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Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 02, 2019 06:38PM

I have been curious about possible flow losses to the engine cooling fan caused by the engine deck lid intake grill, as some of my tests with the stock fan years ago seemed to show that the fan shroud pressure could change at the same rpm with the deck lid open or closed. For example, with the engine dead cold, and the deck lid open (50-55 degrees outside) I could get almost 1" more at 4000 rpm, vs having it closed. I wasn't able to repeat those results with later tests that were more controlled so I decided to see what would happen if
I simply measured the engine bay pressure... unhook the pressure probe from the shroud, plug the hole in the shroud and leave the pressure probe in the engine bay. Super interesting!



Outdoor air temperature= 70 degrees, engine head temps a slight tick over 300,
and the damper doors were "probably" not all the way open.

With the car stationary at 2250 rpm, the manometer reads -.2"
with the car at 2250 rpm at 50mph, the manometer reads +.2"

The "while driving" test was repeated 2 or 3 times, each time the
number came out about the same as long as the car was on flat level ground,
the stationary test was done once, right after I parked. We had a basically
windless day today when I did my testing. More to follow!!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 02, 2019 07:57PM

For reference, the maximum pressure rise from speed of the car that would be expected would be something like 1.2" at 50, 2.3" at 70, and 3.1" at 80, and this would represent a large change in fan pressure, at realistic driving speeds!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 03, 2019 06:45PM

More data from stationary tests: This test is done with outdoor air temps @ 60 degrees:

Engine rpm Engine bay pressure

1000 -.13"
2000 -.18"
3000 -.29"
4000 -.4"

My prediction at 5k based on the above would be -.6" to -.8", which kind of getting up there for a loss that is easily taken care of by more intake area.
It does look like this is partially compensated for by a slight positive ram
effect when the car is moving. It will be interesting to try this same test with different lid mounting arrangements

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: MattNall ()
Date: June 03, 2019 07:00PM

Take the lid off the parts car and remove the Rain shield.... most people are fair weather drivers..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
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..............................110-PG.................................................Webered-Turbo

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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 03, 2019 07:48PM

That's a good idea! I'm thinking for starters anyways to try and mount the front part of the lid blocked up 2", kind of like how Eddie Perez (?) has his mounted... super slick and relatively simple way to take care of a problem like that. I got to see that lift system of his in person, and he did a heck of a job on that. I've had that in the back of my mind ever since. I know on lates it is a much bigger problem than it is on earlies but it is a bit surprising to see that much loss that shouldn't even be there!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: Chi2 ()
Date: June 04, 2019 03:51PM

Does anyone have picture of this?

63turbo Wrote:
-------------------------------------------------------
> That's a good idea! I'm thinking for starters anyways to try and mount the front part of the lid blocked up 2", .......

Jon
Enrolled in the Culver City Automotive School of Hard Knocks
============================================================
Member of South Coast Corsa
-1964 Greenbrier "The Dog Hauler" Rustoleum Charmer 110hp/4sp/.030 over/Pertronics I/Isky 270 Cam
-1962 Monza Club Coupe "Shaken, not stirred" Tuxedo Black with Red Interior 140hp/4sp/Pertronics I/Clark's 260 Cam

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Re: Engine bay pressure tests on an early
Posted by: MattNall ()
Date: June 04, 2019 06:47PM

Jon just make angled spacers...

The trick is the change in angle of the bolt.

If you fab a "U-channel"... it's easy... just needs to be 0.090" aluminum..


U-Channel would be 2" at one end and sloping down to that ever height you need.


Then, of course, you MUST polish it!! GG

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 04, 2019 06:53PM

what I thought was so slick is how the lid could be lifted and angled while driving, with electric actuators... really well thought out!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: MattNall ()
Date: June 04, 2019 06:55PM

True... but more effort / expense than most go for..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
..............................110-PG.................................................Webered-Turbo

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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 04, 2019 08:13PM

There might be more takers though if it was something that was a simple bolt on thing... perhaps something that mechanically linked the front part on the hinges to either be set in a lifted position or a locked down position via a over-centering cam or something like that... when it is hot and dry out, the lid is set to the up position, and stays that way until conditions warrant locking it in the down position so the lid sits like stock. There's something to be said for something like that... heat soak is a thing of the past with the deck lid angled up, and hot restarts would be easier, and, potentially, the cooling vs speed trade problem goes away, or is dramatically reduced as the air keeps getting rammed into the engine compartment the faster the car goes, kind of like how radiators work. I totally understand though about the mods involved with electric actuators and crap, Im not sure I would want to do that, but a reliable, safe, bolt on 2 position mechanical thing sounds really interesting to me, especially if it works well and has real numbers to back it up!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: richard1 ()
Date: June 05, 2019 08:05AM

What is the total CFM, and velocity through the louvers?

Could a set of small electric fans on the hood kick in and increase the velocity through the existing louvers?

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Re: Engine bay pressure tests on an early
Posted by: jjohnsonjo ()
Date: June 05, 2019 08:33AM

Apples and oranges Kevin, but my LM Vert always runs hotter with the top down at highway speeds. 20 to 30 degrees judging but the Corsa temp gauge. I think part of it is the extra aerodynamic load and part it is the air not sliding off the rear window and pressurizing the air at the rear cowl vents. I never put a manometer there, but I should to see what is going on. I always open the engine cover on a hot day if I'm in a safe place to do that. Saves a bunch of aggravation.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa


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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 05, 2019 07:21PM

richard1 Wrote:
-------------------------------------------------------
> What is the total CFM, and velocity through the louvers?
>
> Could a set of small electric fans on the hood kick in and increase the velocity through the existing louvers?


The total cfm through the louvers is only slightly more than the cfms going through the fan, because of the engine consumes air also. Just for "kicks and
grins" assume that only 1800 cfm flows through the louvers (this isn't even
close to enough!) and the area of the louvers is around 105 square inches,
(which is what I measured for my early). Then, Q= VXA, where Q is the flow,
V= velocity and A= area. Solve for V, then V=Q/A and V= 1800/.729 = 2469 ft/min
= 28 miles per hour. The air is not moving that fast through the louvers, but
because of the rain channels inside, it cant flow very efficiently, thus the
flow losses. There's certainly some charm in putting some radiator fans attached to the deck lid inside, and it is pretty easy to find some that can flow enough to help, and it all looks pretty good right up until you realize
that the small fans have to pump air through long skinny slots- each one is over a foot long and a bit over 1" wide, so there's large miss matches in the
fan diameter versus the flow area... and it gets way worse if you go to diameters big enough to only cover the length of one slot. They wont put out
anywhere near their flow ratings because of this area mismatch.
It could work though if you are willing to cut a monster hole on the underside of the deck lid though!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 05, 2019 07:35PM

jjohnsonjo Wrote:
-------------------------------------------------------
> Apples and oranges Kevin, but my LM Vert always runs hotter with the top down at highway speeds. 20 to 30 degrees judging but the Corsa temp gauge. I think part of it is the extra aerodynamic load and part it is the air not sliding off the rear window and pressurizing the air at the rear cowl vents. I never put a manometer there, but I should to see what is going on. I always open the engine cover on a hot day if I'm in a safe place to do that. Saves a bunch of aggravation.

J.O.- I talked with a guy with a late hardtop that claimed he had good cooling when the speed limits were 55, but when they went up to 70... not so
good, and what he ended up doing about it was some sort of hood scoop, and it took care of it. I believe part of the problem with the lates is that the intake grill is too small, and the other is where it is located. It may well be
that the hardtop does flow better than the convertible does with the top down,
but I bet you it doesn't do as well as one that was modified to have the intake area larger and farther back onto the hood and or more outward closer to the fenders, or use an actual hood scoop. It would be really interesting for someone to try this same test that I did with a manometer open to the engine compartment on a late, and run it down the freeway!

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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Re: Engine bay pressure tests on an early
Posted by: joelsplace ()
Date: June 05, 2019 09:03PM

Run a bunch of 1" fans.

Joel
Northlake, TX
5 Ultravans, Lost count at 100 Corvairs...

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Re: Engine bay pressure tests on an early
Posted by: MattNall ()
Date: June 06, 2019 07:59AM

Here's Greg Lloyd's answer... Spent the $$ for the design. Feeds 3000cc... 600 cfm carb. Verticle fan.

Placement most likely is the least drag with greatest Ram effect..


The effect of taking intake air out of the equation would be interesting to know.



Edited 1 time(s). Last edit at 06/06/2019 08:09AM by MattNall.

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Re: Engine bay pressure tests on an early
Posted by: stitch ()
Date: June 06, 2019 09:44AM

Has anyone tried punching vertical slot vents in both rear fenders (ala Wagon / FC style) for better breathability / pressure?. Might not look too out-of-place. Would prolly cool things down, on shut off, as opening the hood?...confused smiley

"If you can't fix it with a Hammer, you have an Electrical problem."
Stitch...
Schertz, Texas.
(Smallish town/burg 17 mi. NE of San Antonio)

'Ms Penny'
!967.. 4th body
8th off the line

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Re: Engine bay pressure tests on an early
Posted by: Willt65 ()
Date: June 06, 2019 11:18AM

How well does the Yenko Stinger flaps increase flow? They are the best looking in my opinion. LM of course.


Will Teeter
Flintstone, MD
65 Corsa project
66 Monza parts car
49 Chevy 5 window project
08 Chevy 2500
13 Honda Odyssey
07 Honda 919
04 Honda Rancher
96 Honda XR400R



Edited 1 time(s). Last edit at 06/06/2019 11:20AM by Willt65.

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Re: Engine bay pressure tests on an early
Posted by: Wagon Master ()
Date: June 06, 2019 11:30AM

stitch Wrote:
-------------------------------------------------------
> Has anyone tried punching vertical slot vents in both rear fenders (ala Wagon / FC style) for better breathability / pressure?. Might not look too out-of-place. Would prolly cool things down, on shut off, as opening the hood?...confused smiley


But But But...that would allow air to bypass your/my A/C condenser.

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Re: Engine bay pressure tests on an early
Posted by: 63turbo ()
Date: June 07, 2019 06:17PM

Next test: outdoor air temp= 60F, car stationary, and rear of deck lid blocked
up 2". Head temp= 300

Engine rpm Engine bay pressure

1250 -.11
2000 -.12
3000 -.14
4000 -.16

Once I get the deck lid safely tied down with the blocks in place I will try
this arrangement while moving.

------------------------------------

Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
first test start on EFI here:[www.youtube.com]
first official EFI boost test here:[www.youtube.com]
My new fan! [corvaircenter.com]
engine less 62 Spyder
Canadian 64 Monza Parts car



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