OMG!!! Twins Rock part II

[Mark_Kendrick]

Just before I bought the truck Craig Monroe Pushed it to ~13. 5. I've slept since then. at race weight it's 6900#.



It has a stronger clutch, bigger turbos (B1-big brother vs HY30-BHT3B), delivery valves(laser cut vs 191s), better injectors(edms now vs honed then) and dual stage nitrous.



I'm not making excuses for not making numbers. It just turns out that when the events come around the time and effort neccessary to make it run well has not been available. I truely believe there is al lot of unrealized potential in the truck. we had problems with clutches with the old turbos. once the clutch got fixed the motor had problems... when the motor went back together the head was cracked and we did not have a ready replacement. With the cracked head the new turbos were bolted on. Since then i've abused it on the street and the head went WAY south. . there's oil pouring out around the #6 injector. Let's just say that I'm not easy on parts



We keep putting on better stuff as time is available. I had to put a known bad head on to get the truck running and out of the shop.



a 13. 5 calcs to ~550. The clutch was not holding well and is the reason for going to the SBC DD. Craig is the best driver in a 5spd I've seen and even he could probably cut . 3-. 4 with an auto. leaving the line under boost and never loosing boost is a decided advantage, enough that I took th e 6sp out of the 24v dually for an ATS auto



the truck dyno'd at 580 on an H2E before the twins and dropped ~. 3 s off the ET with the turbo chage to an hy/38 setup.



BEFORE ANYBODY SAYS IT... I know the dyno is showing better than the ET. Manual trucks may do this because of LAG and shifting in the 1/4 mi. Auto trucks have the advantage at the track over the dyno becuase they are able load the motor hard at the line and continuously for the entire run. . loading the truck harder and longer than on the dyno.



right now the head is cracked and being replaced and the right front hub is rattling in a rather bad way. I have a fella that's interested in buying it so there will be time spent to fix the deficiencies. Hopefully I'll get it to the track and dyno before it goes.



The customer wants it to be a highperformance street/tow rig so it'll be getting smaller turbos, injectors, and delivery valves before it leaves. Even then it'll be a high 5XX truck like it was when I got it.



FWIW,

Mark

 

[Hammer]

Mark Kendrick=The newest version of Miss Cleo... .

When you start building power instead of buying it you'll understand.

At 404 Hp Sir you have not much to talk about. My truck with 1/8 the amount to time and money in it is about where your sales pitch piece is. One thing you need to do is throw all your calculations and mumbo jumbo crapola out as they mean squat. Dyno jets are real world repeatability and do not succumb to adverse weather conditions and traction problems a drag strip et will show.



In my numerous years of driving,wrenching and tuning way too many types of stock/superstock cars I learned that all you Internet figures mean NOTHING. On a good bite track that has all the teeth you can plant the fatties on means way better short times and will increase your HP numbers greatly. Take a marginal track and a marginal car and you will see that it will hook better and run short times about equal,does that mean it has as much HP with your calculations???. Your figures mean squat,period. As for your latent bashing of our Dyno-Jet and its being off I also say BUNK. I myself can send you all of my sheets 15 of them and they all are within a hp of each other. This along with the others who have been there numerous times and dynoed and have repeatability just goes to show how much you actually know or is it that your fishing for info. If the second is the case Mark,just ask away there was over a 100 in attendance,Dodge,Ford and Chevy owners alike and they will all attest to your comment about the 50hp being incorrect.



I will offer this and leave as you now have infuriated me beyond the point of no return and feel its best for me so I don't get into hot water again. If you feel so strongly about Ernie's jet being off I will ask for you or Merv(since it was his truck)to tell us where he wrung out the big number and I will gather 10 trucks that were at either of our Fall shows and take them to this place and see what they do there. I will also take the jet operator as to make sure no games are played in the computer settings so bogus numbers will not be a factor. If the jet is off,and I am sure since Dyno-Jet who was in a month before the show and checked it as they do each year, the owner would like to know as us diesel guys are not his only business and those big paying customers(many of whose HP products you use in some of your gassers)would find themselves in a pickle with false advertising over the incorrect numbers.



If your correct I will post it here and apologize. If your wrong about the dyno being off,you will post it here and send a copy to the jet owner. Its a fair solution to your constant gripe about this jet and the numbers it produces. Time to put up or shut up Mark,balls in your court... ... ... . Andy

 

[Mark_Kendrick]

Hammer,



you and your antagonistic ways neeed to go on a hike over to the local college and start studying the reasons the device you claim to know so much about works the way it does.



Diesels run at lower rpms than gas motors because the diesel cycle takes longer to complete than a gas motor's spark igition cycle. gasoline an volitile fuels like it burn much faster than diesel. it is the reason that we make twice the torque of a similar hp gas motor. HP is a function of rpm. Our motors turn slower so it takes more torque to attain the same hp.



Here's the kicker. . if the truck revs faster under load less of the fuel energy is converted to mechanical force in the cylinder netting you less force at the tires. at the track the truck stays in gear longer and pulls harder at a lower average rpm because of it... because the fuel is given more time to complete the combustion cycle. 12v motors are able to combat this with relatively excessive injection timing



If you want a dyno to read the power that our trucks put to the ground then you have to simulate a similar load.



A lighter race truck is going to need higher gearing to load the truck harder.



next time don't bring a knife to gun fight, nimwit.



later,

Mark

 

[Jetpilot]

... I know the dyno is showing better than the ET. Manual trucks may do this because of LAG and shifting in the 1/4 mi. Auto trucks have the advantage at the track over the dyno because they are able load the motor hard at the line and continuously for the entire run

Mark,



So what you are saying is the internet HP calculators are only good for automatic equipped trucks? This is what I was referring to above... ... These calculators are only an estimate at best. They assume certain conditions are being applied which may or may not be applicable.

if the truck revs faster under load less of the fuel energy is converted to mechanical force in the cylinder netting you less force at the tires

Mark your statement above is crazy... ..... Higher HP trucks rev much faster than a lower HP truck! Dynojets measure acceleration under a set load, so therefore a high HP truck will rev faster and yield a higher HP #. You need to get off your kick that the dyno is not an accurate means of measuring HP and smoking the tires in the parking lot is!



Doug

 

[Hohn]

The DynoJet dyno are possible not an accurate measurement of horsepower. But they DO accurately measure what's even more important-- recovery at load.



There are MANY cases in racing of an engine that "dynos" some 50hp less totally annihilating higher-hp competition.



The MOST important power aspect of an engine is how quickly it can recover-- or rev under load.



Imagine two engines with identical power delivery curves. Now, fit one with a 200lb flywheel. While the engine's power output has not changed per se, it would easily get smoked in a race, because some of its power delivery is being absorbed and stored in the flywheel, and you can only recover that energy in ways that are not always useful, especially in racing where there are so many transient periods.



So yes, generally HP correlates to "recovery" which describes an engine's power as well as how the power is delivered to the transmission.



Yes, it's possible that a Dynojet isn't PERFECTLY accurate for measuring HP, but that's totally fine. If there's inaccuracy, it's more in the value of HP itself.



I am disappointed at the level of thinking in some earlier posts. I would expect more from people intimately (or claimed to be) familiar with physics.



Justin

 

[Hohn]

additional thoughts... .



The real value of a DYNOJET, is not so much measuring HP as an absolute number, but rather in doing A-B comparisons.



Let me take the chance to post here some controversial, but true thoughts on HP from Larry Widmer, one of the most secretive, obscure, but legendary engine builders out there. I accept his perspect on power and torque (as well as airflow) as GOSPEL.

What Is Horsepower, And Do I Need It?



Not having read any of the posted material today, I’ve decided to select a starting place that’s always been a favorite …. Horsepower. What is horsepower other than the formula HP= Torque x RPM / 5252?

Other than something to brag about having, it’s a totally useless term as far as I’m concerned (unless you’re talking steady state, like an airplane, steady cruise, etc. ). I can’t count the number of programs I’ve been involved in that went backwards as we produced more horsepower. Torque is another issue, I suspect you’re thinking about now, and it is, however, perhaps not to the extent you may be thinking.

Any street car or race car is continuously accelerating or decelerating, and, assuming the brakes work and the handling is good, typically, the rate of acceleration is the way we judge the car’s performance and "power". As we’re talking about accelerating a given mass, torque is the most important component, assuming that we’re simply talking HP vs. Torque. If you can’t produce torque at the lower RPM ranges, it’ll take you all day to reach a "higher" RPM where you have torque (or HP. ), and then you shift gears, and you’re back where you started.

If someone is discussing high HP normally aspirated engines of small displacement, I automatically think "RPM" when I hear the numbers, and for those of you unaccustomed to my rambling messages on this board, I do not like RPM. My definition of RPM is Ruins Peoples Motors, and I’ll bet you that you’ll not find any experienced engineer or engine builder who will dispute this notion. I don’t care if you’re discussing imports or domestics, the higher the operating RPM, the higher the stresses, and the sooner you’ll experience parts failures. Before you jump my ass, I think that there are many automobile manufacturers who have done really great jobs in design, material selection, and assembly quality to provide the public with cars with "sufficient" bottom end torque, and reliable upper RPM torque that’s outstanding, and the fact that many modify these engines to produce 2-300% more than the factory anticipated is further testament to the designed and built in quality. However, my point remains relative to RPM. Take two identical engines and run them each "loaded", with one at 4000 rpm and the other at 6000 rpm. Which one would you bet will fail first?

Every program I’ve participated in since 1969 has been designed to build engines that run on torque, and lower rpm than the competition’s engines. If you have torque, you simply gear the car accordingly, and you’ll match the competitions speed, and more importantly, you’ll be more likely to be running at the finish. We used to "recalibrate" the tachometers in our NASCAR, (old) INDY, and ProStock programs to read 1000 rpm high, so when other teams would "casually" look at the tattle tales after running (ProStock was a hoot, as the competition could watch the tach. on the on-board TV broadcasts), and they’d all go deep gear there cars and blow their engines. I damned near shut down some manufacturer’s teams in several racing series because the foundries couldn’t provide enough blocks to replace all the blown ones.

Let’s go to the mystery area that’s really what makes the car run…. or accelerate. I call it Transient Response or Recovery Time. How long does it take for an engine to recover from being yanked down 2000rpm on a shift and accelerate back to the redline again…. that’s the mysterious quality that all killer engines have, and it’s not something that will show up in "conventional" dyno testing. Quite the contrary, I’ve NEVER seen an engine that possessed this quality make big HP. We rarely even look at HP#’s when testing (I stopped that in ’77). The only "number" I’m concerned in is: How much time does it take this engine to accelerate a given "load" from point A to point B. If the rpm range you anticipate operating in is for instance from 5000 to 8000rpm, the combination that will pull the "known load" from the bottom to the top the quickest will ALWAYS be the engine to run regardless of HP. Several years back, one of our NASCAR programs was so dominant that everyone said we had at least 695 HP. to run the way we did, and I will admit that we did have some engines that approached that number, however, all the "big HP. " engines required more than 1. 5 sec. more time to accelerate the load from 6000 to 7600rpm than another "special" engine we’d built. The "special" engine ran almost 10 mph higher lap speeds and it never made more than 590 HP. on the dyno when we decided to "check".

Transient Response is going to become a major topic of discussion in my future writings, as will torque and HP(for what it’s worth). We’ll travel through cylinder heads, manifolds, cams, engine geometry , etc. and we will continuously look at how each affect the "big picture" which is "what happens when you nail it".

Next topic will be more generic: What ingredients are necessary to make "useful" power, and what is "useful" power.

Got ya thinking?



Justin

 

[illflem]

Seems like this thread has outlived any usefulness.