Dyno - hood cracked open or full open?

rcdice

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Having my car dynoed on Friday just because. What's everyones opinion on the hood position for best results? When I've dynoed before, we had the hood totally open. It never seemed quite right that way because the open hood blocked the direct air coming from the fans in front of the car. Would having it just cracked open be better for air flow? Perhaps fully open between pulls to help the engine cool a bit but down during the actual run.

Thanks for any opinions.
 

STUGOTS

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When they did mine they did it full open.

I have seen pics of it just being cracked at heff's open house so honestly i dont know.
 

Silver Snake

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Why have the hood anything but closed? I don't understand this. Do you drive with your hood open or fully open? I don't.

Mark
 

Neil - UK

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after some research ran my gen1 cracked open, and *** did her GTS the same

190hood.jpg


think you can get more air in that way, but overheating wasnt a problem anyway
 

Randy

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Why have the hood anything but closed? I don't understand this. Do you drive with your hood open or fully open? I don't.
For increased cooling, I beleive. When you are moving, you have more air flow than sitting still on a dyno with a fan or two pointing at the front end, while the power train is running over 100 mph - I've not looked at my speedo while doing a dyno run and don't care to go look it up at the moment, but top end of 4th gear (dyno runs are done in 4th on a Viper, since its a 1:1 transmission ratio) is over 100mph on the rear wheels.
 

Russ M

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Have done it in all 3 configurations, and there is no benefits to either way.

However having the hood cracked open allows for a fan to be blowing into the air inlet, and engine bay.

I suggest you do the following if you want the most acurate info.

1. Make the pull when the car is at a minimum of 180 degrees.
2. Make sure you allow the car to cool down before making another pull 190-200 is good enough.
3. Make sure the opperator starts the sample from the identical RPM's in the same gear(4th).
4. Make sure your rear tires are both at 29psi or higher.

PS. Reset your ECU and drive the car like you stole it before you go to the dyno.
 
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rcdice

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Great info, thanks. Cracked it is. These cars run so hot it just makes me nervous to run them that hard just sitting. Should be "reasonably" cool here on Friday. Mid sixties. Certainly better that last time I dynoed when it was 90 o and so humid you'd break a sweat just thinking about it.
 

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