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Competition Ran 12:3 But We Ouched The transmission

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Off Roading skyjacker

yes i agree you will experience greater HP and torque and hp locked vs. unlocked , but again some of us ain't racing dynos , we is racin' trucks down the 1/4 mile ... :-{} :p



a dyno jet roller weighs 5000lbs. ( i have no idea what a mustang roller weighs ) , my truck weighs 7000lbs. , of course it will be easier to get hp and torque numbers when i'm spinning something that ultimately weighs less than the mass i'm trying to move on the street .



as far as this thread is concerned its starter talked about going faster down the track , not on a dyno .



on a dyno i have spun the rollers to 120mph according to the printout , i can't get over 115mph on the street ...



i guess we can agree that we disagree :-{}
 
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Originally posted by CRoth - BD-Power

Horsepower is the end product of torque and RPM. HP gets you places, diesels have so much bottom end torque = High bottom end HP. All the conversions for quester mile times negate any torque value at all. All this bottom end defiantly helps the truck get of the line.






my personal opinion on this is because it all orginally revolves around gasoline fueled engines which make more hp than torque , everyone and their brother gets wood over the larger HP number , as you know diesels are different and make more torque than HP , thats why we diesel guys want to see torque values ...



as far as 1/4 mile slip , your MPH is related to HP and your e. t. is related to torque . guys that race seriously are concerned alot with 60 footing well , thats all torque , you use a hi stall convertor to get you into your perak torque at launch not your peak HP ... or am i wrong on this ????
 
let the equations show us the truth...

Okay guys, I've been reading this and decided to throw my $. 02 in on the subject. It has been argued for ages about which value (HP or TQ) is more important, which one does what, where you want to drive & race at and why. To cut to the chase, to go the fastest possible over a 1/4 mile you want to launch at peak rear wheel torque to provide the largest initial acceleration and then move directly (the best would be instantaneously) to peak horsepower and stay there for the whole run. Of course, this isn't possible, so you have to do your best to get as close as possible. Here's a little explanation in more detail of the two players:



Torque:



Torque is F dot d, the cross product of the force * the moment arm. Now force is obviously what pushes your truck forward, and is the force you feel when you accelerate. The real question is - which torque? It's not flywheel torque that actually moves your car, but rather "delivered torque" (torque to the rear wheels), or torque * gear multiplication. This is why you accelerate faster in first gear than in third (ignoring wind resistance). This is the reason you can hit 120 on the dyno Mopar... no wind slowing you down (and our trucks are bricks at 120!).



How does this work? Say at we have 800 ft-lbs of torque available at an rpm. Now in first let’s say a 4:1 transmission gear and 1:1 rear gear (to make math easier) - so a final drive ratio of 4:1. So in first gear we will have 800 * 4 = 3200 ft-lbs of torque pushing us forward. Say second gear is 2:1 - so we have 800 * 2 = 1600 ft-lbs of torque pushing us forward. 3200 is obviously more than 1600 (twice!), and accounts for that difference.



Now let's look at this alittle differently.



Gearing is fixed for each gear, so velocity and rpm arerelated. Say we have 800ft-lbs of torque @ 2500, and 300hp at 3000 rpm (only 525 ft-lbs). Now lets say we are at a certain velocity where we could be in first gear (4:1 gear reduction) at 3000 rpm, or second gear (2:1 gear reduction) at 2500 rpm. Now in second gear (most flywheel torque) we have 2:1 gear reduction * 800 ft-lbs of torque, or 1600 ft-lbs delivered at the rear wheels. In first gear we only have 300hp * 3000/5250 = 525 ft-lbs of flywheel torque, but it is multiplied by 4:1, so we have 2100 ft-lbs of torque delivered. Now it's obvious that 2100ft-lbs at the rear wheel will accelerate you quicker than 1600ft lbs, so first is better than second here. So basically it's torque delivered, or the product of flywheel torque * gear multiplication that matters.



So what about horsepower?



We determined above that acceleration is determined by:



Flywheel torque * gear multiplication.



Well what is flywheel torque - it is basically the rotational analogue of force. What determines gear multiplication? Well, you have a fixed set of ratios in the transmission (not a CVT transmission) so what determines what gear you can be in? Velocity (road speed). So in other words acceleration is proportional to



Force * velocity.



How convenient! There is an equation for power that says



Power = Force * Velocity!



So basically horsepower is telling us what the magnitude (proportionally) of the product of flywheel torque * gear multiplication will be - or at least when it will be maximized and minimized.



So if you maximize area under the hp curve, you are maximizing this product, and thus your acceleration HP simply takes velocity into consideration (rate at which work can be applied), so you don't have to worry about gear ratio's, etc.



To finish up, I don't agree with the statment that autos don't multiply torque like a manual does. Yes, the gears are different (planatery instead of a side shaft... the planatary is stronger by the way), but it's still a gear ratio and still provides the same multipication. I also disagree that the manual will stomp an auto at a track. I have a 2000 ram air trans am and closely follow some of the fastest LS1 powered cars in the country... they ALL have autos. No one with a stick is within a full second of any auto trannied car. Even being able to launch at 6000+ rpms and putting full power to the ground is not enough to make up for the auto. I think that HVAC could benefit his times by running a looser converter, launching with more boost (VHT anyone???) and locking up once he hits HP peak in 1st gear. Just my 2 cents tho :)



John
 
Wowy Zowy!!!

That was a mouthful Banshee;) It sounds like you feel I'm going the right direction. Prolly the direction to a broken input shaft!:eek:LOL



Mopar Muscle, I bet the 89% converter would be a

better choice for coming off the line. That 94. 5%

converter has been a blessing over the rest of the track however.



So far I've had very good vibes from Suncoast. Joe is very interested in helping me make my truck quicker.



Thumbs up to you guys for creating a REALLY interesting thread. And also for keeping it civil. This torque vs horsepower is totally like mind candy for meOo. Oo.
 
Good description of hp versus torque. It's very rare when someone understands it to that level.



So basically, we agree that horsepower is the main issue for speed. Wouldn't a torque converter with a stall speed of 2400-2600 rpm be ideal for racing? That's where our peak HP usually is.



When the converter locks and the engine is pulled down 900-1000 rpm, you lose a lot of HP. You can choose to rev way past the power band (3200 + rpm) to keep from bogging after the shift, or you can shift it earlier and have the engine down at 1800 rpm. But again this isn't keeping the engine at it's sweet spot (peak HP range).



Drag racers understand this concept, but for some reason people believe it is different for diesels.



It's nice to see people like Jim Fuller and Christian from BD saying that locked shifting is not only hard on the transmission, but also slower. My how times have changed.



But again, great explanation!



-Chris
 
HVAC,



Glad you enjoyed the reading :) I think you're headed in the right direction, but I do agree with the others that it's going to be hard to launch at 20psi without frying the tires. Have you ever tried or considered trying going to a torque arm to help plant the rear? It's amazing how much your traction can be improved by changing the instant center (of mass) of the truck. How about softening up the rear springs & shocks to plant the rear end a little harder? Like the others have mentioned, shaving just a touch off the sixty pays big dividends on the big end.



Chris,



I agree on the rpm drop and the battle to keep the R's at or near the HP peak... it's a tough thing to do. That's where more gears would really help out (six speed allison!!). The car drag racers have a big advatage with being able to turn much higher rpms and having a lot less weight. In general, the higher your can push your hp peak the faster you will be. Also, those guys benefit from having very efficient converters (97-98%) because of the rpms they turn. I'm sure the testing that's going on here will find the right combo.





John



PS... HVAC just be sure to put in a billet input shaft and you'll be worry free :D
 
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John. . great splan'in... . I have been following this thread with great interest, as part of the Red Rocket fan club and sometimes track jack of all trades we need this discussion to continue as we get further along the path of righteousness ;) . . Nowel and I as well as several others involved have agreed on the need of a looser TC [not that our vote counts on his Rocket but it's fun to be in the "loop"] and been "guessing" the first or second launch technique with his present set up. . we have a way to go to get the chassis dialed in and a bunch of experimentation to do to get there... . but the basics need to be addressed first.
 
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Just a question here. Has anyone thought of using a Hydrostatic Drive? I think it would work great... ... but it might be a little heavy.
 
Mopar-Muscle,



For there not to be ANY difference between locked and unlocked the fluid coupling would have to be 100%.



BTW, I have no problems. I just need more HP and track time. :)
 
stake , as long as you feel you have no problems thats all that really matters ... i guess . locked works better for you because of the milled stator you are saddled with , this is my opinion , not bashing anyone product , just making an observation .



banshee , excellent explaniation and i stand corrected . i talked to my pile-it higher and deeper physics buddy and i was thinking the perpetual motion machine in my torque multiplican thinking :rolleyes: , locked would be better than unlocked but by design we would be ultimately breaking parts as the dodge trans is completely wrong for this engines capable power output , so we work with what we have . since we work with what we have , fluid coupling is one option , completely removing the torque convertor is another viable option , anyone remember what a clutchflite is ????



banshee , if you can find an april 2001 issue of chevy high performance ( now there's an oxymoron :-laf ) it has the article i speak of showing the stick kicking the autos butt . you can't really compare your ls1 , the stick from GM in that car is garbage and not a race piece , nevermind the clutch , which is what i was talking about , race specific transmissions , because as we can see in the dodge , the auto is quicker than the stick because the nv4500 and 5600 ain't racin' transmissions .



nowell , i was talking to my machinist , he used to race top fuel in the late 60's , a looser convertor , higher stall is a bad idea in our case as going higher into the torque band , higher rpm is just going to create more wheelspin , your convertor is the best option short of getting rid of the convertor all together and putting your dual disc mcleod back in front of your auto trans and launching at an rpm that builds boost , but this will turn that 727 based trans into rubble in short order .



next
 
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Originally posted by Mopar-muscle

stake , as long as you feel you have no problems thats all that really matters ... i guess . locked works better for you because of the milled stator you are saddled with , this is my opinion , not bashing anyone product , just making an observation .

next



:rolleyes: :rolleyes:
 
At least we are all working in the right direction.



Now we need someone to explain why DTT TC's and now Christian's truck from BD accelerate faster in fluid coupling than in lockup.



-Chris
 
Mopar,



I can see that a puspose built stick that can be speedshifted (a la CART trannies & Pro Stock trannies) could be maybe a shade faster on a very high revving gasser, but not on a diesel. The boost built on the line is much too important for cutting low 60' times that the minor amount of time saved would never make up the difference. The Tremec T56 in the F-bodies (RIP) and Vipers is actually a pretty tough unit, but it too can benefit from mods to the master cylinder, some better syncros, and of course, a much better clutch. Most guys running the really fast times have switched to a TH350 with a transbrake and launch at 6500 rpms. That setup gets most of them into the sub 1. 3X sec 60' time... even at 3000lbs raceweight. I do agree the NVs are a total waste of time for shaving time when drag racing, though.



As far as the dodge transmission goes, I can agree that it's undersized to handle 1500 ft-lbs of torque, but it seems to hold up just fine with the "deadly locked shifts". Mine's held up so far without any problems for 10k miles, and I beat the crap out of it, but that's another matter. It seems an ideal TC would stall at peak torque (~2k rpms), be a little loose to not fry the tires off the line, and then quickly tighten up and then lock once at the top of 1st or possibly 2nd gear. As was mentioned earlier, you shouldn't be dropping 900 rpm going into lockup. . only a couple/few hundred at most. Maybe HVAC needs a slider clutch to zing him down the track?? :D



About the ATS stator, I think it's a lot better than most people give it credit for. I know Eric is cutting sub 1. 7 60's with his... that isn't bad when you're running 6500+ pounds. It's far from milled, though... more like CNC machined :)



John
 
time to call in the engineers.....



What we really need are variable vane stators and turbines inside our TC's... . then we can always have the best of all worlds... .



Keep in mind... . we're trying to launch 6500# trucks..... we're lucky to have these trannies keep together long enough to do one run... . nevermind what some people have done to them.



Hats off to the vendors that have improved these 727-Torqueflites... . We are so much better off than OEM that it hurts.



Milled vs. CNC-machined..... You can CNC-machine a copy of a piece of canine feces... . but all you end up with is a strong and precise copy of a piece of dog crap. No matter how you make your stator... . its actual design (shape/size/# of blades) is the true building blocks for a viable product. DTT did a lot of homework... and it shows.



Matt
 
banshee , true the tremec is a stout piece , it would benifit being proshifted and still be streetable . has of the ls1 guys tried something like a jerico ? heres the numbers from the article i'm talking about ... sorry for straying off topic ... car is a camaro 3450lbs , hot 327 with a turbo 400 . . 60ft 1. 8 , 1/4 12. 25@113. 5 ... coan TH350 $6900 total cost , 60ft 1. 68 1/4 11. 94@114. 99 ... jerico total cost $5300 ... 60ft 1. 62 1/4 11. 70@117. 75



thanks for the correction on the stator in the ATS , i haven't been following it so i really should think before i comment .



matt , DTT did do its homework and i think the word is US patent :-laf ... a CNC machined part in alum can work well , problem with alum is it needs a larger hub to be as strong as a steel part , but that takes away in other areas and hurts its performance some . ( again typing before thinking ??? )



back to the clutchflite thing , i just came up with a thought , if i can get an input shaft machined up to replace the input shaft assembly presently in the dodge trans i have a transmission that was in a truck that burned and it warped slightly the bellhousing , if the pump surface runout is in spec and i can find someone with a manual trans bellhousing and a clutch setup that they aren't doing anything with i/we could give that idea a whirl ... ?????



the only hurdle is building boost on the starting line , this would probably be a race only piece and require monthly rebuilds ...
 
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DTT did do its homework and i think the word is US patent



Serious question, could they get a US patent even though they are based out of Canada? :confused:



Now to throw it back on topic, Nowel, think Lenco. :D ;)



Sorry for straying but never thought of it before,

Andrew
 
Hey mean sombre'ro AKA TDK... . what makes you think we have not talked about many options including the Lenco... . we have bench raced this rig down to 10 sec. and several six packs... . and wow did it go fast LOL
 
Originally posted by TxDieselKid

Serious question, could they get a US patent even though they are based out of Canada? :confused:



Why not? The company I work for has patented a product I work on. The interesting thing I found was people patent things, not the company. Turns out myself and several other guys I work with have a patent in the US, a country or two in Europe, and China. Whoopy I TRIED TO BY-PASS THE CUSSING FILTER, dont know what we can do with it. Did get a nice bonus though. We are based out of Redmond WA, USA so it can be done. --



I would like to know more from legal experts about the people versus company part of my statement.
 
Originally posted by willyslover

Hey mean sombre'ro AKA TDK... . what makes you think we have not talked about many options including the Lenco... . we have bench raced this rig down to 10 sec. and several six packs... . and wow did it go fast LOL



Mean? I'm mean? Gary, I thought we werew friends buddy? ;)



The possiblities are endless, and to "bench race" is much fun, and cheap, even I can do that. Like the pic listed eairly by HVAC with the 4-link. THAT would be the way to go with the Lenco. But money is only money right? ;)



Andrew
 
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