Dyno Deceivery?

[GReddy_917]

I was talking to xchoirboy at the meet this Saturday after he dyno'd his Evo and noticed an interesting point....

He has dyno'd his XFlashed Evo on both Vishnu's DD dyno and ATP's Dynojet now.

His car has not been changed/modded between dyno's (other than miles).

This is what he got at Vishnu...
http://www.norcalevo.net/gallery/albums/album29/064_G.jpg

and according to him he got 230whp at ATP yesterday.

Now what exactly does this tell us?? Im not sure...but the results were surprising and they make one wonder...

[vtluu]

I don't think there's any deception here except maybe self-deception. As has been pointed out, there are so many variables in play that can affect dyno results. IMO a dyno is useful as a tuning tool, and the simplest experiment you can do is to use the same dyno to take before-vs-after measurements when installing a mod, preferrably all on the same day, with the same conditions and parameters (ambient temperature and humidity, engine temp., gasoline, etc.). This is what Marcel did yesterday for example. But to really tune a car you'd basically have it strapped to a dyno for hours while you tweak this and that--and the end result is a car that performs optimally under the conditions under which you dyno'ed it, which may or may not be representative of conditions on the street or track. Such is life--never simple, never easy!

If you want to dyno your car just for the heck of it, just out of curiosity, or to get a pretty graph to stick on your fridge, that's fine, but I wouldn't put much value in the quality of the information itself.

[GReddy_917]

Well said Tam and I agree...but the point is that one dyno is notoriously well known for its lower hp/trq ratings when compared to the other dyno and not just for one particular car either.

[lambtron]

Nope. Stage 1.

[EvoVIII]

stage 1 274WHP??

[smogrunner]

How on earth are we supposed to know what xchoirboy achieved at Vishnu from that picture? Could someone enlighten me?

[EvoVIII]

well that was the 1/24 meeting earlier this year

[evo_dadi]

well brian dyno'ed his stage 1 and came up with 291 hp at atp not sure how much tq.

[xchoirboy]

How on earth are we supposed to know what xchoirboy achieved at Vishnu from that picture? Could someone enlighten me?

At Shiv's dyno I made 230 consistently. On ATP's I had a 227.1, 218.7 :?: , and a 235.9. WTF . The dyno sheets from Shiv's and ATP are in my gallery.

http://www.norcalevo.net/forums/modules.php?set_albumName=album37&op=modload&name=gallery&file=index&include=view_album.php

It's just wierd to me blame it on atmospheric conditions, dyno, whatever also compared to some of the other results.

[MP5]

Choir run by Vishnu and have them check it out see whats going on some pressure lines on the bottom of the manifold are notorious for poping off as they have no clamps from the factory

BTW who was supposed to be decieving? Vishnu? ATP?

[ez76]

xchoirboy - I am wondering if Vishnu tuned your car before or after you installed your GFB/WORKS BOV?

Did any other parts go on since Vishnu tuned you?

What peak boost are you running?

[nebolic]

xchoirboy - I am wondering if Vishnu tuned your car before or after you installed your GFB/WORKS BOV?

Did any other parts go on since Vishnu tuned you?

What peak boost are you running?

would installing an aftermarket BOV change your power output by 10-15%? If so, that's one kick butt mod 8)

In any case, I don't think boost would be affected as much with an aftermarket BOV, maybe at the top end when its "supposed" to hold boost better, but I think that peak boost for the Evo is not achieved at the top end, but near the 3500rpm to 5500rpm mark.

Nebo

If the addition of the BOV increases boost level to a level higher than it was when tuning at Vishnu, then it is safe to say that it can induce timing retard as we see on the graph. If you look at the dyno results at Vishnu, it show equal torque and hp (230 and 230). At ATP, torque is strong at nearly 250lb-ft but hp takes a hit it in the midrange and doesn't fully recover. I'm surprised no one commented on that. But then again, most of those who can comment on this subject have been banned :(

Nebo-- Being a moderator means that you have to be a little more unbaised with your commentary. Sorry but that's just the impression I'm getting.

---

Shiv, stop logging in via your friends accounts. I am generating quite the list of banned ip addresses and soon, there will be quite the list of banned user accounts.

[nebolic]

If the addition of the BOV increases boost level to a level higher than it was when tuning at Vishnu, then it is safe to say that it can induce timing retard as we see on the graph. If you look at the dyno results at Vishnu, it show equal torque and hp (230 and 230). At ATP, torque is strong at nearly 250lb-ft but hp takes a hit it in the midrange and doesn't fully recover. I'm surprised no one commented on that. But then again, most of those who can comment on this subject have been banned :(

Nebo-- Being a moderator means that you have to be a little more unbaised with your commentary. Sorry but that's just the impression I'm getting.

I was being unbiased, I was merely asking a question as I do not know the answer for why Xchoirboy's Dyno numbers are reading the same at ATP and Shiv's Dyno. And someone pointed out that it could be the aftermarket BOV, whether it was tuned with that on when Shiv was tuning his car or whether it was off. The other thing is that the map in Xchoirboy's Evo is a standard Map from Shiv's database and not custom tuned. Therefore I'm merely asking questions in regards to "would the aftermarket BOV make such a difference"? As most people have installed an aftermarket BOV therefore its probable question that many will ask and also will this "timing being pulled" be affected with others? I apologize if I sounded bias but I was just asking a question to hopefully getting some answer too because I too have an aftermarket BOV and if the BOV does affect the Evo the way it is being portrayed, then I will need to reconsider on reverting back to Stock Valve.

CupertinoSteve, what are your thoughts on it? Honestly I was not being sarcastic or stirring up the pot, I was intrigued with the BOV question. Maybe you can shed some light on this.

Nebo
:D

[nebolic]

How do you know its shiv? ASSuming?

re-read the post before mine, its been edited not by me. I don't have the power to do that to figure out who's posting from where etc...

stay tuned for a nice post coming up, I bet some one will appreciate it.

Nebo

[ez76]

Therefore I'm merely asking questions in regards to "would the aftermarket BOV make such a difference"? As most people have installed an aftermarket BOV therefore its probable question that many will ask and also will this "timing being pulled" be affected with others? I apologize if I sounded bias but I was just asking a question to hopefully getting some answer too because I too have an aftermarket BOV and if the BOV does affect the Evo the way it is being portrayed, then I will need to reconsider on reverting back to Stock Valve.

Unfortunately I do think a BOV can make a (negative) difference if it is in fact holding significantly more boost and the timing/fuel curve was not done with that amount of boost in mind.

Here is my thinking.

The mass air flow sensor is a nonlinear device, meaning that for an incremental increase in airflow, you are not always going to see a proportionally linear increase in the sensor reading. To account for this, the ECU has correction factors that translate MAF readings into a load measurement that is linear within a given range of airflow. At airflow (boost) levels significantly higher than stock, the correction factors become less accurate, and the indicated load is a less reliable measurement.

So how do tuners deal with this? When you're tuning a car at higher than stock boost, you figure out a best estimate of the maximum (indicated) load that can possibly be generated, figure out the optimal timing and fuel, add in a healthy safety margin, and then either tune for the rest of the load range (time consuming), or more practically, interpolate appropriate fuel and timing for lesser loads, keeping things appropriately rich until load is in the more easily mapped stock load range.

So a BOV holding more peak boost is going to throw a wrench in this, if the car was highly optimized at a certain boost level and not tuned for seeing that extra boost.

I am not an expert, though, and I think the most important thing here would be to take your car to Vishnu and let them run it through to see if indeed you are indeed making more boost than you were before and if your tune needs to be changed. As Steve pointed out, the torque takes a hit in the midrange that could very well mean the above is happening.

[EvoVIII]

well, first of all, it is kinda weird to me that xchoirboy make a very high HP on his stock evo like 10-15whp higher then ours, my car only make 220whp with the xede :( and he make around 220 without the xede, so maybe that tank of gas is very great? or maybe u put some octone booster on it? I really don't know or maybe on that day the weather is very cold that it make greater HP, who knows

[warpspeed]

When it comes to BOV, as far as I know it does very little in hp gain. We all know that the stock plastic BOV is notorious for leaks. By putting a better than stock BOV(GFB) it holds the boost better. Some people may think that by putting a better holding BOV that they will get more hp, but if you think about it, if your car had a little leak in the beginning and then putting better BOV, they think that they are getting more hp but actually the car is putting out the hp that it should have in the beginning by holding the boost better. If you don't agree....well....me and Pete from Works came up with the same conclusion.

[009]

Again the "JAN" has spoken... :o

[ez76]

I don't think the issue is so much about the BOV giving an HP gain (or loss) so much as the BOV potentially interfering with the tuning of the car.

A stock Evo has a boost cut to prevent overboost, so it does not need to have higher boost levels well-mapped.

Once boost levels are increased and especially after boost cut is removed (i.e. with a reflash), any change in the boost profile which results in increased boost in an "untuned" part of the fuel/timing tables (higher loads) could have a detrimental effect. Not necessarily because of knocking (though it's a possibility), but because the car might be operating in the "oh shit" part of the
maps:

If I were a tuner and I wanted to build a safety margin into my reflashes, I'd dump more fuel and keep timing really conservative above the highest load point I had tuned for. You'd feel this as a drop in acceleration at WOT under some conditions. Another way it might manifest itself would be if 80% throttle (i.e. slightly off-peak boost) felt faster than WOT.

However, if the Evo's MAF is losing resolution at higher than stock boost levels, and the car is highly tuned, then it could indeed be knocking because the reflash is only adding enough fuel for that tuned boost level.

Good luck, and you should get in touch with Vishnu! :D


if your car had a little leak in the beginning and then putting better BOV, they think that they are getting more hp but actually the car is putting out the hp that it should have in the beginning by holding the boost better

This is true if the car was tuned for that higher boost level, but if it was never making that boost before, it's all a matter of how that "best guess"/"oh shit" area is tuned.

[xchoirboy]

With all this :brawl: My whole point in this was I thought the ATP dyno numbers would be higher. I'm very happy with my numbers just seeing the differences was the whole point for me. If by adding a GFB I screwed up my tuning then so be it.

whatever......

[vtluu]

whatever......
That's the most sensible thing anyone has said in this thread. :lol:

[BluEvo]

:crazyeyes: ppl lets just get past the hype and move on. :peace:

[evo_dadi]

lol its kool leroy you should have seen me after my 2 dynoruns that day.like what terrence was telling me i wasnt smiling at the monitor while they were running my car on the dyno ;)

[lambtron]

Why do my posts keep on getting deleted?

[EvolvedDSM]

Why do my posts keep on getting deleted?

Your posts weren't the only ones taken out. Someone was doing there job to keep this thread on course. Unfortunately, it has just gone OT once again.

[GReddy_917]

This is true if the car was tuned for that higher boost level, but if it was never making that boost before, it's all a matter of how that "best guess"/"oh shit" area is tuned.

Wel then....perhaps somone should ask Shiv if a bone-stock car with a BOV requires a CUSTOM tuned Xflash....

If it DOES...then that tells you something about the "margin of safety" on his baseline Xflashes and even how well his "best guess/oh shit" area tuning is.

[ez76]

This is true if the car was tuned for that higher boost level, but if it was never making that boost before, it's all a matter of how that "best guess"/"oh shit" area is tuned.

Wel then....perhaps somone should ask Shiv if a bone-stock car with a BOV requires a CUSTOM tuned Xflash....

That is a reasonable question.


If it DOES...then that tells you something about the "margin of safety" on his baseline Xflashes and even how well his "best guess/oh shit" area tuning is.

In some sense I guess, although keep in mind what I said was my opinion and Shiv is the one accountable for Xflash tuning, not me. That was my impression of how the high boost tuning works and it might be different.

Personally I think it tells you how optimized a reflash is. Because of the limitations of our stock MAF, I look at the proposition of a great reflash as a deal between customer and tuner: "you make sure you don't add add a funky intake or run more boost than you did when you got tuned (weather changes notwithstanding), and your car will be optimized for your level of mods."

I appreciate a tune that only leaves as much performance on the table as is necessary to account for things outside my control (e.g. a bad tank of gas). A lot of reflashes leave your car performing better than it did but can't really be called optimized in the same sense; agree that they might do a better job at protecting you from yourself though.

EDIT: has xchoirboy had Vishnu take a look at his car with the BOV on it yet?

[Option2]

Vishnu does not use a correction factor for their dyno figures. Is there a correction factor applied to the ATP dyno numbers? If so, that's why the ATP numbers are a tad low. I think the print outs that ATP gives out are SAE corrrected.

[GReddy_917]

Vishnu does not use a correction factor for their dyno figures. Is there a correction factor applied to the ATP dyno numbers? If so, that's why the ATP numbers are a tad low. I think the print outs that ATP gives out are SAE corrrected.

The Dynojet has always posted higher numbers than the DD dyno...I dont think ATP has changed their dyno's calculations


http://forums.evolutionm.net/showthread.php?t=81682&highlight=dyno+dynamics

Handy little plug in for excel.

[JanSolo]

Apparently, after talking to George over at the ATP, the Dynojet dyno cannot be altered to change it's readings at all.

[evo_dadi]

...... :D

[EvolvedDSM]

Apparently, after talking to George over at the ATP, the Dynojet dyno cannot be altered to change it's readings at all.

But it does make SAE corrections, right? The Dynojets I've been around have all done this. I haven't seen significant changes, corrected vs. non, but they are present.

[Option2]

Apparently, after talking to George over at the ATP, the Dynojet dyno cannot be altered to change it's readings at all.

But it does make SAE corrections, right? The Dynojets I've been around have all done this. I haven't seen significant changes, corrected vs. non, but they are present.

Yes it does make SAE corrections. It accounts for + - 10 whp.