Brad Personett Runs 6.08 @ 250!!
- Thread starter Buns
- Start date
sdwarf36
Nitro Member
A crap talking punk. Good Yellow Bullet material.
Bobby Bennett
Nitro Member
This is probably the toughest post I have ever made but to do the right thing sometimes you have to do the tough things.
In our article, about Billy Glidden commenting on Brad Personett's 6.08 elapsed time, while we accurately quoted his words, one word we stated leading into the quote changed the context in which Billy's comments could and should have been taken.
In our paragraph leading into the quote, our reporter made the statement --
The run, however, didn’t impress veteran racer Billy Glidden.
In reading over the article, double-checking the audio --- the proper wording should have been --
The run, however, didn’t SURPRISE veteran racer Billy Glidden.
We at CompetitionPlus.com strive for 110-percent accuracy but just like any drag racer or anyone in this world, we are not perfect. Simply put, we made a mistake and as Publisher/Editor, the buck stops with me, not my reporter.
I apologize for any grief this has caused. But, this needed to be said and I am saying it.
Bobby Bennett
CompetitionPlus.com
In our article, about Billy Glidden commenting on Brad Personett's 6.08 elapsed time, while we accurately quoted his words, one word we stated leading into the quote changed the context in which Billy's comments could and should have been taken.
In our paragraph leading into the quote, our reporter made the statement --
The run, however, didn’t impress veteran racer Billy Glidden.
In reading over the article, double-checking the audio --- the proper wording should have been --
The run, however, didn’t SURPRISE veteran racer Billy Glidden.
We at CompetitionPlus.com strive for 110-percent accuracy but just like any drag racer or anyone in this world, we are not perfect. Simply put, we made a mistake and as Publisher/Editor, the buck stops with me, not my reporter.
I apologize for any grief this has caused. But, this needed to be said and I am saying it.
Bobby Bennett
CompetitionPlus.com
I don't speak for the rest of the members here, but as for myself (and I am a daily visitor/poster at the CompetitionPlus forum), you are to be commended for posting this retraction/correction. Everyone is quite aware of the steps you take to ensure your magazine reflects the truth. Thank you, sir.
In my mind, the correction doesn't change the context of Glidden's words at all. I also don't believe Glidden is whining. I believe he's deliberately stirring up controversy and rivalry, designed to generate a bit of interest and excitement...a bit like the Schumacher/Fuller deal and countless others. Unless carried to extremes, such rivalries can be a good thing. In the off-chance that he is simply whining, well, which lane would you prefer, Mr. Glidden?
In my mind, the correction doesn't change the context of Glidden's words at all. I also don't believe Glidden is whining. I believe he's deliberately stirring up controversy and rivalry, designed to generate a bit of interest and excitement...a bit like the Schumacher/Fuller deal and countless others. Unless carried to extremes, such rivalries can be a good thing. In the off-chance that he is simply whining, well, which lane would you prefer, Mr. Glidden?
sdwarf36
Nitro Member
Bobby-thanks for the correction.
Just one quick question on the process-what is the chain from Brads run to Billys comment? Did a reporter call him at home to ask him his thoughts? Was he standing there on the line next to the reporter? Did Billy call you up + say "i have a comment"?-Just wondering how the systems works.
Just one quick question on the process-what is the chain from Brads run to Billys comment? Did a reporter call him at home to ask him his thoughts? Was he standing there on the line next to the reporter? Did Billy call you up + say "i have a comment"?-Just wondering how the systems works.
Bobby Bennett
Nitro Member
We were at the race standing in his pit area.
Bill
Nitro Member
Billy Glidden does an amazing job with a small block Ford-powered race car, I think. But, how his car compares with a heavier, turbocharged car in the first eighth-mile is not a very apt comparison, it seems to me. Sort of an apples-to-oranges comparison. Does he want to look at the last half of the quarter-mile in the same manner? Probably not.
I have watched Brad Personnet's struggle to get that car moving in the first 60-feet, for some time, with lots of questions, and not many answers, so I thought I'd bring up the clutch subject on this forum to see if some of the better-educated fans and racers might be able to explain to me how a car that runs virtually ten miles per hour faster than most of its competition gives away so much to the Roots-blown and Nitrous cars on the initial launch.
Maybe this has been discussed to death on here, and I just missed it???? If so, I apologize.
Here's what (among other things) I don't know and would like to be better educated about:
1. What kind of constraints has NHRA placed on the drivetrains of Pro Mod cars that would prevent the utilization of a Top Fuel type clutch (i.e., one with the timed release of levers to "bring in" the clutch in a repeatable, controlled, manner that was infinitely "tuneable"???) Rules about that sort of thing don't necessarily make it ino the rulebook, it seems. Is this something that a turbo car such as Personnet's could use, or not? Or, any OTHER Pro Mod combination. And if not, why not? Pro Mod is not exactly an "entry level" type of race car, so I would think that minimizing "the cost of racing" wouldn't be a very pertinent or valid point.
2. Are there alternatives to friction clutches that would allow boost to be built before the light goes green, such as a torque-converter "power-brake" action by the driver, or a transmission-brake that would allow the driver to apply SOME throttle before the green light, so that when the car needed LOTS of power, it would be available immediately? I'm talking about a system like the Bruno Massel Comp car, or old Tork-Master B&M stuff.
I have a friend who runs a turbocharged slant six-powered '66 Valiant that weighs 3,000 pounds (race weight.) He power-brakes that little 225 cubic inch six to 28 pounds of boost and leaving the line like that, generates 60-foot times in the very low 1.50s.... Which is in the neighborhood of a car that runs 125 MPH, a feat requiring about 500 horsepower in a car as heavy as his. His car is FASTER on initial launch than it is, for the rest of the quarter-mile trip, by comparison. It seems that he appears to be proving that turbo cars don't necessarily have to be slow in the first part of the track.
3. Is Brad's car "slow" in that first hundred feet, or so, because he's not ALLOWED to use the drivetrain equipment that would make his car competitive with a "conventional" Pro Mod car? Or, is it just incorrectly designed? Kinda doubt that....
Brad HAS to be a really smart, innovative, fellow, and I'm certain that anything I could come up with, he's already, long ago, tried and discarded or dismissed out-of-hand. Having said that, I am loathe to think that NHRA would deliberately throw mechanical "roadblocks" in his way, just to slow him down. After all, before this year's U.S. Nationals, he'd never won a race that I know of; there was no reason to "slow him down."
But, maybe they did... I just dunno...
Can someone better-qualified to explain this enigma, show me and others just what it is that keeps his off-the-line performance from equalling cars who have markedly less power than his?
I'd appreciate some help here ... Thanks a lot for any info!!!!
I have watched Brad Personnet's struggle to get that car moving in the first 60-feet, for some time, with lots of questions, and not many answers, so I thought I'd bring up the clutch subject on this forum to see if some of the better-educated fans and racers might be able to explain to me how a car that runs virtually ten miles per hour faster than most of its competition gives away so much to the Roots-blown and Nitrous cars on the initial launch.
Maybe this has been discussed to death on here, and I just missed it???? If so, I apologize.
Here's what (among other things) I don't know and would like to be better educated about:
1. What kind of constraints has NHRA placed on the drivetrains of Pro Mod cars that would prevent the utilization of a Top Fuel type clutch (i.e., one with the timed release of levers to "bring in" the clutch in a repeatable, controlled, manner that was infinitely "tuneable"???) Rules about that sort of thing don't necessarily make it ino the rulebook, it seems. Is this something that a turbo car such as Personnet's could use, or not? Or, any OTHER Pro Mod combination. And if not, why not? Pro Mod is not exactly an "entry level" type of race car, so I would think that minimizing "the cost of racing" wouldn't be a very pertinent or valid point.
2. Are there alternatives to friction clutches that would allow boost to be built before the light goes green, such as a torque-converter "power-brake" action by the driver, or a transmission-brake that would allow the driver to apply SOME throttle before the green light, so that when the car needed LOTS of power, it would be available immediately? I'm talking about a system like the Bruno Massel Comp car, or old Tork-Master B&M stuff.
I have a friend who runs a turbocharged slant six-powered '66 Valiant that weighs 3,000 pounds (race weight.) He power-brakes that little 225 cubic inch six to 28 pounds of boost and leaving the line like that, generates 60-foot times in the very low 1.50s.... Which is in the neighborhood of a car that runs 125 MPH, a feat requiring about 500 horsepower in a car as heavy as his. His car is FASTER on initial launch than it is, for the rest of the quarter-mile trip, by comparison. It seems that he appears to be proving that turbo cars don't necessarily have to be slow in the first part of the track.
3. Is Brad's car "slow" in that first hundred feet, or so, because he's not ALLOWED to use the drivetrain equipment that would make his car competitive with a "conventional" Pro Mod car? Or, is it just incorrectly designed? Kinda doubt that....
Brad HAS to be a really smart, innovative, fellow, and I'm certain that anything I could come up with, he's already, long ago, tried and discarded or dismissed out-of-hand. Having said that, I am loathe to think that NHRA would deliberately throw mechanical "roadblocks" in his way, just to slow him down. After all, before this year's U.S. Nationals, he'd never won a race that I know of; there was no reason to "slow him down."
But, maybe they did... I just dunno...
Can someone better-qualified to explain this enigma, show me and others just what it is that keeps his off-the-line performance from equalling cars who have markedly less power than his?
I'd appreciate some help here ... Thanks a lot for any info!!!!
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I'll take a crack at it, with some facts and a bit of speculation as it applies to Personett's Camaro.
Turbochargers produce boost (and therefore power) from energy derived from exhaust HEAT, not exhaust VELOCITY as some assume. OK, how do you build heat in the exhaust? By increasing load on the engine, forcing wider throttle openings against that load...which in turn builds more heat, more power, thus more heat, even more power, and so forth - until the engine tears itself apart from the stress. That's what wastegates are for - to blow off boost in excess of a predetermined level.
Back to our situation. Bill, your trans brake / power brake ideas are on the right train of thinking, since both not only load the engine but allow it to launch at an RPM more favorable to it's power range. A fine concept for your friend's Valiant, but not feasable with a car capable of nearly 4000 horsepower. Power braking is out, for obvious reasons, and if you were somehow able to launch with all of those horses at once, the car would go nowhere except insane.
Personett's car engages its' second engine
at half-track, because at that time it's traveling 200MPH in high gear, when both the aero drag and the tall gearing are conducive to heavily loading the engine. At that point the huge twin turbochargers can effectively build bigtime boost, on the order of four atmospheres of pressure, because at that point the energy level from the exhaust heat is extreme. When the car launches, even if you were able to trans-brake it or set the clutch to drag (and therefore load) the engine as the car stages, there's no way to replicate the load the engine sees at 660 feet....not with that car. The net result is a comparatively sluggish first half.
The large turbochargers don't help, either, at slow speeds/ light loads. It takes a lot more heat energy for a 90mm dual setup, as he uses, to effectively build boost than it does for, say, a dual 75mm setup - a single turbo - or even a naturally aspirated car. An NHRA-legal Pro Stock car is just as quick to 60 feet as Personett's ProMod for that very reason. All the power is available, and utilized, instantly.
I still feel that the ideal setup for his car would be some type of small turbo/large turbo arrangement. 2008-up Ford PowerStroke diesels use this exact setup, and many factory street cars utilize two small turbos instead of one larger one for the same reason - low end power and torque. It works, and works well. But incorporating this design into a limited-purpose 3800HP ProMod Camaro, within NHRA's rules, is part of what keeps Brad Personett up late at night.
Interesting discussion. Next year ought to be wild for the ProMod gang.
Turbochargers produce boost (and therefore power) from energy derived from exhaust HEAT, not exhaust VELOCITY as some assume. OK, how do you build heat in the exhaust? By increasing load on the engine, forcing wider throttle openings against that load...which in turn builds more heat, more power, thus more heat, even more power, and so forth - until the engine tears itself apart from the stress. That's what wastegates are for - to blow off boost in excess of a predetermined level.
Back to our situation. Bill, your trans brake / power brake ideas are on the right train of thinking, since both not only load the engine but allow it to launch at an RPM more favorable to it's power range. A fine concept for your friend's Valiant, but not feasable with a car capable of nearly 4000 horsepower. Power braking is out, for obvious reasons, and if you were somehow able to launch with all of those horses at once, the car would go nowhere except insane.
Personett's car engages its' second engine
at half-track, because at that time it's traveling 200MPH in high gear, when both the aero drag and the tall gearing are conducive to heavily loading the engine. At that point the huge twin turbochargers can effectively build bigtime boost, on the order of four atmospheres of pressure, because at that point the energy level from the exhaust heat is extreme. When the car launches, even if you were able to trans-brake it or set the clutch to drag (and therefore load) the engine as the car stages, there's no way to replicate the load the engine sees at 660 feet....not with that car. The net result is a comparatively sluggish first half.The large turbochargers don't help, either, at slow speeds/ light loads. It takes a lot more heat energy for a 90mm dual setup, as he uses, to effectively build boost than it does for, say, a dual 75mm setup - a single turbo - or even a naturally aspirated car. An NHRA-legal Pro Stock car is just as quick to 60 feet as Personett's ProMod for that very reason. All the power is available, and utilized, instantly.
I still feel that the ideal setup for his car would be some type of small turbo/large turbo arrangement. 2008-up Ford PowerStroke diesels use this exact setup, and many factory street cars utilize two small turbos instead of one larger one for the same reason - low end power and torque. It works, and works well. But incorporating this design into a limited-purpose 3800HP ProMod Camaro, within NHRA's rules, is part of what keeps Brad Personett up late at night.
Interesting discussion. Next year ought to be wild for the ProMod gang.
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Buns
Nitro Member
- Thread starter
- #30
I'll take a crack at it, with some facts and a bit of speculation as it applies to Personett's Camaro.
Turbochargers produce boost (and therefore power) from energy derived from exhaust HEAT, not exhaust VELOCITY as some assume. OK, how do you build heat in the exhaust? By increasing load on the engine, forcing wider throttle openings against that load...which in turn builds more heat, more power, thus more heat, even more power, and so forth - until the engine tears itself apart from the stress. That's what wastegates are for - to blow off boost in excess of a predetermined level.
Back to our situation. Bill, your trans brake / power brake train of thought is on the right train of thinking, since both not only load the engine but allow it to launch at an RPM more favorable to it's power range. A fine concept for your friend's Valiant, but not feasable with a car capable of nearly 4000 horsepower. Power braking is out, for obvious reasons, and if you were somehow able to launch with all of those horses at once, the car would go nowhere except insane.
Personett's car engages its' second engine
The large turbochargers don't help, either, at slow speeds/ light loads. It takes a lot more heat energy for a 90mm dual setup, as he uses, to effectively build boost than it does for, say, a dual 75mm setup - a single turbo - or even a naturally aspirated car. An NHRA-legal Pro Stock car is just as quick to 60 feet as Personett's ProMod for that very reason. All the power is available, and utilized, instantly.
I still feel that the ideal setup for his car would be some type of small turbo/large turbo arrangement. 2008-up Ford PowerStroke diesels use this exact setup, and many factory street cars utilize two small turbos instead of one larger one for the same reason - low end power and torque. It works, and works well. But incorporating this design into a limited-purpose 3800HP ProMod Camaro, within NHRA's rules, is part of what keeps Brad Personett up late at night.
Interesting discussion. Next year ought to be wild for the ProMod gang.
Great stuff! Thanks!
After reading the article, and all the responses here, I don't see any reason to be down on BG. I'm not sure why it's such an instant reaction almost anywhere his name comes up. He's blunt. But, this is racing not charm school.
Usually, if/when anyone calms down enough to actually think through his words, they make sense. He's not new at this.
Usually, if/when anyone calms down enough to actually think through his words, they make sense. He's not new at this.
Bill
Nitro Member
Thanks a lot for your explanations and info, Carl. I really appreciate the time you took to write that!
I can understand that some creative control of all that power might be necessary to keep things from getting out of hand at the launch, but consider what happens with the Roots-blown Alcohol cars on the starting line. I'm talking about the diggers AND the Alcohol Funnies.... They rev those big, blown hemis up until they sweat oil and dump the clutch at really elevated rpms, At FULL BOOST, but it seems to work for them. Do you think that Brad's turbo engine is going to be making more horsepower and torque than those blown Alky motors are making at launch? Maybe so, but if he (Brad) utilized a simple fluid coupling (instead of a converter) that did NOT multiply torque (like the fluid coupling out of a Dual Range Hydramatic, which is what was in a B & M Torkmaster, I believe,) the available torque to engender this "going-insane-at-launch" scenario might could be somewhat controlled. It might just be that if he can get the turbos sufficiently spooled before he releases the brakes, a torque converter would not be needed at all; he may have enough power to blow the tires off with a 1:1 torque ratio, (crank to input shaft.)
But then, maybe not...
I see in the "Clutches" section of the rulebook that he is effectively prevented from using a "Top Fuel" style of clutch.
I don't understand why the NHRA Druids are so knee-jerk in trying to keep the technology that could produce consistent, efficient runs, away from these cars.
But, it seems, they want to keep these cars in the 1950s insofar as clutch technology is concerned, and for what? It's a real head shaker, for me.
Time is on Brad's side in this conundrum, though, I think. I am of the opinion that he WILL get this launch figured out, maybe even next year. When he does, he can look forward to some down-sizing of his turbos, probably.
NHRA can't stand (for long) for innovative technology to displace the old guard... It's just not right!!! LOL
Ingenuity in action became just two word a long time ago...
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It's my understanding they rev the alcohol cars (dragsters, floppers and Pro Mods) to 5-5500 RPM or so (these cars hit 10,000RPM in the lights!) and you bet, they're producing a ton of power as soon as the car is launched - considerably more than Personett's, I would think. We're back to that loading thing. A Roots-style engine 'loads' much quicker (immediately upon engaging the clutch) and the power is infinitely more manageable, through clutch tuning and application, than with a turbocharged car.
Personett has access to and is allowed to use the same type clutch as blown alcohol entries use. None of them can utilize max HP right at the hit; there's controlled slippage going on. But the line between not enough HP and too much is much narrower and trickier to negotiate with the turbo machine. You can't load Personett's engine at the launch the same as it's loaded at half-track anyway; it's just not possible - not with a trans brake, footbraking, torque converter or fluid coupling.
For one thing, there's not enough time. ProMods launch using a Pro tree and NHRA's autostart system, which lights the first yellow anywhere from .7 to 1.2 seconds after both cars final-stage. That's not enough time to get that turbo engine loaded up, even if there were mechanical means. The heat energy exchange and boost-building process just doesn't happen that fast, unlike a Roots-style supercharger, which is virtually instantaneous.
Early on, I mentioned heat energy as being the source of Personett's turbo horsepower. It would be interesting to look at his data to see the EGT readouts as he stages, launches and completes the run. I think I've mentioned this before, but you can replicate what I'm saying by taking a quick ride in a turbo diesel Semi tractor. Mat the throttle in neutral while watching the pyrometer, which measures EGT. It'll move from around 300 degrees at idle to maybe 500 or so. Now, if you were to stage the truck and launch it, you'd see something completely different. You'd see 700-800 degrees in short order, rising to well over 1000 as the truck strains against taller gearing and eventually aero drag. Notice the truck feels like it's accelerating harder in the upper gears? It is! Why? Because it's now fully loaded, producing max HP and torque.
If Brad Personett were to figure out how to develop maximum horsepower at the launch, it would either fry the tires or run 5.50's, neither of which is a good thing. He'd only run such a pass one time before NHRA would parity the car into oblivion. He's probably better off just leaving it as is, and work on his lights and launch consistency. Right now, he's competitive but not totally dominant - and the top end charges are a real crowd-pleaser. Don't mess with success, as they say.
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Bill
Nitro Member
That's a well thought out, and well-written reply to my rambling diatribe. Thanks for explaining the reasons behind why this car is so relatively slow off the line. You made a complex problem simple enough that I could easily understand it. Thanks for that!
Having said that (and, I don't disagree with any of your theories,) I still believe in the possibility that a fluid coupling can be maneuvered/manipulated in such a way that the engine CAN be loaded to bring up enough boost to move that car sufficiently quick that he doesn't have to "catch" every competitor he runs.
You have to think outside the box in a deal like this, because this time-value scenario you have presented is correct, valid, and a big part of the problem (getting the turbo spooled "in time" for the green.) These gas turbines were "peaky" like a 2-stroke...
I don't have any idea how old you are. (I'm 72,) but I can remember a time when roundy-round racers (and, probably road racers, too) were trying gas turbines in an effort to get a leg up on the competition (internal combustion powerplants.) One problem they faced was that coming out of the corners, the RPM's had dropped to a level where insufficient power was being produced (not unlike a turbo that hasn't "spooled" yet.)
After much trial and error, the best solution to this "spooling" problem turned out to be that they ran the turbine at FULL POWER ALL THE TIME, and fitted the car with gargantuan brakes capable of hauling it down for the corners, then simply releasing those big brakes, and voila, LOTS of power... instantly! I don't remember how the rpm''s were kept up in the face of decreased wheel speed; maybe a loose torque converter??? I just don't remember, but they got it done.
I don't follow anything but drag racing, so I can't tell you just who it was that utilized that system, nor how it affected the rulesmakers, but it's within the realm of possibility that a version of such a system could be utilized on a turbo-powered drag car, wherein a really powerful. 4-wheel brake system would allow the car to stage (power-braking at part throttle) against partial throttle, spooling the turbos to a greater boost level than is currently being enjoyed by this Personnett car, allowing for a quicker and more formidible application of torque and horsepower than is now the case. Of course, some sort of fluid couipling would be necessary to get this done; no friction clutch could stand the abuse.
Not gonna happen, of course, but there's more than one way to skin a cat...
I'm sure there are a LOT of people much smarter than I, working on this as we speak.
I won't be surprised if they figure it out... The late Jerry Verheuel was well on his way with 240 Gordie's Flo-Rite car, but today's clutch technology hadn't arrived yet....
Insofar as giving it a good "letting alone," so NHRA doesn't render the car un-competitive because it runs "too good," well... that is probably the smart thing to do... but it ain't hot rodding, where I come from... LOL!
Thanks for listening!
Bill
Having said that (and, I don't disagree with any of your theories,) I still believe in the possibility that a fluid coupling can be maneuvered/manipulated in such a way that the engine CAN be loaded to bring up enough boost to move that car sufficiently quick that he doesn't have to "catch" every competitor he runs.
You have to think outside the box in a deal like this, because this time-value scenario you have presented is correct, valid, and a big part of the problem (getting the turbo spooled "in time" for the green.) These gas turbines were "peaky" like a 2-stroke...
I don't have any idea how old you are. (I'm 72,) but I can remember a time when roundy-round racers (and, probably road racers, too) were trying gas turbines in an effort to get a leg up on the competition (internal combustion powerplants.) One problem they faced was that coming out of the corners, the RPM's had dropped to a level where insufficient power was being produced (not unlike a turbo that hasn't "spooled" yet.)
After much trial and error, the best solution to this "spooling" problem turned out to be that they ran the turbine at FULL POWER ALL THE TIME, and fitted the car with gargantuan brakes capable of hauling it down for the corners, then simply releasing those big brakes, and voila, LOTS of power... instantly! I don't remember how the rpm''s were kept up in the face of decreased wheel speed; maybe a loose torque converter??? I just don't remember, but they got it done.
I don't follow anything but drag racing, so I can't tell you just who it was that utilized that system, nor how it affected the rulesmakers, but it's within the realm of possibility that a version of such a system could be utilized on a turbo-powered drag car, wherein a really powerful. 4-wheel brake system would allow the car to stage (power-braking at part throttle) against partial throttle, spooling the turbos to a greater boost level than is currently being enjoyed by this Personnett car, allowing for a quicker and more formidible application of torque and horsepower than is now the case. Of course, some sort of fluid couipling would be necessary to get this done; no friction clutch could stand the abuse.
Not gonna happen, of course, but there's more than one way to skin a cat...
I'm sure there are a LOT of people much smarter than I, working on this as we speak.
I won't be surprised if they figure it out... The late Jerry Verheuel was well on his way with 240 Gordie's Flo-Rite car, but today's clutch technology hadn't arrived yet....
Insofar as giving it a good "letting alone," so NHRA doesn't render the car un-competitive because it runs "too good," well... that is probably the smart thing to do... but it ain't hot rodding, where I come from... LOL!
Thanks for listening!
Bill
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Bill, for a young guy, you're right on top of things...
61 here; I learn something new every day. Like World of Outlaws running gas turbines, something I was unaware of. Garlits tried it (unsuccessfully, for the same reasons you outlined), and Parnelli Jones raced one at the Indy 500 in 1967. Being how that race is run WOT, the turbine was a runaway success until a minor part failed on lap 197. USAC took care of the rest, restricting the air intake to the point turbine cars were uncompetitive.
Torque converters have been tried in the Alcohol Funny Car class and although I can't remember the guy's name, one is actually VERY competitive today (5.50's). Maybe Personett has tried one, or may get around to trying one. (Are converters legal in NHRA ProMod?) I still think there would be a problem with the launch. Turbocharged engines seem to go from zero to hero almost at the flick of a switch...in other words, a really narrow, peaky powerband, unlike a Roots-blown engine which has a much broader powerband and therefore easier to predict and control.
Personally, I think your ideas are worth investigating. But I see a few areas where problems could arise. First, the fine line between not enough power and too much in a turbocharged application, which means the difference between a successful launch and a tire-fry. Second, a torque converter/fluid coupling designed to slip at the launch needs to be able to somehow lock up at speed, or the back half of the run will suffer. And third, there's the reliability factor. Can a slipping converter stand up to nearly 4000HP?
Maybe the guy with the alcohol flopper has some of these answers.
61 here; I learn something new every day. Like World of Outlaws running gas turbines, something I was unaware of. Garlits tried it (unsuccessfully, for the same reasons you outlined), and Parnelli Jones raced one at the Indy 500 in 1967. Being how that race is run WOT, the turbine was a runaway success until a minor part failed on lap 197. USAC took care of the rest, restricting the air intake to the point turbine cars were uncompetitive.
Torque converters have been tried in the Alcohol Funny Car class and although I can't remember the guy's name, one is actually VERY competitive today (5.50's). Maybe Personett has tried one, or may get around to trying one. (Are converters legal in NHRA ProMod?) I still think there would be a problem with the launch. Turbocharged engines seem to go from zero to hero almost at the flick of a switch...in other words, a really narrow, peaky powerband, unlike a Roots-blown engine which has a much broader powerband and therefore easier to predict and control.
Personally, I think your ideas are worth investigating. But I see a few areas where problems could arise. First, the fine line between not enough power and too much in a turbocharged application, which means the difference between a successful launch and a tire-fry. Second, a torque converter/fluid coupling designed to slip at the launch needs to be able to somehow lock up at speed, or the back half of the run will suffer. And third, there's the reliability factor. Can a slipping converter stand up to nearly 4000HP?
Maybe the guy with the alcohol flopper has some of these answers.
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I think I saw a PM in Vegas with a Lencodrive, is that the same thing?
Joe, here's the lowdown on the Lencodrive. The article is several years old but still applies. It does indeed combine a planetary transmission with a torque converter (and even a transbrake), eliminating the clutch entirely.
I found an online copy of NHRA's 2010 rules for ProMod, and the Lencodrive IS legal. I wish someone on this board who has run a Lencodrive would chime in and join this discussion...anyone?
Clutches? We Don't Need no Stinkin' Clutches!
Bill
Nitro Member
Thanks to everyone who has responded. I'm learning as I go... (good thing, too!!!)
A torque converter is just a fluid coupling with a third set of blades called a stator. A stator's function is to re-direct the fluid so that it hits the turbine blades at an angle, thereby multipyling torque. Fluid couplings only deliver what torque comes in... a 1:1 deal.
Ususally, torque converters operate in a torque multiplication range from 2.5:1 down to 1:1 when they "lock up" as well as they can, in top gear, near the finish line. Fluid couplings are usually much "tighter," having no stator in the program.
1956 Buicks empolyed a converter with a stator that had moveable blade angles (the tranny was called a switch-pitch Dynaflow) and used the high-stator-angle like a passing gear; floor the gas pedal, and the engine would rev up into the better powerband environment, and acceleration improved. But there was no actual gear change. I think those sophisticated (for the time) Buick converters had a max multiplication at stall, of about 3.5:1! In 1956 (only) it also worked in Low Range, giving Buick an edge, with a virtual "high stall" (3,500 rpm-stall) converter.
But, Brad's car is likely not to need ANY torque multiplication, given the vagaries of turbo boost, which seems to usher in the simple fluid coupling, the type of which was used in the old 4-speed, Dual Range Hydros that were OEM in a variety of cars, from Oldsmobiles to Rolls Royces to Army trucks, back then. They had a very deep 1st gear (3.85:1) and didn't have need of any more torque multiplication, so came with a simple 2-element fluid coupling. This transmission was the basis for the vaunted B & M "Hydro-Stick," the darling of the blown Gassers, for a while, as you probably remember. Not positive, but I seem to remember that that unit (the fluid coupling out of a hydro) was the working element in the B & M "transmission" used in dragsters of the day. "Torkmaster," I think they called it... implying the use of a torque converter, but I think the truth was, there was none; only a simple fluid coupling, machined for higher stall speed.
Fluid couplings are easy to modify for more stall speed, and don't suffer the same sort of "slippage" at speed, that torque converters do. They don't exactly lock up like a clutch, but something close...
That they deliver power to the output shaft in a linear, 1:1 fashion, makes them a lot easier to manage with regard to traction issues.
Maybe a Lencodrive with a fluid coupling (instead of a converter) could be one answer to this off-the-line dilemma that currently plagues Pro Mod cars with turbos????
BTW, I think the Alky Funny Car that you were alluding to may have been Mick Snyder's; his car utilized a torque converter to limited success, a while back. It wasn't a world beater, but he won his share...
At any rate, as you have said, next year is going to be interesting. I read somewhere that another turbo-Pro Mod is being built.
Bill
A torque converter is just a fluid coupling with a third set of blades called a stator. A stator's function is to re-direct the fluid so that it hits the turbine blades at an angle, thereby multipyling torque. Fluid couplings only deliver what torque comes in... a 1:1 deal.
Ususally, torque converters operate in a torque multiplication range from 2.5:1 down to 1:1 when they "lock up" as well as they can, in top gear, near the finish line. Fluid couplings are usually much "tighter," having no stator in the program.
1956 Buicks empolyed a converter with a stator that had moveable blade angles (the tranny was called a switch-pitch Dynaflow) and used the high-stator-angle like a passing gear; floor the gas pedal, and the engine would rev up into the better powerband environment, and acceleration improved. But there was no actual gear change. I think those sophisticated (for the time) Buick converters had a max multiplication at stall, of about 3.5:1! In 1956 (only) it also worked in Low Range, giving Buick an edge, with a virtual "high stall" (3,500 rpm-stall) converter.
But, Brad's car is likely not to need ANY torque multiplication, given the vagaries of turbo boost, which seems to usher in the simple fluid coupling, the type of which was used in the old 4-speed, Dual Range Hydros that were OEM in a variety of cars, from Oldsmobiles to Rolls Royces to Army trucks, back then. They had a very deep 1st gear (3.85:1) and didn't have need of any more torque multiplication, so came with a simple 2-element fluid coupling. This transmission was the basis for the vaunted B & M "Hydro-Stick," the darling of the blown Gassers, for a while, as you probably remember. Not positive, but I seem to remember that that unit (the fluid coupling out of a hydro) was the working element in the B & M "transmission" used in dragsters of the day. "Torkmaster," I think they called it... implying the use of a torque converter, but I think the truth was, there was none; only a simple fluid coupling, machined for higher stall speed.
Fluid couplings are easy to modify for more stall speed, and don't suffer the same sort of "slippage" at speed, that torque converters do. They don't exactly lock up like a clutch, but something close...
That they deliver power to the output shaft in a linear, 1:1 fashion, makes them a lot easier to manage with regard to traction issues.
Maybe a Lencodrive with a fluid coupling (instead of a converter) could be one answer to this off-the-line dilemma that currently plagues Pro Mod cars with turbos????
BTW, I think the Alky Funny Car that you were alluding to may have been Mick Snyder's; his car utilized a torque converter to limited success, a while back. It wasn't a world beater, but he won his share...
At any rate, as you have said, next year is going to be interesting. I read somewhere that another turbo-Pro Mod is being built.
Bill
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