I've never understood how guys can race with a powerglide 2 speed. When is there an application where a powerglide is better over a TH400 in the 1/4 mile. It seems like you would want more gears to keep the RPM's up. Granted...the fuelies don't even have a trans, but that's also thousands of horsepower. Thanks.
dubs68camaro
There comes a point where an engine makes enough power and rev's high enough that 2 gears are all that is needed to cover 1320 feet. Keep in mind each shift is a moment where the direct application of power to the rear tires is hindered...
If the motor will twist hard enuff + the less times you have to change gears = fast car.
JMHO...as always.
JMHO...as always.
Think of a P/G as a 4-speed tranny where it has two gears and when it is in action, is always trying to catch up to "lock" the converter up!
In other words, low slips off the line, then catch's up to itself, then shift's to high, slips again, and finally catch's up to itself!!
pdq67
PS., and a P/G doesn't have a modern real locking converter tho...
In other words, low slips off the line, then catch's up to itself, then shift's to high, slips again, and finally catch's up to itself!!
pdq67
PS., and a P/G doesn't have a modern real locking converter tho...
I've been kicking this around myself. I've been getting 2 different answers to this question by people who should know, making it a tougher choice. I am building a 2800 Lb. +or- car @ about 1,600 HP. Some say 400 to keep boost up (f2 BBC). Some say glide because a 400 has too low a first gear & I'm asking for tire shake if I go with the 400. A glide has about the same low gear as the 400's second gear. I'm thinking a taller rear end gear should compensate for the low gear in the 400. A glide is lighter & takes less hp to turn. Pro stocks have 4 and 5 speeds, but that's a different animal & more expensive. Glide is more consistent I'm told. If you get the higher end trans. glide or 400 I don't thing the shift points are that much of a liability anymore. They both now have smaller diameter lightweight drums, etc. that not only make the trans several pounds lighter, but make them quicker because the rotating mass is lighter & smaller. Most of the ProMod guys will say glide hands down, so maybe that's the way to go. :yes::noway::yes::noway:
I have done a comparison between a 'Glide & THM350. I've been using the PG and life is good.
I used a THM350 and the intermediate sprag broke, 5 times in two years. I changed to PG with a Turbo input shaft and am currently using a 3500 conv. I gained 0.2 seconds and I'm still dealing with a long shift time, about half sec.
THM400 takes 45 HP to turn. Both drums, 20 lbs,(?) apiece, spin opposite directions in 1st. Second gear, one stops and the other still spins. In 3rd, both spin together in the same direction. An extra shift, more mass to stop and rotate.
Powerglide requires 18 HP to turn and has minimal weight, 12 lbs., to spin. I still shift mine manually with a modified stock valve body. I'd like to get a forward pattern manual v/body.
No doubt, I'm for Powerglide with a high stall. I'll leave the THM400 for my dually to tow.
I used a THM350 and the intermediate sprag broke, 5 times in two years. I changed to PG with a Turbo input shaft and am currently using a 3500 conv. I gained 0.2 seconds and I'm still dealing with a long shift time, about half sec.
THM400 takes 45 HP to turn. Both drums, 20 lbs,(?) apiece, spin opposite directions in 1st. Second gear, one stops and the other still spins. In 3rd, both spin together in the same direction. An extra shift, more mass to stop and rotate.
Powerglide requires 18 HP to turn and has minimal weight, 12 lbs., to spin. I still shift mine manually with a modified stock valve body. I'd like to get a forward pattern manual v/body.
No doubt, I'm for Powerglide with a high stall. I'll leave the THM400 for my dually to tow.
Gee.....when you guys say it like that....it makes perfect sense. Just to take it a slight bit forward though.....
It seems like the TH400 is by far stronger stock (especially if behind a large BBC). So are we talking a really modified powerglide vs a really modified TH400??? I'm guessing so because they only seem to put the powerglide behind 6 cylinders and low HP 307's 327's ect.
It seems like the TH400 is by far stronger stock (especially if behind a large BBC). So are we talking a really modified powerglide vs a really modified TH400??? I'm guessing so because they only seem to put the powerglide behind 6 cylinders and low HP 307's 327's ect.
Apples to apples, yes. Powerglides were installed behind 6-cyl & 307/327 low HP because of the frictional driveline losses kept to a minimum.
If you are towing or have a heavy vehicle, yes, a 3-spd auto is the choice, no doubt.
Apples to oranges, modded THM400 will outwork a stock Powerglide and vice versa.
For those running high horsepower, a 'Glide and high stall conv is the ticket. The builder has taken into consideration the camshaft specs, the operating rpm, vehicle weight, etc, and selected the stall of convertor. Its not uncommon to see a 9 sec car with a 6000 stall, maybe more, and 'Glide.
These are just my thoughts and may or may not be correct.
If you are towing or have a heavy vehicle, yes, a 3-spd auto is the choice, no doubt.
Apples to oranges, modded THM400 will outwork a stock Powerglide and vice versa.
For those running high horsepower, a 'Glide and high stall conv is the ticket. The builder has taken into consideration the camshaft specs, the operating rpm, vehicle weight, etc, and selected the stall of convertor. Its not uncommon to see a 9 sec car with a 6000 stall, maybe more, and 'Glide.
These are just my thoughts and may or may not be correct.
Hey Jake - Why did you ask if you are already know the answer? I have no problem being shown I'm wrong but when someone rubs it in my face it makes me mad. Do you feel good for setting someone up so you could expound and make yourself look smarter or the other guy look dumb?
Ding.....Ding....Ding......and the first round has ended. The ref has sent both fighters to their corners.
Sorry guys. I wasn't trying to start a pissing match. :noway: Really great info though. I do think it's easy to take something that used to be accurate years ago and assume it still applies today. We must be careful though 'cuz there's this crazy thing called technical advances that is re-writing a lot of books. This post has sure given me some really good in-depth info from everyone.
P.S. Comp cams said they couldn't help me when I tried to order my 3/4 race cam!!
Sorry guys. I wasn't trying to start a pissing match. :noway: Really great info though. I do think it's easy to take something that used to be accurate years ago and assume it still applies today. We must be careful though 'cuz there's this crazy thing called technical advances that is re-writing a lot of books. This post has sure given me some really good in-depth info from everyone.
P.S. Comp cams said they couldn't help me when I tried to order my 3/4 race cam!!
No pissing match here, simply preventing an incorrect statement from becoming a "fact" like much of the other info out there on auto trans.
The old HP consumption figures everyone likes to quote humors me.
A high schooler can figure out that that is a BS deal without more info.
The numbers MIGHT be correct IF they also were presented with the rate of acceleration, what gear the trans was in, etc but everyone just assumes that is right.
I'm sure most people here had some basic physics in high school. An object in motion tends to stay in motion unless acted upon by another force, etc.
It's a little more complicated than that because the diameter of the rotating parts, the weight, the rate of acceleration all determine the amount of HP used to accelerate the parts, and the design of the trans, frictional losses, pumping losses add more variables.
I would really like to know the testing parameters for those figures, IF any testing was actually ever done.
The old HP consumption figures everyone likes to quote humors me.
A high schooler can figure out that that is a BS deal without more info.
The numbers MIGHT be correct IF they also were presented with the rate of acceleration, what gear the trans was in, etc but everyone just assumes that is right.
I'm sure most people here had some basic physics in high school. An object in motion tends to stay in motion unless acted upon by another force, etc.
It's a little more complicated than that because the diameter of the rotating parts, the weight, the rate of acceleration all determine the amount of HP used to accelerate the parts, and the design of the trans, frictional losses, pumping losses add more variables.
I would really like to know the testing parameters for those figures, IF any testing was actually ever done.
But if that were the case Jake why is there so many mis-informed soles out there propagating the BS? You see you may know more than someone but if you keep refering to what you know as something so simple everyone should know it, it sounds like you are putting those that don't know it down for not knowing...
Same as my first example, you don't ask the person with the mis-information to explain just so you can set them straight. That's all I'm trying to impart, if you ment no disrespect that fine, I'm just offering up how one might keep from being mis-understood in the future.
Now going back to the topic at hand instead of picking apart my or others mis-information how about answering the orig question. Why is a trans with less gears like a powerglide prefered over more gears like a th300/th400 or a 700r4/2004r in a drag race? Keeping it relative to a power class that would benefit from a built 2 speed...
Same as my first example, you don't ask the person with the mis-information to explain just so you can set them straight. That's all I'm trying to impart, if you ment no disrespect that fine, I'm just offering up how one might keep from being mis-understood in the future.
Now going back to the topic at hand instead of picking apart my or others mis-information how about answering the orig question. Why is a trans with less gears like a powerglide prefered over more gears like a th300/th400 or a 700r4/2004r in a drag race? Keeping it relative to a power class that would benefit from a built 2 speed...
Dennis,
The reason there are so many misinformed people who continue to spread false info is because few take the time to teach them or correct them.
Oftentimes when you do correct someone they become offended.
Some of these principles are really simple, but nobody takes the time to think for themselves and judge whether something is true or not.
One example, and this will start an argument, but why MUST a lifter be NEW on a new camshaft? What makes a used lifter in good condition an issue? Why must a lifter go back on the same lobe?
I can tell you that although this is what camshaft manufacturers recommend, and you will always read it on the net, in hot rod mags, etc, it isn't true.
(Disclaimer, I'm not recommending using used lifters on a new cam, it isn't cost effective)
How do two pieces of metal that should be lubed and never actually physically contact know that they are "mated"?
Just something to spur some thought.
I asked you because oftentimes what you write may not be what you meant or it may not be complete enough for me to understand what you were saying. I even sometime post something quickly and not as complete as it should be and it could be misunderstood.
I suspected your statement was as I understood it but wanted to give you an opportunity to clarify in case it wasn't.
To the topic,
A trans with less gears isn't always preferred. Pro-Stock cars use more gears... Top Fuelers use direct drive.
Many racers go to the glide to get away from potential sprag failures, reduce rotating mass, and mostly for consistency.
Less gear off the line makes for more consistent ETs, and thats the name of the game in bracket racing.
In a heavier car, you need the gear, or if a car is underpowered (stock class deal).
In a lighter car or big HP car, less gear is needed.
However some very respectable racers stay with a 3 speed and use electronics to control power at launch.
The theory is, use the deeper gear to make it easier on the motor, and control it with technology.
We got on this discussion awhile back on NastyZ28.
The reason there are so many misinformed people who continue to spread false info is because few take the time to teach them or correct them.
Oftentimes when you do correct someone they become offended.
Some of these principles are really simple, but nobody takes the time to think for themselves and judge whether something is true or not.
One example, and this will start an argument, but why MUST a lifter be NEW on a new camshaft? What makes a used lifter in good condition an issue? Why must a lifter go back on the same lobe?
I can tell you that although this is what camshaft manufacturers recommend, and you will always read it on the net, in hot rod mags, etc, it isn't true.
(Disclaimer, I'm not recommending using used lifters on a new cam, it isn't cost effective)
How do two pieces of metal that should be lubed and never actually physically contact know that they are "mated"?
Just something to spur some thought.
I asked you because oftentimes what you write may not be what you meant or it may not be complete enough for me to understand what you were saying. I even sometime post something quickly and not as complete as it should be and it could be misunderstood.
I suspected your statement was as I understood it but wanted to give you an opportunity to clarify in case it wasn't.
To the topic,
A trans with less gears isn't always preferred. Pro-Stock cars use more gears... Top Fuelers use direct drive.
Many racers go to the glide to get away from potential sprag failures, reduce rotating mass, and mostly for consistency.
Less gear off the line makes for more consistent ETs, and thats the name of the game in bracket racing.
In a heavier car, you need the gear, or if a car is underpowered (stock class deal).
In a lighter car or big HP car, less gear is needed.
However some very respectable racers stay with a 3 speed and use electronics to control power at launch.
The theory is, use the deeper gear to make it easier on the motor, and control it with technology.
We got on this discussion awhile back on NastyZ28.
This is like a dog chasing it's tail... You just don't step to the podium and say "if you all could think for yourselves I wouldn't need to be telling you this"! Can't you see how that's insulting the ones you are trying to get the message across to? and you are suggesting I don't think for myself? Now that's a perfect way to fuel the fire a bit more!
Nobody else seems to be offended by me saying that...
Maybe it's just me but it seems obvious that if nobody questions it (thinks about it for themselves) then a myth will continue unchallenged until someone does think about it and challenges it.
You seem to be taking a statement personally for whatever reason. I didn't say "you can't think for yourself", I said in generalized terms and in doing so answered your question
Re-read my part about the cam/lifter scenario. How many times have you read you can't re-use old lifters on a new cam? Or that you must place lifters back on the same lobe? Have you ever posted that yourself? If so, did you think of WHY that may or may not be true?
Maybe it's just me but it seems obvious that if nobody questions it (thinks about it for themselves) then a myth will continue unchallenged until someone does think about it and challenges it.
You seem to be taking a statement personally for whatever reason. I didn't say "you can't think for yourself", I said in generalized terms and in doing so answered your question
If a misinformed person is regurgitating what they heard elsewhere (happens OFTEN on the net) then they must be doing so because they haven't taken the time to actually think about the mechanics of it before they stated it, they are simply restating what they read/heard elsewhere as if it's the truth.
Re-read my part about the cam/lifter scenario. How many times have you read you can't re-use old lifters on a new cam? Or that you must place lifters back on the same lobe? Have you ever posted that yourself? If so, did you think of WHY that may or may not be true?
I'd like to indulge myself here for a second and ask "everyones" opinion on my set-up.
approx. 2,800 lb. tube chassis car w/1,600hp pro charger BBC. What are the pros & cons of 400 or glide? Jake has just mentioned a few.
I have the car mocked up with a core 400th at the moment but i haven't made the purchase yet.
I've been told I'm asking for tire shake with the low first gear of the 400.
Couldn't I counter that with a taller rear end gear and still have the 3
gears to get down the track? It looks to me like the pro charger peaks
around 6,200 rpm + or-. So, if I have a 400th I should be able to keep
the engine closer to peak hp with 3 gears?
I was told at a drag expo by a trans rep they ran a glide - then a 400 in the same car (one close to my combo) and there was not that much difference between the two.
If that is true, the consistency of the glide might make it the best
choice?
I need to decide by this winter.
approx. 2,800 lb. tube chassis car w/1,600hp pro charger BBC. What are the pros & cons of 400 or glide? Jake has just mentioned a few.
I have the car mocked up with a core 400th at the moment but i haven't made the purchase yet.
I've been told I'm asking for tire shake with the low first gear of the 400.
Couldn't I counter that with a taller rear end gear and still have the 3
gears to get down the track? It looks to me like the pro charger peaks
around 6,200 rpm + or-. So, if I have a 400th I should be able to keep
the engine closer to peak hp with 3 gears?
I was told at a drag expo by a trans rep they ran a glide - then a 400 in the same car (one close to my combo) and there was not that much difference between the two.
If that is true, the consistency of the glide might make it the best
choice?
I need to decide by this winter.
I don't buy your theory about the cam and lifters Jake, why do we break-in a cam? They are oil coated surfaces, have you ever pulled a cam and the lobs not have a pattern on them? If you believe that it's ok to place used lifters on a new cam why wouldn't you recomend folks do it? What does "it's not cost effective" mean? IMO it means "the potential for failure is greater than the cost associated with new lifters" That's really what everyone else is saying too by saying not to reusing old lifters on a new cam...
I'm the only one speaking up because nobody wants to step in at this point, several voiced their opinions about your approach early on Jake... See you have just proven to me and many of the folks reading this that you are here feeding your ego with your replies. I'm not offended but I'm a moderator here and I felt you were being condecending towards others and yes that includes me. You may have read the words I posted but you have not even considered what I have said. If you had you would understand and we wouldn't be having this conversation. You are like talking to a block wall so lets just end this here!
I'm the only one speaking up because nobody wants to step in at this point, several voiced their opinions about your approach early on Jake... See you have just proven to me and many of the folks reading this that you are here feeding your ego with your replies. I'm not offended but I'm a moderator here and I felt you were being condecending towards others and yes that includes me. You may have read the words I posted but you have not even considered what I have said. If you had you would understand and we wouldn't be having this conversation. You are like talking to a block wall so lets just end this here!
Hi just some facts. NY drag racer that I know (His car is featured in chevy performance this month Arrives in stores 9/11) picked up some MPH and ET. Only cahnge was he went from a th 400 to a Glyde.
http://www.fbperformance.com/RacerInfo.asp?key=39
In addition Rod Sdabury (from the worlds fastest street Car Fame) made the same change with the same result. Trans builder is F&B transmission in NY. Now here comes the wierd part the best results they got was by using a Ford AOD trans.
http://www.fbperformance.com/RacerInfo.asp?key=39
In addition Rod Sdabury (from the worlds fastest street Car Fame) made the same change with the same result. Trans builder is F&B transmission in NY. Now here comes the wierd part the best results they got was by using a Ford AOD trans.
:boxing: It's okay Dennis........I'm guessing that Jake really knows his stuff. There are people in my company that really do too, but we don't let them ever talk to the general public. It would be really bad for business. Some of the smartest people have the worst people skills and that's why their in back, not at the front counter or in the field. I'm not trying to take a shot at jake, but he did come at you way too hard for the subject line. This isn't world politics or an abortion topic....it's a damn question about a th400 vs a glide. I hit people all day with a velvet hammer and they never knew what hit them. That's 17 years in sales. Jake.....man I wish I knew your stuff, and I never will. Don't have the time. That's why I use this wonderful site. I didn't take a lick of physics in school, but I do earn about 300% more per year than the ones that did in my company. Sometimes when someone has the knowledge you do......you have to package it in a way so the less knowledgeable people like me can understand it. Thanks again for the info!!!!!
In my opinion the Glide is the best all around. We have used them in 3100# Novas for years and only had one planetary let go. Beyond that nothing beyond a freshen up on occasion, usually 700 passes or so. Usually the converter was getting tired by then as well. Use the good clutches, good input shaft, cooler and drum and away you go, footbrake or Transbrake. We had excellent luck with a TH400 in a 66 Chevelle w BBC until we put a brake in it. It was downhill from there and in came the Glides. Better than ever. Having said all of that I do ahve a TH400 I bought from a guy a couple of years back. It is a Hughes piece. Rev manual valve body. I bought it for a project street/strip car and never got around to it. Hard to ship but if the right deal comes out I would part with it.
Jake, I read both links from the nastyZ threads and I'm still on the fence. I guess it's a good thing I've got some time before I need to nail down a trans.
It looks like either one will do the job, (people have has success with both) just a different approach to how they & the car are set up. This is all great info.
It looks like either one will do the job, (people have has success with both) just a different approach to how they & the car are set up. This is all great info.
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