Thanks for the great educational video, and a huge thanks for not ruining it with crappy background music while you're talking. I don't know why some people are compelled to add annoying background music throughout the video.
Let me simplify this for everyone....the front spinny thing uses fluid to make the back spinny thing go around and around. The engine speed required for the front spinny thing to spin the back spinny thing when you mash the accelerator thingy as fast as you can is called the stall speed. I don't know why they call it stall speed because it doesn't stall when its spinning.
This is a great video. Years ago I had a Rover 800 2.0 litre with ZF HP14 4-speed automatic gearbox. They were sold as Sterling in the US and I expect they had the 2.7 litre Honda engine over there. As I was having the engine and gearbox rebuilt I took the opportunity to have a custom-made torque converter. I told the torque converter company that I wanted the lowest stall speed possible. They said they could do it, but it wouldn't work as the engine would stall as soon as it was put in gear. I went away to think about it, and the maths involved, and I concluded that they were wrong, so I asked them to go ahead and build it that way. They supplied it to the mechanic who was putting the gearbox back together, and after having supplied it, someone higher up in the company rang him up and said, "We're sure it isn't going to work, so if you return it now before it's fitted, we'll put it back to normal at no extra cost". Clearly, the discussion about it had filtered up and someone more senior had eventually taken a look at the spec after it had already been despatched. I went away and thought about it again and simulated it in my head, and I concluded that I was simply going outside their normal envelope of experience, and that they were extrapolating linearly outside of their experience instead of in proportion to the cube root, which is indicated by the maths. Plus, I'd reached the point where I had to know if I was right or not. So I told the mechanic to go ahead and fit it. I've got to say that it was almost perfectly how I expected it to be, in that there was a bit of an extra 'kerthunk' when it went into Drive, and the engine vibrated a little more on tickover when stationary, as the torque converter was pulling harder at tickover, but it didn't even come close to stalling the engine. Driving through traffic was lovely, because a lot of the time I only needed to take my foot off the brake to keep up with slow traffic as it would creep at a much higher speed than normal. To make decent progress I only had to breathe on the accelerator and the first to second gear change was extra silky because then engine was revving so slowly when it happened. Commuting right across London at the time I managed to average 35mpg over a tankful, which is pretty good considering that it was a 2-litre, long and relatively heavy car, driving through one of the heaviest traffic areas of the UK for most of my journey each day. But I was especially delighted that my experiment had worked, and the experienced, qualified professionals were wrong. The downside is that at the traffic lights Grand Prix it was definitely slower, because the torque converter was holding the engine speed down to a lower speed all the way through each gear, but if you use a car for normal commuter driving and not racing, then a lower-stall-speed torque converter is much nicer to drive with.
When my dad explained a torque converter to me in 1964, I was amazed. Now almost 60 yrs L8R, I see this vid & I'm still amazed! Thanks so much for making & posting this.
I read a number of explanations over the years from 1979 to maybe 2005 and none of them mentioned the one-way clutch. But it never made sense the way the stator was said to divert the fluid and add to the torque unless there was also something to stop it from spinning backward. Finally, in 2005, I just added "one-way clutch" to a Google search on the subject and found a more complete explanation than I'd ever seen before. I guess I could have just asked a transmission shop, but the few I'd had reason to visit seemed too busy for educational questions.
Funny, he never answered the question posed... Stall speed is the speed at which the converter holds back or limits the engine speed if the transmission output is prohibited. When your torque converter prevents the power transfer from your engine to your transmission, it increases the engine’s RPM stalls. For example, when you press down on your gas pedal, the stall speed is the gap between where your vehicle ideals and begins to move. The more stall speed you have, the more pressure you have to put on the gas pedal before your car begins to move. Why is Torque Converter Stall Speed Important? High performance torque converters can do a lot for your vehicle when the proper stall speed is selected. For racing, the proper stall speed will increase your launch and get you off the line quicker. In towing, the proper stall speed will help your engine pass more power to your transmission, causing your tow capacity to increase. How To Choose the Right Stall Speed: When you are selecting the right stall speed for your vehicle, be sure to match the engine’s peak torque, torque curve and vehicle weight. Peak Torque - The maximum torque your engine can exert at a certain RPM. Torque Curve - The place where the engine has the maximum amount of power at a certain RPM. Vehicle Weight - The weight of your vehicle has a big impact on the measurement, and don’t forget to factor in aftermarket modifications. If you don’t know these exact specifications, we recommend giving a conservative estimate. If you over estimate, your stall speed will be lower than intended, which will reduce your torque converter’s performance. If you are unsure about these modifications, the experts for help. In general, the desired stall speed should be 500-700 RPM below the engine RPM at peak torque. This ensures a margin for application for the torque converter to take off. You don’t want to have to floor your gas pedal and wait a few seconds for your vehicle to move. Think of it as a balancing act.
What exactly is stall speed, and how does it affect your vehicle? With the introduction of the Banks Billet Torque Converter, you’ll hear a lot of talk about stall speed. What exactly is stall speed, and how does it affect your vehicle? This article assumes you have a basic knowledge of how torque converters work. If you’d like more in-depth detail, see “Understanding Torque Converters” elsewhere on this site. Let’s start by illustrating how the stall speed works. Even under light loads, a vehicle with an automatic transmission will start moving as soon as you take your foot off the brake. The stall speed comes into play under all load conditions. When we talk about stall speed, we’re referring to engine RPM. If the vehicle isn’t moving by the time the impeller reaches the stall speed, either it will start to move, or the engine RPM will no longer increase. In other words, stall speed is the engine RPM at which the torque converter transfers the power of the engine to the transmission. In the real world, the torque converter’s stall speed roughly equates to the clutch engagement point on a manual transmission. Let’s say you’re driving your stick-shift car around town. Normally, you’d give the car a little gas and ease off the clutch pedal gently enough to get a smooth start. Likewise, under most driving conditions the torque converter will start delivering power to the transmission at relatively low engine RPM. Now, let’s say you need lots of power, either to make a fast getaway or to start with a heavy load. You’d rev the engine up to a point where it delivers more power before letting up on the clutch pedal. It’s under those same circumstances that the stall speed becomes important. The torque converter will allow the engine to build RPM without turning the output shaft (the turbine) until the stall speed is reached. Unlike gas engines, diesels develop massive amounts of torque (pulling power) at low RPM - enough that it’s possible (and, in fact, desirable) to get a heavily-loaded diesel truck rolling by simply easing off the clutch without touching the accelerator. Banks’ dynamometer tests show that Ford’s 7.3 liter Power Stroke hits peak torque at 1,600 RPM and begins to drop off at around 1,850 RPM, while the Dodge’s 5.9L Cummins engine peaks at 1,400 RPM and drops off at 1,800 RPM. As RPM continues to rise, torque decreases even further. How would you translate this to a torque converter? With a low stall speed. But both the Ford and Dodge torque converters stall between 2,000 and 2,500 RPM - so with a heavy load, the torque converter won’t start turning the rear wheels until well beyond the engine’s torque peak. In this case, the stall speed is too high - it is literally impossible to get the engine’s full power to the rear wheels! In order to access all of the engine’s potential power, the stall speed must be lowered. Lowering the stall speed has another advantage: It reduces the transmission’s temperature. Let’s go inside a high-stall torque converter under heavy load. The impeller (input side) of the torque converter is spinning quickly, while the turbine (output side) is spinning slowly or not at all. The motion energy of the impeller is being converted into heat energy, most of which is passed on to the transmission fluid. The higher the stall speed, the more heat will be generated. Heat is the enemy of a transmission. You want to keep the fluid temperature as low as possible. With a lower stall speed, less time elapses before the motion energy of the impeller is converted to motion energy to drive the turbine, so the transmission runs cooler and lives longer. What many people don’t know is that the torque converter is a tunable device. Stall speed is determined by several factors, including the distance between the impeller and the turbine and the design of the stator. By properly modifying the converter’s internal components, it’s possible to alter the stall speed and create a torque converter that is tuned for a particular engine.
Thank you for getting right to the point here and being actually educational. I know very little about how automatic transmissions work and i want to understand more so i’m gonna binge this whole series
As a student, I appreciate information that I can understand. This video helped me understand stall speed and the factors that influence its variability. Thank you.
Nice to know RU-vid listens to or watches my text messages..... 5 hours ago I had this exact discussion with my buddy about stalls and tq converters lol
Oh baby, this video packed a punch, I learned a lot, especially that I should call for recommendations even on a mils street combo, I finally get it. Excellent.
Last time I spoke with Jim Hughes he told me the Billet core halves cost less then having to source down OEM cores, So with that said even though I've always had great experience with your convertors I just recently went with a new FTI again as a $100 core fee you guys at Hughes have added to the cost of buying a new convertor is B.S
I was glad to hear that about the foot brake stall. I don't like power braking at all and don't do it. I've taught my sons it's an embarrassment. If the car won't spin the wheels on it's own free will then build a bigger engine.
Turbo hydramatic 425s had a variable pitch stator. VERY efficient. Shame they quit making them. Caterpillar hydrostatic transmissions had a unique torque converter design... Ever seen one ?? Great video Sir.
Hi I have a 93 dodge dakota with a 5.2 318 motor and I believe am A500 tranny. Im Pretty sure. I was gonna get a $144 t.c. from autozone but I'm not entirely sure which one. Can you help. Someone anyone plz
Thank you for making these videos. Curious about stall speed application. I’m guessing a high rpm hydraulic hookup would be used for drag racing where ya only care about 4-8k rpm. A slow hydraulic hookup, say 800 rpm for a Diesel tractor. Am I in the ballpark?
Thanks for your support and for commenting! We really appreciate it!! You're definitely thinking along the right lines. The vast majority of torque converters that we build for dedicated drag racing applications will typically provide a flash RPM of anywhere from 4,500 RPM to as much as 7,000 RPM and beyond, depending on the application. We tailor the necessary stall speed characteristics and converter coupling point to each specific application when it comes to our custom converter builds. Modified street-driven diesel applications will typically utilize a torque converter that only provides around 1,000 - 1,500 RPM of flash stall speed. Due to the torque output of diesel engines and the relatively low RPM ceiling, diesel applications typically need a very low coupling point in the converter. Hope this helps!!
So my truck makes 265 full at 2000 rpm. (Ford 300) if I foot brake it it does about 1500 rpm. Is there anyway to determine how to determine my stall speed based on that?. Its totally stock E4OD transmission
Maximum stall speed is determined by whatever RPM the engine will flash to upon initial acceleration under load whether that be from a stop or very slow roll. You can transition to wide open throttle immediately at the same time of releasing the foot brake at 1,500 RPM, observe the tachometer while doing so, and the initial flash RPM is the maximum stall speed of your converter. You'll probably only notice another 200 - 300 RPM of flash over your current footbrake stall speed with that combination.
I have a 72 350 motor 4 Main with a turbo 400 miles it and I can’t get the torque converter with the torque transmission through a belt was a shift kit what do I need in the torque in the transmission it would work with that transmission
The most important aspect of explaining stall speeds that you missed is uses of stall speeds. Why you'd want a low stall speed vs high stall speed. What benefits from low stall speed and high stall speeds. Should have done that just after you explained what stall.speed is at the beginning before going into what affects stall speed.
Sorry, I failed to grasp what difference it makes. Is this a drag racing thing? Is the rpm of the so called stall speed related to the max torque or how rpm? Does it mean for example the engine must reach 3k rpm and the transmission engages? I am a pilot and stall speed means an exceeded angle of attack and you fall out of the sky. So does the stall speed mean the fluid in the converter no longer flows and it cavitates? Some of your audience meaning me needs more explanation.
So if I have a LS swapped conversion and I feel that at idle the engine is over powering the brakes do I get a bigger converter? Or should I consider a different automatic transmission with a lower first gear ratio
i really appreciate this video, in short the more you slow down the fluid coupling from happening/ efficiency the higher the stall speed/ the more torque can be output by engine without overriding torque converter, trans, etc. Thank you so much finally understandable. :)
very good presentation thanks for posting your host of knowledge i have a few questions id like to ask i will try giving you guys a call early next week thank you
I watched several other videos on stall speed and was nothing but disappointed. All of those people need to come and watch this and get an education from you professor. Fantastic video and 100% convinced me of who I need to go to for parts.
Our part number 25-30LHD torque converter would work well with your combination. This is our Pro Street series billet single disc 265mm model featuring an advertised stall speed rating of 3,000 RPM. This converter works really well in high performance trucks; offering a nice overall blend between great drivability along with a significant improvement in overall acceleration and performance as compared to an OEM torque converter.
Can you talk about or make a video about convertor slip ?? I lost mph and et as my convertor aged. I still don’t understand why it happened and how to prevent it
what stall do you recomend ? I have a 1982 dodge d150 short bed with mildly built 318 with stock 30 over flat top pistions with factory 360 Hipo cam . 727 auto none lockup with racing shift kit and rear is 8-1/4 with 3:55 gears . the front 15 x 7 with 235 /75/15 and rear is 15x 8-1/2 with 255/75/15 I was thinking 2000 stall ?????
Can you make a video dedicated to the Allison 1000 TC considerations and different applications. I want a truck that can do it all. Street, track, tow/haul. I'm at 454hHP de-torqued to 800 lbs. with a 120hp tune looking at getting a transmission built and throwing in a 250hp tune for my 68mm, 10mil.stroked CP3 and 60 over injectors. Goal of 750hHP/1300TQ.
We don't get into Allison transmission builds here at Hughes, nor do we offer much for the diesel market apart from the typical billet triple disc converters and deep pans. If you're looking for hardcore diesel performance transmissions then you really need to be dealing with Suncoast.
Not usually as an automatic transmissions clutches are internal. And the new "manumatic" type automatics simply allow to specifically select an individual gear. Actual manual transmissions do not use a torque converter, just a clutch. To have both would require a massive bell housing and a very complicated hydraulic system from the transmission. Also, why would you want both? The complexety of an automatic is enough for most people. Why add to that by throwing an additional fly wheel clutch to the mix.
Lock-up torque converters first began use by US domestic manufacturers in 1978. A lock-up converter features a clutch inside the torque converter that applies at cruising speeds typically around 35 - 40 MPH depending on the application. This feature was originally incorporated by OEM's to help increase fuel efficiency and reduce engine emissions. The aftermarket has since adapted lock-up converter technology to some extreme high horsepower drag racing applications.
In the early days of automatics, there were actually Chryslers with a pedal-operated clutch and a fluid coupling (a torque converter without the stator). Some shifted automatically between 2 speeds, but you had to use the clutch to switch between "ranges". They were probably less confusing to drive than to explain. The comments on this video explain it better than I ever could. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-p-wfIrtVUmk.html Also, VW had something called an "Automatic Stick Shift" in the 1960s, with a torque-converter, a vacuum-operated clutch and a 3 speed manual gearbox. The clutch automatically disengaged if the transmission lever moved so the driver just had to shift. Both of these seemed kind of kludgy, but they still could idle in gear, and could be driven in high gear with no shifting as long as you weren't in a hurry.
I am getting started on my 1971 Nova build. Just got my 383 stoker built, I was thinking in my mind I need a 2,500 stall. I wake up this morning and this is the first video on my recommend list. LMAO 😂
I am Still Trying To Have My Older 7004 And My New Blue Print 383 Stroker Working Properly, I have PurchasedA Hughes 2600-2700 Stall Converter And The Engine was Surging I was Told To Unhook Plug On The Driver Side Of The Transmission .After Doing So The Engine Surge Has Gone Away But I Don't Want to Burn Up My Transmission. I Am Getting Conflicting Information On Whether Or Not This Will Happen. This Combination Is In My 55 Belair 2Dr. Htop Which I Have Owned For 51 Years And It Is A Beautiful Car! I Would Appreciate Any Assistance In Resolving This Problem! Thank You!
I am so screwed! prior to watching the video, I ordered from you guys based on shelf stall speed, WTF!!! Ordered a 22-20L 2000 stall Hughes converter for my 64 Chevelle, 700r4, 350 zz-4 eng with 20" wheels and it just doesn't feel right, what a waste of time and money. this was based on Hughes recommendations my understanding is that this only equates to about a 1700 stall due to it being an A/T. Unfortunately, the guy I spoke with was very irritated with my lack of knowledge of torque converters and I felt he just wanted me off the ph. i do however like and support their product.
I've got a .060" over 427 12.5:1 CR, Single plane intake with a 800 cfm dbl pmp Holly. Solid lifter cam, Advertised Duration: 304 Duration at .050" : 258 Lobe Separation : 108 .615" lift, 400 THM 4:56 12-bolt posi in a 4000lb 72 C/10. Can you recommend what stall speed I need? This truck wont see much street, track truck mostly...Thanks!
You guys do anything with the new 6 & 8 speed Chevy trans stall converter .like camaro and trucks, About 2400 stall, something to handle a 1k idle, and lock for street, I want to swap one into a older car, with older engine,
What is the difference between a low hp max effort small cu in converter, like an NHRA stock eliminator like a K/SA, and say a 400hp bracket car of equal weight?
Are there any markings/#s on torque converter to know if it's stock or performance ? (Part # ?) I bought a used C-4 with a converter. Was told it is 4,000 stall. Haven't found any #s to know if it's stock or performance.
I've been working on cars my entire life and for the life of me this concept seems like snake oil! I bought into the hype and had my mechanic install a 2800 stall after having a stage 2 cam installed as well and I'm like, did he really install this? I can't see it? Is the performance better? I guess, is the engine surge gone? Mostly, was it with the money,? Hmm I guess, still confused
If you are running a converter with a stall speed of 2200 to 2600 and you are running at 65 mph on the freeway with the engine turning at 2000 rpm's at 65mpr will the torque converter, be slipping causing heat and poor efficiency?
My old torc converter was a 2500 stall speed” for a 3800 supercharge engine behind a fiero” I went to a 3000 stall speed because I ditched the supercharger and went to a big turbo.....I did the 3000 torc converter for turbo lag prevention” the engine has good low end torc” not as much what it had the supercharger” the torc for that engine” without the supercharger is 250 pounds of torque, but builds up to 540 Horsepower....I did the higher stall speed so I wouldn’t have to add Nitrous oxide for launches. I didn’t want the Porsche issue if anyone knows about some of the late model Porsche that would break the tires loose when the turbo engaged at low cruising speeds.....those cars were dangerous.
Great video! The only question I have is how much a typical car torque converter waster energy (in kW) when the transmission in on Drive, the engine idling and the car is hold on brakes? Does different stall speed affect this?
Good afternoon, I have an edelbrock performer kit, for a 302, 81 of a bronco, they estimate 320 hp and 260 foot pounds of torque between 2000 and 4000 rpm (5500 rpm max). It has a 3-speed c6 box, standard differential and 33 wheels, I need to replace the torque converter, I appreciate your suggestion to choose the right one for these characteristics, the camshaft indicates, intake duration 204 degrees, exhaust duration 214 degrees, elevation intake .448", exhaust elevation .472", lobe separation 112 degrees, intake center line 107 degrees, vacuum 16", thank you very much and congratulations for the videos, they are of great help to incorporate knowledge.
i got a question for u ..i got a 1990 k5 blazer 700r trans 2000 to 2400 torque converter in it and im thinking about buying this race motor it has 12.5 to 1 sbc 355 030 over with elgin e-1090p solid flat tappet cam with scorpion 1.6 rockers for total lift of 573 intake 594 exhust can i use the torque converter i have on this engine,,..i no i got alot of things to change because it is a tbi fuel injection
Thank you for this great explanation. I was wondering why does the slip ratio reduce as RPM increases, I.e.: if you have a flash stall of say 3,000 rpm then you have close to a 3,000 rpm difference in input shaft to output shaft speed, but once the engine reaches say 6,000 rpm the output shaft would be much closer to the input shaft speed. Thank you for explaining that centrifugal force enables the fluid to transfer more energy.
Sorry to be offtopic but does anyone know of a method to log back into an Instagram account? I stupidly lost my password. I would love any help you can give me!
@Jayce Jaime thanks so much for your reply. I found the site on google and im in the hacking process now. I see it takes quite some time so I will reply here later with my results.
Understeer: The front of the car hits the wall. Oversteer: The back of the car hits the wall. Horsepower: How fast the car hits the wall. Torque: How far the car pushes the wall.
Up to the end of the 1967 model year, GM made "switch pitch" torque converters, which increased the stall speed if the accelerator was depressed most of the way. It seemed like the best of both worlds, but I've heard it could be a reliability trouble spot. Do any aftermarket builders make switch-pitch converters today?
I have a Dodge Charger 5.7 AWD and find there's not enough stall which makes the engine not rev enough when hitting the gas fully to get the performance it should compared to a RWD... What can be done for this?
@@HughesPerformance NO, thank you for building quality parts. That's something we lost in this country over the years is quality, but you guys understand quality. I inspected the 2500 converter and it's great! Keep up the good work. 👍
do people upgrade torque converters to deal with larger mud tires ? Seems like a good idea to me. I know a lot regear. I don't hear many people talking about torque converters though which to me would make sense also.
Great video on understanding converters. Some shops i have spoken to ask specific engine build details is this really needed. Also is converter diameter a big factor in achieving what is needed as in smaller engines need smaller diameter for it to work. Thanks ray
Yes, when we provide a torque converter recommendation we want to know as many engine specifics as possible as well as vehicle weight, rear gear ratio, rear tire size, how the vehicle will be used, etc.
A steel stator is ultimately stronger than an aluminum stator. That being said, modern billet aluminum stator designs are incredibly strong as well. What it really boils down to is selecting the right stator design that will provide the correct flash RPM, torque multiplication, and converter coupling characteristics for a given combination. Correctly designed steel stators will typically (though not always) offer increased flash RPM, less torque multiplication, and greater converter coupling ability when compared to similar aluminum stator models.
hello, i have a 1969 ford galaxie sportsroof (Heavy car), 3.50 rear gears, wheels = 255 60 15, C6 trans (w/ transgo shift kit), 390FE, edelbrock perfomer intake, holley carb 600cfm, FPA shorty headers, isky RV part#351256-262 cam (Hyd Flat Tappet, Advertised Duration 256/262, Lift .492/.488) what can you do for me for stall? It's a street car (won't see strip)
Part number 35-20 would be a fantastic choice for your combination. This is our Street Rod series converter featuring an advertised stall speed rating of 2,000 - 2,200 RPM. This model will provide a noticeable improvement in low speed acceleration and general performance while still maintaining excellent overall drivability, responsiveness, and converter efficiency. We keep this model in stock and ready to ship. 😉
I actually had a couple sent to me when I talked and said this is what the gearing is this is what the trans is set up as hp rating and what my customer is looking for. getting the right torque converter to every set up is always a good thing when dealing with the final set up no one wants to take back out the trans just to fix a issue
Thank you for the video, I’m interested in buying a convertor from you, what would you recommend running with a 2016 Camaro SS 6.2 LT1 engine automatic 8 speed with stock gears, I’m looking to use a GPI track attack cam 237/255 duration .648/.630 111 LSA. On their website they recommend a circle d 4000 stall converter, but I’d like a second opinion seeing I do not want the extra stall if I do not need it. Stock weight 6 gen Camaro ss 3,685 curb weight 275/35/20 in rear and 245/40/20 in front. Thank you
Hey guys. I have a 2011 Camaro SS full boltons with 3200 Circle D stall with 391 gears.it makes 380 rwhp and 400 ft lbs torque. I can't footbrake it past 1800 rpm with pushing through the brakes. Is that right? Thanks
Yes, because as he mentioned, foot-brake is your lowest read stall, because you're limited by your traction. Now if you can get your wheels to remain locked and do it again, you should be far closer to your stall speed.
There's not necessarily a "right" amount of footbrake stall speed. Flash stall speed is really what's more important. That being said, we can tune your Circle D torque converter for increased footbrake stall speed if that's something you desire.
Can you tell me if there is anything like more or less hp or cam than one thinks that would cause the stall to be effected,I mean more or less than advertised?
This video is making my brain hurt but thank you for making his videos I'm not trying to build a race vehicle I'm trying to keep my old plow truck on the road and I'm trying to understand every system from bumper to bumper on a molecular level
In my Dodge truck, I could foot-brake stall and get the same as static stall. I pressed foot down hard on the brakes, and also pulled the E-brake, and that was enough to keep the tires from spinning under a WOT punch. Got ~2200rpm
@@lost1mp Yeah really, in a dodge it won't put up with that long, sad when a company makes a worse slush box than GM does, but yet fiat dodge does LOL.
Some vehicles do have enough brake system holding power to achieve maximum converter stall speed. As engine torque output increases with modifications, that becomes much more difficult to achieve.
