Hood Vents and Under Hood Temps

[M-Sport fan]

I'm combining them with some low pressure zone funnels on my skid to remove the air from under the car and direct it up through the engine bay and out - hopefully it works well.

I'd like to do something like this as well, since I run the Skid Plate Guy's plate in the summer months for rally worker season.

What I have found out (which I never knew, just took for granted that they were using a carbon/kevlar hood all this time), directly from M-Sport in Cumbria, is that there is NO actual full carbon fiber WRC spec hood, as that is verboten by the FIA, so the actual WRC cars are just running a steel hood, with those vents installed.

 

[jeffreylyon]

I'm really wondering WHY you think rain guards are necessary... I'm going to be ensuring that the electronics on the driver side are as water resistant as I can get it but I'm not concerned really. Then again I live in a dry climate...

Shit, I lightly pressure wash my engine bay... Water follows gravity and with some forethought and dielectric grease I'm sure I can get things sorted.

EDIT - I'm combining them with some low pressure zone funnels on my skid to remove the air from under the car and direct it up through the engine bay and out - hopefully it works well.

'Cuz I'm a'scared. The driver's side looks like it's right where the battery and fuse box are and I don't like the idea of water falling directly on them, even though my FiST is, mostly, a sunny day car.

 

[MRX330]

I did. It's cool (hehe).

Did you just make a joke?

 

[Woods247]

Not sure if it’s been mentioned yet but a couple of my buddies removed the lower cowl and were convinced engine bay temps decreased. I don’t have temp problems with the Mishimoto radiator so I haven’t tried it. It’s pretty easy to do and worth a shot.

 

[MRX330]

Not sure if it’s been mentioned yet but a couple of my buddies removed the lower cowl and were convinced engine bay temps decreased. I don’t have temp problems with the Mishimoto radiator so I haven’t tried it. It’s pretty easy to do and worth a shot.

Well JeffreyLyon said he was venting for less lift and better aero. I thought it was for heat. I got confused with another thread

 

[jeffreylyon]

Well JeffreyLyon said he was venting for less lift and better aero. I thought it was for heat. I got confused with another thread

I'm venting the hood because I deleted the stock air dam. There's enough venting in the cowls that I would think that any under hood pressure could escape, but @Woods247 is right, it's too easy to remove the cowl not to try. @Siestarider - how did you measure differential pressure w/o buying $2000 of instruments?

 

[maestromaestro]

Did you just make a joke?

You really need to get a life, bub. Then again may be this IS your life.

 

[MRX330]

You really need to get a life, bub. Then again may be this IS your life.

Now you just didn’t make a joke.

 

[MRX330]

Man, you really aren’t the sharpest tool in the shed eh?

I’m placing the hood vents where there is a natural low pressure zone which will pull under hood air out. This is documented. It’s not just some slap dash hood vents ‘because race car’.

Go understand the aerodynamics at play with our cars, then come and provide something beneficial to the conversation.

Tri-vent? New TriVent! Now with 33% more holes in your hood!

 

[Siestarider]

I'm venting the hood because I deleted the stock air dam. There's enough venting in the cowls that I would think that any under hood pressure could escape, but @Woods247 is right, it's too easy to remove the cowl not to try. @Siestarider - how did you measure differential pressure w/o buying $2000 of instruments?

I bought a digital manometer, maybe $100, easy to use.

 

[Clint Beastwood]

I bought a digital manometer, maybe $100, easy to use.

Yeah I was thinking something like my homemade carb balancer, just fluid in a tube with a loop lol. Put the tube/loop on a board in the passenger seat and mark how high the fluid pushed with the cowl in place, then drive and mark how high it went without. It won't provide exact measurements, but it will show if things changed. You could repeat the test 3 times each way and average it all out.

Also balancing carbs on a 6 cylinder bike sucks.

 

[Clint Beastwood]

Has anyone ever tried making a hood out of stainless steel mesh? It'd be a pain in the biscuits to form, but boy would it flow.

 

[MRX330]

Has anyone ever tried making a hood out of stainless steel mesh? It'd be a pain in the biscuits to form, but boy would it flow.

Just make sure there’s a fixture for the hood umbrella

 

[Clint Beastwood]

 

[TemecFist]

I have hood vents a Mountune radiator, 70/30 mix, water wetter, IC and my track temps are right around 120ish. 188* under normal driving. I dont KNOW if there was an improvement, but I do know that I can see ALOT of heat escaping thru the hood when I'm sitting still. It sounds like you have air in the cooling system like others have stated.

 

[johnny5]

There is no air in the system.

Cruising temp: 188-192F
Air condition in traffic: 192-194F
Under decel and fuel cut can drop to 182F

There is no air in the system, if there you would not have these temps.

 

[johnny5]

Back out on track with the hood vents, ECT was between 212-220. On the cool down lap with the AC on, temp dropped to 190-194.

 

[shouldbeasy]

So, I've got my hood vents now.

They're not cheap and I'm thinking I may reproduce them for the future (in case I get in an accident etc) and I want to make some molds for carbon fiber reproductions.

Anyone interested in sets? Would remove the need to have them painted (at least I hope I can get the finish to an acceptable level).

 

[shouldbeasy]

Back out on track with the hood vents, ECT was between 212-220. On the cool down lap with the AC on, temp dropped to 190-194.

Which vents did you install?

 

[johnny5]

I didn't go with the "standard" hood vent.