Thread: Project "Left Overs"

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Originally Posted by Itoldyouso

Here is a site I have used in the past and it makes it very simple to figure out your rpms. All you do is plug in your gear ratio (no periods or colons), your tire size and your intended speed, and it gives you the rpms for an automatic, aod, manual, and 5 speed transmission. It is very accurate, my tires on the 27 are about 29 inches tall and it pegged my rpms at 2984 and change. On the road I was turning 3,000 at 60 mph on the gps.

http://www.reiderracing.com/rtech-engine-rpm.php

Try this with your cars info and see how it compares.


I have been considering changing to Hurst brand slicks this time on the rpu, but they are a little short, only 28.75 tall, and the Firestones I had on my 23 were 30. That 1.25 makes a little difference, and also looks better IMO.

Don

Don,
The problem with the Reider Racing calculator is you cannot plug in your actual OD ratio. Their 5speed calculation assumes a 0.80 final drive ratio in 5th which may be right for some, but not for me. My TREMEC is 0.64 in 5th, and TREMEC also has their 6 speed (used in the new Hemi Challenger) that has a final 0.50 to 1 OD ratio. Plugging in a 0.80 OD ratio into the calc I gave you yields the same answer as the Reider calculator, which it should.

That's probably true. I can't afford an overdrive transmission, so it works ok for me.

Don

I'm confused... 5280 x 60 x 12 / pi =121,008.4...

Anyway, I missed the part that says "OD ratio". DUH!! If you take my calculated rpm of 3119 x the .64 overdrive it comes out to 1996. Our figures confirm each other then... Where they got the 336 still eludes me though.

Does anyone else have a new screen appearing at the top of the threads? It shows the members who have posted on that thread and their comments. Is this some new feature, or did I hit some button like I usually do without realizing it?

Don

Nothing different here on my screen... Not yet, anyway.

Don, with the 3.73s, no overdrive, and 30 in. tall tires you will be turning 2507 rpm at 60 mph. With the 28.75 in. tall tires you will got up to 2616 rpm. Not a huge difference...

Yeah, that isn't a big difference. For some reason my CHR site has changed tonight. When I used to go to a thread it would take me to the last viewed post, now it goes right to the very first opening post on page one of that thread. And a new blue screen has shown up at the top of every thread, listing what members have posted on that thread and the first line of what they have posted. Very weird! It also has a lttle tag above it that says Post Reply.

Don

Here, I took a picture of that screen. It is also showing that there are 5 pages to this thread already, but I can only click onto the first 4. Plus, if I click on page 4 it would normally bypass 1 2 and 3, but it just goes to page 1 now.

Originally Posted by Itoldyouso

Does anyone else have a new screen appearing at the top of the threads? It shows the members who have posted on that thread and their comments. Is this some new feature, or did I hit some button like I usually do without realizing it?

Don

Don is the screen showing you logged in as Itoldyouso?
Sometimes my computer doesn't get recognized when I connect to this site, so I have to manually log in, and when this happens I get a different screen.

whoops just saw this new post of yours, never seen that screen!

Yep Steve, I am logged on as usual, but suddenly that new screen has appeared and no matter what I do the thread always starts at the very first post and I have to scroll through to the last one. No one else is getting that screen?? I see Brent is logged in, hope he sees this and has an answer.

Don

I never log off Don, Why do you log off, I can't see any point ???

Screen as normal for me

I don't log off either, Steve. That screen is stil there this morning.

Don

I just logged off and back on and it went away!!!!!!!!!!!! Very strange.

Don,
I didn't see that it had gone away before I posted - I had never seen that screen before, but I replicated it. Go to User CP, then to Settings & Options - select Edit Options, then select Thread Display Options and Thread Display Mode. I believe you will find yours set on "Threaded", while "Linear - Oldest First" is the default. Once you make any changes you have to save the settings at the bottom of the page and you should be back to normal.

Originally Posted by J. Robinson

I'm confused... 5280 x 60 x 12 / pi =121,008.4...

Anyway, I missed the part that says "OD ratio". DUH!! If you take my calculated rpm of 3119 x the .64 overdrive it comes out to 1996. Our figures confirm each other then... Where they got the 336 still eludes me though.

Jim,
Not to beat a dead horse, but the string [(5280ft/mi x 1hr/60min x 12in/ft) divided by pi] has a numerator of 5280 divided by 60 times 12 which equals 1056, which divided by pi equals 336.13. In the original formula

RPM = (mph x Differential Gear Ratio x 336 x OD Ratio)/Tire Diameter in Inches

you're entering MPH so the values in the 336 factor get you to a numerator of revolutions and speed in inches per minute with pi being dimensionless. Then when you divide by the denominator tire diameter in inches you're left with RPM.

Originally Posted by rspears

Don,
I didn't see that it had gone away before I posted - I had never seen that screen before, but I replicated it. Go to User CP, then to Settings & Options - select Edit Options, then select Thread Display Options and Thread Display Mode. I believe you will find yours set on "Threaded", while "Linear - Oldest First" is the default. Once you make any changes you have to save the settings at the bottom of the page and you should be back to normal.

You can do the same thing on this page in the blue (on my screen) bar across the top (under the page count) with the hot links. Click "display mode" and you get a three choice drop down. You're correct that "linear mode" doesn't have the posting tree, whereas "hybrid mode" and "threaded mode" does. Sounds like Pops is in threaded mode. The old goat just changed modes in one of his "moments".

Well, i've got all these buttons on my keyboard and I get curious every once in a while what they do. You are right, I must have changed some setting inadvertently. When I logged off and back on it changed back. I thought I was in the Twilight Zone there for a little while.

Don