ok i am wanting to know if the 700r4 tranny is any good with lock in converter and all:confused: :confused:
and what are the limets to these trannys????:whacked: :HMMM: :rolleyes: :LOL: **)
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ok i am wanting to know if the 700r4 tranny is any good with lock in converter and all:confused: :confused:
and what are the limets to these trannys????:whacked: :HMMM: :rolleyes: :LOL: **)
You can get a 700/R4 that will stand up under 450 HP for a little over $1000, and up to 630 hp for about $1300. A matching converter goes for $270 - $570.
In a 700/R4, you NEED, I repeate REALLY NEED to use a locking converter. If you drive it on the street without a 4th gear lockup, you will burn it up in short order. All the trans suppliers have wiring kits.
Homework assignment:
Read a bunch of stuff at http://www.bowtieoverdrives.com
ok but i found one in a old buik and it is pretty cheap would it do the same as the one for $1000 it has a lock in converter and all???
NO. You can't compare a "cheapie" out of an old Buick to a new, rebuilt transmission. If you could, it would cost #1000 too. The $1000 unit I priced was rebuilt for up to 450 HP. I have a 700-R4 in my '93 Vette, which was rated at 300HP, and it's lasted 110,000 miles.
You can get lockup wiring for it. Also, the TV cable and linkage is very important. Improper TV adjustment will kill a 700-R4 in short order.
They're very reliable, solid transmissions if installed correctly, and have proper cooling.
yeah well would it hurt to do a burn out in one of these trans after it locks it is kind of like a straight sift right or wrong until you hit the brakes???
No, hard acceleration won't hurt it - but there's a limit to hard driving. You find the limit when the parts break.Quote:
Originally posted by TRUCKGUY
yeah well would it hurt to do a burn out in one of these trans after it locks it is kind of like a straight sift right or wrong until you hit the brakes???
A locking converter does just that. It locks the engine to the transmission, eliminating the slip in the converter.
Most kits have a disconnect switch in the brake lines. When you hit the brakes, the converter unlocks.
yeah thats how i was thinking it would work would it be a good trans to put in my 72 pickup????
The Buick 700R-4 will most likely have the BOP (Buick, Olds, Pontiac) bolt patern. If it does you will need an adapter to put it behind a Chevymotor.
A used automatic transmission and converter out of a RUNNING doner car can be a good deal. Same out of a wrecked vehicle. But a transmission out of a yard with no history is a core - just a place to start rebuilding.
it is running and i was wanting to buy the whole car it has the 305 in it and i figured it would be good till i got a better one for it kinda temporaty i suppose.
Thank's
well from what i read on the site you gave me i think i will just try to find me a m22 muncie it would be cheaper and i can use it for daily use and dont need all the other stuff to go with it.
thank's anyway's
An M20 with a 2.54 low gear would give better off-the line, and they put them in high horsepower Chevelles, GTOs and 442s.
The rock crusher M22 has a 220 low, and is much harder to find.
well then i guess i will go with the m20 wich ever i can find as long as its a muncie i heard alot of good things about them
How about a muncie sm420 " granny tranny ", there geared very low but with the right diff ratio, it woulden't be too owfel bad, they were designed for those old trucks also.
never heard of it but if it was designed for trucks it probly would be geared low and not be good for racing would it???
i have a 4 speed truck tranny
I got a 700r4 in my 82 Silverado, with the mild build & it handled my 383 stroker with a 292 cam for 135,000 miles before it started to slip & I give 'er what for ALL the time. The 700r4 is the closest to the M22 in gear ratio, and is also great for crusin.....
They were the optional 4wd tranny and the standard towing tranny If I remember right, with fairly high diff ratio ( say a 3.00 maby( might be too drasticly high but, you get the point ) you would deffinetly be a contender for drag racing, a little diffrent approach than most because most put the low gears in the diff and have a high geared tranny. You could actully, in theory have a better chance than most because the low gears are in the transmission and go away when you shift up a gear, when there less and less needed but, with a car/truck with the low gearing all in the diff, there always there. Mind you, this is all based on theory and logic and I have yet to see a truck granny tranny be used for drag racing.:)Quote:
Originally posted by TRUCKGUY
never heard of it but if it was designed for trucks it probly would be geared low and not be good for racing would it???
i have a 4 speed truck tranny
I have been busy working on a sun room for my wife and bogged down with finding someone to do a double-flare on my stainless brake lines but this topic is right on my thinking for my roadster. I purchased a rebuilt street version of a 700R4 from the MegaMonster (Eat my shift) folks in Florida but it will be at least a year until I can test it while I finish the roadster. Here's the question as related to this thread. The recommended converter that came with the 700R4 is a 1600 rpm stall speed and now with the four speed and the OD I can have mileage and acceleration, BUT (!) with my existing 2.79 8 inch rear the 0.7 OD is way too high and now I can and must change the rear gear to a lower value. Note for this discussion that the MegaMonster 700 R4 has a hydraulic lockup for the OD and NO WIRES! Using the site given below and with my 735/75/15 tall rear tires I find that a 3.55 ratio will just reach 1600 rpm at about 56 mph where I suppose lockup will be complete. Although the shift points are determined by the trans settings, the converter will still slip if the rpm dips below 1600 rpm?? I know Streets says we ought to research the old threads and I have looked at quite a few threads discussing rear gear ratios. So far it looks like a 3.55 rear gear is a safe bet over 55-57 mph but what happens if I am doing 45 mph on a black top two lane road, will I be in third gear or worse a slipping OD? From this point of view maybe a 3.70 rear gear would be better so that I could stay in OD at lower speed without converter slip? So, the question is which is better keeping in mind my desire to get over 20 mpg AND a quick car. By the way isn't the low gear of a 700 R4 3.06?
3.55 rear, 2.485 OD above 55 mph
3.70 rear, 2.59 OD above about 50?
Thus won't I actually get better mpg with the 3.70 rear by going into OD at a lower mph? Then again in one of the old threads Streets recommends a 3.70 rear gear so that you don't have a NASCAR restrictor plate situation on the street. Again trying to remember performance of early Ford 3.78 rears with less than 100 H.P. it would be neat to keep the 3.70 gear now with a 270 H.P. SBC! So the question is can I run in the OD gear at lower speeds with the 3.70 gear and still get over 20 mpg? Maybe Henry Rifle can answer the mpg question since he has quoted a 3.55 gear 700 R4 in a Vette and a 3.70 rear in a Model A/B? Part of my motivation is caused by finding a nearby Kit car builder of Cobras (York Sport Cars, John York, Ashland VA) who will be able to do the double flares on my brake lines (3/16" stainless) and he casually mentioned that he uses 3.70 rear gears in the 9 inch rears he builds along with a five speed manual trans having a top gear of 0.68. He only uses 351 Windsors but rated at 350 H.P. so I guess he can lug the OD better with the 3.70 rear. SO which is better for performance AND mileage, 3.55 or 3.70?
http://home.tampabay.rr.com/1bking/c...calculator.htm
Don Shillady
Retired Scientist/teen rodder
700R4 is O.K. but if ya want the strongest try a 4L80E :toocool:
http://truckmoxie.tenmagazines.com/i...e_transmission
Don
I may be wrong here but it seems that you have the misconception that the OD lock is going to stay locked in once it reaches the speed required to reach 4th gear. It doesn't, it will shift down when your speed drops below your cable controlled settings, just like a 3 speed turbo 350, or your rpms drop accordingly.
I'm running 3;08's in my pick-up (full size) and will haul up to 1500 lbs. most of the time to the tune of 15 mpg. and I go over the mtn. passes all the time- never overheats, pulls strong, and thats a 5800 lb. truck.
Hambiskit, Thanks for your continuing advice. I guess what I am asking is whether a 3.70 rear will allow a shift into OD at lower mph than if I use a 3.55 rear gear? I hope Henry Rifle can answer since he has both setups and knows the comparison. It seems to me that shifting into OD at 50 mph rather than staying in third gear of 1.0 will increase mileage while at the same time a 3.70 gear will give tremendous response in low gear. Is the originator of this thread aware that MegaMonster can convert the electrical OD lockup to a hydraulic lockup without wires? Also for the answer to this web question I learned that of the three 700 R4 rebuilding companies I studied, all three would not rate a rebuilt stock 700 R4 as handling over 250 H.P. Maybe this is their way of generating sales for their beefed-up versions, but maybe it is also true that 250 H.P. is a pracitcal limit for a stock 700 R4? I am trying to understand the four speed auto trans. On my Pontiac Sunfire ('98) once it shifts into 4th at about 50 mph you can decelerate and stay in 4th down to about 30 mph before it down shifts, but I do not know the stall speed of the converter in the Sunfire.
Don Shillady
Retired Scientist/teen rodder
Don,
You can expect average mileage to vary pretty much according to the ratio of rear axle gears. When I changed my '93 Vette from 2.90 to 3.55, my mileage dropped from 25 to 20 - about 20% - about the same ratio as the gears. Going from 3.55 to 3.73 would drop you about 5% - from 20 to 19, for example.
They may say that a 700-R4 is only good for 250 HP, but the one in my 93 Vette has lasted 110,000 miles.
I'm not sure how the hydraulic lock-up works. The Bowtie Overdrives electrical system always locks the converter when in OD (4th), and has a disengage switch in the brake line in case you lock up the tires in OD.
OD is the most important gear to lock the converter because of the torque needed to overcome the reduced mechanical advantage. BTOD also supplies a manual switch so that you can lock up in 2nd or 3rd gears if driving for extended periods in lower gears.
Henry Rifle,
Thanks a bunch, I value your experience and maybe if I get my roadster running within the next year I can visit you on the way to the beach! I wonder why the 3.27:1 ring and pinion for the 8" rear is so rare and expensive, except that maybe that is what everyone wants and they are out of stock? I only found one site that has 3.27 gears for the 8" Ford rear at a price of $750! Anyway, you offer real data so maybe I need to look at 3.00 instead of 3.55 since the low gear of the 700 R4 is, I believe, 3.06 which is quite a bit lower than low gear in either the TH350 or TH400. Anyway I am trying to learn about the auto trans 4 speed operation. "Experiments" with my '98 Pontiac Sunfire show that there is probably only one setting for shift points at about 3500-4200 rpm, but once in 4th gear you can coast down to about 20 mph and stay in 4th with the tach showing about 1900 rpm. Then you can goose the engine up intermittently with an increase in the tach reading and only a small change in speed, so I think this means the Pontiac (Japanese) 4-speed auto DOES NOT have a lock for 4th gear. Still I get about 24 mpg with the Sunfire, but the performance with a 4 cyl 110 H.P. engine is just slightly better than pathetic! I recall in an old Thread Don Meyer mentioned obtaining a 3.27 rear gear but I don't recall if that was for a 9" rear or and 8". The gear selection seems to be much more readily available in a wide range of ratios for the 9" rear but there is a gap between 3.00 and 3.55 for the 8" rear. I would welcome references to a site for a reasonable price for a 3.27 ring and pinion set for the 8" Ford rear. Thanks Henry, it looks like at least you have ruled out the 3.70 gear if I want to get at least 20 mpg.
Don Shillady
Retired Scientist/teen rodder
Don,
If this makes you feel any better, 3.55s with a 700-R4 are the equivalent (in first gear) of 4.27's in a Muncie wide-ratio 4-speed.
(3.55 x 3.06)/2.54 = 4.27
That's a pretty hairy drive ratio in a light roadster.
Guessing gas mileage on your roadster vice my Vette is chancy at best. Bear in mind that the Vette has a 350 LT-1 with a pretty decent fuel injection system on it. A carbureted 350 of the same hp isn't likely to get the same mileage. I don't even begin to know how to compare. Also, keep in mind that the Vette weighs about 3300 lbs. The roadster would be much lighter.
However, I'm guessing that if I get 20 average in that car, you should be able to get a similar number in your much lighter roadser with the same gearset. Besides, if it gets 19 instead of 20, that's 16 miles less on a 16 gallon tank. In 5000 miles, that amounts to $25.00 with $1.90 gas.
If you drop down to 3.00 gears, you've got the equivalent of 3.60s in my Muncie comparison. Not bad, but not enough to put a grin on my face. In your shoes, I'd go with the 3.55s. Good punch, decent mileage.
I knew that a sm420 was not suited for drag racing and, I just wanted to see if anyone would catch on.:pQuote:
Originally posted by Streets
Dan ... The "Granny Tranny" talked about here is NOT what you'd use fer Draggin material.. 1st gear would getcha 6,000 RPMs at a speed of 10 MPH with the standard 4:10 rear gears usually found in trucks with this tranny..(And the engine would blow up before the 60 foot mark) It weighs in the neighborhood of 300 pounds and is a top shifted tranny, MOST everyone that has a big heavy truck or a heavy load to pull uses these trannys if they like sticks.. When just cruisin' around town you start out in second gear.. saves on the killer engine rpm's!! It also has a PTO drive on the passenger's side AND a bolt-on u-joint assembly!!
Streets, you are a kidder! With VWs and my MG Midget it was fun to give away mpg with performance improvements and still stay above 20 mpg while with these V8s you have to be careful to get above 20 mpg. Thanks to Henry Rifle and Tech1 I saw the light and got a 700R4, now I can hopefully get performance and good mpg cruisin'. Anyway what I really want is to get back to the performance of my Dad's '69 Chevelle in a Model A body. Today I found a site that offers 3.25 rear gears for 8" Ford rears for about $200 so with bearings and labor adding up to about $500 maybe I now have to worry a little over 3.25 versus 3.55, although the 1600 rpm full converter lockup at 55.3 mph argues for a 3.55 for sensible driving where I get into 4th soon and easy and then run in overdrive with occasional blasts staying in low and second longer. Thanks for your suggestion for the stainless flaring, I will take my bent tubing to John York tomorrow for double flares. He is building some beautiful Cobras in his shop and you can have one for a mere $35-40K, I am still hoping to build my roadster for under $20K, but we will see how it goes.
Don Shillady
Retired Scientist/teen rodder
Don,
I don't understand the 1600 rpm lockup you mentioned. How is that accomplished? Just based on converter stall?
The reason I went with Bowtie Overdrives was the positive electronic lockup in 4th gear. As long as the car has shifted up to overdrive, the converter is locked, and the manual switch allows the same in 2nd and 3rd. As I understand it, if the RPM drops below the stall of the converter, the transmission still stays locked. It will downshift and unlock if I hit the loud pedal, or if I move the shifter lever, but otherwise, stays in high gear and locked.
Henry Rifle, Well I had a long chat with the Tech guy at Megamonster and maybe the difference is that with the hydraulic switch I won't be able to stay in the fourth gear as with the electric lock. As I understand it (?) it will down-shift just like a third-to-second with a TH350. As I calculate it I will be able to stay in fourth longer and get to fourth sooner with the 3.55 rear gear and so get better mileage with an effective (0.7 x 3.55 =) 2.485 drive ratio as compared to my present 2.79 in third gear with a TH350, but I need to get to that gear at a reasonably low mph for "normal driving" so I am using the 1600 rpm stall speed to estimate when the lock might down shift. Estimating roughly with the 1600 rpm value the down shift might occur at 55 mph (?) so this will be great on the Interstate but I will still have a 3.55 gear for city driving. I may make more rapid progress on the roadster buildup now that I have found John York's Cobra shop just a half mile away and maybe the electric switch is better, but I did not want to get into a situation where I had to worry about the wiring. Maybe I will just spin the wheels with the low gear and not get 20 mpg after all, but it looks to me that the 3.55 rear gear will get me into OD sooner at lower mph and that will help the mileage; especially since a lot of my driving is on Interstates. Then again, comparing a full-fendered '29 body to a Corvette body surely will lead to a need for more gear once the air resistance builds up at 60-70 mph speed so I will just have to wait and see. On the other hand maybe someone on this Forum can tell me how much the shift points can be changed so as to make sure I can get to fourth gear at maybe 50 mph with a 3.25 rear gear????? Then the problem is to ask whether the engine woud pull a (0.7 x 3.25 =) 2.275 OD below 2500 rpm?? I am sorry to bother you guys with my worrying, I guess I will just put it together and take what I get within reason. Another way to look at this is that my '98 Pontiac Sunfire has a Suzuki 4-speed auto and the gears are nearly identical to the 700R4 in the trans and the rear (FWD) is 3.60 so the 3.55 gear with the 700R4 should be streetable although maybe with a V8 instead of a little 4 cyl. engine the mileage will have to be lower than the 24 mpg I get with the Sunfire. Of course auto engineers can try various combinations on a test track while I am trying to learn from the collective experience of Forum members; it is like choosing a cam with the same sort of possibilities for guessing wrong.
Streets,
Now you tell me you get 31 mpg with a 2.79 rear in your T-pail? I thought you said in an earlier thread that you got 18 mpg with the blower turned off? Gee you could have really got me going if you had told me 31 mpg earlier! Anyway I got the 700R4 now and hopefully I will get a tire burner in low gear and good mileage in fourth gear. Maybe you could define your actual mileage with what engine, what rear and w/wo the supercharger. My understanding was that you got 18 mpg with the supercharger mounted on a 383 but the clutch to the blower drive disengaged. Of course many of us were impressed with the clever clutch on the blower drive but I was more interested in estimating the mileage as compared to the Magoo '29 which claimed 18 mpg with a Hi-Po 327, TH350 and a 3.08 rear gear. Can you tell us/me how you got 31 mpg with what engine, what trans and what rear gear?
Don Shillady
Retired Scientist/teen rodder
Don- I belive that there is another wiring set-up for the 700r4 that may be the one that your looking for, I know that there's one for it to go in the other direction to raise the shift points- if you will call Emanuel Zavackis shop there in Richmond, or Paul Scott's Speed Shop in Chesterfield I think they MIGHT have something to help you.
Don,
Here was my thought pattern with the electrical control.
- The wiring isn't difficult at all. Plug in the trans, connection to hot, connection to the brake switch.
- I always have the trans in lockup in OD.
- My trans only downshifts when I make it downshift.
- The stall speed of my converter doesn't matter.
- I have much less worry about burning up a $1000+ trans.
There is a wiring setup that uses a stock GM brake pedal switch instead of the Bosch relay.
http://www.bowtieoverdrives.com/cata...php?ITEMID=332
Guys this a great thread, I really appreciate all the input. Thanks to all the contributors, both those asking and those answering!
Pat
Well I still think about a 3.70 rear gear with the 700R4 trans. I am farming out the change of my rear gear after Christmas from 2.79 to ? Henry Rifle comments that with the 3.06 low gear in the 700R4 a 3.50 or 3.55 gear should be plenty low enough for acceleration. Then I looked at the site on acceleration:
http://www.alienplanet3.com/hotrodmath/quarter.html
There if I put in 2500 pounds and 260 H.P. at a mere 4200 rpm the program predicts a 1/4 mile time aound 12 seconds and recommends a 3.27 rear gear. Although I know that the laws of Physics can be used in an ideal way to assume perfect traction and predict these times, I do not know the assumptions of the transmission gears in that calculation. Assuming there is only one shift in the 1/4 mile run I would guess my trans would use low (3.06) and second (1.64) gears from a standing start but I have no idea what gear ratios the acceleration calculator uses, so what does the 3.27 rear gear recommendation mean? Interestingly, if the weight of the car goes up to more like that of a Corvette around 3300 pounds the predicted rear gear gets lower. Soooo, the question is, maybe a 3.55 rear gear is too low for a light roadster? Apparently there are a few places which still offer a 3.25 rear gear so that is possible, but then I will not be able to get into OD gear until a higher mph, so maybe after all the 3.55 rear gear is an all around compromise considering that I am using tall tires of 735/75/15? Just wondering while I consider what to tell the guy who will rebuild my 8" rear with a new gear.
Don Shillady
Retired Scientist/teen rodder
Don, I tried inputting some scenarios into their calculators and came up with some real suspect results. I would not trust them.
Pat
Don,
A couple of thoughts:
First, what do you tell a guy that wants to build a hot rod with decent gas mileage? :LOL:
Most of those horsepower/ET/speed calculators are based on empirical data, not Newton's laws, so they don't make assumptions about gearing and traction. They are what they are, and your setup may or may not get the performance predicted. The best predictor, though, seems to be trap speed.
The difference between 3.27 and 3.55 gears is only 8.5%. Considering all of the variables, is that really significant?
In a light roadster, 3.73's may be overkill, considering your desire for gas mileage. But, I don't think you can go wrong with either 3.27 or 3.55.
Of course, I'm putting 3.73's and 440 HP in my lowboy, so what do I know? :3dSMILE:
Oh, and I'm with Pat. That calculator looks a bit hinky.
that sound's like the one i just put in my 79.Quote:
Originally posted by Streets
Dan ... The "Granny Tranny" talked about here is NOT what you'd use fer Draggin material.. 1st gear would getcha 6,000 RPMs at a speed of 10 MPH with the standard 4:10 rear gears usually found in trucks with this tranny..(And the engine would blow up before the 60 foot mark) It weighs in the neighborhood of 300 pounds and is a top shifted tranny, MOST everyone that has a big heavy truck or a heavy load to pull uses these trannys if they like sticks.. When just cruisin' around town you start out in second gear.. saves on the killer engine rpm's!! It also has a PTO drive on the passenger's side AND a bolt-on u-joint assembly!!
I knew that a sm420 was not suited for drag racing and, I just wanted to see if anyone would catch on.
i catched on all right:HMMM: :rolleyes: :D :LOL: **)
no truck tranny will drag race unless the truck has had a trans put in or it was a highporformance truck when it came out that is for the 4speeds.
i dont know much about the three speeds besides i DON'T LIKE THEM!!!!:eek: :D
Henry and Stu, Thanks much for your comments. I went back and played with the acceleration calculator some more. I have spent most of my career fitting polynomials to data and I am familiar with the case that a certain equation may fit the data in a narrow range but not elsewhere. I tried their first set of mph-rpm equations and got the same numbers as on another site so I think that part is right. Then I tried the acceleration formula with:
2500 pounds wt.
250 H.P. at 4500 rpm ( I have a low rpm cam with 1.6 rockers)
28.82" tires (735/75/15)
their formula predicted:
11.99 sec 1/4 mile elapsed time (?????)
108.7 mph trap speed
Suggested ideal rear ratio: 3.55
The 12 sec elapsed time seems pretty optimistic, but the input seems realistic and makes me feel better about the 3.55 rear gear. From my perpective I recall that the AMBR No.1 roadster did not break 15 sec elapsed time with a built flathead, so even 13 sec seems pretty quick to me. I guess a 3.55 rear gear will be a good compromise for me with a relatively mild SBC. Maybe Proz or someone else with actual speeds and times could check the formula in this site, but I guess it looks more and more like the 3.55 rear for me and hopefully I can crack the 20 mpg barrier at least on the Interstate. Thanks for your comments.
Don Shillady
Retired Scientist/teen rodder
Ah yes . . . I did some power spectral density function applications in my earlier years. Determining what lab generated inputs to hydraulic actuators would create realistic loadings on structural members used in earthmoving equipment.
....I had an '84 Camaro with a 700R4 that was built by Art Carr {years ago before Art sold the business} with a converter {don't remember the stall} the whole set up was around $2500 or so. But anyway, it wasn't a cheap unit. It was behind a 415 small block that dyno'ed at 499 Ft/Lbs @4000 RPM & 438 HP @ 5250 RPM {flywheel dyno}. I had 4:56's with Posi. in it & cheater slicks. The car was stripped big time, 2800 pounds the last time I weighted it and I took some stuff off after that. Anyway, the trans blew up so I personally wouldn't use a 700R4 unless it was for a non-performance application. They said the 700R4 would handle my HP, but it didn't. I took it back and got a GREAT deal on a 400 turbo so that was ok but I'd start out with a stronger trans if you plan to hot rod around ;) .... Bill.....
Here we go boys and girls read the info on this site and u will have a better understandin of the matter at hand.http://www.transmissionhead.com/:D just a detailed site for these trannies and it covers just about everything in those trannies!((((((c-mon get ur head into it !!))))))lol**)
Bill,
Two questions:
1. How did you cool the 700/R4?
2. Did it have an 4th gear lockup?