duallydave

hi all,ive been doing alot of reading on guys dyno#s.ive noticed almost everyone with over 400hp still has under 1000lbs torque.are there upgrades to get more torque with the same hp?a buddy of mine dynoed at b-d-in canada and he ran 456hp and 1120lbs torque.he showed me the dyno sheet.what i recall he had 155hpxxx injectors,edge comp,pusherpump and a k+n filter that looked like a bhaf.he also removed grid heaters,he says that was his secret.ive seen lots of over 400hp dynos but not much over 1000 torque.any truth to the grid heater secret?he had the stock turbo and had about 40psi if i remember.

KATOOM

Are you thinking of trying to achieve that? MAN THAT IS A LOT OF TORQUE! 1000+lb. and lets not forget the Cummins in these trucks is ONLY a 5.9L. I dont know of to many motors around that displacement size that put out that much HP or torque. Gas or diesel. The line haulers these days are putting out around 2000 lb. of torque and their built like tanks. I honestly dont understand how the Dodge drive train can stand that kind of pressure.

1320

I ve thought about taking the grid heater out....partly for that reason , the other is, that it just doesn t get very cold here. I don t know how he gets by in Canada though.

That tq number seems unussually high thats for sure, esspec for a stock turbo. I would wonder if that was a spike on the dyno pull, like from a shift or something?

As for the drivatrain standing it.....I broke my driveshaft last summer being alittle to aggressive pulling a hill at 28k lbs....Im esspecially gentle now, and honestly worry about breaking my gooseneck. It pulls so dam well.

Im gonna add a second intercooler between my twins, I ve heard someoone had done it and makes around 1500-1600 ft lbs, but its not confirmed to me. I just think the lower I get the incoming air temps the lower they are going out, so lower egts, so more fuel......

Haulin_in_Dixie

Doesn't work that way, in order to have higher torque at the same horspower, the engine would have to derive the same horspower at a lower rpm.

600 Megawatts

HP = [Torque * RPM] / 5,252

Thats all, nothing more, nothing less.


As for goofy HP and torque numbers that dont seem to make sense... thats easy.... they came from an inertia 'dyno'.... which, most of us know is not a real dyno and gives you a printout of its calculated and estimated HP and torque..... inertia 'dyno's' are a joke.

And if anything at all, removing the grid heater could make a higher peak HP number, but I doubt you would even see the effect on the torque peak since that occurs at such a low RPM. So rest assured, his little 'secret' is safe... cuz its nothing....


Kevin

1st gen Hobie

How do you seal everything up with the heaters removed?

duallydave

i think theres a alluminum block you can get to replace the heaters,i remember my buddy makin his own.its only like 1/2inch thick.he also told me that removing the heaters lowered his egts.hes probaly pulling my leg.so his dyno #s arent very acurate cuz they were on a enertia dyno?all the trucks dynoed at b-d- in canada are not acurate?why would b-d use such a machine?are the mustang dynos ive read about more acurate?does 456hp and 1100lbs seem unreasonable for a stock turbo?he also told me he had a heavy duty head gasket and intercooler boots.and made his own 4"exhaust.i dont want to start a battle,was just wondering why his torque seemed so high compared to other 400hp trucks.

mr T

those seem like bogus numbers with a stock turbo for sure...as for mr KATOOM...1000+ foot pounds of torque isa daily driver for alot of guys on here...alot of guys are pushing over 1500 in the competitions...torque and horsepower are always methematically related using the formula as stated above...the only way u may somewhat have more torque on paper and less horses(though not in reality) is if u cut off fuel with a governor before peak horesepower is supposed to occur....so as u get more and more torque at say 1600rpm ud have to cut off the rpms at 2400 and then at 2200 to have "more torque than horsepower" on paper

DZLPWR

Im only 100lbs short @349/902 The Tq #'s have alot to do with how exactly your pump is set up. 24v's have a harder time producing high tq/hp ratios because of slightly limited tuning ability.

Like mentioned above, its all about how low your peak HP comes on.

DavidTD

Kevin - Your formula is correct but do you know at what rpm he made max TQ and max HP? Without knowing where he makes peak tq we cannot calulate it. Without RPM there is no way to know if the number is bogus.

And why do Inertia dyno's provide goofy numbers. A Dyno Jet is inertia. Why are they a joke?

Small factory turbo's spool very well. With lots of fuel, they will make power very quickly. "Quick power" is power made at a lower RPM hence the BIG Tq number. As you get bigger with turbo's it requires more effort and exhaust gasses to spin. Given the same engine displacment for each, the bigger turbo will have more lag. Correct? More lag results in less low rpm HP which results in less TQ at that rpm. Bigger turbo's usually peak tq at a higher RPM range over a smaller one.

It is real common to go from a stock charger to a bigger one and not have as much TQ. It is also common to gain HP. It is also common for the power curve to shift higher in the rpm band with larger turbo's. But the bigger chargers gain airflow on both sides, providing better quality air with less back pressure. But less low end torque.

600 Megawatts

David, here is a cornacopia of posts I made during a HUGE argument on here about intertia dynos vs. loading dynos... Over on the TDR there was a 10 times larger argument on it too... check that out...


_+++++++

As for 'dyno' numbers, chassis dynos are inertia machines, that’s it. The 'HP' calculated (yes that’s right the HP is calculated not measured on these 'dynos') is a function of how quickly you accelerate a rotating mass. Factors which are involved in this are, among others: Weight of your wheels and tires, weight of your flywheel and clutch assembly, gear ratio, camshaft duration, turbo spool up time, injection pump fueling rate of increase, rate of timing advance and how the 'driver' operates his truck on the dyno. These factors are not standardized between trucks. These dynos are indicative of the RATE of rpm increase capable of the machine (truck) driving the heavy rollers. This happens to be a good indicator of how 'peppy' a truck feels on the street, but it has nothing to do whatsoever with actual steady state HP that the trucks either make or don’t. This is one of the reasons why seemingly even matched 12v vs 24v engines, the 12v always 'makes' more HP/torque on these 'dynos'.

It is a complete farce to even call that machine a dyno.

Take the engine out, put it on a water brake or eddy current DYNO and then talk to me about dyno number



___++++++


Yes, these dynos can be used to determine how quick a truck feels on the street and more importantly, changes that are made to the engine of ONE particular truck. It is a RELATIVE tool these inertia 'dyno'. They, however, are NOT accurate, fair or reliable in comparing DIFFERENT trucks, and in determining the amount of HP they make. Furthermore as the HP and torque levels increase, the inertia of the trucks components becomes a bigger and bigger percentage factor relative to the inertia of the 'dyno'. Therefore when trucks make serious power, they 'wing' the 'dyno' up so fast that they are also 'winging' their own components up faster and faster, thus using more hp PRIOR to the

____+++++++++

I wont retract my statement at all about high HP trucks being unfavorably represented on chassis inertia 'dynos'. Build a chassis inertia dyno with 30 ton rollers, so that the rate of RPM rise isn’t so quick and that would be fine. Right now, the RPM's increase too fast with a high HP truck on these 'dynos' that too many other factors taint the results as I previously stated.

And just to clarify how I have not wavered from my remarks I'll say it again....

CHASSIS INERTIA 'DYNOS' ARE NOT DYNAMOMETERS since they don’t MEASURE torque. They are comparative machines nothing more. The 'HP' and torque they come up with is a joke of estimated calculations the likes of which Hillary Clinton would use while selling her socialized heath care program to the unsuspecting tax payers of this country......

DavidTD

Ok, so on what basis do you have these claims?

A Dyno Jet measures HP. It calculates TQ. A Mustang measures TQ and Calculates HP. Not sure on a Dyno Dynamics or Superflow which one they measure.

A Dyno Jet uses a fixed mass (drums) and as you said, they are measured as they accelerate. That IS HP. (The rate work is done) Using the measured RPM, and the measured HP, it will calculate TQ. This is about as basic to the definition of HP as you can get.

A loading unit will create the environment to which the truck will run in. A load is generated to slow the run down. (alter the rate) It uses the force applied against the brake to measure TQ. But in this measurement is a calculation that includes the %of load applied and other information. In other words IMO potentially a less accurate method because you introduce more variables and formula's.

You mention that an Inertia dyno has factors such as clutch or flywheel mass, tires/wheels, trannies and differentials impact the dyno number. They should. That is what RWHP IS. If you have heavy 44" tires do you not think it will take more HP to turn them over than a set of 31's?

My problem was this original poster was told the numbers were bogus, no way for a stock turbo, and it was because it was on a bogus inertia dyno. But not one explanation as to why the numbers were bogus other than opinion or the easy one, blame the dyno.

Did my reply make sense? I dyno'd yesterday a 94 2500 with 370's and a HX35-14 at 497hp and 1160 tq at 38 psi boost.

Don M

IMO, the guys who use any dyno other than a DynoJet will be woefully behind come race day. So, keep dancing and we will pass you at the stripe.

I can measure a HP increase on the DynoJet and directly relate that to a better ET and MPH at the track.

So far the DynoJet has given me:

The fastest 24 Valve, 4x4, Diesel only time of 11.89 @ 111 MPH
The fastest Common Rail, 4x4, Diesel only time of 12.83 @ 106 MPH
The highest powered 24 valve on Diesel only @ 659 HP uncorrected
The highest powered Common Rail on Diesel Only @ 623 HP uncorrected

All this from the "joke" DynoJet.

Anyone is free to chose any brand or type of laughing generator they choose.
Guess I will be keeping the Dynojet as my primary indicator of gains and losses.

Don~

1dslram

David:
Thanks for an intelligent answer backed by fact. As most of us know both are good dyno's, but the inertia dyno is a lot easier on the drive train. I have found the Dynojet to be more repeatable than a mustang type dyno.
Bruce

DavidTD

My my Don. Quite impressive. You must know a great injector guy.