blowin smoke 03

I doubt his truck could be that lite,We have a full fiberglass bodied short bed 99 dodge drag truck,with nothing for steel but a tubing frame,and at race weight it weighs 3000 on the dot,with a 180 pound driver!!!!

timbeaux38

Fletchers run is NOT a DHRA Record. it is a NHRDA record.
Ive seen Darren Morrison run a 10.77 AND A 10.61 in his reg cab 4x4 12v. has a cage and a racing bucket, but it is not 5500 lbs.

If you like, you can go here to watch it. http://www.dieselperformancemotorspo...dia/Darren.wmv
This truck had a problem with the BOV the day before and was only making 55lbs of boost- dynoed around 680 the day before.

As far as Fletcher's run goes, i dont think that truck would have fit into the DHRA pro street category.....

gunracer1

then how do you explain the runs that have been going down with the 6k# trucks???

CTD NUT

I think the big thing being overlooked with the equations is the MASSIVE difference between torque and hp on the CTD drag trucks as compared to similar hp gas motors. How else can you explain the CTD rail car running 7's on #2 only? I highly doubt the CTD in that rail was making 1000 hp......I suspect quite a bit less.....but what about the torque? It looked like a massive Lenco rear end in that car - I suspect to handle all that torque.....you certainly don't see rears like that in rail cars that only run 7's. I was just curious if the difference in torque would affect these hp equations in some way.

HOHN

CTD Nut-- it wouldn't.

Power is all that matters. Tq just tells you how much force there is. Power is all that matters because you are dealing with TIME. TIME is what sets power apart from tq.

Every single one of Kev's posts in this thread I wish I could just copy, so I'll say it: DITTO, DITTO, DITTO.

Guys who think that low 8 at 8000lb are not far away have VERY little understanding of physics, money, or drag racing.

Look at a guy like Maddog. He's thrown away more money on engines then I'll make in 8 years probably. A LOT of development has gone into getting him where he is.

But as the CTD moves faster and faster, we will soon approach the point where the inherent limitations of the engine loom larger and larger.

Most of these guys have changed so many design aspects of their engines that to say that "they are putting the CTD in the Nines" is like saying a Fuel car is "putting the Hemi in the Fours".

Is it a Hemi? Well, yes. But is it a factory 426? NOT EVEN CLOSE. They are so highly modified that they bear little resemblance to their namesakes. IF by HEMI, you mean a KB Stage ten block, dual MSD magnetos and an overdriven blower burning Nitro, then maybe I'd agree.

So it's pretty misleading (and I'd say intellectually dishonest) to say that a 2300lb "truck" with a "CTD" is going to be put in the 8s. Who cares if the body is SHAPED like a truck, IT'S NOT A TRUCK. It's a drag car with a truck body. If I put on a Brad Pitt mask, does that make me rich?

These engines are so highly modified that everything aside from the block and basic head form is basically a custom piece. Pistons, pumps, injectors, cams, turbos-- all are custom pieces.


I'm FAR more impressed by a stock-chassis, full-factory bodied, full size diesel pickup running 11s than I ever will be by the big-money tube frame jobbies running 8s.

jmo

cumminsboy

Thank You HOHN.

bama

nhrda,,thanks for the correction timb............i thought the whole intention of this thread being started was a 4000lb`er in the eights,not a full bodied truck in the 11`s?as in all motorsports,,just seeing how far you can push the limits is what makes the sport,if not,we would all just go bracket racing...........bama

600 Megawatts

6 k trucks running low 12's and mid to high 11's are perfectly inline with everything else we have said regarding power output.

A 4,000 lb pickup truck running 8's however is not even in the same universe.



Kevin

gunracer1

i would put some money on it, or say a case of beer. it may not happen this year but it will happen soon enough. the reall trick part of hittin the 8s will be a killer launch, and when some more trucks get serious about playing and getting every thing dialed in, it will happen.

Don M

Diesel engines produce a different power, IMO than other engines. The definition of HP and TQ and the relationship between the two is great for most engines though. Diesels need a new specification and definition for power measurement. As things progress on my end I intend to try and help shape a new definition for my own work/use.

The old Watts fart was able to define HP using horses/weight and time. Maybe I will use a Jackass Joking of course.

I dont for a minute think the world standard will change for my sake, but I am certain I can use a better way to measure the output and help myself.

I am having a company custom build me a dyno now and we are working toward a different way to calculate the output. A different standard, so to speak.

Don~

DavidTD

I guess I will jump in here.

Those that have never gone fast are the ones that say 8's or 9's or 10's are easy. The faster you get, the harder it becomes to improve on it. Just my opinion of course.

ET is a function of traction. MPH is a function of HP. Nail them both and you get a great pass.

Peak HP is not the end all of making good passes. The entire area under the curve is just as important, and then the driver has to drive it there to make the most out of what he has.

Darren came off my dyno at 720-730 uncorrected hp (don't really remember the exact number now) and ran 124 and change at the track in Georgia. That run calculated out to 723.7hp at 5590 lbs.

At Indy, where he scaled 5590, he ran 10.61 @ 122 in hot air which calculated out to 689hp. Given the intake air temps, I can see the loss of power, and in fact expected it. That is what makes running events like IRP fun, everyone has to make power in the same air, not talk about "best passes".

So far, every truck built and tuned on my dyno calculate out. If my dyno is not correct and we need to load to get the "real" number, then the real number does me no good because I then cannot equate that "real" number to the track. The dyno is a tool. We enjoy setting a power level at the shop, then know when we get to the track what to expect.

Anyone can build a hand grenade. Building a race vehicle that can compete and finish the race is something I think gets lost in the HP wars. Darren has never hit the track with full power. We step it up as the rest of the set-up dictates. He has not won 4 out of 6 races because he was fastest, he won them because he could finish. (or atleast 4 of them

)

600 Megawatts

Very, VERY well said David. And I know we have had our differences on here before, but you nailed that one bigtime.


KP

bama

go ahead david,its all in fun anyway..........what would it take in your opinion to make 8`s at 4k?...what was jeffs fastest pass at what weight with his glass truck and at what app. h/p??.................bama

Don M

Yes, yes, absolutly! Track times and HP were put to a solid calculation years ago by Patrick Hale. He spent countless days, months, years at the track logging ET and MPH. These internet, on-line, Java based calculators that so many use are all based from Patrick Hales original work. Using two constants of 5.825 and 234.

ET is calculated using 5.825 and MPH uses 234.

ET is the cube root of the weight to power ratio multiplied by the constant of 5.825.

MPH is the cube root of power to weight ratio multiplied by the constant 234.

Notice the difference for ET and MPH. You want the weight to power, i.e. the pounds per HP for ET and for MPH you want the the HP per pound.

These formulas come deadly close without considering any other factors. Wind resistance, temperature, etc. I can come within 3-4% of the HP an engine makes if I know what it weighs and can see the ET or MPH slip. I can also get a fast idea if the turbos are sized wrong, the fueling wrong, etc. Just from taking the formulas and the known ET/MPH most of the vehicles I work around are running.

The DynoJet numbers will nearly always coincide with the ET and MPH calculations of the Java scripted websites and the calculations you see above. This is because they all deal with HP, weight and speed. The DynoJet uses clocks, a known weight, and they clock time it takes to accelerate that known weight to measure HP. These calculations were constantly crossed linked/checked back to known ET/MPH and HP numbers from tens of thousands of vehicles as well. The result is a nearly perfect copy of the two types of data. ET/ MPH and DynoJet.

So, if you have a DynoJet and you also race, you can tune for a higher number of HP on the Jet and translate that higher number to the track with better ET and higher MPH. Well no kidding or Duh or whatever you like to say. Its obvious.

That being said, there are other ways to measure progress. The DynoJet tuning way is great and is the easiest for anyone. Make the power register higher on the rollers and it will translate to better performance at the track. The problem I have with using that way alone is you end up leaving a sizeable data set off the table. There are parameters that are not being analyzed and tweaked when you look at one thing like HP. The relationship between TQ and HP are not fully understood and accounted for using that method. And there is a relationship. My idea has been to use a different way to measure the output and include the low speed TQ rise, crossover, etc on the Diesel engine in the calculation. This can be missed altogether with the DynoJet from the low inertia. There are few other "things" I did not include in the whats missed columb, but you get the idea of where I am trying to head.

Its all about the short time in drag racin'.

Don~

HOHN

Good move, Don on getting the custom dyno. I agree that the current "measurement" techniques for determining HP are woefully inadequate.

The problem isn't the dynos, though-- it's our definition of HP. HP is just a formula-- it CANNOT describe the QUALITY of torque delivery. So, power should be measured in quality AND quantity, imo.

Since power is just a time function of torque, we should ditch the concept of hp in favor of something that describes the quality of tq application of time.

Witness the Mustang (load) style dyno. This thing can tell you useful info about how much of a fight the engine will put up to being dragged down by increasing load. But what will it tell you about acceleration capabilities? ALMOST NOTHING!! The dyno can't "see" if you have a 600hp Caterpillar or a 600hp Corvette. Even given identically weighted vehicles, the Caterpillar would accelerate much slower, thought the Mustang dyno will never show this. It can't account for the flywheel effect.

Since we typically think of "performance" in terms of acceleration, the Dynojet has no equal as far as tuning for competitive acceleration events-- i.e. drag racing. Even if it doesn't accurately measure HP, it tells you something better-- "recovery time". In other words, the faster than an engine can accelerate a known mass from point A to point B, the better it is in competition-- period.

I've heard of NASCAR programs that got slower as the engine made more "power" on the dyno. Track testing has shown that faster lap times can be turned by engines that have less "power", as measured on the dyno.

Great racing engines have that mysterious ability to "recover" that most dynos cannot measure or show. The dynojet imo comes the closest.

The ideal, imo, would be an intertial dyno like a DJ that could vary the weight of the rollers on the fly. I guess sorta like the Superflow does with the Magnets.

Wouldn't it be nice to have a dyno that can very resistance on a run in accordance with a pre-programmed profile? So, it can account for how much more load the engine sees in 3rd gear vs 6th gear? I'd like a dyno that shows the same curves and numbers no matter what gear the run is made in.

I'd like a dyno that eliminated the variables of traction and tire rolling resistance, and instead bolted something directly to the hubs.

To make progress in tuning, you HAVE to be able to control for more variables than we can currently control for. I'd like a dyno that can give me a "reference" run directly off the wheel hubs, then let me tests the effects of inflation pressure, tire diameter, tread design, etc. on a traction roller similar to a DJ248C. Eliminating the tire variable has huge benefits, imo. For example, repeatability. As you make multiple DJ runs, the tires warm up, pressure changes, and things get imprecise. (remember, precision has to do with reproducibility, not ACCURACY, per se).

Once you ditch the tires, you could measure differences from changing axle lube viscosities/brands, engine oil differences, etc. You can tune the ENGINE, which is what you want to do-- THEN you can tune the COMBO-- tire size/pressure, gearing, launch rpm, etc.

The big weakness of existing dynos is that they only measure the SYSTEM-- you can't break it down to see the contributions of each component to the overall whole. Wouldn't it be nice to see what the engine does? Then what effect the tranny has on it? Then the T-case? Then the axles? Then the tires/wheels?

So why aren't you big-dog racers running superlightweight axles-- I mean, low rotational inertia? Think of all the stuff that you CTD is trying to move!

Why not ultralight wheels and smaller tires-- especially up front? You should only run as big a tire as you need to get traction-- anything bigger is a waste. If you launch in 4wd with all corners wearing slicks or Drag radials, then you could run a smaller tire, couldn't you?


I'm frustrated at the lack of innovation I see in certain things, just as i am positively inspired by the innovators like Smokey Yunick and Larry Widmer.

Don-- you should take a drive over to Larry Widmer's shop (Endyn) and pick his brain. If only he would ditch the Hondas in favor of diesels!!!

Justin