Dyno testing on fans, alternators and oil.....all here!


Dyno testing on fans, alternators and oil.....all here!
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by Steve Jack
HOTRODSRJ@AOL.COM
Concept One Pulleys
Jackstands at Old Cars Only

Well guys...the dyno results are baked and ready to be served up. It has been a really interesting project to look at and took more time than I had anticipated...I still have a regular job to keep two kids in college you know!!

The idea just came up when a group of us started talking about the results of a fan test that ran a couple of months ago in one of the industry periodicals. Coincidentally, I had a 350/350HP that was sitting just ready to be broken in and tuned on the dyno (it pays to have drag racing buddies with dynos...a local pro-stocker to boot) ....and the owner said that I could borrow it for a week or so.....just stay out of his way in the shop (they know me too well there...dang!).

The set-up is easy and we broke the engine in at 2300RPMs for 30 minutes and let cool for a day. Then came back to tweek the carb (a jet change and rods as well on the Edelbrock 750)to peak specs. I ran the engine at differing RPMs for 4 hours and let cool. The sucker put out an expected 358.6HP and 385 ft-lbs of torque. I made ten pulls and all the numbers where within a half percentage point so I figured everything was pretty consistent and stuck together!

The goals of the other testing was to fool around a bit with some salient issues that perplex many a rodder and once an for all, see for myself what the heck is happening. It's the engineer in me that forces my curiousity to amble on I quess. I set out to do fan/hp loss testing and cfm measurements (really a secondary project in and of itself), alternator load losses, and a last minute thought of seeing if synthetic oil would produce any hp in my engine.

The set-up for the fan/hp loss thing was pretty simple. I used a stock plastic shoud (for a camaro radiator) and built it on a screen box (a frame from which a fine mesh metal screen is stretched to simulate some air resistance like that through a radiator) and used two aircraft pitot tubes (opposed in the shroud) and an aircraft airspeed indicator from both to give me a starting point for calculating CFMs.....it worked beautifully! I actually calibrated the radiator/box simulator, as we called it, with an known good source of CFMs to see how close our calculations really were with two differing electric fans. The calculations came in at around plus or minus 5%, and we can't figure if the simulator is off or the calibration has error, but the important thing is that we established a yardstick for CFMS that was consitent. We already had the dyno for measuring the hp and torque thing. Another feature of the radiator simulator "rads" for short, was that the frame was built so that we could adjust the opening of the rads in three plains! This was a time saving feature and made it easy to fit each fan.

All of the fans were directly mounted on the 350. The 350 was fed from a separate water source at a constant pressure. The water pump was a Howard Stewart Stage II (an excellent pump albeit pricey...I guess you get what you pay for). The shroud actually measures 18 inches and is perfect for 18 inch, 17/16 inch (used flex moulding on the opening to bring the edges in for a good fit...hard to explain but worked). Each fan was tweeked to its maximum reading moving the rads in/out to give a good base start. Once the fan was calibrated at base the rads was not moved again. It just happens that we tried to move the rads at higher rpms and the base setting was usually the best performer......and so represents the real and fixed world.

The fans in testing were the Chevy repo big-block fan (956N from Yearwood), seven blades and pitched with taper ends, the same fan with a GM repo thermo-clutch (9189N from Yearwood), the Aspen/Volare six cyl fan that Skip etal likes (and is darn difficult to find....I had alot of mosquito bites after that trip!)and I lovingly refer to as "Skipper", and last but not least the popular Flex-o-lite stainless 17 incher (from NAPA #823-1240). To get the thermo-clutch to work we heated the clutch with heat guns to replicate a hot situation. It really worked pretty good.

The testing was to determine the CFMs at idle (800rpms) and at a slow engine speed (1600 rpms) and hp losses at 4500rpms as well as, and this is an interesting catagory....engine spin-up time from idle to full throttle at 4500rpms (a test that measures the ability of the engine to spin itself up to the given rpm and is directly proportional to the stuff you have hanging out front....this would tell give us a torque expenditure that is dedicated to doing nothing but getting the fan mass up to speed!). A figure of 100% was used for the engine with no fan or accessories involved. We checked all the fans for balance and corrected where necessary! The figures below for this measurement reflect an additional time taken per apparatus!...... And awaaaaaaaaaaaaaaay we go!

FAN TYPE IDLE (800) IDLE (1600) HP LOSS (4500) TIME LOSS %
_____________________________________________________________________

BB18 1680 2355 40.8 8%

BB18C(heat) 1580 2205 35.6 13%

BB18C(COOL) 1104 1400 19.3 11%

SKIPPER 1503 2020 31.5 7%

FLEX 17 1420 1814 20.2 5%

______________________________________________________________________

Having presented this here, I want to say one thing. It isn't a perfect scientific test...but I think it represents a close proximity to real world.
The conclusion I reach here is that the flex fan is a poor performer and certainly many of you have raised safety issues with this design as well that should be taken seriously. A better choice is a Skipper from the stand point of idle air flow but gives up hp on the other end (if you are interested in that...it may be a moot point), and the fact that it is alot cheaper if you can find one. The Skipper is a fine performer at idle and moves alot of air for its size, but ours had to be rebalanced whereas it was out of shape some how...but you couldn't tell it by looking at it....must have been hit or something. The real air mover and hp eater here (and there is no surprise to me) is the BB18. It performed the best and of course has the fattest, longest and highest pitched blades. When coupled with the themo-clutch it gives up some CFMs depending on temperature etal, but doesn't eat up hp on the other end as if fixed. Notice the torque percentage difference with the clutch attached. This is due to the work it takes to get the mass of the thermo-clutch up to speed. One other note here....I played with one fan at several differing RPMs and found that there is a performance envelope that the fan is designed for which will give linear results until the fan starts to have losses due to cavitation and or non-productive eddy losses at the ends of the blade. Some losses are at the center axis as well, but the engineers from flex-o-lite predicted this phenomenom before the testing started. Just remember....Being that we didn't have access to the design specs for these fans, the performance envelopes will vary with application.

The best choice here may be to combine the Skipper with a clutch arrangement to get the best of both worlds...a high mover and diminished hp losses on the other end.

One other note....the themo-clutch was difficult to get to perform consistently with what we set up. We would heat it up and everything was fine then all of a sudden it would lock up under high rpms. We never could get it to stop all the way....even after putting it in the refrig over night. The results posted here took the most time to get the consistent 4 pulls and all of the results were averaged anywho! I would suggest that it would work more consistently in a car with a larger heat source etal.

Of course if its pure air movement that you want the BB18 is the choice for the mechanical fan but is a beheamoth massive structure.

Enough about fans and let's move on to the alternator test. I simulated a test with a Summit one-wire, 100 ampere alternator and tested it at several RPMS. I loaded the alternator down with what I thought a fair representation of typical application of 65 DC amperes output at 13.65VDC. At 4500RPMs the alternator averaged over the 4 tests a measily 1.28 hp loss. It was really consistent with the high being 1.29 and the low 1.26 over the testing pulls.

Last but not least.....is the oil change out. I did a series of pulls after all the testing that we had done and got a reading of 360.4 hp, a slight and expected increase due to friction loss improvements and ring sealing (compression improvements)! I changed to Valvoline Synthetic 10W30 and did it all over again. The test revealed a 363.5, a slight improvement. But there is one other thing that I noticed that I can't explain. The regular oil was measured at a temperature during these testing cycles consistently. The synthetic showed a reduction of 9 degrees??? What?.......the thermostat was the same...the water temperature was the same. My estimation of this is that the surface/friction loss reduction diminishes the heat production and therefore the oil is cooler? Hmmmmmmmmm? I have to think on this some more. Anybody got an answer to this?

Anyway it was a fun and informative project. I had to give the dyno back or I would have run the Skipper with a clutch to see the results. I also wanted to change my roller rockers out to see the difference with my own eyes on my own engine but didn't have time either. Darn......

Steve Jack
HOTRODSRJ@AOL.COM
Concept One Pulleys
Jackstands at Old Cars Only


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George Carnut McDowell
 
An Interesting article I found a few weeks back researching.
Neat old article.


I ran a few errands earlier today with the Suburban Grumpy.
About 90 F outside .
When I came back I let the 350 TBI engine idle for 1 hour with the A/C on High.
Water temp was at 210F steady on the dash.
The 350 SBC just idle & purred away 100 % Happy.
195F T-stat with no drilled holes. Just a Napa stock replacement T-stat.
I revved the engine up to 2,600 RPM's and checked Hot Oil Pressure, 65 psi.
I held my foot on the throttle steady @2,600-2,800 rpm.
The Thermal Fan clutch was engaged almost 100% lockup.
Water temps dropped down to 190-195F after 2 minutes.
454 BBC Radiator I have & installed back in 2012.

On the the 1963 Grand Prix since I have a Vertex magneto ignition system.
The engine will continue to run with ignition key off till the Holley float bowls run out of fuel.
Mallory electric fuel pump Comp 110 I am using.
The Flex-A-Lite 398 Syclone fan I have relay wired to come on with the ignition key and stay on always till key switched off.

Shutting of the factory ignition switch & the 425 Olds Revs higher by about 150-200 RPM's.
So despite what we are told prior, electric fans driven off the alternator Current output- voltage output does require Crankshaft HP/ Torque to drive it.
How much HP I am not sure.

I don't have enough room for a Fan Clutch setup on the Grand Prix but I do have just enough room for a Flex Fan.
Going to try it soon.
Found the Fan I want.
The 425 has ample torque & hp on the street thus far for me, keeping it cool at all times more important.
 
I bought my Flex-A-Lite Fan I wanted Grumpy.
It was shipped out today.
Should see it in a few days.
And I bought the correct fan spacer today.
Checked beforehand with a Tape Measure I & used coat hanger wire straightened out in all planes to verify clearances.

New simple project soon.
Real world test & drive verify operation.
A chance for me to make a New You Tube Video also.
 
I fixed the Cold water Indicator light in the 1963 Grand Prix today.
A nice touch from the factory .
A Green light Marked COLD in the Speedometer cluster comes on when the engine is cold or water temp is at 120 F or below.
Last time I saw it work was 1998.
18 years ago.
 
I have been researching on my own.
Nearly all aluminum performance radiators of the past 10-15 years were good for cooling just 350-400 HP.

Some of the Best info I found on the early Mopar Boards & small forums.

The Vintage Brass & Copper 4-core factory GM Radiators found in select GM Musclecars were likely BEST & Now rare also aftermarket DESERT Cooler Radiators with 5-core construction.
To find for a Pontiac Musclecar today is nearly impossible.
A wild guess the value would be $1,000 nice OEM used & $2,000 NOS GM.
 
Given all, the best deal is to try & pull at least 5,000 cfm airflow through the radiator core at engine idle speeds.
10,000 cfm airflow preferred.
 
I also found a very rare 1963 Grand Prix & Bonneville GM Fan shroud used on only Air conditioning equipped cars.
Was rare new.
Its by Rick in Oklahoma.
Also want 350 for it.
All steel construction & its made like no other fan shroud. It full encapsulates 100% of the radiator from side to side.
Bolts on direct to the radiator core support.
Low profile like whats needed.
I think I can duplicate it close in Eds garage.
Have the the Huge sheet metal shear , sheet metal brake, & TIG welder there.
 
clutch fans have a viscus clutch that spins the fan based against the resistance its working against
the fans generally spin the fastest at about 2000-3000 rpm
,so from idle to about 2500 rpm fan speeds increase along with but not directly related too engine rpm,
much above that rpm the resistance won,t allow the fan speeds to increase nearly as fast as rpms increase
so the clutch fans do soak up some engine power , but not nearly as much as a solidly mounted fan would have.
generally the more blades on a quality clutch fan, the better it cools
I generally used to look for the clutch fans of caddys and buicks as many will mount to chevy water pumps with minimal or no mods
http://garage.grumpysperformance.co...-mostly-over-looked-component.2756/#post-7161
most were available from salvage yards dirt cheap in years past you ideally want something similar to this
FANKIT-7BL.jpg

https://www.ss396.com/chevelle/FANK...MIqpLemIjB6QIVDtbACh1uzwYdEAQYBSABEgKWbvD_BwE
http://www.network54.com/Forum/215655/message/1066184641/Car+Craft+Cooling+Fan+Dyno+Test
don,t forget a matching fan shroud that matched the radiator and fan diameter,greatly increases cooling efficiency
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ccfan1a.JPG

ccfan2a.JPG

Quote:
Originally Posted by DjD View Post
No doubt you'll gain a few ponies with an electric fan but is it worth the extra expense? Here are some test results I got from an issue of Car Craft (May 2000) All these tests were run on Flex-a-lite brand fans except for the factory 4 blade. To baseline things the first dyno run was no fan at all but did include an alternator.

No fan = 496hp
Electric = 494hp
Thermal clutch = 487hp
Nonthermal clutch = 485hp
HD thermal = 476hp
HP flex fan = 476hp
Stock 4 blade = 473hp
Low-profile flex = 466hp
One piece plastic flex = 460hp
OE replacement 6 blade = 449hp

You can see your fan choice makes a difference. The cost difference is quite a bit though and the electric fan they used cost $170 as opposed to the thermal clutch fan at $66 and the nonthermal clutch fan at $56 (remember these are all Flex-a lite products and the testing and prices are from May 2000) Also note that this test didn't go into cooling ability.

Both types of fans can keep your mill cool just like both std and alum radiators do as well. Alum and electric adds a wow factor under the hood but are costly compared to the alternative. I have no proof for you that one flows more air than the other at idle I do feel that most electric fans may actually restrict flow through the radiator and around the engine at higher speeds though.Electric fans also require your electric system to be up to the task and power relays and proper setup is critical. If power fails, the fans don't work. I know a fan belt can fail and cause a mechanical fan to quit working as well so it's a draw unless you are not very good with trouble shooting wires... I bring this up because you hear guys talk about wiring things so the fans run as soon as the key is turned all the time. This is because they couldn't figure out how to trouble shoot and fix the problem or just don't understand how it's susposed to work.

I am using Flex-a-lite's nonthermal clutch pn 5255 and fan pn 5718 ($56 through summit) I had my stock rad recored with the biggest core that fit between the tanks (under $200), a stock water pump and a Robert Shaw (Mr Gasket) 180deg stat ($10 - $12). I run about a 60/40 water to antifreeze mix with no other additives. I have sat in traffic for over an hr creeping along and my 383 didn't get to 190 degs. Moving it stays between 175 - 185 no matter how hot it gets outside.
My point, (as it so often is) is all about budget. If you are not on one your car ought to look and perform like the Mule. If you are on one you need to pick the most cost effective parts to get the job done so you have money for the rest of the project. Nothing worse than seeing a project take years and years and never getting completed do to lack of funds!!
 
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