I'll be dynoing the Z this weekend and was wondering whats the best way to get the highest HP numbers. From what I've read are these true?:

1. Do the runs in 4th gear.
2. Heat the car up? I don't know why this one.
3. Add octane boost??????
4. Make sure there is a fan blowing air in the front.
If there are any that I missed or if any of these aren't correct please let me know.


Thanks

 

1: dyno gear in 1:1 ratio (not sure which one)
2: heat as in not a cold motor. operating temp
3: bs
4: fan is a good idea
5: tire pressure
6: ????

 

5th is the 1:1 ratio.

 

By octane boost, i believe they mean high octance racing fuel, like above 93 octane

 

oh i see, he could be the first to test it out. Dyno first with out o-boost, then add boost, dyno two more times and see if it improved on the 3rd pull. 2nd is always the best (most of the time, hehe)

 

From what I remember:

1.) 5th is preferred since it is 1:1 however it will result in very high dyno speeds. The dyno operator might not let you do this. Also, it will take longer to redline in 5th so there is more danger of overheating if the fan(s) aren't that good. From what I understand, 4th gear is the next best.

2.) You want be at optimal operating temperature, not sure what that is. Make note of the temp for future dynos (including ambient temp, humidity, and barometric pressure from the weather channel).

3.) I've read the octane boost argument before. It's supposed to remove the variability of the fuel. However, on the Z I think SCC dynoed to prove that the Z's ECU detects higher octane and will adjust timing. Therefore your dyno will not represent your normal driving conditions. I might instead recommend that you always use the same brand of gas.

4.) Make sure its a good fan at the shop you go to.

5.) If your air filter is old, replace it. You might want to keep a spare air filter around that you only use for dynos. If you have a CAI, I'm not sure if it's worth cleaning or not. I probably wouldn't bother unless it was obviously very dirty.

6.) There is a knock sensor that is used by the ECU for applying knock retard (KR). Some people suggest "grounding" the knock sensor so that it won't affect the dyno run. I'm not sure how to do this, and I haven't seen a HOWTO posted yet on this website for grounding the knock sensor.

7.) Get the tire pressure perfect and make note of it for future dyno comparisons.

8.) Make sure dyno operator does not use any BS adjustment factors for barometric pressure, ambient temp, humidity. Might want to bring these measurements with you.

9.) Some dynos will give you an electronic file of your dyno. Bring a blank, formatted floppy for them to save you dyno to. Also, get the paper printout.


10.) I'm not sure about cars, but motorcycles are very sensitive to oil levels because the crankshaft slapping in the oil will affect parasitic losses (basically you get more horsepower the less oil there is as long as you don't overheat). I'd check to make sure your Z has the optimal oil level every time you dyno.

11.) There are some smoothing factors for the dyno's output. One setting is considered better than the others. I'm not sure which it is, so someone else will have to answer that. Whatever setting turns out to be the best, be sure to request that.


--
Jeff

 

12.) Oh and turn off traction control/VDC and also turn off all accessories--especially the air conditioner. However, running the heater at full fan speed might help with the engine cooling.

13.) I recall reading that someone did something special with the radiator fans. They either waited until they turned off or they always made sure that they're on. I guess the main thing to do is be consistent.

I think that an ODB-II data logger is often used to monitor coolant temp and radiator fan state.
--
Jeff

 

most important!!!

 

Thanks guys I'll post results

 

Cool, we'll compare numbers.

We have at least 10 cars doing dyno runs as well on Saturday (including 6 procharged 350Z's). I'll post all the numbers.

 

Car should be at normal temp. A good clue is warm it up on dyno until fans come on. Let it idle until the fans turn off. Make your run. Let idle until fans turn off again. Make next run . . .etc

Some times it takes more than 3 pulls. We usually see the best numbers on pulls 3-7.

Good luck.