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Windtunnel Testing the Datsun S-30 Z


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I added a dead on rear view I found this morning.

 

Yea, I live on top of a hill in the escalante valley which is the esophegous for the tri state area, this valley runs 300+ miles north to south and balences the northwest and southwest jet stream weather fronts. We get hilatious winds anytime there is a High/Low pressure differential from one end of these states to another. See http://www.milfordwind.com/milford/

 

These pics were taken about 2 winters ago, wind out of the north head on to the front of my Z at the top of the hill, with fine fluffy snow that filled in all the eddys. I quickly got my camera out after discovering this in the morning out on my puppy walk :mrgreen:.

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  • 3 months later...
I just thought I would share my 1976 280z 2+2 Wind Tunnel Testing I completed recently, I figured it would be great food for thought for our resident aerodynamics specialist to comment on, as well as everyone to benefit from.

 

Best of all this testing was done for free overnight while I slept and yielded the optimum aerodynamic profile for a S30.

 

I find the affect of the drip rails the most interesting.

 

Cameron

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I just thought I would share my 1976 280z 2+2 Wind Tunnel Testing I completed recently, I figured it would be great food for thought for our resident aerodynamics specialist to comment on, as well as everyone to benefit from.

 

Best of all this testing was done for free overnight while I slept and yielded the optimum aerodynamic profile for a S30.

 

Here you go:

 

i wonder if stretching the windshield out about 6-9 inches on the bottom will cure the air building up on the bottom of the windshield problem.

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i wonder if stretching the windshield out about 6-9 inches on the bottom will cure the air building up on the bottom of the windshield problem.

I think it would lower drag. I also think that if lowering drag is your main goal, you should start with a different car. We know the base of the windshield is a high pressure area. How much would downforce be affected by lessening the angle of the windshield is probably similar to asking how much downforce would be affected by lessening the angle of attack of a spoiler.

 

The Primadonna Z's have the center of the base of the windshield moved out quite a ways, so it wouldn't be the first time it was done though...

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I think it would lower drag. I also think that if lowering drag is your main goal, you should start with a different car. We know the base of the windshield is a high pressure area. How much would downforce be affected by lessening the angle of the windshield is probably similar to asking how much downforce would be affected by lessening the angle of attack of a spoiler.

 

The Primadonna Z's have the center of the base of the windshield moved out quite a ways, so it wouldn't be the first time it was done though...

 

I was thinking along the principle's of splitting the air along the sides as much as possible and using downforce creating devices to make a majority of the downforce.

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  • 3 months later...

This thread deserves some more love after being asleep for a few months.

 

I saw some mention of this but never any insight. Test 4 to 5, popping the hood dropped the front lift 100 pounds? Anyone have any insight as to why this is? I know the general idea agreed on is that the windshield is a high pressure area, and popping the hood vents some of that pressure into the engine bay (bad). But is it possible the sides of the hood are releasing enough air pressure to counter-act this and reduce the over all force under the hood of the car?

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This thread deserves some more love after being asleep for a few months.

 

I saw some mention of this but never any insight. Test 4 to 5, popping the hood dropped the front lift 100 pounds? Anyone have any insight as to why this is? I know the general idea agreed on is that the windshield is a high pressure area, and popping the hood vents some of that pressure into the engine bay (bad). But is it possible the sides of the hood are releasing enough air pressure to counter-act this and reduce the over all force under the hood of the car?

Seems that there is less positive pressure at the base of the windshield than what can be vented along the sides and possibly the back of the hood. If the lift is reduced, the underhood pressure is going somewhere. I think you'd have to do some yarn tests to figure out where air goes in or out. I know we've talked about one guy who did such a test with a cowl induction hood and he found that the yarn went alternately in AND out of the cowl. Even if it is venting out the back of the hood part of the time, it certainly doesn't seem like the best place to do it.

 

I'm convinced that the better way to deal with air under the hood is to prevent it from getting there in the first place. I'd like to see a yarn test on a popped hood or a cowl induction hood from someone with a radiator duct and the rest of the grill blocked off. I would put money down that the air goes solidly into the cowl under those conditions. I'd up the money on such a bet if there were hood vents installed. A good hood vent would allow the high pressure under the hood an escape and would actually help to suck it out with low pressure on top, making the pressure differential at the cowl greater still.

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Have to concur with you entirely on that notion. If no one does this within a month or two, im going to do it myself and post some videos.

 

Anyone know for sure if the fenderwells are low pressure areas or not? OR have a pracitcal way to allow them to be? Ive seen mention of it and keep playing with the idea of opening the engine bay to the fenderwells via vents. I really need to get myself one of those gauges that let you measure air pressure haha.

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  • 1 year later...

After reading all of this data and other test results, this is what I get: Install headlight covers (tested), block off a majority of the MSA air dam opening (tested), ensure air is shaped through the radiator (tested), hood vents need to be closer to the back side of the radiator and possibly directed up from underneath (tested). A closed cowl hood, higher center bulge, may help reduce some of the high pressure at the base of the windshield (untested). Fender vents may also help pull air out from the engine bay/firewall zone (tested already?). Whale tail or SDI spoiler will add rear downforce (tested).

 

How much would running a ZX with the fan on high and rear 1/4 windows open help (relatively)?

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  • 8 months later...

After trying to read through all these old post I wonder if anyone has looked into V-mounted radiators and Inter-cooler (IC)?

 

 

I am considering this configuration.

Most of the air going into the front of the car, either above or below the bumper would flow up through the IC and the radiator would take its air and blow it down to the ground?

 

Would this airflow configuration reduce the high pressure created in the engine conpartment?

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After trying to read through all these old post I wonder if anyone has looked into V-mounted radiators and Inter-cooler (IC)?

 

 

I am considering this configuration.

Most of the air going into the front of the car, either above or below the bumper would flow up through the IC and the radiator would take its air and blow it down to the ground?

 

Would this airflow configuration reduce the high pressure created in the engine conpartment?

 

You do not want to direct air underneath the car, but rather the opposite. The radiator should vent to the hood. Simply put, you want air pressure to be higher above the car and lower below the car (aka: downforce).

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  • 4 years later...

Well for now Im not putting in the turbo engine, instead Im installing a 5.3LS into it. Im still considering closing off the upper grille (above bumper) and opening up bellow the bumper. The air that goes through the radiator I will vent out the top of the hood. Like this Vette and this GT.

 

2006 Chevrolet Corvette C6 R Hood Scoop

Ford GT hood

 

what are your thoughts?

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