gears to 3:91 or 4:10 but I'm afraid I won't hardly pickup.
Ryan J went from 3:55 to 3:91 or 4:10 and picked up nothing.
Posted By: maximum entropy
Re: Why not use 727 like a glide - 02/26/10 09:52 PM
imo, the right converter is key to the whole deal. i've had cars with loose converters and very tall gears, and everytime i put steeper gear in it, i'd end up going back to the freeway gears. the gain was not worth the cost in wear and tear, noise, fuel mileage, et cetera. but i always had the best converters i could afford, and i believe that was why my combos worked.
Posted By: Dart451
Re: Why not use 727 like a glide - 02/26/10 10:21 PM
I was planning on getting the convertor restalled. The glides work with the overall final ratio being similar.
Posted By: MR_P_BODY
Re: Why not use 727 like a glide - 02/26/10 11:14 PM
Quote:
I already have a trans brake why couldn't i use it?
My mistake... I thought you werent using low gear but
you are and not using high gear(racing).... sorry
Posted By: Bob_Coomer
Re: Why not use 727 like a glide - 02/27/10 01:54 AM
Quote:
Thats what i dont under stand with the OP... neither the the 727 or the PG has is OverDriven in 3rd? Were is the OD you guys keep talking about? They both have a final drive a 1:1
In this case a A518 would be optional..
no, it would not "actually" be overdrive, but the overall ratio would be as if it were overdriven, capice? yer making a very simple concept into something complicated.
Im making it complicated LOL...
2.90's a trans brake, and tire with any height at all.
how would this be diff that your average everyday race car with a mismatched reared gear set?
Sure it will work, sure it will run..why wouldn't it?
If its the hos setup we all would be trading in out 4.88's for 3.23
I wasn't trying to be negative, as was just trying to understand what the OP was trying to achieve...
still don't know
Its all in good fun boys....
(Sling Blade Carl's Voice here)
its winter
its winter...
hmmmm...
its still winter.
I hate snow 
Posted By: MR_P_BODY
Re: Why not use 727 like a glide - 02/27/10 02:07 AM
Im making it complicated LOL...
2.90's a trans brake, and tire with any height at all.
how would this be diff that your average everyday race car with a mismatched reared gear set?
Sure it will work, sure it will run..why wouldn't it?
If its the hos setup we all would be trading in out 4.88's for 3.23
I wasn't trying to be negative, as was just trying to understand what the OP was trying to achieve...
still don't know
Its all in good fun boys....
(Sling Blade Carl's Voice here)
its winter
its winter...
hmmmm...
its still winter.
I hate snow
Its a street car and doesnt want a steep gear....
but its still a sacrifice... you wouldnt see a RACE
car doing it because he would be giving up alot of
torque multiplication of the different rear gears
Posted By: Jeepmon
Re: Why not use 727 like a glide - 02/27/10 04:19 AM
I dont know if I'm hijacking this thread by asking as question... but this topic has caught my interest..
My Duster is a true street car that I race alot.. Currently its 3180 lbs plus driver, 727 reverse, 4.10 gears with 28.0" tires..
I cross the line at 6800 rpm and cruise the freeways at about 3500 rpm... The stall is 3500 and the flash is right around 4400 rpm..
The car will 60' in the 1.6x range and the last variable is the gearing in 1st gear, which I dont know..
My question is this.. What would happen to my 60', 1/4 mile ET and MPH.. and lastly what would the freeway cruising rpm be if I was to convert to a 3.23 or higher gear?
Posted By: Anonymous
Re: Why not use 727 like a glide - 02/27/10 04:24 AM
Quote:
Uhhhh...can I sprinkle in a little common sense?
Anyone ever run a stock'ish gear (3.23), and then put more gear in the car (4.56)?
Remember how much quicker the 4.56 gear was?...lol...
Sure, it'll peg the butt dyno, and back in the day when everyone had stock converters or a stick car a low gear picked the cars up, but this is 2010 and converters have come a LONG way.......I've done so much gear and converter testing/swapping trying to pick up ET it's crazy, and believe me when I say that with the right converter, gear ratio has very little effect on ET.......
Quote:
Also, loose converter with a gear like that will absolutely sucks for drivability on the street... (ever taken off from 2nd or 3rd on accident, it's terrible)
So why couldn't you do it? Oh you can, it will just be A LOT slower...
Again......that's just not the case............
Quote:
My question is this.. What would happen to my 60', 1/4 mile ET and MPH.. and lastly what would the freeway cruising rpm be if I was to convert to a 3.23 or higher gear?
It depends on how much torque the car makes, but I bet you'd be surprised.......Try it and post your results....... 
I'm going to make a few different transmission videos and I'll also go into torque converters and stall and flash.........and I will take a car to the track and show how stock, a 3,800, and a 5,000+ stall converters compare, back to back......
Posted By: rowin4
Re: Why not use 727 like a glide - 02/27/10 05:03 AM
I think the idea was to run the quarter in first and second gear with the torque flite, just need to figure out what tire size , gear ratio and what torque converter would work for max rpm's at the stripe. It would work out for a street driver, Seems easier to go with a proven combo's for a track car.
Posted By: Dart451
Re: Why not use 727 like a glide - 02/27/10 06:46 AM
Quote:
I dont know if I'm hijacking this thread by asking as question... but this topic has caught my interest..
My Duster is a true street car that I race alot.. Currently its 3180 lbs plus driver, 727 reverse, 4.10 gears with 28.0" tires..
I cross the line at 6800 rpm and cruise the freeways at about 3500 rpm... The stall is 3500 and the flash is right around 4400 rpm..
The car will 60' in the 1.6x range and the last variable is the gearing in 1st gear, which I dont know..
My question is this.. What would happen to my 60', 1/4 mile ET and MPH.. and lastly what would the freeway cruising rpm be if I was to convert to a 3.23 or higher gear?
at 65 mph with 3.23 you would turn 2520 rpm. The rest of 1/4 mile times would depend on lots of variables and how well your convertor works
Posted By: Dart451
Re: Why not use 727 like a glide - 02/27/10 06:55 AM
I understand there would be more drag in the transmission compared to a glide.
The torque multiplication would be about the same as a glide.
The glide would be a 1.8 first gear x 4.56 rear gear so 1.8x4.56=8.21 torque multiplication
the 727 would be 2.45 first gear x 3.23 rear gear
so 2.45*3.23=7.9
The pic at top is two differnt examples of how the mph and gears react. I probly should label it better.
It would really come down to how well the torque convertor works. A bad convertor can make or break any combo.
Posted By: dizuster
Re: Why not use 727 like a glide - 02/27/10 09:59 PM
It kind of opens up the 727/PG debate in combo. Many people have had a hard time making low torque or heavy cars work with a PG.
However, there are few that say it can be done. I totally agree it's all in the converter.
THe problem is, most people don't have the time/patience/money to test converter after converter to get it right...
Posted By: 446acuda
Re: Why not use 727 like a glide - 02/28/10 02:53 AM
Quote:
Was running some numbers around and was wondering why not use the first two gears on a 727 like a glide then third will be overdrive.
The 727
1st 2.45
2nd 1.45
so 2.45/1.45=1.69
a glide is 1.76 first to second ratio
I understand the extra drag on internal components and needed to get the convertor set up right.
[image]https://board.moparts.org/ubbthreads/upload2/5829790-Glidevs727.tif[/image]
I don't know a heck of a lot about automatics but I always thought that running a high stall converter below that stall speed for long periods of time makes some major heat but I guess a really big cooler would take care of that. For example, a car with 2.76 rear gear with a 3500 stall converter would be way below 3500 rpm at highway speeds and would put some serious heat into the trans fluid. 
Posted By: Dart451
Re: Why not use 727 like a glide - 02/28/10 04:10 AM
You can easily cruise under the stall speed. There is not much load on stall at 55 mph.
Posted By: B1Fish540
Re: Why not use 727 like a glide - 03/01/10 01:35 PM
the only problem i see with this scenario, is most cars running PG are light and over powered. That acomplishes two things, it calms down the launch making the car more consistant and applies the torque more evenly thru-out the 1/4. In your case, you do not have too much TQ/HP to begin with plus your car may not be very light(requiring more TQ multiplication to get it moving). IMHO, you will simply have a slower car, this is a case where the numbers..altho acurate..dont add up in the real world of drag racing.
Posted By: Dart451
Re: Why not use 727 like a glide - 03/01/10 04:32 PM
I got more hp then my friend that runs a glide and he 60' in the low 1.3 area with more tuning needed. So not worried about being under powered.
Posted By: Monte_Smith
Re: Why not use 727 like a glide - 03/02/10 05:19 AM
Wow...some of you guys are making this difficult. It is simple math. You multiply the trans gear, by the rear gear, for the "theoretical" gear ratio. If the glide has a 1.80 low and a 4.10 rear, do the math, that makes the theoretical gear the same with the 2.45 low of the 727 and install that rear gear. Converter it the same and you should get similar results as the glide in low gear. Obviously second won't be one to one though.........As far as a glide calming a car down and making it more manageable on the line, I totally disagree in most instances, but that is a whole other discussion.
Monte
Posted By: Irun5snd8th
Re: Why not use 727 like a glide - 03/02/10 05:35 AM
I would certainly like to hear that discussion. Monte you are well respected so if you think it wont calm the car down on the launch; I want to hear the theory behind that. I know it definitely calmed mine down.
Posted By: Monte_Smith
Re: Why not use 727 like a glide - 03/02/10 03:43 PM
Wheel speed is what gets a car down the track quick, not rpm. Now I am generally talking about cars with pretty big power. Properly geared and with the right converter, most cars I have ever switched from 3 speed to powerglide, just became animals on the starting line, because of the wheel speed and it takes serious work to get it under control, but when you do, it will work. Everyone pays way too much attention to 60 foot times anyway. 330 times are what is important and a quick 60, does not always equate to quick 330. Got to have wheel speed to be fast. A ton of gear in the rear, low trans ratio and super loose converter, may scream the engine and sound tough, but most are not going anywhere, just making noise...
Ask Andy Mayes about his car becoming an instant tire smoker with the glide and see if he thinks it calmed his down..
This is not the case for every car, but I can't stand to see those vague generalities about different things just thrown out here, every time a discussion comes up. Every time this comes up, we hear "calms the car, slows it down, kills 60ft, etc, etc" and I know for a fact, that is not always the case, or even the majority of the cases.
Monte
Posted By: Streetwize
Re: Why not use 727 like a glide - 03/02/10 04:22 PM
Isn't the MAIN benefit of the PG the fact that with only a LOW and HIGH there is much less rotating mass (and frictional losses) within the tranny so that even though you have a higher (lower numerical) first gear you have proportionally MORE available engine power getting to the tires all the way down the track, this offsets the lack of the deeper first gear in a light high powered car.
By using only 2 gears of a 3 speed trans you are still carrying all the drag of the heavier 3 speed internals....so even if you mathematically work the gearing out the same, it won't perform the same.
I would imagine these 2 speed 727's will incorporate the (similar) mechanics of a glide or else.
I agree that there are way too many generalizations tossed around, but if this discussion is about simply using the 1-2 (or 2-3 for that matter) of a 727, it's not an accurate comparison to a glide in my opinion.
Posted By: B1Fish540
Re: Why not use 727 like a glide - 03/02/10 06:24 PM
Quote:
Wheel speed is what gets a car down the track quick, not rpm. Now I am generally talking about cars with pretty big power.
Monte
Thats what I'm talking about too. i dont see how a moderately powered car (500 to 700 hp)will benefit from a switch to only 2 speeds. Its easy too see the problem with wheel speed in your scenario...but first you have to have the power to overcome the chassis. I would guess that any car with a 1000+ hp (like Andys) will have the power/wheel speed to overcome a chassis on launch. on calming down the launch, that has always been the conventional wisdom..i dont see the error in pointing that out.
Posted By: jakesz28
Re: Why not use 727 like a glide - 03/09/10 07:30 PM
Quote:
the only problem i see with this scenario, is most cars running PG are light and over powered. That acomplishes two things, it calms down the launch making the car more consistant and applies the torque more evenly thru-out the 1/4. In your case, you do not have too much TQ/HP to begin with plus your car may not be very light(requiring more TQ multiplication to get it moving). IMHO, you will simply have a slower car, this is a case where the numbers..altho acurate..dont add up in the real world of drag racing.
Quote:
I got more hp then my friend that runs a glide and he 60' in the low 1.3 area with more tuning needed. So not worried about being under powered.
It's funny I didn't see the op saying any thing about the power his car makes.
But I do know about his friend thats running a glide.
Posted By: jakesz28
Re: Why not use 727 like a glide - 03/09/10 07:36 PM
Quote:
Wheel speed is what gets a car down the track quick, not rpm. Now I am generally talking about cars with pretty big power. Properly geared and with the right converter, most cars I have ever switched from 3 speed to powerglide, just became animals on the starting line, because of the wheel speed and it takes serious work to get it under control, but when you do, it will work. Everyone pays way too much attention to 60 foot times anyway. 330 times are what is important and a quick 60, does not always equate to quick 330. Got to have wheel speed to be fast. A ton of gear in the rear, low trans ratio and super loose converter, may scream the engine and sound tough, but most are not going anywhere, just making noise...
Ask Andy Mayes about his car becoming an instant tire smoker with the glide and see if he thinks it calmed his down.. This is not the case for every car, but I can't stand to see those vague generalities about different things just thrown out here, every time a discussion comes up. Every time this comes up, we hear "calms the car, slows it down, kills 60ft, etc, etc" and I know for a fact, that is not always the case, or even the majority of the cases.
Monte
Monte, when I switched converters my car slowed down in the 60' area and picked up at the 330'. I would have to agree the 60' time isn't the best area to look on the slip.
Posted By: Dart451
Re: Why not use 727 like a glide - 03/09/10 09:41 PM
Quote:
Quote:
the only problem i see with this scenario, is most cars running PG are light and over powered. That acomplishes two things, it calms down the launch making the car more consistant and applies the torque more evenly thru-out the 1/4. In your case, you do not have too much TQ/HP to begin with plus your car may not be very light(requiring more TQ multiplication to get it moving). IMHO, you will simply have a slower car, this is a case where the numbers..altho acurate..dont add up in the real world of drag racing.
Quote:
I got more hp then my friend that runs a glide and he 60' in the low 1.3 area with more tuning needed. So not worried about being under powered.
It's funny I didn't see the op saying any thing about the power his car makes.
But I do know about his friend thats running a glide.
100%.......Everyone wants an overdrive or Gear Vendors 
, but a 727 with a decent converter (3,800 and up) is JUST as driveable as an OD and will run VERY well at the strip.....been there, done that MANY times....... 