Hood Questions #2

[Iowa 409 Guy]

http://www.glasstek.com/results.php?year=1964&make=19&model=119 Link to cowl induction hood here.

Anyone have any dyno info on what a hood scoop will do compared to a cowl induction hood like this that is free flowing to the intake-not directly hooked up? SWAG? I wonder how much the COOL air flow would dyno over and above the hot air coming from the usual engine compartment.

I like the way Brian's (MRHP)setup is if any of you guys saw it at Great Bend. http://www.348-409.com/forum/threads/great-bend-pictures.28655/ Post#13--- Domino's powder coated 14" pan style.................

 

[Fathead Racing]

I know that with the front facing hood scoop there is no ram air effect worth talking about if that helps.

 

[1961BelAir427]

Brian (BSL409) has or had a cowl induction hood on the '62 and a Super Duty style scoop on the '61. He could probably give some good input on the pros and cons of each. I wanted a cowl hood on my '61 way back before they became so popular just because I think they flow with the line of the hood and dash. ('61-62 dash looks like the rear of my cowl sticking up.) Now that I've found a W motor I'm leaning more towards a stock look. The cowl induction is very effective at reducing under hood temps compared to the stock style fiberglass hood I have. I've never tried sealing mine to the air cleaner to see what power advantage that might be worth.

 

[Fathead Racing]

Brian (BSL409) has or had a cowl induction hood on the '62 and a Super Duty style scoop on the '61. He could probably give some good input on the pros and cons of each. I wanted a cowl hood on my '61 way back before they became so popular just because I think they flow with the line of the hood and dash. ('61-62 dash looks like the rear of my cowl sticking up.) Now that I've found a W motor I'm leaning more towards a stock look. The cowl induction is very effective at reducing under hood temps compared to the stock style fiberglass hood I have. I've never tried sealing mine to the air cleaner to see what power advantage that might be worth.

Jim and Jim in Canada may have something to lend to the conversation. The only thing I have to offer is what everyone knows already, cool air makes power and most of us know why so I'm not going to bore you with details. Although I have this to offer. Denny Ford was in the 10's with his 62 with no hood scoop and no cold air hookup.

 

[Ronnie Russell]

Was fun looking back through the pictures. Can't believe I missed looking at so many cars. Dave, that '64 is gorgeous. Looking at the pics did prove that I was entirely wrong about the Street Demons not working well on a single plane intake. Pat's white car obviously has a Walden intake and Street Demons and it made big hp on the dyno. My theory about 4 "little" and 4 "big" throttle bores must be wrong. Oh well, not the first time I've been wrong and won't be the last.

 

[1961BelAir427]

Denny Ford was in the 10's with his 62 with no hood scoop and no cold air hookup.

That is very interesting to me in particular. Off subject of this thread, but interesting he got a package to fit under the stock hood and run into the 10's. Haven't seen many that could pull that off. I have pictures of his rear suspension and car, but not of under the hood. Gotta go find that now. THANKS for the info Ray. Sorry for the Dave.

Edit: Found video on youtube and Denny's has an 881 intake, stock carbs, and no spacers. Didn't think about the fact that it is a D stocker. Man that car is CLEAN!!

 

[Iowa 409 Guy]

Jim and Jim in Canada may have something to lend to the conversation. The only thing I have to offer is what everyone knows already, cool air makes power and most of us know why so I'm not going to bore you with details. Although I have this to offer. Denny Ford was in the 10's with his 62 with no hood scoop and no cold air hookup.

Ok Ray, let's use that for an example.

I'm wondering, for instance, how much better Denny Ford would run with a cold air hookup? Not to say anything against him or his car, just for example?? I like the idea of creating HP with something fool proof and that won't break...............Lots of guys here have forgot more than I know for sure.

I'll see what happens for conversation here and paste these 2 hood threads in Racing or Engines in a day or so.

 

[MRHP]

Once upon a time I had a cowl hood on my 62. I had the rear portion of the scoop that faced backwards opened up to create better airflow. It did help. I later took it off and installed the cowl aircleaner. I was told the cowl aircleaner was worth a couple tenths and a couple mph.

 

[Fathead Racing]

Was fun looking back through the pictures. Can't believe I missed looking at so many cars. Dave, that '64 is gorgeous. Looking at the pics did prove that I was entirely wrong about the Street Demons not working well on a single plane intake. Pat's white car obviously has a Walden intake and Street Demons and it made big hp on the dyno. My theory about 4 "little" and 4 "big" throttle bores must be wrong. Oh well, not the first time I've been wrong and won't be the last.

Just like the rest of us Ronnie, leave your car home next time and see the race!

 

[1961BelAir427]

I like the idea of creating HP with something fool proof and that won't break.

Very good point there Dave! If you can drop some pounds off the front end and gain some power with a cowl induction that's a win-win that won't break. That GlassTek hood looks like you could easily seal it to an air cleaner assembly since it has stock style bracing. The one I have is just a big opening under the whole scoop.

 

[Don Jacks]

Well Dave,you might see a slight increase on the dyno,but because of air flow,you will see a significant increase in power[lower et,higher mph on the track.The difference between sealing the carb to the hood,verses open was ,015 seconds and 1 1/2 mph in the 1/8th in favor of the carb sealed to the hood on my 78 Malibu.Other set ups may vary depending on tuning but thats what I found.

 

[Fathead Racing]

Ok Ray, let's use that for an example.

I'm wondering, for instance, how much better Denny Ford would run with a cold air hookup? Not to say anything against him or his car, just for example?? I like the idea of creating HP with something fool proof and that won't break...............Lots of guys here have forgot more than I know for sure.

I'll see what happens for conversation here and paste these 2 hood threads in Racing or Engines in a day or so.

I asked this same question a long time ago, I hope it goes somewhere this time.

 

[Barry Taylor]

Don, was that with a scoop or a cowl hood.

 

[Don Jacks]

It was a 2 1/2 in.cowl,BT .When I first built the car,I had a 7 in snorkel type scoop sealed with a pan.I later found a glass replacement cowl hood,because the scoop had cracked from viberation during street and road use,it was a pain to see around at night on a 2 lane country road,and then Va.declared anything above the hiegth of the cowl illeagal ,and since this car was street driven,it had to go through a safety inspection anually .The hood,as I got it,had no provision to seal to he carb,and when I installed it,I noticed the slowdown. After I aquired a large ,thick of plexiglas and installed it so I could seal the carb back up,my et and mph returned to normal.

 

[Barry Taylor]

Thanks Don, that explains it well.

 

[63 dream'n]

Back in the day.......Z-11 guys ditched their cowls for scoops.....I'm not poo-poo'n.anything here,but if they'd gained 2 mph wouldn't they have kept them.

 

[1961BelAir427]

Not sure about the other guys, but I was talking about a cowl induction scoop (3 1/2" in my case) not the cowl inducted air cleaner assembly.

 

[jim_ss409]

I did some research on this a while back.

Apparently, a cowl scoop works but it's important to have the carb sealed to the hood, otherwise the hot air from the engine compartment will just push right through and exit out of the cowl opening at the windshield. There is a bit of high pressure at the base of the windshield but the pressure at the grill is much higher so it will push right through.

A good forward facing scoop gives a stronger ram air effect, but the ram air effect, isn't as important as the gains from drawing in cooler air.
I might be able to dig up a graph that shows the effect later tonight.

There was also the famous case of the Z11 style induction picking up a few mph on the test track. Again, I thing the majority of those gains came from the cool air and a little bit from the air being drawn from the high pressure area at the base of the windshield. A good forward facing scoop would likely have worked even better.

The best scoops are these modern looking ones with a small opening and a big chamber.




If I've got it right, the idea works something like this... the fast moving air enters the chamber and slows down,,,
the energy in the fast moving air gets converted to pressure as it slows,,, so a bulbous scoop like this will create more pressure than an old school looking hood like the ones pictures below, but I don't think the difference is all that great, so I'll stick with this style just because I think they look better on our old cars.

 

[MRHP]

I don't recall who told me that, I think Russ Campbell? Whoever it was, did it on their car and saw the change.

 

[63 dream'n]

Not sure about the other guys, but I was talking about a cowl induction scoop (3 1/2" in my case) not the cowl inducted air cleaner assembly.

Hey Jason,yes I know I kinda changed gears there but ram air,cool air,volume,direction all are part of the equation....I guess I threw that out there because the factory knew it(high pressure area at the base of windsheild)added a couple of mph,and yet race teams nixed the idea for the forward facing scoops......and raising the rear of the hood