|
Tech Talk Technical Discussion About The Nissan 240SX and Nissan Z Cars |
|
Thread Tools | Display Modes |
|
02-12-2011, 07:22 PM | #1 |
Zilvia FREAK!
|
Do vented hoods actually work?
Do vented hoods actually bring down temperatures inside the engine bay? I'd like to keep my RB cooler since it is going to be the daily driver now and i'm wondering how effective vented hood actually are. Real data would be appreciated but i guess i will listen to fact-less opinions too...
|
Sponsored Links |
02-12-2011, 07:49 PM | #2 |
Zilvia FREAK!
Join Date: Mar 2010
Location: philly area
Age: 34
Posts: 1,408
Trader Rating: (29)
Feedback Score: 29 reviews
|
Think about it heat rises. Stock hood doesn't let it out vented hood does. I have an rb too and I've always rocked vented hoods. I don't have evidence but there was an issue of super street were they proped the back of the hood up and it was 10% cooler so imagine vents.
|
02-12-2011, 07:54 PM | #3 |
Zilvia FREAK!
Join Date: Nov 2007
Location: South Korea
Age: 39
Posts: 1,320
Trader Rating: (13)
Feedback Score: 13 reviews
|
In theory yes
Do allot of companies just throw a vent on a hood without any R&D on how well it performs............yes
__________________
1 year tour in Korea = no car. FML. |
02-12-2011, 08:42 PM | #4 |
Post Whore!
Join Date: Apr 2004
Location: Houston, TX
Posts: 2,701
Trader Rating: (16)
Feedback Score: 16 reviews
|
Yes. I dropped my coolant temps about 5-10 deg F depending on the day with a vented hood over the stock one on track. Seemed like less drag on long straights too.
__________________
S13 Hatch - Goes around tracks quickly DEFSPORT |
02-12-2011, 11:57 PM | #5 |
Zilvia Member
|
+1, it will do wonders if you do a little bit of homework first.
While you're at it, maybe do some ducting of the air passing into and out of the radiator if possible. Very cool stuff once you get into it. (assuming you like somewhat technical things)
__________________
'95 240 | @SleepySteve72 |
02-13-2011, 11:53 AM | #6 |
Zilvia FREAK!
|
Alright cool, thanks for the info. Interesting what Def said about less drag at high speeds, i would have never thought about that.
Guess its time to buy a vented hood. |
02-13-2011, 12:27 PM | #7 |
Zilvia Junkie
Join Date: Oct 2009
Location: In the garage
Posts: 430
Trader Rating: (12)
Feedback Score: 12 reviews
|
correct me if im wrong but proping your stock hood up in the back can also help cool everything down. hence why lots of drift cars have them propped up in the back. it acts like a cowl hood. and it looks cool....or like youve gotten into an accident lol kinda like hat slideslidegnarslide said. its deffinitly more efficient with a vented hood depending on your budget of things
|
02-13-2011, 12:31 PM | #8 |
Post Whore!
Join Date: Apr 2004
Location: Houston, TX
Posts: 2,701
Trader Rating: (16)
Feedback Score: 16 reviews
|
You're wrong. The base of the windshield is a high pressure area at speed. It will force MORE air into the high pressure underhood area.
__________________
S13 Hatch - Goes around tracks quickly DEFSPORT |
02-13-2011, 02:37 PM | #9 |
Nissanaholic!
Join Date: Sep 2006
Location: Bremerton, WA
Age: 39
Posts: 2,037
Trader Rating: (23)
Feedback Score: 23 reviews
|
this is what ive heard from a lot of ppl that track their cars. however ive also heard (& speak from experience) that @ a stop, ie traffic light & 'pit stop areas'.... vented/raised hoods do help to allow hot air to escape from under the hood.
|
02-13-2011, 04:18 PM | #10 |
Bandwagon.
|
its like saying its hot in your car, you have no windows, theres a sunroof, if you open it, does it vent out the heat? lol
|
02-13-2011, 04:54 PM | #11 |
Zilvia FREAK!
|
|
02-13-2011, 05:13 PM | #12 |
Bandwagon.
|
que?
vents should work, but DB explain it even more, but basically what im saying is you crack your sunroof cause its hot, thus letting the hot air vent out. technically same as a vent on a hood. |
02-13-2011, 07:35 PM | #14 |
Zilvia FREAK!
Join Date: Mar 2010
Location: philly area
Age: 34
Posts: 1,408
Trader Rating: (29)
Feedback Score: 29 reviews
|
With vented hood that high Preasure area wouldnt matter cause yOu have vents so propin may not work but this thread is about vented hoods and they clearly work
|
02-13-2011, 07:50 PM | #15 |
Zilvia Member
Join Date: Jan 2007
Location: Los Angeles, CA
Age: 43
Posts: 269
Trader Rating: (7)
Feedback Score: 7 reviews
|
Just make sure the vents aren't over any critical components, like the MAF or spark plugs. The vented hood I have, Seibon DV, has a vent directly over the MAF. During the rain, the MAF shorted out from all of the water that came into contact with it. However, I placed a make-shift cover underneath the hood that now protects the MAF.
__________________
(888) 611-1776 |
01-28-2021, 05:54 AM | #17 |
I’ve been looking for a CF single vented hood for a while now and all I can find is the multi vent. I had one on my old s-3 back in the day. It was a D1 style with just one vent. I guess I could go with the multi vent to help my RB but I’m just not a fan of the others. Any ideas guys?
|
|
01-29-2021, 11:34 AM | #18 | |
Premium Member
Join Date: Jun 2003
Location: torrance, ca
Age: 42
Posts: 12,685
Trader Rating: (130)
Feedback Score: 130 reviews
|
Quote:
VIS make 2 styles |
|
01-28-2021, 12:58 PM | #19 |
Nissanaholic!
Join Date: Nov 2003
Location: "St. Chuck", MO
Age: 38
Posts: 2,094
Trader Rating: (15)
Feedback Score: 15 reviews
|
Hood vents work, but you have to make them work correctly, and direct airflow through them. Sealing off the underside, and providing correct ducting for airflow through the FMIC, Radiator, Oil cooler, etc...
__________________
-Kyle |
01-30-2021, 10:02 AM | #20 |
Post Whore!
|
As mentioned above, in order for them to function correctly, the components being vented must be sealed underneath and directed out said vent. I plan on cutting and 03’ cobra style vent into my hood behind the radiator and ducting that up and out.
__________________
*My SR20VET* Does your VTC gear rattle in your S14/15 SR? PM me. |
01-30-2021, 01:14 PM | #21 |
Post Whore!
Join Date: Jul 2005
Location: South Florida
Age: 41
Posts: 4,829
Trader Rating: (17)
Feedback Score: 17 reviews
|
The second most mis-understood aspect of combustion engines besides PCV is heat flow.
The engine itself needs to be insulated. It should have thick, cast manifold, plastic intake insulation, blankets, exhaust wrap, coatings, shields, covers. The OEM does more and more of this as the years go on. The temp rise created by burning fuel is your $$$ from that fuel so to conserve the heat and insulate the engine/exhaust is to save money on fuel and get the most from the fuel in terms of shaft power. Power plant engineering fundamentals always revolve around conserving heat, insulating the power plant, getting the most from the fuel. If you start ripping that heat away by removing the exhaust wrap and removing the hood (extreme example) you are ruining the engine efficiency, lowering fuel economy and increasing the amount of fuel that needs to be sprayed by injectors to maintain the same temperature steady state. Its like opening the cover on a propane grill, now you need to turn up the propane gas (fuel) to compensate. Vented hoods can be used effectively in performance applications, but they should NEVER be used to directly cool an engine, or exhaust system. Those parts need insulation and to be wrapped up tight to conserve energy. Exhaust gas velocity increases as it warms up, it expands and takes up more space (it can move a turbine better at higher velocity, or move to the exit quicker) the hotter it gets. If you need more info ask questions I dont wana make this into a huge long post basically the engine bay should be kept cool by insulation, not a vent. Its okay to vent whatever is left but the vent should not be a first line defense. The radiator needs to deal with the waste heat, and insulation makes sure that all the waste heat makes it to the radiator, and if the rad has trouble THEN you upgrade the radiator, fans, make sure the panels are intact and functional, and finally add a vent to help the radiator as needed. |
01-31-2021, 07:12 PM | #22 | |
Nissanaholic!
Join Date: Nov 2003
Location: "St. Chuck", MO
Age: 38
Posts: 2,094
Trader Rating: (15)
Feedback Score: 15 reviews
|
Quote:
__________________
-Kyle |
|
08-10-2023, 07:32 AM | #23 |
Zilvia Junkie
Join Date: Apr 2019
Location: Clearwater, FL
Age: 34
Posts: 342
Trader Rating: (0)
Feedback Score: 0 reviews
|
Love all this tech talk. Leaning heavy toward a TA style hood for kouki S14 front on my S13 vert.
I confess the reason was to lower the engine bay temps a bit. I do have my downpipe wrapped with DEI mummy material and a turbo blanket. The 1JZ is so long and my bay small that the dual electric fans fit one centimeter from the serpentine belt and I can't run a radiator shroud nor properly duct the waste post-radiator air up and out. My thought was that the low pressure area behind the rad would draw some warm air out. I do also like the look.
__________________
'93 RHD S13.4 1JZ | '22 Suzuki DR-Z400S | '18 Suzuki GSX-S750 | '07 Harley |
08-16-2023, 09:02 AM | #24 |
Post Whore!
Join Date: Feb 2006
Location: Hightened State of Emergency
Posts: 6,053
Trader Rating: (9)
Feedback Score: 9 reviews
|
Yes. I also noticed adding back undertrays and fender liners helped too. Basically keeping the factory ducting plus a hood vent = better cooling.
Folks often make the mistake of putting the vent too far back though. As close to the rad as possible is ideal. Source: Neil DeGrasse Tyson |
08-17-2023, 04:35 AM | #25 |
Leaky Injector
Join Date: Jun 2020
Location: United Kingdom
Posts: 116
Trader Rating: (1)
Feedback Score: 1 reviews
|
Yes they work.
They work even better if you can direct the air to them and are best served on ambient engine bay and cooling packs. The area over the hood when you're moving is for all intents and purposes negative, so air is sucked out the hood. But as has been said, ambient engine bay temps that are low are good, but engine components should be nice and hot. |
08-24-2023, 01:19 AM | #26 |
Post Whore!
Join Date: Jul 2005
Location: South Florida
Age: 41
Posts: 4,829
Trader Rating: (17)
Feedback Score: 17 reviews
|
Hey I remember this thread
Heres my engine bay currently Plastic intake is an insulator, it runs 135*F Exhaust Downpipe is wrapped and double shielded Radiator ducted with shields and flow separated from intake plumbing Stock hood closes tightly with OEM rubber seal at the back Heat shield separates exhaust crossover and downpipe from exhaust manifolds I have a couple shields that aren't shown in the pictures because I'm just being lazy. But the idea is basically reflect as much of the radiant heat back into the exhaust while insulating as much heat as possible into the engine while keeping the components such as coil packs, injectors, electrical stuff cool. You measure their temps with the infrared temp gun, the coils should not really exceed the temperature of the valve covers and the valve covers should not exceed the temperature of the oil and if you have done your job correctly the oil should not exceed the temperature of roughly boiling water at atmospheric pressure- near 210 to 220*F max temp oil is ideal for daily drivers. The coolant needs to stay near the temp of the oil as well, I run 195 to 205*F coolant and 200 to 215*F oil temps almost all day everywhere no matter what the situation is. This car sits in daily driver traffic bumper to bumper high noon, it sits in drive through, it cruises highway for 200 miles, it does stoplight stuff, the fans kick on and off sitting in traffic. Have some video fun Tire chirps video https://www.youtube.com/watch?v=RswyLY1kqac Un-cut un-edited drive https://www.youtube.com/watch?v=1y09lYL4Now 0:05 get on highway cruise note 16's 3:38 note 15.8 to 16.0:1 still cleaning plugs @ 65mph in traffic 5:18 kick out of lockup and small boost in 4th to move up in traffic 6:29 step down lightly into lockup for some boost in 4th 7:18 get off highway 8:23 downshift rip the tires loose at 50mph 9:12 slowing down for stoplight 9:20 Showing A/F Stopped at stoplight note 14.7 to 15.0 open loop steady 10:51 leave light, turbine whistle 11:30 cruising 15.6 to 16.0 housekeeping plugs 12:18 rip tires loose at 50mph 'spool character' 13:05 stopping for traffic light 13:10 show a/f for traffic light stop 15.5 walking into 14.7 to 15.0 open loop 13:52 2nd gear chirp coming leave light |
Bookmarks |
|
|