Shimming your hood

[Garrison]

Hey,

I was talking to the local turbo shop again today and they mentioned that turbo Honda owners sometimes shim their hoods ~1/2" to allow more air to flow through the engine bay, keeping temperatures cooler, especially intake temps. I was thinking of trying it. Anyone have anything they want to chime in? Advice?

[Wiscon_Mark]

Well, it's going to reduce aerodynamics, probably eliminating any performance/efficiency boost you'd get on the highway. But if you have a low speed track, it might be worth doing...

I've taken a temp gun to the surfaces in the engine bay after long trips, it's not usually that hot. The underside of the hood (right over the manifold) only gets to about 100 degrees. Surfaces away from there probably aren't that warm.

[Garrison]

This is more to reduce heat from the turbo, should I ever decide to pummel it. But I hear what you're saying, costs outweigh the benefits.

[DevC]

Then all the fumes, etc from your engine bay go into your hvac intake and into your interior. Also, the air is designed to be drawn out under the firewall and under the car causing negative pressure drawing air through your rad/grille, spacing the hood MIGHT screw up this process.

Adding a lip or something similiar further back under the rad support to guide more air through the rad instead of under the car would be better.

[hansvonaxion]

I know someone who did this on an NA car, but he was pretty serious about autocrossing. He also had an air pressure sensor to check what was going on under the hood...oh, and... bonnet pins!

[phi11]

You know what else Honda guys do?

Led spray nozzles!

[MarkSubi]

If your talking about what I think your talking about I'm used to seeing Nissans with that and if its what I think it is mine is like that

[Garrison]

Did you see any real world benefits? I understand it can fog your windshield.

[anothernord]

I personally think it looks silly. I think the only reason to do this is if you have a clearance issue, or have a high-performance track car. A hood scoop looks better and does kinda the same thing.

[Garrison]

Word. Unfortunately, you can't really modify the oem scoop too much so I'm thinking 06 wrx scoop to add more air at sometime in the future. Thanks all

[MarkSubi]

Honestly, to me its just a show thing, I don't have any benifits from it and it wont necessarily fog your windows up when its cool.

[StatGSR]

There is only one practical purpose to do this for most honda's (civics, integras, crxs) and that is because they did an H2B swap. What that is is a H-series engine from a prelude bolted to a B-series transmission with an an adapter plate, and some adaptive motor mounts. This retains stock B-series engine mounts and proper Axle alignment, but eliminates all your hood clearance. This is done because b-series transmissions can be substantially better than h-series and because most H-swaps sit very low to the ground which will leave your exhaust scraping the ground if your car is low. several of the H2B kits come with hood spacers so you don't have to cut out all the hoods webbing to make it fit, and even if you do cut out the webbing you might need some small spacers...

if the hood is spaced up for any reason other than what i have said then it was done for appearance only and has no real value what so ever...

[Huffer]

^^ it's a trend. Shimming your hood is generally for looks UNLESS you have terrible underhood clearance for some reason.

You want better cooling? Do what the earlier generation of Impreza's had from factory, install hood vents.

[Garrison]

^^ it's a trend. Shimming your hood is generally for looks UNLESS you have terrible underhood clearance for some reason.

You want better cooling? Do what the earlier generation of Impreza's had from factory, install hood vents.
I'm thinking along those lines as well. I'd love to get a pair of those ebay mini-scoops and bolt them in there, but I think I'm going to buy a regular "L" hood and scoop it at the same time. Hello, project :smt006

[hansvonaxion]

^^ it's a trend. Shimming your hood is generally for looks UNLESS you have terrible underhood clearance for some reason.

You want better cooling? Do what the earlier generation of Impreza's had from factory, install hood vents.

If your intake is between the hood and grille/radiator/lights then it can create more/better airflow to the intake/allow a larger opening for better airflow. Not claiming it would be beneficial, just saying.

[nikolaus.conrad]

I'm not 100% sure what 'shimming' is. Can I see a pic? lolz

[Garrison]

Shimming is the process of unbolting your hood and sticking shims (or washers) on the bolts that secure it, at the top right and left corners about a 1/2". This raises the rear of the hood and lets air flow out the rear, as opposed to remaining in the engine bay.

[httrdd]

Word. Unfortunately, you can't really modify the oem scoop too much so I'm thinking 06 wrx scoop to add more air at sometime in the future. Thanks all

That is all you need. The 06-07s are the best performance and look scoop out there. The 04-05 STi may be the most functional, but I think it looks HUGE.

[chuckthefuk]

I've shimmed my old GT hood when I ran a tall-style impreza strut bar.

I used 2-4 washers...

If you plan on going higher you may want to get larger bolts so you have sufficient threads.

Or you can get the JDM Tight Yo! stuff..

http://www.ebay.ca/sch/i.html?_nkw=hood ... m270.l1313 (http://www.ebay.ca/sch/i.html?_nkw=hood+spacers&_sacat=0&_dmpt=Motors_Car_Truck_Parts_Accessories&_odkw=hood+shims&_osacat=0&_trksid=p3286.c0.m270.l1313)

Little flashy and to tall for my taste..

The under-hood temps do drop drastically however some setups cause "whistling" if the rubber seal is loose.

-Chuck

[nikolaus.conrad]

OOOHHHHHHHH that!! There's a Honda civic hatch in my school parking lot that has a shimmed hood haahahaha. If you had a functional scoop, wouldn't shimming your hood make that work less?