I know nothing on gear ratios Reply #30 – January 28, 2013, 10:19:40 PM Quote from: QUICKSHIFT;3630144.10s here. Had 3.73s with 225/50/16s. I had an extra 8.8, so I rebuilt the posi, added an extra clutch and installed a set of 4.10s. Swapped out the rear and went to 255/50/16s and actually picked up mileage! The reasoning was that I could play with different tire sizes if I went to slicks. I'm with TOM on gear. My Comet ran 11.9xs with a 289 ,6.00s a 2.78 liberty top-loader in full race trim. When we put it back to street trim, my street gears are 5.43s and 375/50/15 Pro-Tracs.....and NO OVERDRIVE! LOL! NEVER FEAR THE GEAR! This is my moto don't fear the gear lol Quote Selected
I know nothing on gear ratios Reply #31 – January 29, 2013, 01:29:02 AM Quote from: STANG8U;408319This is my moto don't fear the gear lol Depends on what you're doing. Once you're moving, it depends on how wide your power curve is and what speed you want the most gearing. Would you believe me that with all others being equal, a 6000rpm shift point and an AOD, the 2.73 gears would provide 25% more torque multiplication over 3.73 gears in between 53-73mph? I spent probably dozens of hours trying to come up with a spreadsheet that would tell me these numbers when I was choosing gearing some years ago. The graphs match the numbers in EEC buttstuffyzer so I assume I did the math correctly. My spreadsheet also accurately provides me fuel economy numbers for both city and highway - it was dead on for 2.73, 3.08, and 3.55 gears in my car A 5000rpm shift point moves this advantage to being between 44-60mph, making 3.73's more useful for the street. Since not many 302's breathe well past 5000 rpms, it makes it easy to decide. If course the huge 37% gearing advantage in first up until these shift points helps pull ahead from a stop, if you have traction.Like with anything else, you have to plan your parts for your desired outcome. Mine was having a good passing range for those times when you get people going 40-50 in a 60+ zone. The 4r70w changes skewed the numbers a bit so my 3.08s (which are right at the middle of 2.73's and 3.55's gearing wise) that I switched to from 3.55's would actually be better if they were 2.73's for that 2nd gear passing. I didn't like the 3.55's because of the impact on economy and the lack of traction that I had with stock tires, in the middle of summer on summer tires. I figured with future engine ideas, it'd be a better bet anyway.As for stock SO motor, the more mechanical advantage, the better! Go with 3.73's, or if you want to use reliable mechanical parts and have your speedo remain accurate, use 3.27's.Quote from: creekcougar1988;408308I have a 88 xr7 that i race at the local track, i know from experience that a 4.10 is too much for a stock cars 3.55 is about right in my opinion, My car gets up and goes from 0-60 takes no time to bury the speedo and the car cuts out at a certain rpm. And what're you doing diggin up a thread that died in 2011? :p Quote Selected
I know nothing on gear ratios Reply #32 – January 29, 2013, 02:34:16 AM and yet a perfect example of a "good thread" to dig up imho.i learned a lot just now. ive got a gear here made in italy still in the box i have no idea what to do with. Quote Selected
I know nothing on gear ratios Reply #33 – January 29, 2013, 03:24:38 AM Quote from: jcassity;408330and yet a perfect example of a "good thread" to dig up imho.i learned a lot just now. x2. It really got me to thinking about the rear end swap I will be doing in the near future. 7.5 with 2.73 to 8.8 with 3.55. Deeper would be better, but I can't wait to see what the 3.55s will do. Quote Selected
I know nothing on gear ratios Reply #34 – January 30, 2013, 01:27:20 AM what i know is that i have still yet to find a thread here with a good tutorial on "how" tear down the rear and "set" it correctly. the shop manual explains in great detail how to measure the play and i have it down to a science but they are not speaking to upgrading ect, just repair / assembly so i suppose i could follow the instruction when i need to. Quote Selected
I know nothing on gear ratios Reply #35 – January 30, 2013, 06:11:15 AM I did a complete Final drive rebuild and posted it on the LS site. Been doing final drives all my life. You need a lot of specialized tools to do it correctly. The DIY weekend worrier can overhaul a pre-set unit. But a gear change is a horse of a different color!!Here i am doing very hard unit on the bench. NOTE the home made crush sleeve eliminators. I think i invented that. But who knows!!Just a few photos of a pinion bearing being shimmed and selectedHere is the home made crush sleeve eliminator i made.And the pinion is installed torqued to 135 FT/LBS with the proper drag of 12 INCH/LBS !!! SUCCESS Quote Selected
I know nothing on gear ratios Reply #36 – January 30, 2013, 11:07:08 AM You can buy solid crush sleeves Quote Selected
I know nothing on gear ratios Reply #37 – January 30, 2013, 01:43:54 PM Quote from: STANG8U;408400You can buy solid crush sleevesNOPE NOT FOR THIS UNIT!!!! And there are many units out there that they are not available for. Basic final drives like popular Ford Chevy yes. But not this one. I made my first sleeve eliminator when crush sleeves showed up many years ago. Try and crush a sleeve on a Chevy 12 BOLT WHEEEE!!!. That is interesting at best. Thanks Quote Selected
Topic: I know nothing on gear ratios (Read 5296 times)
previous topic - next topic
