I was reading a thread in the F/I forum at My350Z

http://www.my350z.com/forum/showthread.php?t=318406

On the second page , one of the later posts . The OP posted up his before and after dyno's

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Actually I was going to post this ina different thread but I just got back from dynoday at JER. And I have a comparo from before and after the turbos were rebuilt...

Before: DynoJet: 545rwh, 500trq -13psi
DynoDynamics:450rwh, 500trq -13psi

After: DynoJet: 535rwh, ?trq - 14psi
DynoDynamics: 430rwh, 530trq -14psi

These new rebuilt jobs obviously lose out a little..but it feels like it spools faster and in alot more responsive at the lower rpms...


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Does this seem strange to anyone else ? Im mean I see a 20% to 25% difference in the two . I know that Dyno Dynamics read lower [ 8 to 12 % ] But this is clearly much wider difference . Any one want to go ask where the dynos were run at ? Im banned on that site for a few weeks . I was being bad! lol And cant go ask my self . Could this be because the DynoJet dyno is a high reader like Church's dyno that I hear about ?

 

Well yes...but you dont set up a load base dyno to read lower than it should . Normally shops do the oppsite and have them read higher . Thats why I asked if the DynoJet used was a high reader . I think [ not sure ] a dynojet can be altered to read higher or lower if you put in high or low temp and humidity set points .

 

https://g35driver.com/forums/tuner-dyno/104399-dyno-facts.html

Post #17

and to quote yourself:
and the response to your post:

 

Calvin

that is my point and why I asked if someone wanted to go ask ? As you can see by the past posts by Alberto . There is about a 30 to 35whp difference between the two . And the post I was reading and showed , there is a 90 to 105whp difference . Much greater ! I was just wondering which dyno is off so much .

 

I was primarily addressing your second post in this thread, regarding dyno operators being able to "adjust" output numbers or not.

Judging from what I've quickly read/skimmed though, Dynojets appear to be the ones that are "off" in that they put out inflated numbers.

But as I'm sure you can agree, these numbers really mean nothing. Most people drool over large numbers, but considering that all these dynos will yield various numbers they mean nothing! Dynos are simply tools for tuning, but people tend to use them for bragging rights.

***I am by NO means an expert on dynos, if that is what people are inferring. My posts here are based off a quick skimming through various posts/threads/sites. Just doing what I could to help make things clearer.

 

I have been around the block with dyno's and that they can be different and are there to be a tool and nothing more .But if the DynoJet used is reading that much higher than most all other DynoJets , or the DD dyno is reading that much lower . People might want to know which is which and what shop has what .

 

IMO, dynos should be used for two things: tuning and seeing gains by mods (given that the before and after dyno are done on the same day/dyno or at the very least under very similar conditions).

Again, just from what I've read...

Dynojets are "notorious," if you will, for reading high. The way I see it is, they know that numbers sell and that people will want to use dyno numbers as a measure of their "***** size" (to quote Trey). Hence, they are made to read high. Regardless of the numbers read, a Dynojet should suffice for what it should be meant to do - tune.

Dyno Dynamics, although known for reading low, are very accurate for tuning.

I'd assume that people that wanna boost their ego would use a Dynojet, while people who are more interested in tuning wouldn't really care what numbers the dyno puts out...just the difference (before/after the tune).

 

Yes I know all this...I have only dynoed my car on a load base dyno [ Mustang ] DynoJets are used as the comparo between cars at diff cities and diff shops because they are suppose to be less tamper proof .

Now if the dyno's I posted about are that far off from each other . And the DynoJet looks to be the one . Wouldnt you like to know what shop uses that dyno ? This is my point of the thread . To have maybe someone go ask where the DyoJet and the DynoDynamic Dyno are at [ what shops ] That all . Im not trying to argue about which is which and which is better or anything like that .

 

trap speeds dont lie...

 

Love to have one in my back yard . We only have a 1/8th

Would still like to know where that guy dynoed his car at !!!

 

No one wants to go ask ?????

 

Yes, but they don't tell the whole story either. When I ran my car on the same day...about 8 runs...my traps started at 125mph, and I worked my way all the way up to 131whp over the course of the 3-4 hour time period I was there. Same boost.....I just got better an launching, shifting, and driving the car.

 

i know, BUT, you cant add 13 % to your trap speed and say thats what it would do somewhere else.....


you know as well as i do that comparing dyno to dyno is just stupid, you have done a really good job of having a dynojet for reference to show the difference.
there are a lot of ways on certain dynos to make false numbers, but not one time can you trap higher than your car should if the power is not there.


thats why i stand behind my statement, "trap speeds dont lie"

you might not trap up to your cars potential, due to tires or track conditions. you will never, ever, not even once, trap higher than you should....

 

Ah, now I see your point. It's not possible to add a correction to a timeslip.