Loss of 22.5% HP

Ryan@IP · 08-14-2009, 03:06 PM

Quote:

Originally Posted by lando76

So basically most of you agree that not one dyno is accurate. One thread said " A normal dyno" which to me sounds a little broad. How about this I will go to three different dyno shops and pay three times what I want to pay and take the average. I do believe that most dyno shops have to have their machines calibrated by the state of some sort to charge customers money and be considered a business.

All dynos are accurate on their own scale, as long as they are well maintained (ours is). Even car manufacturers can't always agree on what to accurately rate engine power at. What you also have to consider is the formulas behind each dyno and how the numbers are determined. It is a fairly complicated process that takes in a scary amount of values to determine what numbers to output on the screen. As a previous poster pointed out, some dynos are load bearing; others are not. Some, like a Dynapack, measure from the hubs rather than the mounted wheels and tires.

There is no such thing as a "normal" dyno or a right vs. wrong dyno. We have our reasons for choosing a Dyno Dynamics over the other choices, but that does not mean that we feel DynoJet numbers are irrelevant. They are simply using a different scale than ours. The important thing is that you remain consistent on the brand of dyno that you go to. A DD's numbers will be comparable to just about any other DD's numbers, but directly comparing a DD result to a DynoJet gets a little more fuzzy. The only *true* way to measure horsepower output is through an engine dyno, not a chassis dyno. All we can realistically do is measure gains from our baseline on X dyno to the results on the same type of dyno.

wstar · 08-14-2009, 04:02 PM

Well, in *theory*, the value of a a ft/lb of torque is based on international standards. Therefore any machine reading ft/lbs of torque from the spinning wheels of a car under the same loading conditions (meaning, some standardized approximate simulation of the weight of the car and aerodynamic load), with the same (hopefully minimal) wheel-slip error on the rollers, should read the same value.

I understand, to some degree, why the situation is as it is, but I think there is a "right answer" as to how much rwhp is actually being put out of the car, and I think the dyno mfgs could be doing a better job than they are of getting their results in line.

tbss370z · 08-22-2009, 09:54 PM

What gear should be used when dyno testing? Is there a formula that you can use to adjust for weather conditions such as temperature, humidity & atmosphere pressure?

theDreamer · 08-22-2009, 09:55 PM

Quote:

Originally Posted by tbss370z

What gear should be used when dyno testing? Is there a formula that you can use to adjusted for weather conditions such as temperature, humidity & atmosphere pressure?

Some allow for things like these, but the best thing to do is either a) do the dyno tests on the same day b) try to recreate the weather conditions as best as possible.

wstar · 08-24-2009, 09:24 AM

Quote:

Originally Posted by tbss370z

What gear should be used when dyno testing?

For your 6MT, do it in 5th, as this is the 1:1 ratio and it's what others have been using. 7AT guys have to do it 4th at the highest, as we hit the stock speed limiter before we hit redline in 5th and higher, even though 5 is also our 1:1 ratio (we have a different rear end ratio, that's what makes the difference).

tbss370z · 08-25-2009, 07:51 PM

I believe I was told the dyno was done on 3rd or 4th gear. How does that affect the results?

nogoodname · 08-13-2009, 08:36 PM

what......urs is a 7AT.....i thought it was a 6MT all this time

zZSportZz · 08-13-2009, 08:43 PM

Quote:

Originally Posted by nogoodname

what......urs is a 7AT.....i thought it was a 6MT all this time

The 7AT near his avatar didn't give it away?

2theextreme · 08-13-2009, 08:44 PM

Quote:

Originally Posted by nogoodname

what......urs is a 7AT.....i thought it was a 6MT all this time

Nope....7AT......good thing actually since I broke my left foot back in March!

zZSportZz · 08-14-2009, 07:21 AM

My

dyno reads really high.

tooohip · 08-14-2009, 03:10 PM

I'm going to the dyno that gives my car the most HP! I'll feel better that way!

SpawnAeroJohn · 08-14-2009, 08:53 AM

You know removing the a/c frees up HP.

m4a1mustang · 08-14-2009, 08:54 AM

What I am interested in, then, is how gains are going to compare across dynos. I'm going to go back after I install my Injen intakes, which Injen claims gains 15whp. Their test was on a DynoJet and the gain amounted for about a 5.3% gain with a 279whp baseline.

If I baseline at 243 whp, I wonder if I could use that 5.3% and estimate a gain of 12whp. I think there are too many variables so I doubt I can do a linear comparison but it will be interesting to see what comes of it.

tcarretti · 08-14-2009, 08:57 AM

Am really looking forward to your dyno with the intakes... am waiting to pull the trigger on the Injen but would like some more real world numbers.

m4a1mustang · 08-14-2009, 09:02 AM

Quote:

Originally Posted by tcarretti

Am really looking forward to your dyno with the intakes... am waiting to pull the trigger on the Injen but would like some more real world numbers.

I will post up a detailed thread. Install pics, dyno vids, and all. I should have the intakes next week and will install them over the weekend. I'm planning to drive the car for a week before a dyno just to give everything time to adjust.

08-14-2009, 04:02 PM	#2 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3595	Well, in theory, the value of a a ft/lb of torque is based on international standards. Therefore any machine reading ft/lbs of torque from the spinning wheels of a car under the same loading conditions (meaning, some standardized approximate simulation of the weight of the car and aerodynamic load), with the same (hopefully minimal) wheel-slip error on the rollers, should read the same value. I understand, to some degree, why the situation is as it is, but I think there is a "right answer" as to how much rwhp is actually being put out of the car, and I think the dyno mfgs could be doing a better job than they are of getting their results in line. __________________ 7AT Track Car! Journal thread / Car setup details

08-22-2009, 09:54 PM	#3 (permalink)
tbss370z Base Member Join Date: May 2009 Location: King of Prussia, PA Posts: 40 Drives: 09 Nissan GP 370Z M6 Rep Power: 17	What gear should be used when dyno testing? Is there a formula that you can use to adjust for weather conditions such as temperature, humidity & atmosphere pressure? __________________ 09 Nissan 370Z Base + Sport/Ichiban spacers/Takeda Intake with heat shields/HKS Exhaust/ 88 Porsche 944T, 06 Trailblazer SS/ Last edited by tbss370z; 08-22-2009 at 10:08 PM.

08-25-2009, 07:51 PM	#6 (permalink)
tbss370z Base Member Join Date: May 2009 Location: King of Prussia, PA Posts: 40 Drives: 09 Nissan GP 370Z M6 Rep Power: 17	I believe I was told the dyno was done on 3rd or 4th gear. How does that affect the results? __________________ 09 Nissan 370Z Base + Sport/Ichiban spacers/Takeda Intake with heat shields/HKS Exhaust/ 88 Porsche 944T, 06 Trailblazer SS/

08-14-2009, 07:21 AM	#10 (permalink)
zZSportZz A True Z Fanatic Join Date: Mar 2009 Location: Maryland Posts: 1,095 Drives: 370z Blk on Blk 6MT Rep Power: 19	My dyno reads really high. __________________ --Rick

08-14-2009, 03:10 PM	#11 (permalink)
tooohip A True Z Fanatic Join Date: May 2009 Location: Columbia, MD Posts: 1,626 Drives: 09 370z CY To/Sp Rep Power: 271	I'm going to the dyno that gives my car the most HP! I'll feel better that way! __________________ Lance KW Variant 3 Coilovers \| Stillen Sways \| Stillen Gen III Intake \| AAM HFC \| AAM True Dual CBE \| AAM Comp Oil Cooler \| Hawk HPS Pads \| Volk TE-37 \| Hoser Keg Tap

08-13-2009, 08:36 PM	#7 (permalink)
nogoodname Lifetime Premium Join Date: Nov 2008 Location: Montreal Posts: 22,357 Drives: E46 M3 Rep Power: 1765	what......urs is a 7AT.....i thought it was a 6MT all this time

08-14-2009, 08:53 AM	#12 (permalink)
SpawnAeroJohn NOT A CURRENT VENDOR Join Date: Jun 2009 Location: Chicago Posts: 609 Drives: you Rep Power: 18	You know removing the a/c frees up HP.

08-14-2009, 08:54 AM	#13 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6963	What I am interested in, then, is how gains are going to compare across dynos. I'm going to go back after I install my Injen intakes, which Injen claims gains 15whp. Their test was on a DynoJet and the gain amounted for about a 5.3% gain with a 279whp baseline. If I baseline at 243 whp, I wonder if I could use that 5.3% and estimate a gain of 12whp. I think there are too many variables so I doubt I can do a linear comparison but it will be interesting to see what comes of it. __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

08-14-2009, 08:57 AM	#14 (permalink)
tcarretti Base Member Join Date: Jul 2009 Location: Texas Posts: 78 Drives: 09 370Z Rep Power: 17	Am really looking forward to your dyno with the intakes... am waiting to pull the trigger on the Injen but would like some more real world numbers.

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