05-07-2016, 05:05 PM | #1 |
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RPMs?
What is a comfortable RPM for an Insert Bearing Engine, and what is the limit you should not exceed?
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05-07-2016, 10:23 PM | #2 |
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Re: RPMs?
2200 gives you about 50 mph. I would not cruz over 55 & then only if I felt I needed the speed for safety in heavy traffic. 2400 will give you 55 mph if you have 3.78 ratio and 19 inch wheels. Not sure what 21 " wheels will do. But mph x 44 is very close to rpm. Almost exact with 19"
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05-07-2016, 11:24 PM | #3 |
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Re: RPMs?
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05-08-2016, 06:08 AM | #4 |
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Re: RPMs?
I have a 3.54 ratio and 16 inch wheels.
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05-08-2016, 06:31 AM | #5 |
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Re: RPMs?
You can use the Wallace Racing Calculators to work out revs for any given speed if you know rear end ratio and tire diameter.
http://www.wallaceracing.com/Calculators.htm On the sand at Pendine the '29 CCPU in my avatar did 69.87mph at 2411 revs on 21" tires with a 3.27 rear end Fun with maths. Who knew? |
05-08-2016, 10:47 AM | #6 |
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Re: RPMs?
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05-08-2016, 10:56 AM | #7 |
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Re: RPMs?
And DON'T lug it, BUT, is PARADE MODE considered LUGGING???
Bill Uncertain
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05-09-2016, 09:20 AM | #8 |
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Re: RPMs?
My Coupe has a stock Model B engine. The differential is the original 3.78:1 ratio. I regularly cruise this car at 60 mph, and I have had it over 70 mph many many times.
At one time in its life, I had speed equipment (camshaft; Mallory 12V ignition; Holley 94 downdraft, hi-compression head) on the Coupe that enabled some really high speed cruising. The maximum I drove this car was to 85 mph which I held for about 2 miles, and the engine survived. So based on my experiences (approaching 50,000 miles) for a maximum rpm, my guess is at least 4000 rpm with babbitt bearings and synthetic motor oil. By the way, 85+ mph was a frightening experience with the stock Model A suspension. The motor was still pulling hard at 85 mph, but the car felt unstable so I backed-off and have not gone that fast again.
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Bob Bidonde Last edited by Bob Bidonde; 05-09-2016 at 09:26 AM. |
05-09-2016, 10:34 AM | #9 |
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Re: RPMs?
What wheels/tires did you have on it for your 85mph run Bob?
Can then work out your revs using the calculator above Cheers Juggs |
05-09-2016, 10:44 AM | #10 |
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Re: RPMs?
A quick calc; With Bob's 3.78's and 30" tire (my guess) he's turning ~3600 RPM.
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