Trackspec Hood Vent Aero Test (Video)

[eacmen]

I taped some yarn to the trackspec hood vents just to see how it was doing. I have been having temp issues on track and decided to do some experiments. What I found is that it seems that the front 2/3 of the center vent is actually sucking air into the engine bay versus venting out. Curious if anyone has ideas on how to block the vent to prevent this, foil tape?

I have pusher fan retained for A/C but the factory puller fan and associated ducting have been removed.

https://www.youtube.com/watch?v=VdXdWfu46Jk

[Fresh1179]

I actually met a guy who worked for Mazda racing for decades in the aero department. He didn't speak much English, but he said to put a small vertical deflector about 3/4' high on the front edge my of my side Trackspec vents. I have no idea if this would fix your issue, but he had enough credentials that I made sure to listen.


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[eacmen]

I actually met a guy who worked for Mazda racing for decades in the aero department. He didn't speak much English, but he said to put a small vertical deflector about 3/4' high on the front edge my side Trackspec vents. I have no idea if this would fix your issue, but he had enough credentials where I made sure to listen.


Sent from my iPhone using Tapatalk

I am hearing this from multiple sources so seems legit! I'll try it out!

[eacmen]

So looking at it with fresh eyes it seems the parts of the front vent that are getting sucked down coincide with where the front intake duct is. I suspect this isn't having as of an much effect on cooling performance as I originally suspected.

[enjoy_m3]

I actually met a guy who worked for Mazda racing for decades in the aero department. He didn't speak much English, but he said to put a small vertical deflector about 3/4' high on the front edge my side Trackspec vents. I have no idea if this would fix your issue, but he had enough credentials where I made sure to listen.


Sent from my iPhone using Tapatalk

I second this, I think it's the same as putting a gurney flap in front of the vent to direct the air in front of the hood over the extracted vented air from the engine. I think some vents already has this. Def worth a try and let us know results! Good luck!

[elbert]

So looking at it with fresh eyes it seems the parts of the front vent that are getting sucked down coincide with where the front intake duct is. I suspect this isn't having as of an much effect on cooling performance as I originally suspected.

What intake do you have?

[eacmen]

What intake do you have?

Stock intake

[elbert]

In that case, I would try the gurney flap as others suggested. It will create a low pressure zone right behind it, which should help extract some air.

I think the primary issue is the hood bulge is forcing the vent to be placed too far forward. Maybe some high pressure is spilling over from the front of the car, or maybe that part of the vent is sitting over the radiator (instead of behind it). I think the flap will overcome this.

[eacmen]

In that case, I would try the gurney flap as others suggested. It will create a low pressure zone right behind it, which should help extract some air.

I think the primary issue is the hood bulge is forcing the vent to be placed too far forward. Maybe some high pressure is spilling over from the front of the car, or maybe that part of the vent is sitting over the radiator (instead of behind it). I think the flap will overcome this.

Agreed. The front 2/3 of the vent is in front of the radiator. My intuition is that the high pressure air going over the hood is actually getting sucked through the vent and into the intake. Without a smoke and wind tunnel not sure how to prove that though.

At least all the tufts aren't getting sucked in 😂

[heinzboehmer]

If part of the vent is in front of the radiator and you add the flap to get air to flow out of the vent, won't you be depriving the radiator of some airflow?

Following question is probably much harder to answer, but if the gurney flap reduces the amount of heat transfer at the radiator, then I wonder if that reduction is enough to negate the cooling benefits brought on by the hood vents in the first place.

[elbert]

I don't know if that air entering the center vent is actually getting to the radiator. Since he has the stock intake, there's the plastic front air intake and duct (that go from the grill to the filter airbox), which would block airflow in that direction.

My guess (and I emphasize guess) is the gurney won't reduce the amount of air being fed to the radiator, as there will still be a much higher pressure area in the front of the car, which would feed to the radiator.

But there is only one way to find out...

[bigjae46]

Cool video!

The gurney flap creates a low pressure zone right behind it which results in more airflow up and through the vent. A radiator's cooling performance is greatly affected by the air flow through the vent. Flow is generated by a pressure differential between the front and back of the radiator. You want high pressure in front and low pressure behind the radiator.

It's a guess here...but without ducting behind the radiator, you likely have reduced flow through the radiator. You're not creating a high enough pressure zone behind the radiator to create enough of a pressure differential vs the flow over the hood. I'd bet that if you closed off the side vents you'd get a lot better flow through the vent.

I'm trying to figure out how to best duct the OEM radiator through the hood. Its proving to be challenge. I want to surface mount a single large oil cooler on the back of the radiator so I can eliminate the oil thermostat and 10' of braided hose. I should have a lot more water and oil cooling with less radiator surface.

[eacmen]

Cool video!

The gurney flap creates a low pressure zone right behind it which results in more airflow up and through the vent. A radiator's cooling performance is greatly affected by the air flow through the vent. Flow is generated by a pressure differential between the front and back of the radiator. You want high pressure in front and low pressure behind the radiator.

It's a guess here...but without ducting behind the radiator, you likely have reduced flow through the radiator. You're not creating a high enough pressure zone behind the radiator to create enough of a pressure differential vs the flow over the hood. I'd bet that if you closed off the side vents you'd get a lot better flow through the vent.

I'm trying to figure out how to best duct the OEM radiator through the hood. Its proving to be challenge. I want to surface mount a single large oil cooler on the back of the radiator so I can eliminate the oil thermostat and 10' of braided hose. I should have a lot more water and oil cooling with less radiator surface.

Agree that ducting the rad would be ideal!

I've A/B tested the factory fan ducts and no ducts. And without the puller fan in place the factory ducts don't seem to make any discernible difference. Would be an interesting to do the yarn test with and without the factory ducts. That might be my next experiment.

I just replaced the CSF with the OEM rad. Hoping that solves my cooling issues.