8th Generation Honda Civic Forum banner
1 - 20 of 127 Posts

·
Registered
Joined
·
2,735 Posts
Discussion Starter · #1 · (Edited)
UPDATE: Test of rubber insulator removed from plastic cowl, no hood spacer vs stock setup!

So I've heard so many friggin' things about hood spacers. Some love them, most hate them, some swear by their effectiveness, others throw around physics and logic, but I couldn't find any REAL DATA. Hence, I went out and I tried to collect some of my own. For all you guys to know, performance mods I have include injen sri, ws2 exhaust, nst pulleys, hondata IMG and of course the wonderful Cobb accessport that made this possible!

It isn't perfect but I compared before and after on the same night within an hour of each other at 67 F. Temperature stayed constant here throughout.

The test was done to test the max temperature of the Intake Air Temp (IAT) at idle and how long it took to get there and the average IAT at 80mph (cruise control on flat ground on the freeway for around 5 minutes). The reason for this is because some people have said this vent method might actually hurt effectiveness of airflow out of the engine bay by messing with proper air flow AT SPEED (low pressure, high pressure and all that jazz that I won't pretend like I completely understand).

So, I have the excels sheet that I gathered from my Cobb Accessport , but I'm too lazy because I have nothing to gain by lying since I'm not selling anything.

Caveat: I did the DIY hood spacer from 0720steve (thanks btw) because really, there's no difference between it and the ones corsport is selling. I used 3/8 nylon spacers, but with the washers I also added in, it's about a fingernail's difference from corsport's 1/2 inch spacers as far as gap.

My results:

At idle, the stock hood without spacers took approximately ~20 minutes to move from 95-156 degrees. I messed up my timing so I didn't get the exact minutes and seconds, but it definitely wasn't less than 15 minutes or more than 25.

At idle, the stock hood WITH spacers took 21 minutes to move from 96-156 degrees.

BOTH topped out at 156 degrees after the test. Maybe they could have climbed a couple more degrees, but I wasn't going to sit and waste gas for another 10 minutes, it's not practical anyway since you'll never be stopped in traffic half that long. And any movement quickly lowers and stagnates your IAT.

I have data across speeds, but I decided to take average IAT at 80mph since most people drive around that speed or slower on freeways. At 67F outside, my average IAT was 95.6 WITHOUT hood spacers.

Average IAT was 98.141 at WITH hood spacers!

Yes that's right, hood spacers actually measured nearly 3 degrees hotter!

ALSO, I took the average grams of air per second (g/s) the intake was bringing in when I was cruise controlling at 80mph.

Without spacers=33.43g/s (average)
With spacers=25.60g/s (average)
Hence, at idle, the the spacers were providing less grams of air per second to my intake at 80mph.

Apply whatever margin of error you want, but honestly, I felt that if my IAT wasn't at least 10 degrees cooler at either idle or at speed, I couldn't justify this mod. It's ugly (at least to most), likely slightly more dangerous (it isn't OEM fit and messes with the car's intended aerodynamics), causes more drag, costs you money (no matter how cheap), and allows more water into the car. And frankly, even if I did realize 10 degrees lower with the spacers, that's only, in theory, 1 hp. I was hoping to see at least a significant slowdown in heating up or a lower max temperature at idle.

Maybe the results would have been different if it wasn't so cold out (it was night time), but either way, I've tried it and trying to pass on what I've learned.

Also another caveat nobody has talked about, when removing one of my stock bolts, the female thread part in the actual hood came off! It's weird but I guess they welded in the threaded part of the hood into the hood (since the sheet metal itself is so thin). Long story short, I'm back to stock but my hood's only being held on with 3 bolts now. Grrr. Anyway, you run that risk if you mess with the OEM hood.

Hence, according to my admittedly simple test (although really time consuming!), hood spacers DO NOT WORK and in fact, made things worse. For those who say they feel the heat coming out, I'm sure they do, but if you've ever felt the hood around there without the spacers, you feel a lot of heat coming out anyway. I really don't know how to explain the no-duh logic that a vent should allow lower temps. This is my data and that's all I can bring to the table.

UPDATE: Now, moving onto testing the stock hood vs. removing the rubber insulator on the plastic cowl
The test was done at 64 degrees.

Stock Hood it took 26.25 minutes to rise at idle from 109-156 degrees.
IAT at 75mph=88.6 degrees (average)
mass airflow at 75mph=28.36g/s (average)


VS
Removed rubber insulator on stock hood took 25.93 minutes to rise from 109-156
IAT at 75mph=88.3 degrees (average)
mass airflow at 75mph=28.36


Hence, removing that weather stripping/insulator didn't do squat. Especially because I did it second and it only got colder as the night went on (between 12:30 and 3am).

FINAL NOTE: I can't say corsport's spacers are useless/detrimental. My test was on what's theoretically pretty much the same thing. Still, I'm not here to bash their product or people who want to go with this mod. This is just my opinion. Also if you have any complaints that I didn't do something right and my results make no sense, you may be right, but honestly, I can't imagine my errors could equal significantly slower heating up of the engine, significantly lower max temperature, significantly higher airflow, or anything else to justify this mod to me. Not at this point anyhow. Maybe somebody else will post up their data and correct me, but until then, I'm happy with my properly aligned hood and smooth body lines!

Hope you all benefit from my experience! and Special thanks to my girl, who stuck with me all night and helped me with the spacers! Love you babe!
 

·
Super Moderator
Joined
·
11,559 Posts
:think:
 

·
Registered
Joined
·
2,735 Posts
Discussion Starter · #6 ·
lol, thanks for the info earlier cambodian ricer. i went out and did the mod and these were my results. if any of it was inconsistent I'd begin to second guess more, but so far, no benefits at all. I was disappointed. I lost hours, tons of gas, 5 bucks on the parts, and worst of all, broke one of my threads on my hood and now only have 3 bolts in it.
 

·
Registered
Joined
·
18,666 Posts
lol, thanks for the info earlier cambodian ricer. i went out and did the mod and these were my results. if any of it was inconsistent I'd begin to second guess more, but so far, no benefits at all. I was disappointed. I lost hours, tons of gas, 5 bucks on the parts, and worst of all, broke one of my threads on my hood and now only have 3 bolts in it.
its alright!, you did it for 8th!
 

·
Banned
Joined
·
8,234 Posts
Good maybe the dumbasses who swear by these things will finally shut up about them. But hey, people do stupid mods that aren't functional and make their car uglier at the same time all the time (*cough*Konig wheels*cough*) so this probably won't have any effect whatsoever.

Good test though! Thanks!
 

·
Registered
Joined
·
154 Posts
this is very very interesting.....
now i am considering removing my hood spacers today who knows..

anyone else ever done anything similar to measure temp/airflow?
 

·
Registered
Joined
·
1,142 Posts
:cheerleader:

After my review (which was noting stellar and upset some people) I always second guessed my decision to disliking the spacers.

I am glad to see there is validity and more information surrounding my dislike for this mod.

Thank you for taking the time to do this.

If you are like me you are going to be sick to your stomach for a while now (about your hood). Now you can justify getting yourself a carbon fiber hood (gotta have all 4 bolts holding onto it right? ;) )
 

·
Banned
Joined
·
24,191 Posts
ImTheVoiceOfGod also tested these in the other Hood Spacers thread and found that they reduced his IAT's at the MAF by 20 degrees.It's entirely possible that the spacers allow for more airflow(and thus turbulence) to mix the warmer and cooler air thus bringing the temperature of the air in the area of the SRI up a few degrees.God job on the info though,but I say it's still inconclusive for everyone because the main benifit is'nt decreased IAT's but lower underhood temps overall.
 

·
Premium Member
Joined
·
4,294,967,295 Posts
ImTheVoiceOfGod also tested these in the other Hood Spacers thread and found that they reduced his IAT's at the MAF by 20 degrees.It's entirely possible that the spacers allow for more airflow(and thus turbulence) to mix the warmer and cooler air thus bringing the temperature of the air in the area of the SRI up a few degrees.God job on the info though,but I say it's still inconclusive for everyone because the main benifit is'nt decreased IAT's but lower underhood temps overall.
:word:
 

·
Registered
Joined
·
2,681 Posts
what about removing the weather stripping on the cowl???

it vents some heat but it doesnt interfere with the aerodynamics because the hood is still in stock position

i really dont know if it helps or not
 

·
Registered
Joined
·
340 Posts
maybe the key is finding the optimum angle of the hood. maybe the lift/angle the hood spacers provided was excessive causing turbulence, hence hindering the hot air to exit efficiently.
 

·
Registered
Joined
·
7,091 Posts
what about removing the weather stripping on the cowl???

it vents some heat but it doesnt interfere with the aerodynamics because the hood is still in stock position

i really dont know if it helps or not
It wouldn't do much, the hood closes and touches the weather stripping, if you remove it, there might be a 1/8s inch of clearance. It won't affect anything but will let water in.
 

·
Registered
Joined
·
2,735 Posts
Discussion Starter · #17 ·
:cheerleader:

After my review (which was noting stellar and upset some people) I always second guessed my decision to disliking the spacers.

I am glad to see there is validity and more information surrounding my dislike for this mod.

Thank you for taking the time to do this.

If you are like me you are going to be sick to your stomach for a while now (about your hood). Now you can justify getting yourself a carbon fiber hood (gotta have all 4 bolts holding onto it right? ;) )
hahaha, I said that exact thing to the gf! I've always wanted CF but I can't justify the price nor painting a target on my back for the cops. if I could get a nice vented one (functional) and paint it back to OEM TW, then I'd consider it, but the cost to do it, I'd rather buy cams or something lol

ImTheVoiceOfGod also tested these in the other Hood Spacers thread and found that they reduced his IAT's at the MAF by 20 degrees.It's entirely possible that the spacers allow for more airflow(and thus turbulence) to mix the warmer and cooler air thus bringing the temperature of the air in the area of the SRI up a few degrees.God job on the info though,but I say it's still inconclusive for everyone because the main benifit is'nt decreased IAT's but lower underhood temps overall.
yeah, like I said, I don't think my data necessarily makes sense since at idle, I'm basically making the car more like an open hood which I definitely know dropped temps.

However, how much does underhood temps help your performance? I'm curious because isn't it, for the most part, your car's performance is about the intake temp since that's the only place the car's really using oxygen? I mean, I guess aside from the radiator or something. I know engines are supposed to be more efficient at 212 or something right? I just figure that it's best to have a warm engine but cool air (hence CAI).

but seriously, I don't know. like I said, I really wanted to believe I broke a thread for a reason and wasted hours for a payoff. I actually didn't even think it was that ugly at all. I was ready to just leave it as is if I noticed ANY benefit.

what about removing the weather stripping on the cowl???

it vents some heat but it doesnt interfere with the aerodynamics because the hood is still in stock position

i really dont know if it helps or not
I really wanted to know about this myself, but honestly it was late and that'd require another whole test and drive. I could theoretically go out and test stock (since I'm back to it) and then remove the cowl I suppose, but I'm wondering how bad it really is to remove that cowl.

maybe the key is finding the optimum angle of the hood. maybe the lift/angle the hood spacers provided was excessive causing turbulence, hence hindering the hot air to exit efficiently.
yes.

Can somebody with real physics knowledge correct me if it's wrong, but I heard this somewhere and I don't know how much of it is BS and how much of it is true:

Basically, by keeping the hood sealed (stock) you create a high pressure area in there and then when the car moves the low pressure area over the hood forces the low pressure air in the engine bay out, thus making stock formation efficient. Therefore, without the stock placement of the hood, you lose some of that high pressure in the engine bay and more hot air is trapped under the hood.

The argument for hood spacers then is that you would hopefully sacrifice some of that ability to move hot air out at speed with the ability to vent it out at idle/stopped.
 

·
Registered
Joined
·
2,735 Posts
Discussion Starter · #19 · (Edited)
another thing I wondered was whether in conditions where I'd really want venting, like 90f on the freeway in traffic, if the open vents would do more since so much more heat would be trapped and trying to push out the vents and lead to drastic drops, but in the end, I don't know, the car has no torque as it is and I felt a little dumb making drag worse and inviting water into my engine. I've had a LOT of bad luck with my car so that's something I was definitely considering happening, even though I believe everyone's accounts.

speaking of, I have been bored and frustrated with my heat soak at times and been wanting to try to make a custom hood with a vent cut out like this:

Venting your hood

but now I don't know. Honestly so many cars have vents that I really can't imagine is does nothing. like I said, maybe it's more of a difference for hotter temps and turbo'd cars and stuff.
 
1 - 20 of 127 Posts
Top