VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1930 RPM

Has anyone put a tach on a stock 194 with stock gears. I am curious to know what RPM you would be turning at 50 MPH

50 MPH? I was thinking (dreaming) about 50 if I took out the 4:11 and put in the 3:50. Maybe I'm too conservative, is 50 ok with the 4:11?

RPM's I would guess would be fairly high, would like to know also. Good question.

With a 4.11 rear end and 19" wheels it should be about 2500 RPM.This is auuuming that the speedo. is acurate at 50 MPH.

gator & chevgene,

I've driven our '30 at speeds of 50 or just over (assuming our speedo is accurate)...is this not recommended?..

epi

Should be safe if engine is in good condition-ie no loose bearings.Wouldn't recommend too much over that for long distances.

45 MPH is usually ideal, but, as Chev Nut says, if your engine is in good condition, 50 won't hurt either. But, I wouldn't go over that with the stock ring and pinion. With the new 3.50 gears, 60 to 65 MPH down the freeway is a breeze!

I normally travel at 40-45, I have hit 50 downhill, but those skinny tires and flexible frames do not really like it. I am guessing the RPM is around 3000 by engine sound. I was just curious.

Since Florida is flat (hope the icecap doesn't melt too much) and no mountains to climb, I thought a 3:50 would be the way to go (no pun) for me. 50-55 MPH for shorter trips would suit me just fine.

I don't know about getting on the interstate, it scares me now in my daily driver.

For my '32.

1918 RPM's for an 18" wheel, 3rd gear, 50 MPH, w/4.11 rear?

1633 RPM's w/3.50?

Is that right?

Is 3rd gear "1 to 1"?

Just a side note!

I noticed that everyone was talking about the 3.50:1 gears that Larry makes. I was talking to him about 3 months ago and he said that the next time he makes gears might be the last.

Hum.......it sounds like everyone that needs those gears should get their orders in so that they won't miss out on the next run! :eek: :eek: :eek:

You can calculate from charts all you want.Piston speed means nothing on a 1930 Chevrolet as the engine can't turn fast enough to have a piston speed problem.The lubrication of the rod bearings and pounding of the mains (with no oil pressure except to the center)is the limiting factor.The end rod bearing troughs get only the oil leaked thru the end mains.Looking back at the proving groung figures for a 1930 50 MPH is about 2458 RPM.60 MPH is a little over 2930.The top speed is listed at 62 MPH.-which would be about 3000 RPM.I know they will go faster down hill or with the wind ,but not for long.The 3.50 gears will give about a 13% reduction in engine speed.That would give a 2565 RPM engine speed at 60 which is still above the safe RPM range which I would consider about 2500 max.A little highr RPM would be safe for a '32 due to the improvements in oiling.....Wheel and tire size.at 50 MPH the 1932-33 engine is turning at 2495 with 5.25 X 18 tires.Engine speed for the 1930-31 is 2458 ---both running a 4.11 rear end. When you get to 6.00 X16 tires its over 2500 RPM.

dog & chevgene,

I agree that the engine seems to cruise happily at about 45mph...the fifty-ish speeds are occasional, going downhill, & while not paying enough attention...

thanks for your comments,

epi

Larry Jackson (the fellow who is currently making the 3.50 gears for the 1930-32 Chevrolets) did an indepth article (based on 10 years of research) on the subject back in the February, 1992 issue of the G&D. It makes for some great reading regarding the issue of going up hills, carrying passengers and etc. with the new 15% reduction gears. In his article he gives specific formulas as to how he arrived at the ideal 3.50 gear ratio without sacrificing power and performance. He also states in the article that "After taking on a few hills and with passengers in the car, 3.50's seemed just right because there was still enough power in these situations." He also says "Of all the things I've ever done to my car, these gears are the single best. They're almost magical. I can cruise 60 all day, 50 is effortless. I can wind out to 20 in low, 35 in second, and it's easy to keep up with modern cars in traffic." The rest of the article is extremely interesting as well and it contains a lot of good information on the subject of the 3.50 gears. :cool2:

Johnny, So if I understand what you said, if I drive like a have a 4.11 when I have a 3.50 it would be even better for the motor.

JYD, where can I go to read the article? Is it on line?

I would be happy to pay for (or send a SASE) xeroing and mailing, if someone was willing to copy and send it to me.

No, the article is not on line. However, you can get back issues of the G&D from Jean Fink, the editor of the G&D. Her address is in the magazine. Also, Larry's article includes several photos as well, and he also offers adaptors so that your speedo will still read correctly with the new 3.50 gears.

Cool, thanks.

Any speed over 40 is too fast for a car with machanical brakes! Specially if your free-wheeling....

Not really. If you have the correct linings for the mechanical brakes on your car, and your brake system is as it should be with the brakes properly centralized and adjusted correctly, going over 40 is definitely not a problem! I have several friends who drive their cars 60 to 65 miles per hour. One is a 1931 Chevy coupe (with overdrive) and the other is a 1930 Chevy sport coupe with the 3.50 gear set. I have ridden in the two cars (even driven the 1931 coupe) and both cars stop on a dime at those speeds because they have the correct linings, and their brake systems are up to snuff. :cool2:

Free Wheeling, now that's another story. It's dangerous to drive a car in free wheeling, and that's why it was outlawed in 1933-34. :eek: :eek: :eek:

and the correct linings would be?..

epi

Woven. :cool2: