Quote:
the group dyno is the only semi-accurate way to measure deltas between mods. I sure wished more people would do the group dynos.
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If all vq's put out the same power from the factory, this would be true. However, I would argue (based on info from Q45tech that there could be a +- 2 hp variance from each cylinder, which seems perfectly reasonable) that there could be as much as a 24 bhp difference at the crank from engine to engine straight from the factory. Therefore, a coupe could be putting out anywhere from 268 to 292 at the crank in stock form.

 

"One thing that definitely would suggest for this very reason, is that you get an accelerometer."

Great minds think alike! This actually is my next move when I get back from vacation (going to Kalifornia on the Left Coast for a few days, then on to Magnum PI land).

2004 Sedan 5AT STS
Huper Optik Ceramic 50/Underbody Diffusers/Clear Corners/Brake Cover
GroundingGear 7 Wire/Z-Tube/Stillen High Flow Airbox/HKS Sport Exhaust/Technosquare F-Spec ECU

 

Al503,

All I can say is “ah baloney”! Q-45tech says a lot of useful and in depth things, but do you really think that Nissan quality control could produce a 24bhp delta? NO WAY!

At the Central FL Dyno Day we had several 5AT's with only the Z-Tube and JWT P/C. They all were dynoed and showed less than a 1rwhp delta. The exact same results were had with the 6MT's. No one was +6 or -12 rwhp more/less than anyone else. Heck, even the stock G35’s all dynoed about 5rwhp lower across the board than the Z-Tube and JWT P/C guys (just like you might have expected to see). The point is that there were some 6 or 7 dynos of stock cars or intake only modifications and all of the results were EXTREMELY repeatable and the gains shown were reasonable and expected. There were no abnormalities nor was there that “one special run” that had to be adjusted or thrown out.

Don't believe everything you read. Even if someone who is extremely knowledgeable and credible is typing it like Q45tech. (BTW, That goes double for what I type [img]/w3timages/icons/tongue.gif[/img]).

<font color=blue>The above statements are only my take on the issue. If you disagree with anything I typed then you are 100% right!</font color=blue>

 

Damm man... So wait, gurgen if im getting my car dyno'd this week on a dyno jet, i shouldnt use manumatic mode? Will it mess up the numbers or anyone?


Martin
2003.5 BS G35
Nismo Aero/Sport Package
Injen CAI
B+G Springs
ADR M-Classic 19's..

 

Your point is well-taken, neff. However, 2 hp per cylinder seems to be reasonable when the engine is making 280. Also, the 24 hp delta is the most extreme situation where all of the cylinders suck or where the owner had good karma coming around. I'm sure that in most cases, the good and bad even out to where the output will be fairly close to 280.

I don't believe in everything I read, which should be quite evident by my first post in this thread. However, I do place some credibility in Q45tech's position based more or less on again, what I think is reasonable/common sense.

 

No NO Martin

You MUST use the MM mode. What i was talkign about is that out trannies still downshift when in MM mode (at leat the sedans do unless you have the 04.5 sedan) and thus you have to do partial throttle run (about 70% in 3rd gear (MM selected)) to about 3800, and right at that mark, mash the gas pedal and contiue the RUN in WOT. Your dyno will register the FULL THROTTLE hp numbers passed 3800-4000 rpm. So us at people lose the ability to measure the true low end power of our cars (2500-4000rpm)

Gurgen

 

Ohh I see gurgen, thax for the clarification.. We'll see how it goes friday. Martin


Martin
2003.5 BS G35
Nismo Aero/Sport Package
Injen CAI
B+G Springs
ADR M-Classic 19's..

 

gurgenpb ("Team Transport - Hello Kitty!")
07/19/04 05:51 PM

No NO Martin

You MUST use the MM mode. What i was talkign about is that out trannies still downshift when in MM mode (at leat the sedans do unless you have the 04.5 sedan) and thus you have to do partial throttle run (about 70% in 3rd gear (MM selected)) to about 3800, and right at that mark, mash the gas pedal and contiue the RUN in WOT. Your dyno will register the FULL THROTTLE hp numbers passed 3800-4000 rpm. So us at people lose the ability to measure the true low end power of our cars (2500-4000rpm)

Gurgen

Gurgen,

When you said the above are you saying that for the 04.5 5ATs you actually run the whole dyno in 3rd gear...and then at 3800 you go WOT, but still remain in 3rd gear?

When I just did my dyno run, I was in MM 4th the whole time and about 2900 or so I went WOT...course it dropped down to 2nd, then up to 3rd and then 4th which is where my DATA is all taken from...but as you mentioned it's all above 4K which really sucks b/c you miss the whole entire bottom to mid range of your car which is the entire beginning to any race or 1/4 mi run....

Let me know what you thinks and if I ran that dyno correctly ok, thanks.

John
03.5 G35 5AT 14.2 @ 96.4
10 Wire Grnd Kit
K&N CAI w/Injen HS
UR UD CP
NISMO Mid Pipe
Crawford V 5.0
TS
350 Z 170F Thermostat
02 Maxima SE 4AT 14.5 @ 95
87 Mustang GT 13.2 @ 107

 

Nissan points out in the FSM that the maxinum allowable variance between cylinders [in a cranking compression test] is 14 psi -------if standard is 185 psi new: 14/185= 7.5% variation allowed. This translates to BMEP which is torque equivalence thus HP...............20 HP variation.
This does not count the allowable variations in flow of each injector nor the differences in air flow per cylinder [heads, valves, runner, plenum].

Since the dynojets allow the engines to accelerate faster than possible on the street in the gear selected..........the graph/numbers tend to COMPRESS the differences between vehicles/engines/trannies/diffs, driveshafts, tires.

Take 4 G35 which show the same dynojet numbers say within 5 lb/ft and 5 HP, on the highway one will out accelerate the other by what appears to be a significant higher margin than the 0.05 seconds [they should stay within 2- 5 feet of each other in quarter mile] you would expect no differences right.................

Take the same 4 G35 to a PROPERLY setup Mustang Dyno use the same eddy correction factor same tire s same tire inflation............you will see a wider difference than on the Dynojet. Vary the tire pressures by ONLY 3 psi and you will see differences again.

I am sure Nissan Quality Control is better than 20HP [that they specify] maybe 10 HP maybe many within 6 HP.

Variances depend on breakin and mileages.