RB's With Vented Hoods

[180boy]

Anybody put a vented hood on their car? If so , what kind ?, post some pictures please.Trying to find one that will clear ,most are made for 4cyl,I'm afraid the timing belt cover on the Rb will be a problem in clearance ,most hoods I found sloope down in this area,n't.I contacted one company but could come up with dimensions, high dollar hoods and shipping ,end result not fitting is bad. Any help appreciated.180boy

[Shocker]

stock hoods look the best.... but if you are going aftermarket with a scoop/vent your most likely going to have to loose the over head plenum.. its what has clearance problems not the timing cover hell thats almost as low was the top of the rad support... so looks like an inline plenum such as the greddy is the way to good for any vented hood

[driftjunke]

We did a RB20 swap with a vented hood, its an Erebuni hood, http://www.e-emotorsports.com/jeremyrb240.php

Check it out

E

[krayton]

i just used a cheap VIS with front vent.

but thats for my s14. looks like yoru going for the s13

[NightKids2]

I have a spare hood for my car so I bought a 10 dollar plastic stick on scoop off ebay, cause as far as I know they dont sell a 240sx hood with a front facing vent. Thought Id cut a hole in the hood inbetween the bracing in the middle, screw the scoop on the top and bondo over it, and probably cut 2 or 3 slots over the intake but I havent got around to it yet. My friend says a front facing scoop isnt even going to help me that much.

[Audi180]

http://pic.hevre.co.il/Files/9...1.JPG

Masa motorsprorts vented hood - S15 front end as you might noticed

with the RB26....

no clearence problems....

[Shocker]

yea it has no clearance issues because its a 26.. the plenum isnt sticking 4 inches over the head.. lol and that first hood looks nasty.. s-15 hood is yummy tho

[Darius]

yeah obviously the 26 won't have clearance issues, but my question is why someone would want a vented hood? Are you looking for cooling or looks? As far as looks go, that's debatable. As far as cooling aide goes, that's highly debatable. I don't have direct experience but it seems like the cooling by air flow through the engine bay would be minimal even with a vented hood.

[krayton]

yeah obviously the 26 won't have clearance issues, but my question is why someone would want a vented hood? Are you looking for cooling or looks? As far as looks go, that's debatable. As far as cooling aide goes, that's highly debatable. I don't have direct experience but it seems like the cooling by air flow through the engine bay would be minimal even with a vented hood.

vented hoods release under hood temps. your radiator makes a good amount of heat, and keeping it trapped in the engine bay increases temps.

air comes in through the radiator gets heated up, and a properly setup vent will send that air right back out.

[300Plus]

I'm thinking of using the small dryer vent I've scene used to ducted air to brake rotors. To route air from the front pumper area to behind the radiator to help push out that hot air.

[krayton]

I'm thinking of using the small dryer vent I've scene used to ducted air to brake rotors. To route air from the front pumper area to behind the radiator to help push out that hot air.

i dont see that working to well.

if u want to try a cheaper solution, then try propping your hood with spacers on the back. technically will allow more air to be released.

[180boy]

Cheap is not my solution, It doen't matter to me what it costs as long as it has clearance in my S13, I do have a front mount intake ,I'm just concerned on the area around the timing cover where most of these hoods slope down,I like the BV style,but can not get dimensions.I hate to buy it and can not use it. As for having a vented hood ,talking with the Aussie's they recomend it highly cause of the heat generated by the RB and being in an S13,but most of them have Silvia front end and those front end are up higher not like the s13. thanks guys180boy

[krayton]

if your near a stock setup, i wouldnt worry to much.

id start upgrading your radiator, get some good strong fans. get your car nice and cool from the radiator end, before looking into the hood part of it.

[ceno]

I'm worried about clearance too. My hood rests on my timing cover, not the plenum. Looks like the hood has about 1.5 inches to go before I can close it. I'm going to cut out the frame underneath it, and if I still can't get it closed, I was going to cut open the top and make some type of "vent" for it, that hopefully won't look like complete ****.

But getting a hood, or putting a vent in the hood for clearance is really only a temporary fix imo *shrug*.

[Sil240]

Has anyone figured out which reverse vent hood will fit a RB20 in a S13?

I've seen some pics of a S13 with a 26 and they can to make cuts in the vents for the twin pipe and the timing cover.
But I don't know what hood it was.

I'm having a problem with my LS2 coils hitting my hood. I really don't wanna move them. Plus I wanna cool off the engine bay.

[FinkenS14]

I found that putting a fan behind the radiator, essentially in front of engine but behind the radiator and make it a puller, dropped my temps grealy. When it was a pusher I think it blocking most of the radiator was reason for my car running hot.

So when I switched it to a puller, I aslo used hollow aluminum rod and longer bolts (looks better then a s*** load of washers) and cowled the back of my hood.

In the mornings I have to keep my fan off or the car never warms up, and on a 90* day the needle sits between quarter and halfway.

Running a ISIS radiator with a 16inch fan.

[Sil240]

Yeah I think ill just raise my Hood up. Ill get my clearance and maybe it'll help the cooling.

Only problem I don't think o have any space to put a puller.
right now I'm using a spal 13" pusher. Sad part is I have another brand new one. But I would have to custom mount it since my rd only has tabs for 1.

[Cjmartz2k]

Just FYI, I've seen two articles out there showing that the spacers in the back of the hood trick as well as vents in the hood were WORSE for cooling (along with removing the under the engine tray). I know somebody here in Oki that has had first hand experience with this also. I'm not saying vents can't help, but engineers spend time in a wind tunnel finding low pressure areas on the car and putting the vents there to help draw heat out at speed. A lot of aftermarket hood manufacturers are just putting vents where they think they look cool.

[ST240]

Just FYI, I've seen two articles out there showing that the spacers in the back of the hood trick as well as vents in the hood were WORSE for cooling (along with removing the under the engine tray).

I can see how removing the splash guard would make them worse: you're allowing the air to go around instead of through the engine bay... But shimming the hood making it worse? Hot air rises does it not? Unless its causing turbulence to somehow not let the air flow through the rad or something. I'd like to hear the explanation on that one.

I was actually considering putting several air temp sensors in my engine bay and playing around with the hood and stuff and seeing what worked best.

[radianation]

I have a Seibon CF vented hood. Car runs super cool, although the 2 side vents basically end up around my shock towers.




p.s. My side skirts were just "test fitted" during the second pic, so they aren't actually on the car, hence the shadow around the edging.

[240z4u]

Just FYI, I've seen two articles out there showing that the spacers in the back of the hood trick as well as vents in the hood were WORSE for cooling (along with removing the under the engine tray).

I can see how removing the splash guard would make them worse: you're allowing the air to go around instead of through the engine bay... But shimming the hood making it worse? Hot air rises does it not? Unless its causing turbulence to somehow not let the air flow through the rad or something. I'd like to hear the explanation on that one.

I was actually considering putting several air temp sensors in my engine bay and playing around with the hood and stuff and seeing what worked best.

The cowl area is a high pressure area, when you are driving with the hood propped the air goes back into that slot. Think cowl induction. It would help at idle or very low speeds, but above those you want that shut.

[Cjmartz2k]

The cowl area is a high pressure area, when you are driving with the hood propped the air goes back into that slot.

And that was exactly their point proved by under hood thermometers. There is high pressure there, and it does force air into the opening at the back of the hood. Thing is, that pressure also makes less air flow through the radiator in the front since there is now higher pressure in the engine bay.


And about hot air rising, I don't think anybody here is talking about their car sitting idling. If that's an issue, you need a stronger fan.

[Sil240]

I guess ill just see if I could clearance the Hood. Easiest and cheapest route. If I have cooling problems I have a second 13" pusher fan I can try to Hook up.

[ST240]

The cowl area is a high pressure area, when you are driving with the hood propped the air goes back into that slot.

And that was exactly their point proved by under hood thermometers. There is high pressure there, and it does force air into the opening at the back of the hood. Thing is, that pressure also makes less air flow through the radiator in the front since there is now higher pressure in the engine bay.

Hm. Interesting. Kinda counter intuitive. You'd think a guy would increase the amount of hot air escaping the bay by opening up another place for it to get out... But i guess yeah, as you increase "oulet area" in a system velocity decreases and pressure increases... Unless it's a supersonic system

[Cjmartz2k]

Yeah, for sure counter intuitive. I thought it was a pretty interesting read. Probably why it stuck in my mind.

[kamikazeee]

Got this h0m0 hood and fenders with my car, rb20 fits wonderfully,

Got used to it, but I say go stock man, i'm just keepin it cause its so damn light! looked way worse before.

[radianation]

I have the dual flex fans (puller) and the car doesn't even think about overheating even on the track.