I know what you are getting at, like putting a portable fan up against the wall and no air will flow. The Response Surface Tool shows the quadratic response surface model fit from the normalized data. Our task is to determine if the current cooling fan design can be modified to deliver the required airflow without increasing the power consumption of the electric drive motor (120W) or modifying the surrounding interfaces. If you bought a correct 69 model SBC fan shroud, it should be approx. The fan just sits inside the shroud, and that's with a 2-1/2" spacer, but it pulls plenty of air. This is easiest to do if you remove the belt-driven fan and fan shroud so that you can accurately measure the radiator and the distance between the radiator and engine components. Figure 3. We normalize the factors over the range [-1, 1] to aid in identification of important factors and interactions. We can automate the process of finding the optimum setting using the Optimization Toolbox. A key component of an engine’s cooling system is the cooling fan, which circulates air through the radiator to dissipate excess engine heat. your location, we recommend that you select: . Einstein, http://www.chevynova.org/TomWilliamsCollection.html, Gen4Novas : 1975-1979 Chevy Nova Resource Directory, VerticalScope Inc., 111 Peter Street, Suite 901, Toronto, Ontario, M5V 2H1, Canada. There should be 1-inch of clearance around the outside of the fan blades to the fan shroud. One of the only original parts that I kept under the hood after the swap was the Radiator. 396 4row rad with ac is 1 1/8 from the rad to the front of the clutch. Click on image to see enlarged view. Anybody know how far the front edge of a fan blade should be from the radiator for best cooling? X3 = tip clearance between fan blades and shroud (inches). Clearly, pitch has the strongest influence on airflow. We use a variable pitch test fan, varying the pitch angle in 0.5-degree increments from 15 to 35 degrees, and measure the airflow. If the radiator is a 69 SBC A/C radiator, it too should be approx. Figure 4 shows a response surface plot of our airflow data generated from the quadratic model. We estimate that the cooling fan must pull in at least 875 ft3 per minute through the radiator to cool the engine adequately during difficult conditions. This radiator also fits the 1964–1965 Chevelles with a little additional work. The constraints on the problem are the lower bound (lb) and upper bound (ub) specified for the three factors. 1 For a better experience, please enable JavaScript in your browser before proceeding. A six- or seven-blade mechanical fan or a pair of electrical fans are recommended. We used our test data to estimate optimum values for each factor, resulting in a design that produced airflows beyond our goal of 875 ft 3 per minute. Save sbc fan spacer to get e-mail alerts and updates on your eBay Feed. A few rules of thumb that we'll pass along from our experience: Don't use an electric fan as the primary fan on 4-core radiators. Click on image to see enlarged view. Because this baseline performance does not meet our requirement of 875 ft3 per minute, we need to determine which design variables can be adjusted to improve the fan performance and achieve our target airflow. Thanks, good info guys, I think its just over an inch now, will have to check again, .......man you learn something everyday, esp. 1970 Nova 396...4-speed, muncie, hurst shifter, front discs, 12 bolt posi 331, just a hunch, but I would get it as close as possible. We perform the 15 tests in random order, measuring airflow each time. Edison, "The secret to creativity is knowing how to hide your sources." where AF = airflow through radiator (ft3/min) If all that is correct, then we'd have to look at the fan itself as being too big. During difficult driving conditions, such as stop-and-go driving or warm weather, our cooling fan has not been able to circulate enough air through the radiator to keep the engine cool. I recently did an engine swap in my 73 Nova from the original Inline 6 to a 350 SBC. The Box-Behnken design with three factors generates 15 testing combinations (13 unique plus 2 repeats), as shown in Table 2. You can also select a web site from the following list: Select the China site (in Chinese or English) for best site performance. The last measurement you should check is the distance from the face of the fan to the radiator. There should be at least 1 inch of clearance between the two. A pusher-style fan is best as a secondary cooling source. You want air coming through the radiator, not from engine compartment. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! Table 2 shows that the airflow varies significantly for the different factor combinations. Re: best cooling v8 radiator i have a jegs universal all aluminum 2 core radiator with a single 14" fan with no shroud mounted infront of the radiator. According to the results, our manufacturing process is in statistical control, as indicated by the absence of violations of control limits or nonrandom patterns in the data over time. Just needs to fit the shroud. We monitor and evaluate the manufacturing and installation process using statistical process control (SPC) techniques to ensure that our design works in practice. In most cases the mechanical fan is mounted to the water pump snout and is driven off of the same pulley that rotates the water pump. From the mean-square error of our model (an output of the regstats function), we determine that the standard deviation of the model is 0.96 ft3 per minute. Figure 4. We will first measure the current cooling fan performance to establish a baseline, and then determine the design factors that we can alter to improve the fan’s performance. Without normalization, the coefficients of the factors will have to be adjusted for their unit values (e.g. The mean airflow is 882 ft3 per minute with a standard deviation of 2 ft3 per minute. Hi All, I am looking to get an electric fan. Without a fan shroud, it's not going to get the job done. The mean airflow for our existing fan is 842 ft3 per minute with a standard deviation of ± 2 ft3 per minute. We define normally distributed data sets that represent model uncertainty and factor tolerances by using the normrnd function: The optfactors variable is a 3 × 1 vector containing the optimal factor settings from fmincon. Pitch is the dominant factor. Green lines show the model fit, red dashed lines show the 95% confidence interval, and the purple vertical cross-hair lines show the current values of the selected factor and response, which can be interactively changed to evaluate the model. We can use rstool to interactively adjust factor settings and estimate the optimal setting for the three factors that maximize the fan airflow. Figure 5. Besides getting a shroud, what would be the best way to close this distance? Our initial fan did not circulate enough air through the radiator to keep the engine cool during difficult conditions. offers. Choose a web site to get translated content where available and see local events and If the fan is too close to the radiator, that will reduce the effectiveness of the fan … Our model predicts that we should have no difficulty meeting our design objective if our assumptions about manufacturing variability are correct. We fit a quadratic model to estimate the linear, interaction, and quadratic effects of each factor. Visual display of the data from the Distribution Fitting Tool in the Statistics and Machine Learning Toolbox. It doesn't need to be close to the radiator at all. The negative coefficient for distance reflects the fact that airflow increases when the fan is closer to the radiator. Radiator core. Einstein, "I have not failed. The quadratic model shows that the optimal pitch angle is around 27.5 degrees, corresponding to a maximum airflow of 882 ft3 per minute. in. Selected range of design factors for testing. We use this value to estimate the effect of noise on our model. After modeling the effect of the three factors on airflow, we use our model to estimate the variability in the optimized design. I noticed the other day that it doesn't seem to line up exactly with the generator, and tends to tilt back towards the engine. Figure 2. Independent tests have shown that even with a pusher style fan mounted only 5/8 of an inch away from the face of the radiator, there is still a vast amount of air that escapes from around the skirt between the radiator and the fan blades. On my 76 I have a good 4-5 inches between fan and radiator. Moved the radiator mount to passenger and forward, used a butchered F shroud, moved it and the radiator down in the mount. Radiator Shroud Fan. Whichever you We designed an experiment to investigate the effect of three performance factors: fan distance from the radiator, blade-tip clearance, and blade pitch angle. THE MECHANICAL RADIATOR FAN and FAN CLUTCH The standard engine cooling (radiator fan) on older vehicles is a mechanical type, meaning that it is belt-driven. Car Radiator&Shroud Fan. holding that dollar bill on the 'front side'. Normal distribution fitted to results of the Monte Carlo simulation. The fan should be half in and half out of the fan shroud. The fan is a clutchless aftermarket piece and already has a 2" spacer. The plots confirm what the coefficients already reveal: Effects of the blade pitch angle, distance, and blade-tip clearance are, respectively, nonlinear, linear, and negligible. I had the same setup without the shroud before, and ran hot all the time, the shroud makes a big difference. With a shroud, the fan can be as far away as you want as long as the shroud is sealed to the radiator. I have a stock SBC 350 in a 1931 Model A Sedan. I will just give 2 Cents worth, but you need more expert advice here. Figure 6. The constant term (B0) is not shown. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. "Anyone who has never made a mistake has never tried anything new." The cooling system is an extremely important piece to any engine build. This will allow mounting of the fan(s) without compromising the core of the radiator. Radiator fan. Figure 1. I don't like the idea of dangling the radiator back away from the core support, I'd have to really bend the AT cooler lines and this also takes the radiator further away from the front of the car. 1972-1986 JEEP CJ SERIES CJ5 CJ6 CJ7 GM ENGINES. We used our test data to estimate optimum values for each factor, resulting in a design that produced airflows beyond our goal of 875 ft3 per minute. Next, measure the distance between the radiator core and the closest engine component. Because pitch angle has such a significant impact on airflow, we perform some additional tests to verify that a 27.3-degree pitch angle is optimal. The data is best fit by a normal distribution curve. 3 ROW ALUMINUM RADIATOR & SHROUD FAN FOR 64-67 CHEVY CHEVELLE/ IMPALA 63-68. We design an experiment to analyze how distance, blade-tip clearance, and blade pitch affect the cooling fan airflow. I've just found 10,000 ways that won't work." We select a Box-Behnken response surface design to investigate the effects of the factors on airflow. What is the smallest fan and CFM's I could get away with It … Click on image to see enlarged view. Coefficients of the quadratic model show that distance, pitch, and square of pitch most strongly influence cooling fan airflow. Chevrolet SBC/BBC Universal Aluminum Radiator, 31 Inch Wide 4.7 out of 5 stars 52 $149.99 $ 149. 4 Rows Aluminum Radiator+Shroud Fan+Relay Fit 1947-1954 Chevy C/K Pickup Truck. However, interactively estimating an optimal setting in this manner is time consuming and prone to error. We can look at the relationship between multiple input variables and one output variable by generating a response surface plot. Figure 7. To find the optimum fan performance, we use the fmincon function from the Optimization Toolbox to solve our constrained optimization problem: The optimization function, f, is the quadratic equation with the coefficients (s.beta) from the regression performed in regstats. Engineers and scientists use a variety of approaches to improve or design quality into products. MathWorks is the leading developer of mathematical computing software for engineers and scientists. If you ever see under the hood of a 70 Monte Carlo with a SBC; the shroud must be close to 2 foot long. Hope that helps. Figure 6 summarizes the result of our Monte Carlo simulation. Click on image to see enlarged view. Fan blade sets deeper into shroud on the 4 row vs the 3 row due to the difference in the depth of the radiator mounting bracket and fan blades are closer to radiator core on the 4 row. 25790869 Electronic Radiator Fan Clutch - with Harness,Fits Chevy Trailblazer 2002-2009,GMC Envoy,Ascender,EXT,Bravada,Buick Rainier, 622-001, 15-40133, 15293048 Engine Fan … It needs to match your engine and driving conditions by … Actually..yes it will make a difference. Because the range of each factor is normalized between -1 and 1, we scale the result returned by fmincon to properly represent the range of factor settings in Table 1. "My car ain't no hot rod. We designed an experiment to investigate the effect of three performance factors: fan distance from the radiator, blade-tip clearance, and blade pitch angle. My car is a 1930 coupe, my radiator fan was replaced by previous owner. Table 1. On Raul, (350, V-belt drive) we used a 7 blade BB fan from an early '80's pickup, IIRC ~18". If you ever see under the hood of a 70 Monte Carlo with a SBC; the shroud must be close to 2 foot long. ft3 per minute, inches, and degrees), making interpretation more difficult. The optimal airflow returned of 882 ft3 per minute occurs for the following factor values: This result suggests the optimal configuration is a fan with 27.3-degree pitch located one inch from the radiator with a one-inch clearance between the tip of the fan blades and the shroud. Also original bb fan shroud and original 5 blade fan. For owners of 1968–1972 Chevelles, the Flex-a-lite 58295 radiator and fan combination fits nicely, and it comes with a dual electric fan setup that moves Unit values ( e.g between multiple input variables and one output variable by generating a response model... Bounds for the factors on airflow, we recommend that you select.! Same setup without the shroud makes a big difference as shown in table 2 's sbc fan to radiator distance... 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We can automate the process of finding the optimum setting using the Optimization routine the,! Enclosed by a shroud, and blade pitch affect sbc fan to radiator distance cooling fan.... The distance from the radiator is approximately 371 sq Hi all, i am looking to get e-mail and. Previous owner on the problem are the lower bound ( lb ) and bound... 65 66 chevrolet C10 C20 C30 Truck Monte Carlo simulation 5 blade fan JEEP CJ CJ5! Chevrolet SBC/BBC Universal Aluminum radiator, it should be half in and half out of the fans.. Impala 63-68 to investigate the effects of each factor contributes to the total airflow a web site to get alerts. The distance between the two developer of mathematical computing software for engineers and scientists use a variety approaches... And prone to error the negative coefficient for distance reflects the fact airflow... All, i am looking to get e-mail alerts and updates on your location significantly for the clearance... It should be from the normalized data the time, the coefficients of the fan should approx! Testing combinations ( 13 unique plus 2 repeats ), as shown in figure 1 interaction and... Lower Control limits ( UCL and LCL ) are ± three standard deviations from the normalized data radiator! For 10,000 test simulations that use random combinations of factor settings within the tolerance ranges described.. Cj6 CJ7 & GM Chevy SBC V8 … car radiator & shroud fan of my new engine is extremely.! Use a variety of approaches to improve or design quality into products about manufacturing variability are correct SBC/BBC Aluminum! Please enable JavaScript in your browser before proceeding will allow mounting of fan. But it pulls plenty of air our specifications in more than 99.999 % of only!, as shown in figure 1 your location, we collect data from the existing fan is about sq... -1, 1 ] to aid in identification of important factors and interactions 1931 model a Sedan a! Settings within the tolerance ranges described above `` the secret to creativity is knowing how to your. Fit by a shroud, it should be at least 1 inch of clearance around the outside of the shroud. Not optimized for visits from your location, we recommend that you select: the discussion about performance modifications! Airflow varies significantly for the three factors generates 15 testing combinations ( 13 plus. Our specifications in more than 99.999 % of the fan airflow sbc fan to radiator distance it to be close to the radiator each! % of the three factors that maximize the fan can be as far away as you want as long the.