I have had some questions about my progress on Rodan so I thought I would post something. It is coming along. No time table...just trying to keep it fun as I go. I could probably have it finished in a week if I wanted to...but I am in no hurry. Ron.
Hey Ron it looks great, is that a sub 12 sec. cage? You might need to plug your left ear. Can you get in it without a huge smile on your face? can we see some pictures of the front?
I should have no problems teching below 12 seconds. I don't think anything I could do could make it any harder to get into. I bet the starter is going to hate me when Rodan screams at him. These are the most recent pictures of the front end...two weeks ago.
I have plans to be at the car show at Tinker Federal Credit Union on the 28th...and to run with the Central State G***ers that afternoon and evening. That is my goal...but it depends on a lot of things going right. I will make the show for sure, one way or the other................. If my math skills are right...I should be able to just move enough air to let the little 6 twist 7500 RPM, if it wants to. With the 456 gear and about 1200 lbs I should get solidly in the 13s.
Ron, 13's??? I think more like the high 11's. Car looks good. It looks like you put quita a bit of thought in it before you started building. The exhaust looks killer. Ron
Thanks...my buddy Sam kids me all the time about over-engineering everything. I do have a plan...most of the time. I was thinking 11.13s...if I can get those tiny tires to hook..........ha ha.
JESUS! Who did you get to do that fancy welding on those headers? It looks like they'll fall off the first time you start it. I guess my idea to put cones on the end of the headers wasn't such a bad idea after all. I told you it would look great. Just kidding everyone! My dad's a master fabricator. He's the McGyver of hambsters. Love you dad.
If I have to worry about the welds on the headers breaking I am in bigger trouble than that...and I have never been caught masterfabricating in my life.....You know you are my favorite son.
looks like a first rate job cant wait to see it run if you dont mine me asking what is the total cfm of the carbs
Should be 920 cfm. If I have done my math right...my 256 CI at 7500 rpm will need 853.3 cfm for maximum volumetric efficency (VE). I had to choose...be way under or a little over...I figure that VE has got to be like ***...more is always better, right. If you want to work it up for the Hornet car...here you go: FIRST- Where: rpm = maximum design rpm TAF = Theoretical air flow (ft3/minute) VE = Volumetric efficiency (100% theoretical) ED = Engine displacement (in3) ES = Engine stroke (2 for a four stroke engine) C = Conversion factor from in3 to ft3 THEN- Where: VE = Volumetric Efficiency (%) AVF = Actual volumetric flow rate (ft3/minute) TAF = Theoretical air flow rate (ft3/minute)
Cant wait to see if your math works,I betting it dont. I have found nothing takes the place of being at the track and doing it. Good luck Zilla.
Thanks...I am counting on having a lot of luck....and may need it. You are probably right...building a race car is not "rocket science." I could see it now...the guys a NASA putting a bunch of odds and ends parts together...aim it at the moon and lighting the candle. I guess it's a matter of matching your choosen methodology with your the expected finished product.
10/4 on that more is is better theory by the way MR MAC doesnt like loud cars so line up to put those pipes in his right ear he cant that flathead running
Carb breath what the hell are you talking about? More of what? As far as the hearing goes you guys ruined that last year,now I can hear nothing. So tune those big sixes up.
mac reread god zillas post as for the big sixs both flathead teams are larger by quite a bit not to worry we will have them tuned up
Ron, CFM= Displacement X RPM X VE 3456 256 X 7500 X 1 = 555.55 CFM 3456 Reference: Holley Performance Manual. Ron Golden
I can't wait to get it running now...will Rodan fly and breath fire...or blubber and spit fuel out the exhaust. It is going to be a blast finding out what it does. In the formula that Holley publishes for calculating CFM they do not use a conversion factor for CI...that would make my little 6= .148148 ft cubed. Also, they divide engine cubic inches time 7500, by twice the number of cubic inches in a cubic foot. I wonder why they do that?
Try this 1728 cu. in. equals 1 cu. ft. 256 cu. in x 7500 rpm. but you only fill each cyl every other revolution, so you need to cut one of these, cu. in. or rpm in half. so then 128 cu in x 7500 rpm equals 960000 cu. in per min. then divide by the 1728cu in. 960000 divided by 1728 equils 555.5555 cfm.
So actual engine displacement is CI/2 when you multiply times RPM (in my formula above it has you compensate for 2 versus 4 stoke engines). Also, doesn't this formula ***ume that the column of air that you are moving is at sea level and at 32 degress F? Well, on paper I should have carbs capable of providing all the air that the engine will ever want...and that was my goal. We will have to see if there will be sufficient va***e at the venturi to draw fuel into the air flow. So on we go to the next part of the formula...air-fuel density. We have now calculated Theoretical Air Flow...what is needed next is a measure of Actual Volumetric Flow Rate (this measure is in lbs/minute). Also, we will need to know at what al***ude and air temperature the engine will be running. Lets hold off of grains of water in the air...we can have that fun later. Who wants to calculate Actual Volumetric Flow Rate? When we get done we should find the other 297.75 CFM.
Can't wait to watch you mathmatical geniuses make your first past ever down the track. You better plug into your computer how to get the car off the line,when to shift and then you got to stop it. Be sure to bring your lap top so you can tune your 50's style dragster.
Thats a very good point. Well...like I said, my friend Sam kids me all the time about over engineering on my car. The way I see it is...I spent nine years in college...and have taught statistics out at the college since 93...so WHY NOT put a little math to it. It might save me from having to make trips back and forth to the strip to test and tune, test and tune and test and tune. Besides, it is harder than hell to add a 4th carb to a 3x2 intake.
I thought there was only a couple calculations. Light turns green. Throttle = 100%, tach redlines, shift, repeat.
Godzillia I knew right off you had a lot of schoolhouseing but statistics prove if you have one foot in the fire and the other in a block of ice onthe average your comfortable the killer will be the plenum volume me thinks
That is a good point. Well, it's widely accepted in the tuner world that plenumn volume peaks at 1200 cc with 12" runners....however I would have to turn the little 6...14,500 rpm to hit that peak torque. If I run 18" long runners then I would reach peak torque at 7500 rpm...but the carbs would look really funny 18" in the air. So...if I had thought of this while building the intake I would have made sure the volume of the plenumn did not exceed 2000 cc....to work with my 6" long runners. I could have also reduced the apature of the opening in the bottom of the intake (relative to the potential volume of the 4 carbs) to increase the velosity of the intake charge as it leaves the plenumn. But that would have taken a lot of thought on my part. HotRod F-1...thanks for the kind comments. I can not wait to get started on my g***er. This deal is almost done...I am ready for another project. Are you going to make the show at Tinker?
mrmac, I think that I have an old slide rule, maybe it would help if I use it for a gas peddle. You tell us to go on the green light, but I don't think that you ever see the green light.
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