Dyno didnt seem right...thoughts?

SledPuller21

SledPuller21

Never enough
Joined
Jan 18, 2007
Messages
2,214
Just got in from sarver and put out 650hp and 1052tq. I felt from driving my truck and riding in other CRs I've worked on that I should've been well into the low 700's. My question is why so low on the tq? I dynoed last year and got 572hp and 1162tq with a different setup and the stock charger. Also I was told by the operator to run my truck in 6th (5 other times I've dynoed other places they go with 1:1 in 5th). Anyhow went God knows how fast and only saw 1250 egt(I hit 1800 WOT by 3700 in 6th on the street)... didnt get a boost reading since I blew my line off the gauge on the way there. I know I have enough fuel to heat a large house, and a enough air to support 700...what gives? Any thoughts or just not enough load on the dyno? I'll get my sheet up when I can and hopefully someone from sarver got a vid of my run. Thanks.
 
I think your truck is about 500, but you never like what I think.LOL

Take it up to Cyclone, and put it on Johnboys Superflow.
 
Wheres that at? I really like the superflow I was on at Predator but I just talked to Mike from there and they're closed:banned:. Haha 500 is what my sheet is readin at 3700 when the revlimiter hits.
 
IMG_0321.jpg
Heres the sheet, kinda hard to see but peak power at 32-3300.
 
SledPuller21 said:
Just got in from sarver and put out 650hp and 1052tq. I felt from driving my truck and riding in other CRs I've worked on that I should've been well into the low 700's. My question is why so low on the tq? I dynoed last year and got 572hp and 1162tq with a different setup and the stock charger. Also I was told by the operator to run my truck in 6th (5 other times I've dynoed other places they go with 1:1 in 5th). Anyhow went God knows how fast and only saw 1250 egt(I hit 1800 WOT by 3700 in 6th on the street)... didnt get a boost reading since I blew my line off the gauge on the way there. I know I have enough fuel to heat a large house, and a enough air to support 700...what gives? Any thoughts or just not enough load on the dyno? I'll get my sheet up when I can and hopefully someone from sarver got a vid of my run. Thanks.
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Sledpuller21, I spoke to you briefly after you got off the dyno today. I would have to say that the injectors your running need alot more air than you have. That thing was a smokey pig. My truck only made 40 psi. on the dyno today. Your seat of the pants dyno is alot different than the real thing everybody makes 600 HP on the street. Just a side note I realize who you are now, be glad you left Sarver before my cousin who you sold some junk parts to knew you were there. Thanks Steve B.
 
nwpadmax said:
A Dynojet is not a load cell dyno.

Any further questions, class?

Little Power Shop
Click to expand...

Not entirely true...a Dyno Jet 248 is not a load cell dyno, but at the shop we have a Dyno Jet 224x that has a eddy current load cell.

So DJ, does make dynos that do and dont have load cells.
 
SledPuller21 said:
Just got in from sarver and put out 650hp and 1052tq. I felt from driving my truck and riding in other CRs I've worked on that I should've been well into the low 700's. My question is why so low on the tq? I dynoed last year and got 572hp and 1162tq with a different setup and the stock charger. Also I was told by the operator to run my truck in 6th (5 other times I've dynoed other places they go with 1:1 in 5th). Anyhow went God knows how fast and only saw 1250 egt(I hit 1800 WOT by 3700 in 6th on the street)... didnt get a boost reading since I blew my line off the gauge on the way there. I know I have enough fuel to heat a large house, and a enough air to support 700...what gives? Any thoughts or just not enough load on the dyno? I'll get my sheet up when I can and hopefully someone from sarver got a vid of my run. Thanks.
Click to expand...

Were you brake boosting at all??? If you are running on a 248, you need to brake boost up to 15-20psi then begin your run or else you will experience exactly what you did...low boost and low numbers.

At LCD weve got a Dyno Jet 224x with a load cell that we can apply load until boost comes up then begin the run. When running on a non-load cell dyno you have to apply a load with your brakes to get a good boost number which in turn gets you a good power number.
 
2007 5.9 said:
Not entirely true...a Dyno Jet 248 is not a load cell dyno, but at the shop we have a Dyno Jet 224x that has a eddy current load cell.

So DJ, does make dynos that do and dont have load cells.
Click to expand...

Agreed, but what is the dissipation capacity?

My understanding is that the 224X can provide "some" load, but the absorber is not the size needed to absorb the whole shootin' match like a SuperFlow does.

For example, the dual absorber SuperFlow 800 series can absorb 700rwhp for TEN MINUTES. The 224X literature doesn't even say how much it can hold for how long. And it's a single absorber.

And just keep in mind that a DJ does NOT measure torque directly. It is calculated. A true load cell unit (of whatever brand) measures torque directly with a load cell.

My other main beef with the DJ is how brief the test is....*zing* and you're done. That's about as far away from a pulling simulation as you can get. It doesn't seem to mimic street driving either.

But to each, his own.
 
nwpadmax said:
Agreed, but what is the dissipation capacity?

My understanding is that the 224X can provide "some" load, but the absorber is not the size needed to absorb the whole shootin' match like a SuperFlow does.

For example, the dual absorber SuperFlow 800 series can absorb 700rwhp for TEN MINUTES. The 224X literature doesn't even say how much it can hold for how long. And it's a single absorber.

And just keep in mind that a DJ does NOT measure torque directly. It is calculated. A true load cell unit (of whatever brand) measures torque directly with a load cell.

My other main beef with the DJ is how brief the test is....*zing* and you're done. That's about as far away from a pulling simulation as you can get. It doesn't seem to mimic street driving either.

But to each, his own.
Click to expand...

Yes, you are right, the 224 cant keep a constant load for 10min, more like 5-6min. Does that make it a bad dyno???

All dyno's are good for is a tuning tool, you run on one, make a change, run again to see if that change was a +/-, comparing dyno's for calculating the most HP is futile.

There was a time when I believed that the ever popular 248c was the standard in measuring HP, until I dynoed at Left Coast in 2008 right before the Nor Cal Diesel Rally which i knew was going to be having "The Humbler" Maddog dyno. I ran a 545hp run at LCD, then proceeded to Nor Cal Rally and put up a 575hp run. How is one to explain this...other than going from one dyno to another is only going to be a guess on weather or not you make more power or not.

It really doesnt matter which one you use, if you want to truly know what HP you have, you need to spend the time on the exact same dyno everytime which will give consistant readings. You can accuratly measure HP changes on the same dyno...then when you think you have maxed out, go to the track and compare your trap MPH with you HP and see if you are close.

So to the OP, your numbers sound a little low but the only real way to know is by trap MPH at the strip. Who's to say the air on your first day wasnt better than you last one...when you started your run...boost numbers to begin with...how quickly you applied throttle....there are lots of variables that go into becoming a consistant and repeatable vehicle operator on a dyno.
 
Hiya

Interesting topic. I just was finishing up dyno tests on a truck I had done some work to yesterday morning. We were having a similar discussion to this one. So we decided to do an interia run to see how it compares to a load run. Below are the results:

loadvsinertia.jpg


Run 2 was a load test which I brought the boost up as high as it would go before letting the truck go. (30 psi) Run 20 was an inertia test which I just floored it like you would on a Dynojet. I didn't do any brake boosting or anything like that.

Btw, the truck being dynoed was an 05 Dodge Cummins with the following mods: II 40% CP3, Edge Juice with hot unlock, stock/400 twins, CFM intake, 5" Magnaflow exhaust
 
J Anderson said:
Interesting topic. I just was finishing up dyno tests on a truck I had done some work to yesterday morning. We were having a similar discussion to this one. So we decided to do an interia run to see how it compares to a load run. Below are the results:

loadvsinertia.jpg


Run 2 was a load test which I brought the boost up as high as it would go before letting the truck go. (30 psi) Run 20 was an inertia test which I just floored it like you would on a Dynojet. I didn't do any brake boosting or anything like that.

Btw, the truck being dynoed was an 05 Dodge Cummins with the following mods: II 40% CP3, Edge Juice with hot unlock, stock/400 twins, CFM intake, 5" Magnaflow exhaust
Click to expand...

From what I am seeing, a loaded run produced the most power, which in most cases is true.

Again, if you test on the same dyno everytime and run the exact same way everytime then you can see if power adders actually do add power or take away. Dynos are just tools for tuning.
 
ctd8999 said:
Sledpuller21, I spoke to you briefly after you got off the dyno today. I would have to say that the injectors your running need alot more air than you have. That thing was a smokey pig. My truck only made 40 psi. on the dyno today. Your seat of the pants dyno is alot different than the real thing everybody makes 600 HP on the street. Just a side note I realize who you are now, be glad you left Sarver before my cousin who you sold some junk parts to knew you were there. Thanks Steve B.
Click to expand...

Haha I didnt sell him junk parts they were used. The oil pan had a dent(apperently he thought it was braned new for $75?) and the tranny adapter had a crack that I had no idea about, I'm an honest guy not out to screw anybody I would have gladly gave him his money back but he was getting real chitty with me on the phone before I could even get a word in. Glad I left eh? Hmmm maybe he was gonna slash my tires? Anyhow back on topic...I have the air required to see 700+ it was smokey because I dynoed it 6th gear starting the run at 55, is that hard to understand? Needless to say I've been on a superflow and agree with Mat 100%. Every other dyno I've been on has been a waste of money, shame on me I've learned now.
 
2007 5.9 said:
From what I am seeing, a loaded run produced the most power, which in most cases is true.

Again, if you test on the same dyno everytime and run the exact same way everytime then you can see if power adders actually do add power or take away. Dynos are just tools for tuning.
Click to expand...

I agree that dynos are just tools for tuning. That very statement makes any inertia dyno absolutely garbage for tuning most diesel engines. If you can't simulate a real world condition, you can't tune the vehicle. Period. While inertia dynos are very good tools for gasoline power vehicles, they are completely worthless for diesel. (At least from experience.)

Now I realize I am coming from a biased position since I own a Superflow dyno, but let me explain. For all gas vehicles, I always use inertia pulls. It works very well. Once in a while if I am tuning a gas truck that I know works really hard, I will do a couple of load pulls to make sure there is no detonation under heavy load and any strange things going on. If you compare a load test against a inertia run on a gas vehicle, the load test will show lightly lower horsepower but a little more torque typically. So, for gas vehicles, the only thing I usually use the load cell for is steady state tuning or slowing the drums down at the end of the run. Diesels are much different animals though.

On the diesels, if you can't simulate street or track conditions, any tuning you do is working off false data. If your truck makes 50 psi and gets to 1800 degrees on the street, you need those same conditions in order to make any worthwhile adjustments. On the Powerstrokes in particular, I can be sure that the programs I'm building for the truck on the dyno are only going to run so hot. You can tune for egts on lower hp tow rigs and send them out the door confident they will only see that temp when towing. I realize that it is a slightly different application than a pulling truck, but the basic principle is the same.

I have a 12v Cummins coming in tomorrow for some tuning. It is a tow vehicle that runs too hot. I will be able to dial everything in on the dyno without ever driving it on the street once. 9 times out of 10 the settings will be spot on the first test drive. There is no way possible to do that on a Dynojet or inertia dyno.
 
J Anderson said:
I agree that dynos are just tools for tuning. That very statement makes any inertia dyno absolutely garbage for tuning most diesel engines. If you can't simulate a real world condition, you can't tune the vehicle. Period. While inertia dynos are very good tools for gasoline power vehicles, they are completely worthless for diesel. (At least from experience.)

Now I realize I am coming from a biased position since I own a Superflow dyno, but let me explain. For all gas vehicles, I always use inertia pulls. It works very well. Once in a while if I am tuning a gas truck that I know works really hard, I will do a couple of load pulls to make sure there is no detonation under heavy load and any strange things going on. If you compare a load test against a inertia run on a gas vehicle, the load test will show lightly lower horsepower but a little more torque typically. So, for gas vehicles, the only thing I usually use the load cell for is steady state tuning or slowing the drums down at the end of the run. Diesels are much different animals though.

On the diesels, if you can't simulate street or track conditions, any tuning you do is working off false data. If your truck makes 50 psi and gets to 1800 degrees on the street, you need those same conditions in order to make any worthwhile adjustments. On the Powerstrokes in particular, I can be sure that the programs I'm building for the truck on the dyno are only going to run so hot. You can tune for egts on lower hp tow rigs and send them out the door confident they will only see that temp when towing. I realize that it is a slightly different application than a pulling truck, but the basic principle is the same.

I have a 12v Cummins coming in tomorrow for some tuning. It is a tow vehicle that runs too hot. I will be able to dial everything in on the dyno without ever driving it on the street once. 9 times out of 10 the settings will be spot on the first test drive. There is no way possible to do that on a Dynojet or inertia dyno.
Click to expand...

:clap:
 
SledPuller21 said:
Just got in from sarver and put out 650hp and 1052tq. I felt from driving my truck and riding in other CRs I've worked on that I should've been well into the low 700's. My question is why so low on the tq? I dynoed last year and got 572hp and 1162tq with a different setup and the stock charger. Also I was told by the operator to run my truck in 6th (5 other times I've dynoed other places they go with 1:1 in 5th). Anyhow went God knows how fast and only saw 1250 egt(I hit 1800 WOT by 3700 in 6th on the street)... didnt get a boost reading since I blew my line off the gauge on the way there. I know I have enough fuel to heat a large house, and a enough air to support 700...what gives? Any thoughts or just not enough load on the dyno? I'll get my sheet up when I can and hopefully someone from sarver got a vid of my run. Thanks.
Click to expand...


Honestly that number sounds about right to me. I am not sure I trusted predators numbers. I do trust the Superflow the John has. To get a good number on a DJ 248 your setup needs to be spot on or it will show low. A superflow will load you hard and the pull takes a set amount of time everytime so it is far easier to see where you went wrong. Over fueling at 2500rpm can and will hurt your topend end power on dynojet 248 because it is all about momentum. Been there done that. I like the dynojet 248 for comparing things because I feel it is the most repeatable but I like the Superflow much better for actually tuning you setup it can do thing a DJ can not.
 
J Anderson said:
I agree that dynos are just tools for tuning. That very statement makes any inertia dyno absolutely garbage for tuning most diesel engines. If you can't simulate a real world condition, you can't tune the vehicle. Period. While inertia dynos are very good tools for gasoline power vehicles, they are completely worthless for diesel. (At least from experience.)

Now I realize I am coming from a biased position since I own a Superflow dyno, but let me explain. For all gas vehicles, I always use inertia pulls. It works very well. Once in a while if I am tuning a gas truck that I know works really hard, I will do a couple of load pulls to make sure there is no detonation under heavy load and any strange things going on. If you compare a load test against a inertia run on a gas vehicle, the load test will show lightly lower horsepower but a little more torque typically. So, for gas vehicles, the only thing I usually use the load cell for is steady state tuning or slowing the drums down at the end of the run. Diesels are much different animals though.

On the diesels, if you can't simulate street or track conditions, any tuning you do is working off false data. If your truck makes 50 psi and gets to 1800 degrees on the street, you need those same conditions in order to make any worthwhile adjustments. On the Powerstrokes in particular, I can be sure that the programs I'm building for the truck on the dyno are only going to run so hot. You can tune for egts on lower hp tow rigs and send them out the door confident they will only see that temp when towing. I realize that it is a slightly different application than a pulling truck, but the basic principle is the same.

I have a 12v Cummins coming in tomorrow for some tuning. It is a tow vehicle that runs too hot. I will be able to dial everything in on the dyno without ever driving it on the street once. 9 times out of 10 the settings will be spot on the first test drive. There is no way possible to do that on a Dynojet or inertia dyno.
Click to expand...

I just relized who you where John. LOL

Good to see you on here!
 
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