I got a Harwood Cowl hood, since I promiced myself if I ever smack-up my front end, I'd get a glass hood.
Anyway how does COWL INDUCTION work?
Does having a cowl induction hood do anything for a TPI motor? I know it has come efffect on a carburator/TBI set-up(round air cleaner) but does it have any benefits on a TPI engine w/a cone-type filter mounted to the throttle body.Am I getting a "cold air" effect or is there a specific function?
I do like the extra noise that comes from those holes.
Any help is appreciated.
Mike


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1990 Formula
Factory:TPI-305/Dual Cat(230hp),5 Speed,3.42 rear, Dealer:Aluminum Drive Shaft
Mods:SLP air foil,K&N Filter, Accel:wires,coil cap,rotor.Hypertech Thermomaster chip,Stat,Fan switch,TES headers,MSD6AL,AFPR(46), Harwood fiberglass hood,original GM "Notchback GTA" hatch.
Flowmaster 3" Cat-back exhaust,TB coolant bypass, Centerforce clutch (going).

 

I have a cowl hood (not Harwood) with a TPI setup, and I can't see it helping the TPI system in terms of cold air flow.

HOWEVER, the cowl hood does an AWESOME job of keeping the underhood temperatures cool. Whenver I go on the highway, I can see my temperature gauge drop and stay at about 160 degrees..

Would it be fair to say that for TPI setups, a cowl hood would keep the plenum/runners cool?

 

I immagine so. It defenetly should keep the under-hod temp. lower. But what does Cowl Induction really mean?

 

what happens: there is a low pressure area at the cowl( the area where the opening is at the windshield) when the hood is opened up, the air rushes in and is the carborator's(spelling) version of ram air.

The area where the engine bay and the windshield meet is the cowl. COWL INDUCTION is a term for air going into the intake from the cowl. kinda like ram air, how it is rammed in from the front. well, with cowl induction, the air is ducted into the engine from the cowl.

hope that clears it up a little. i am sure i could have made it a little clearer.

if you have any other questions, shoot me an email.

later,
Jesse

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85 Z28, 305 TPI A4
pretty stock with a few toys
15.2@91mph
http://photos.yahoo.com/j_hougnon

http://screamindeamin.cz28.com/images/jesse/

 

Actually, Cowl induction works by using the high pressure air at the base of the windshield to "ram" air into the engine bay. By ducting it to your air filter, you will experience the ram effect, as your speed increases, pressure at the base of the w/s increases as well, thus, it becomes more efficient at higher speeds. A side benefit is, cooler intake temps due to drawing outside air into the engine, instead of getting the nice, hot, underhood air.

Simply putting the hood on will reduce underhood temps, and therefore give you better performance, but, it also increase the air pressure under the hood, contributing to "floating" the front at high speeds....

Ideally, you should fabricate some duct work to channel the air to the intake, and not simply letting it build the pressure under the hood. However, on Firebirds, this becomes really interesting because of the location of the air filter. (this is where you want the air to go....) On Camaro's, it is a little easier, again, due to the location of the air filters, and would most assuredly increase performance.

 

I just got a Harwood cowl the other day and was wondering if maybe we can use the 4thgen SS induction to get the cool air effect. Has anybody tried this? The only problems I can see myself having is my MAF(its longer and skinnier than the LT1s I think)and the fact that I have the Superram. Worth a shot though!

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355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s. Chip is custom(doing it myself) Just got a 2 1/2 Harwood and soon to be painted.

 

if you want cold air get rid of that dumb cone, that is just breathing the hot air thats coming off your engine.
if you want to keep, the dumb cone get the cowl hood, but the air your engine breaths will still be hotter than if you had the stock setup.
and running duct or whatever to the t.b. would be a pain in the a**

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The problem that I experience with simply removing the piece of metal from the cowl on my stock bird hood is that you get fumes from the engine compartment into the car since the air intake for your a/c // heater is right there. Anyone else notice that. It would not happen if you make a airtight box arrangement for your intake, rather than simply mounting a cone filter near the cowl.

just my .02

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Michael Graeber

My Garage

1)83 Z-28 T-Top: Full cage, 9" w/ lad.bars, Midwest Engine Tech 406sbc,Strip Dominator, Demon Carb, Phase VI Chevy Bowtie heads, .630" Crower roller set-up, 1 3/4 coated Hookers 3" true dual exhaust th400, fuel cell & still not running

2)89 Formula WS-6 305 TPI Auto For the road: minor motor, more suspension stuff. MODS