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#61
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Here's more info to help out.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#62
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A few years ago I called K&N and asked about the air flow requirements for my my 505 cubic inch engine at 6000 rpm. It made peak power on the dyno at that rpm. They said it required about 745 cfm of air flow. I noted my dyno sheet indicated the scfm at 6000 rpm was 839 cfm. Also with other formulas on the internet to determine the cfm requirements of a engine based on cubic inches and rpm can differ. I mentioned all this to the K&N rep and his reply was they had their own methods to determine required air flow.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#63
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This thread seems to tell me that with my stock built 68 YS engine, 068 cam, .040 over that the OEM air cleaner is my best bet ... am I correct? Would I be better off with a "free flowing" OEM dimension filter? Or just a standard off the shelf filter?
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#64
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As it relates to this topic I'm sure just about every single open-element type air filter assembly will meet the minimum CFM requirements for your engine.
The problems I've seen are NOT related to CFM, they are caused by disrupting the airflow into the carburetor. Every single time w/o exception we've done things to raise the carb closer to the hood then have to move air cleaner lid closer to the carb it has caused some sort of performance issue or loss in ET/MPH at the track. What throws a monkey wrench into some of that sort of testing is running an open element lid or no lid at all and having issues or it not working as well as something else. In any case guiding air into the carb can have a major impact on power production and vehicle performance, so it's something to think about when you start adding spacers, taller intakes, combinations of both, etc........Cliff
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If you can read this, thank a teacher. If you can read this in English, thank a Veteran! https://cliffshighperformance.com/ 73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile), |
#65
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Efficient high performance well thought out combos / motors will make more hp with less CFM, and them VE numbers well above 100% are the icing on the cake!
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#66
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Quote:
I had problems with mine, at any speeds above about 80 mph, blowing out the little filter element for the crank case that sits in it's plastic housing. Every pass at the track I'd pull the air cleaner lid and it would be sitting at the very back of the air cleaner housing. It would stay all day under normal driving conditions but as soon as I hit higher speeds, either on the highway or the track that thing would be at the back of the air cleaner every time. I ended up wrapping a little chicken wire around it to keep it in place. The air coming in that fresh air setup apparently is pretty strong at higher speeds. I don't have that issue with the other cold air packages on the 2 cars that use the cowl plenum area. I've tried all kinds of different open element setups on my Formula, with the scoops open (just dumping in the engine compartment) and the scoops blocked. It's never been able to duplicate it's best times with any configuration other than having that factory ram air setup in place, it just flat works!! What I thought was odd, and why I tried other open elements on it, is that the factory fresh air base and lid is so shallow, it only takes a very short 1 3/4" or 2" filter, and the lid is literally right on top of the carb just 1/4" away from the choke horn. I thought for sure that shallow base with it's short filter would choke it, but larger drop base open elements proved to be worse. Just shows how getting fresh outside air to the engine can be worth while I guess. It's why I suggested early on that Mchell may find even better results if he bought the factory air cleaner setup and made his hood functional, it's basically the same setup my Formula uses, and his scoops are front and center like my Formula, which is said to be one of the most effective hoods for grabbing outside air. If it were mine, I'd even go as far as porting the stock iron intake and performing the mods that has been done for decades by many, so that I could fit the factory ram air setup on the car. I'd like to see that comparison. My money says that there would be some gains there. Last edited by Formulajones; 01-14-2021 at 11:30 AM. |
#67
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Tid bit from a magazine that might be of interest. And relates to Cliff's comments......
When designing a cold-air package, remember that an optimum entry will provide a nonturbulent air supply above atmospheric pressure. Front-facing hoodscoops typically begin supplying air at lower speeds, while rear-facing scoops supply air at higher speeds with less turbulence. Inside the scoop, all air ducts should be designed so that air entering the carbuertor will do so smoothly- preferably through a air cleaner or other diffusing device. Be sure that the bottom of the air cleaner's lid does not rest too closely to the top of the carbuertor where it will restrict air flow. You should leave at least 2 inches of clearance. If your building your own scoop, make sure the incoming-air opening is at least 10-15 percent larger than the carburetor venturi size. This typically equates to about a 20- to 25-square-inch opening in the scoop. For optimal performance, the roof of the scoop should be placed about 2 inches above the carburetor. Be careful not to build the scoop too high because additional clearance can sometimes create turbulence. Adding a scoop to the carburetor system can also effect the air/fuel ratio of the existing combination because the incoming air will hold more oxygen molecules. As a general rule, you might want to begin your tuning by jetting up about two jet sizes (from prior optimum jetting) after you've added a cold-air package. On another note.... and take this one with a grain of salt ! Very successful Pontiac Super Stock racer John Clegg stated that a front-facing hood scoop will work as a ram air source only if the car in question is doing 200 mph. He used a small Harwood scoop mounted backwards on the hood of his 8-second former record holding Firebird ( it looked like a large size Trans Am scoop ). .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#68
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Quote:
Unfortunately with that factory setup, and the low profile of the Formula hood, the lid is literally 1/4" away from the choke horn and there is nothing I can do about that. I'd love to raise the lid, but you can't even get a mouse fart between the lid and hood as it is now. I don't like the very thin air filter that fits in there either, I don't even think it's 2 inches tall, but despite my best efforts to try anything else, the car runs best with this setup. |
#69
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If the boundary layer on the hood of your car behaves as one on a flat plate, estimate how far from the front edge of the hood the boundary layer becomes turbulent. How thick is the boundary layer at this location?
Might be of interest.... http://justacarguy.blogspot.com/2011...of-factoy.html .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#70
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WFO proven performance.......supporting 600HP, mid-11's @119, 4 speed, 3:23 gears
Assemblies available direct, $185 plus shipping in conti US
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Home of WFO Hyperformance Shaker induction. |
#71
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Remember the SCFM is measured and was for the measured Uncorrected HP. A 505 ci @ 6000 RPM @ 100% VE wants 877 CFM. Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#72
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Quote:
That is why it is nice to see Fuel lb/hr and BSFC on the dyno sheet. Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#73
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Stan, you are correct the 839 scfm number is on the uncorrected sheet.
On the 'corrected' sheet at 6000 rpm: Volumetric efficiency was 106.9 percent BSFC was 0.491 Fuel A lb.Hr - 144.3 and fuel B lb/hr - 150.9 659.2 HP at 6000 rpm. At peak torque rpm it was 707 scfm 110.1 VE 0.427 BSFC My point to the K&N rep was their formula to estimate the required cfm was different to other formulas used. No big deal. just an observation. .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#74
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Yep, and quick math will tell you if they are fudging the numbers
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#75
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I'll have to see if I can find that test. |
#76
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Within his articles Rocky Rotella has brought up the related subject regarding the Trans Am shaker scoop when functional. Was as it's more than a hot-selling gimmick to draw potential customer traffic onto the showroom floor and whether the factory sales literature aerodynamic drawings showing high-pressure air at the base of the windshield are accurate or not. Whether it actually worked that way is debatable. Some suggest watching water drops roll off the top of the shaker and backwards into the opening prove it works.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#77
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The pressure developed at 130 mph is 0.3 psi according to Bernoulli's equation and 0.7 psi at 200 mph.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
#78
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So, how fast do you need to go to overcome 14.7 psi atmospheric pressure to gain "RamAir"?
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#79
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Pressure decreases with increasing altitude.
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#80
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Those were gauge pressures, absolute pressure minus 14.7 psi.
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1967 Firechicken, 499", Edl heads, 262/266@0.050" duration and 0.627"/0.643 lift SR cam, 3.90 gear, 28" tire, 3550#. 10.01@134.3 mph with a 1.45 60'. Still WAY under the rollbar rule. |
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