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Discussion Starter #1 (Edited)

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WOW :eek What is up with that? I have heard that the dyno will record a lower number on the first run due to the computer learning the WOT if you drive it easy all the time. This is a huge difference.

The air fuel ratio looks real good on the second and third sheets. With your tune you want to shoot for a 12 to 1 AFR.
 

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What kind of dyno Matt? Where did you have it done?
 

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Discussion Starter #4

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Dyno

With a dyno there are a lot variables to take into account.
Weather, barometer, air intake, correction factor, base pull, fuel rate, air to fuel ratio, and so on just to start with the weather.
Now lets get with the engine water temp, oil temp, rpm range per second climb rate. and so on.
Plus the trans, clutch or the converter slipage %. Temps, lag in shift delay per sec. and so on.

A base line must be set first. Zero must be Zero to get a number to build on accurately.

Most Dyno's don't tell the truth. Because on variables and no accurate base line.

Jacking a dyno up or down is so simple it's scary. By accident or on purpose.

Save you time and money.

Never seen a dyno win a race.
 

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Dynojet seems to give the most compareable #'s. If I dyno in FL I can likely compare my numbers to someone in California on another Dynojet.

Inertia/ acceleration of mass is a simple solution (what Dynojet uses) ,but does not have as many bells and whistles or tuning capabilities (limited load holding).
 

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Discussion Starter #7
Jim G - Where are you?

I'm looking forward to Jim G's info on this. He's the best source for this kind of stuff.

With a K & N Air Charger; Magnason Supercharger; Dynatech Long Tube Headers; Dynatech Hi-Flow Cats; Corsa Sport Exhaust; and a Custom HP Tuners VCM Suite 2.1.2 Tune - I was actually very disappointed with only about 400 HP at the rear wheels. I was hoping for more like 500+ HP.

All that time, work and money - and I only gained about 100 HP over a rock stock engine.

By my calculations, a stock SSR has 390 HP at the crank and about 312 HP at the rear wheels. My SSR now has about 400 HP at the rear wheels and about 500 HP at the crank.

:banghead
 

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Matjow: I am certain that your dyno operator screwed up. No way the variances should be that large.

I tried examing your charts, but could notread them legibly as loaded here. Please send me via email to:

[email protected]

all 3 charts in the original uncompressed size, and I will examine them and see what's going on.

The mods you made are all good except that exhaust system. You need MUCH less restrictive exhaust than that to realize the benefits of the supercharger (but I think I mentioned that to you already before!)

On a PROPERLY calibrated and PROPERLY run dyno, your SSR should have delivered at least 460 rwhp, but probably more. I would have expected at LEAST 130 rwhp more than stock, because of the supercharger and headers combined effects, unless that Corsa exhaust is actually more restrictive than even the stock exhaust.

Send me those charts in a clean electronic file, that shops all the text data too (ambient conditions, SAE factor used, etc).

Jim G
 

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Almost forgot: While dyno runs do vary from run to run as the engine heats up, etc, and because each dyno is calibrated and mathemtically formulaed differently (yes, despite what some dyno manufacturers want you to think), and sometimes because the engine is retuned in between runs, the variance in your results is ridiculous and is obvious evidence of botched runs.

NO way that the engine picked up 150 hp between runs, even if tuned aggressively!:)

Jim G
 

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Matjow: I analyzed the charts you sent me. They are garbage.

They fail the most basic of integrity tests. Some examples:

- The ambient air pressure is stated to be 32.90 in-Hg. This is UNBELIEVABLY high. Normal readings are 30.xx. I checked the weather records for the dyno shop's zip code for that date and time, and the weather service says the actual air pressure at the time of the dyno run that day was less than 30.10.

- The correction factor shown as calculated (or entered manually - it's possible to do) for run 1 was 0.93. But that is inconsistent with the data shown:
air pressure = 32.90
Temp = 75.1 (much lower than ambient, presumably because of air conditioninig)
Humidity = 33% (MUCH lower than ambient, presumably because of air conditioning)
The combination of these 3 ambient conditions, if they were real (which they were not since air pressure has already been proven to be much lower than 32.90), would generate correction factors as follows:
Under SAE J1349 (the newer more conservative standard): 0.87
Under SAE J607 (the older standard used by most dyno shops): 0.913
However, this shop shows the calculated correction factor as 0.93! That is just plain WRONG, and means that their software got screwed up somehow, or they are manually entering incorrect values.

Also, the SAE standards, and the dyno manufacturers, will tell you that any data generated when the factor is more than 7% from 1.00 (i.e. less than 0.93 or more than 1.07) is not to be used, as this indicates that the ambient conditions are too skewed to give reliable results.

- The big numbers you quoted were from the artificial imaginative "loops" created somehow by the software on some of the printouts. The software blindly reads the peak values, even when those peak values are obviously fictitious when viewed by human eyes.

Without belaboring this sad collection of useless charts and fictitious data, I'm going to advise you to go to a dyno shop that understands how dyno testing is really supposed to be done, and that does its own sanity checks on its output before the client's friends point out the wild inconsistencies. If this shop has any integrity, they would refund your money and the dyno operator would hang his head in shame.

By the way, I WOULD have comented that for a supercharged engine, your air fuel ratio is too lean (too numerically high), but since this shop has demonstrated poor credibility, I think I'll delay making any conclusions on the A/F ratio until you get a REAL dyno chart.

Jim G
 

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Discussion Starter #13
Thanks, Jim!

Thanks for the advise Jim. I really appreciate it.

Matt
 

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Matjow: Don't sweat this. Once you get your ride into a proper dyno facility, you will likley find much better results than you are probably thinking.

Jim G
 
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