dyno jet?
- Thread starter evilduramax
- Start date
Dockboy
Comps BFF
duke1n said:
Michael,
The weather station is part of the Dynojet equipment. It continuosly monitors atmospheric conditions and adjust the CF accordingly. You can actually do 3 or 4 back to back pulls and have a different cf on every one due to small changes in the conditions. Or you can just have it read actual (uncorrected) if you want it to. The operator does not get to "decide" what the CF is. You either use what the weather station determines it to be, or use uncorrected.
duke1n
Banned
Interesting. How often are they baselined and need recalibrated?
David, I'm sure you've forgotten more about dynos than I'll ever learn. That said I don't follow your reasoning that a dynojet is a better measure when baselining for drag racing. I would think that a vehicle that has to accelerate it's own mass not the mass of a drum as well as push against wind resistance and such could be more accurately measured on a load dyno that can simulate load other by means other than just accelerating a drum? I would think a ricemobile would have a harder time accelerating the same drum than a 1200ft lb diesel would? Either way and not saying one is better than the other, I worry about hurting stuff a lot more on a load dyno than an inertia dyno lol.
Greg, you're saying the operator has no control over CF? I thought dynos could be configured to measure both naturally aspirated engines as well as forced induction?
David, I'm sure you've forgotten more about dynos than I'll ever learn. That said I don't follow your reasoning that a dynojet is a better measure when baselining for drag racing. I would think that a vehicle that has to accelerate it's own mass not the mass of a drum as well as push against wind resistance and such could be more accurately measured on a load dyno that can simulate load other by means other than just accelerating a drum? I would think a ricemobile would have a harder time accelerating the same drum than a 1200ft lb diesel would? Either way and not saying one is better than the other, I worry about hurting stuff a lot more on a load dyno than an inertia dyno lol.
Greg, you're saying the operator has no control over CF? I thought dynos could be configured to measure both naturally aspirated engines as well as forced induction?
Burner
slow poke
Duke1n..... sounds like you're in a pickel. :bang
You'd think that the drum weight and the race weight of a Diesel Pick-up would have some relevance. Looks like a Diesel takes care of the wind with TQ. On the other hand, the cars don't have the TQ and the drum weight would make up the difference in drag coefficient. This seems to be right.....until you see a wide spectrum of low/high HP Diesel trucks and gas cars turning comparable numbers to their track times.
.......I guess the only factor you've left out is fuel.
I'm stumped as well.:dead-horse-fast2:
You'd think that the drum weight and the race weight of a Diesel Pick-up would have some relevance. Looks like a Diesel takes care of the wind with TQ. On the other hand, the cars don't have the TQ and the drum weight would make up the difference in drag coefficient. This seems to be right.....until you see a wide spectrum of low/high HP Diesel trucks and gas cars turning comparable numbers to their track times.
.......I guess the only factor you've left out is fuel.
I'm stumped as well.:dead-horse-fast2:
C.A.P
New member
Wow , this is painful to read.:bang I was coming on this thred for some DYNO information and all I got was some trash talk about who's truck will do what, and what they are going to do about it.:dead-horse-fast2: This is WAY off topic . :aiwebs_029:
Thank you David for steping in and educating us all !
Load cell dynos are very good if operated in the right hands ,......... and if they are accurately calibrated. A Dynojet, inertia dyno has no human factor to error on, you roll the rollers and that is it, you can have a correction factor ;however if you just read the uncorected hp # you are as acurate as you can get . WHEELS SPIN DRUM............you get hp readings . simple as that . :huh::
Thank you David for steping in and educating us all !
Load cell dynos are very good if operated in the right hands ,......... and if they are accurately calibrated. A Dynojet, inertia dyno has no human factor to error on, you roll the rollers and that is it, you can have a correction factor ;however if you just read the uncorected hp # you are as acurate as you can get . WHEELS SPIN DRUM............you get hp readings . simple as that . :huh::
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I actually am still learning with the dyno and it's important to understand my knowledge is largely "southern or east coast" based. :1tooth:
I have not tried to run a dyno in Denver, nor have I tried to race in Denver.
The Dyno Jet weather station reads temp, vapor pressure, and barometric pressure. With these readings it selects a correction based on the factor used. Example, SAE would have a correction formula based on those readings and the dyno would apply it.
Calculating 1/4 mile MPH based on a dyno run. In many cases they won't be exact. That can depend on a ton of stuff from wind direction, accuracy of the dyno, accuracy of the track timing lights for MPH, and accuracy of weight. They all have impact. From having to scale at every Pro Street race, scales vary largely from track to track. Wind direction can play a large role, and I would expect (don't know this) that at higher elevations where air is thinner, it's also easier to move these bricks of ours through it.
The reason I like a dyno jet for street/strip is because the dyno jet will tell you how responsive the truck is. If I can't get 10 lbs of boost on a turbo before the run, it's laggy. If it's laggy then it will be harder to launch on both street and strip. A truck that will make that 10 lbs will be responsive, and aside from much more fun on the street, it will launch harder and yeild a better ET. So in this example, a truck with a slow responding turbo may make a bigger number on a load cell than dyno jet, yet lose the race.
There is always talk about not making street boost on a dyno jet. Some trucks don't that is for sure. Some do. So I have to ask why is that? When I put tubz 7.3 on my dyno, when I got into it, it spun the boost guage hard, the truck slapped down a great number on the dyno. Many PSD's I do have a lazy boost gauge and don't make peak boost until the upper RPM's. Many duramax's I do will make a good boost number in the beginning of the run, then the boost will fade as the run progresses. Why?
I figured I would not be able to get Maddog's turbo's lit. Those are the largest chargers I have had on my dyno. His small charger was an A5000. Before the run I asked how much boost did it make. After the run it had made the same number. Even stage boost was where it should have been. This set-up was right IMO and the result was a new dyno record.
In 2002, I raced a Denver truck here in Atlanta that had dyno'd 90hp more than me. Same truck configurations, the only difference was mine was 90hp less on a Atlanta dyno. We ran identical times and speeds. So then you have to ask, where was the 90hp or was that 90hp corrected to altitude that was in fact bogus?
Bottom line is none of accepted methods of measuring HP is gospel. One track I was on showed I had gained 3 mph. Yet the dyno said I had gained no power. So what was up? A quick run through the pits and I discovered EVERYONE was 2 - 3 mph faster at this track which told me the timing lights were wrong. So in this case, without checking, I could have said the dyno was wrong. But was it?
Again, I like load dyno's. You can do some cool stuff with them. I also remain open to the day when turbo's may get to a point where I have a hard time loading them, It's just that so far, when I can dyno two trucks with the same set-up, one hits hard and runs well and the other does not, I have to point to the truck, not the dyno. But I am sure I will be proven wrong sooner than later... LOL
I have not tried to run a dyno in Denver, nor have I tried to race in Denver.
The Dyno Jet weather station reads temp, vapor pressure, and barometric pressure. With these readings it selects a correction based on the factor used. Example, SAE would have a correction formula based on those readings and the dyno would apply it.
Calculating 1/4 mile MPH based on a dyno run. In many cases they won't be exact. That can depend on a ton of stuff from wind direction, accuracy of the dyno, accuracy of the track timing lights for MPH, and accuracy of weight. They all have impact. From having to scale at every Pro Street race, scales vary largely from track to track. Wind direction can play a large role, and I would expect (don't know this) that at higher elevations where air is thinner, it's also easier to move these bricks of ours through it.
The reason I like a dyno jet for street/strip is because the dyno jet will tell you how responsive the truck is. If I can't get 10 lbs of boost on a turbo before the run, it's laggy. If it's laggy then it will be harder to launch on both street and strip. A truck that will make that 10 lbs will be responsive, and aside from much more fun on the street, it will launch harder and yeild a better ET. So in this example, a truck with a slow responding turbo may make a bigger number on a load cell than dyno jet, yet lose the race.
There is always talk about not making street boost on a dyno jet. Some trucks don't that is for sure. Some do. So I have to ask why is that? When I put tubz 7.3 on my dyno, when I got into it, it spun the boost guage hard, the truck slapped down a great number on the dyno. Many PSD's I do have a lazy boost gauge and don't make peak boost until the upper RPM's. Many duramax's I do will make a good boost number in the beginning of the run, then the boost will fade as the run progresses. Why?
I figured I would not be able to get Maddog's turbo's lit. Those are the largest chargers I have had on my dyno. His small charger was an A5000. Before the run I asked how much boost did it make. After the run it had made the same number. Even stage boost was where it should have been. This set-up was right IMO and the result was a new dyno record.
In 2002, I raced a Denver truck here in Atlanta that had dyno'd 90hp more than me. Same truck configurations, the only difference was mine was 90hp less on a Atlanta dyno. We ran identical times and speeds. So then you have to ask, where was the 90hp or was that 90hp corrected to altitude that was in fact bogus?
Bottom line is none of accepted methods of measuring HP is gospel. One track I was on showed I had gained 3 mph. Yet the dyno said I had gained no power. So what was up? A quick run through the pits and I discovered EVERYONE was 2 - 3 mph faster at this track which told me the timing lights were wrong. So in this case, without checking, I could have said the dyno was wrong. But was it?
Again, I like load dyno's. You can do some cool stuff with them. I also remain open to the day when turbo's may get to a point where I have a hard time loading them, It's just that so far, when I can dyno two trucks with the same set-up, one hits hard and runs well and the other does not, I have to point to the truck, not the dyno. But I am sure I will be proven wrong sooner than later... LOL
jponder
RESIDENT MAD SCIENTIST
David,
I been following this thread as i spent some time thinking about the effect of a turbo at elevation. Isnt that why they have turbos o turbo prop aircraft toi negate the effect of reduced atmospheric pressure? my opinion is if a turbo can produce the same ABSOLUTE pressure into the manifold then it wont matter elevation. If you are talking guage pressure then that is a different ballgame. Looking at it from a purely gas law perspective and reserving the right to be wrong. I think a Turbo engine is going to defy the classic CF associated with barometric pressure and a dyno that doesnt treat a turbo differently is going to add too much HP at altitude via a CF. Now the air coming out the exhaust is going to be less dense and it wont spin the turbo as effectively so you will have a slight dimished ability but it is going to be heads and tails different from a turbo VS a NA engine
You did say something that interested me. You said your dyno measured Temp, vapor pressure and Barometric pressure. By Vapor pressure you mean the vapor pressure in the air associated with water correct? I dont think it could measure vapor pressure directly but it could certainly measure Relative humidity and then calculate the vapor pressure of water from the barometric pressure. Does your dyno actually display humidity as vapor pressure of water? That would be cool actually
Here is what a load dyno could do in my opinion and it is something I have never heard anyone using one for. If you put the exact load on the dynoed truck that it would get from a certain speed AND you put a high quality fuel monitor then you could calculate exactly what the best speed of travel was to yield max MPG! And as we all know thats all we really care about anyway right? :banned:
Like david's disclaimer, i would like to say my opinions are a product of LSU and south louisiana
I been following this thread as i spent some time thinking about the effect of a turbo at elevation. Isnt that why they have turbos o turbo prop aircraft toi negate the effect of reduced atmospheric pressure? my opinion is if a turbo can produce the same ABSOLUTE pressure into the manifold then it wont matter elevation. If you are talking guage pressure then that is a different ballgame. Looking at it from a purely gas law perspective and reserving the right to be wrong. I think a Turbo engine is going to defy the classic CF associated with barometric pressure and a dyno that doesnt treat a turbo differently is going to add too much HP at altitude via a CF. Now the air coming out the exhaust is going to be less dense and it wont spin the turbo as effectively so you will have a slight dimished ability but it is going to be heads and tails different from a turbo VS a NA engine
You did say something that interested me. You said your dyno measured Temp, vapor pressure and Barometric pressure. By Vapor pressure you mean the vapor pressure in the air associated with water correct? I dont think it could measure vapor pressure directly but it could certainly measure Relative humidity and then calculate the vapor pressure of water from the barometric pressure. Does your dyno actually display humidity as vapor pressure of water? That would be cool actually
Here is what a load dyno could do in my opinion and it is something I have never heard anyone using one for. If you put the exact load on the dynoed truck that it would get from a certain speed AND you put a high quality fuel monitor then you could calculate exactly what the best speed of travel was to yield max MPG! And as we all know thats all we really care about anyway right? :banned:
Like david's disclaimer, i would like to say my opinions are a product of LSU and south louisiana
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jponder said:
No it measures Relative Humidity as you said.
And I think you are correct about the MPG thing. There is supposed to be a book published by the DOT that list "road load" ratings for most all vehicles at like 60 mph or sonmething. If this book exist, I'd bet you could set-up a load cell to do just that.
I've thought alot about the elevation issues too. No doubt there is less oxygen content as we go up, but we have turbo's compressing that "thinner" air. How efficient is it?
jponder
RESIDENT MAD SCIENTIST
David
Dont get caught up in less Oxygen at elevation, that is what the Turbo charger does. at altitude the percentage of O2 is the same its just that the ambient pressure is less so if you swing a cup and fill it with air at 18,000 feet and cover it with your hand and say, " How does this cup compare with a cup at sea level" Then True, it is going to have 1/2 the number of O2 molecules you would have at sea level and a true 14.7 psi. You compress that air to the same ABSOLUTE pressure as yall run when you are drag racing and there will be no difference.
David, one day you get a contract for rich Russians and Americans who want to Dyno their rigs in space and you and mike set up in your full blown 1 atmosphere space suits and you feed that engine air and compress it well its going to run in a vacume just like on earth, No its going to run better cause as soon as that exhaust valve opens it is going to get additional speed due to the vacume. Youd blow a head gasket sooner.......... Ineed to think on this some more, maybe eat some red Beans. Red beans always help me think clearer
Dont get caught up in less Oxygen at elevation, that is what the Turbo charger does. at altitude the percentage of O2 is the same its just that the ambient pressure is less so if you swing a cup and fill it with air at 18,000 feet and cover it with your hand and say, " How does this cup compare with a cup at sea level" Then True, it is going to have 1/2 the number of O2 molecules you would have at sea level and a true 14.7 psi. You compress that air to the same ABSOLUTE pressure as yall run when you are drag racing and there will be no difference.
David, one day you get a contract for rich Russians and Americans who want to Dyno their rigs in space and you and mike set up in your full blown 1 atmosphere space suits and you feed that engine air and compress it well its going to run in a vacume just like on earth, No its going to run better cause as soon as that exhaust valve opens it is going to get additional speed due to the vacume. Youd blow a head gasket sooner.......... Ineed to think on this some more, maybe eat some red Beans. Red beans always help me think clearer
jponder
RESIDENT MAD SCIENTIST
David,
Just hung up on the phone with you and enjoyed talking with ya. I did eat some split pea soup which is kinda like red beans and i am thinking clearer now. Here is the rub, when yall are in in Atlanta vs Denver does your guage change when the truck is off? In Atlanta truck not running does it read zero? In Denver with the truck off does it read zero? I mean manifold pressure. It reads the same but the pressure aint the same. Yall need some absolute pressure guages like they use on air conditioning equip. I think 50 psi in Atlanta does have to be different than 50 psi in denver. I think absolute pressure is different so there is a diff but like you said, where are the other 11 second trucks? I still think the CF are way off base
I am fixing to start whupping some butt in my truck and Billygoat is going to be my first victim. I got a cantalope with his name on it!
Just hung up on the phone with you and enjoyed talking with ya. I did eat some split pea soup which is kinda like red beans and i am thinking clearer now. Here is the rub, when yall are in in Atlanta vs Denver does your guage change when the truck is off? In Atlanta truck not running does it read zero? In Denver with the truck off does it read zero? I mean manifold pressure. It reads the same but the pressure aint the same. Yall need some absolute pressure guages like they use on air conditioning equip. I think 50 psi in Atlanta does have to be different than 50 psi in denver. I think absolute pressure is different so there is a diff but like you said, where are the other 11 second trucks? I still think the CF are way off base
I am fixing to start whupping some butt in my truck and Billygoat is going to be my first victim. I got a cantalope with his name on it!
duke1n
Banned
Great discussion. What's wrong with a little trash talk lol. Stiff...
Keep in mind my knowledge is from Metro State in Denver which is a mile high so maybe my brain was starved for oxygen lol.
I'll say it again, anyone that wants to come up to dieselfest and get on the rollers, if you can make even close to your sea level numbers with even a 6% CF, I'll buy your dinner and shop time It would interesting to ask some of the folks that have ran up here and sea level. I know Richard has. I know Rhonda did. I think I remember Greg up here a few years ago. Might have someone else but they had a tube chassis and a big single. Couldn't even get the thing to run and it never got on the track when I was there. Come on up you low elevation, flat landers hehe
Why do they turn up the Top Fuel cars up here to get equivalent time/trap?
Keep in mind my knowledge is from Metro State in Denver which is a mile high so maybe my brain was starved for oxygen lol.
How do you figure? You could think of this as a square inch column of water that extends to the edge of the troposphere. In Denver there is x number of less gallons of volume and thus let pounds per square inch pressing down on that square inch. Why is that? Because the mass of h2o molecules is less in that square inch chamber weighing down on someone at 5000'. Air is the same it's just o2 molecules. At seas level there are 14.7 lbs per square inch pressing down on you and at 5000' it's something like 10.x. So now think about the turbine. Let's start from the exhaust side. You are supplying the same amount of fuel no matter elevation but there are less o2 molecules per square inch to react with and burn that fuel. Hence there are less expansive exhaust gasses coming out of the exhaust because there is less energy. Now since you have less energy to spin the turbine you will transmit less energy through the shaft to the compressor wheel. That compressor now is trying to compress air at the same volume but with less o2 molecules into the engine. Can't do it. It would have to overspeed relative to normal speed at sea level to compress the fewer o2 molecules into the same area and on top of that there is less energy available to the turbine to turn the compressor. If you can convince me that there is the same exhaust gas energy regardless of altitude then I'll rethink that assertion. Who knows I can barely spell physics let alone remember all of it lol.
I'll say it again, anyone that wants to come up to dieselfest and get on the rollers, if you can make even close to your sea level numbers with even a 6% CF, I'll buy your dinner and shop time It would interesting to ask some of the folks that have ran up here and sea level. I know Richard has. I know Rhonda did. I think I remember Greg up here a few years ago. Might have someone else but they had a tube chassis and a big single. Couldn't even get the thing to run and it never got on the track when I was there. Come on up you low elevation, flat landers hehe
Why do they turn up the Top Fuel cars up here to get equivalent time/trap?
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duke1n
Banned
David, you should drag that Dyno out here for DieselFest. That is one thing that is lacking at that event. Huge event but most people don't want to get on the track. They would get on the dyno I bet you could have 30-40 truck run on it. It's a great event you should come out. It's an all brand deal. Talk to Shay Black who is the pres of the Colorado Powerstroke Club. She's on TDR...
I bet you could have 30-40 truck run on it. It's a great event you should come out. It's an all brand deal. Talk to Shay Black who is the pres of the Colorado Powerstroke Club. She's on TDR...
jponder
RESIDENT MAD SCIENTIST
duke1n said:
Okay I'll come back with Straight LSU Logic. You confusing me when you mention the weight of H2O molecules. Water of course is much lighter than air (18 gms/mole) air is 80% N2(30 gms/mole) and 20% O2(32gms/mole) AIR IS WAY WAY heavier than water. so air with 90% RH is much lighter than air with 10% RH. I just got lost after that, I need more red beans.
Dude if you get them boys to come up there you wont have enough money to buy all the dinners. Them boys are NUTS they got the POWA, I dont but they do. I'm scared of my stock 239 hp. You get around dem boys in the south and they crazy as ell. They will put a shure nuff country style whupping on you(wes norwood 2004)
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duke1n said:David, you should drag that Dyno out here for DieselFest. That is one thing that is lacking at that event. Huge event but most people don't want to get on the track. They would get on the dyno
I'd actually love to make a Colorado event, I love that state. But it would be one without the dyno. 3000 or so miles means I have to do way more trucks than I possibly can just to cover expenses. But I have thought about making one of those events should I have the time and money... I might not get Penny back home from there... LOL
partsguy662
You know damm right
DavidTD said:
Is that a reason to go, or a reason not to go?
LOLpartsguy662 said:Is that a reason to go, or a reason not to go?
LOL LOL Well maybe I should have said she may not want to come home which means we'd stay. We'll let the Colarado guys decide if this is a good or bad thing. LOL LOL
Would it be :welcome:
or
would it be :umno: :badidea:
LOL
jponder
RESIDENT MAD SCIENTIST
I To love Colorado David, I remember sking in Aspen in 1978 with real leather boots. Like I have told you before david I will pull that Dyno anywhere anytime, No Charge, i will eat the diesel. You got to give me a min speed though as i will try and set records pulling it. Then you can just fly in and i will be your assistant. You set the time and place for us TO SHOCK THE WORLD! I do want a Garmons diesel strapped to the back to be the terminator of the dyno runs.
I'm dead serious, I have pulled many differnt sizes of dozers and I will put that dyno on station, I GARONTEE!
I'm dead serious, I have pulled many differnt sizes of dozers and I will put that dyno on station, I GARONTEE!
duke1n
Banned
My brain hurts now lol. Not sure what you mean by southern boys whoopin up though? The fact is we can all dig out our old physics books and throw stuff up on the wall hoping some will stick. My degree is in Math and Comp Sci so I can't really begin to argue physics or chemistry in anything but laymans terms. The fact remains everyone thinks they can come up here and make the same power and the fact is you won't. Try it
David, sounds like you have an offer to drag that dyno on up here. Have you ever heard of Shotgun Willy's? haha Come on up boys it's a good time.
Burner... I think it's mostly nitrogen if I remember right. My example was only an analogy. I'm still waiting for someone to explain to me why the Fuel cars when they come out in July for the Mile High Nationals turn up the chargers and nitro to run similar times? That's the week after Dieselfest so come out and then spend a week up in the mountains and then hit the T/F cars on your way back through Denver the next weekend. If you've never seen 7000hp of eye burning nitro, you have no idea what you're missing. Will forever redefine your idea of power
David, sounds like you have an offer to drag that dyno on up here. Have you ever heard of Shotgun Willy's? haha Come on up boys it's a good time.
Burner... I think it's mostly nitrogen if I remember right. My example was only an analogy. I'm still waiting for someone to explain to me why the Fuel cars when they come out in July for the Mile High Nationals turn up the chargers and nitro to run similar times? That's the week after Dieselfest so come out and then spend a week up in the mountains and then hit the T/F cars on your way back through Denver the next weekend. If you've never seen 7000hp of eye burning nitro, you have no idea what you're missing. Will forever redefine your idea of power
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