71 Grabber with a 1986 WC T5. Just ordered 3.80 Trac Loc and I have now heard that 3.80 is way to steep and 1st gear will be useless among other issues. Bunch of people say 3.55 should be max. Comments online all over the place.....any credible help is much appreciated. The logic I used (which I have less than a novice on ratios) was that I had the same T5 in a 1979 Fairmont 5.0 and a 3.55 worked great but always left a little to be desired. Thanks for your help.
i have 4.11's on the back and you sure do go through first gear quick like a dump truck but I wouldnt change it at all for anything else when you get to accelarate so fast..I see 60mph around 2200 rpms too so thats not even that bad at all with a t5. With the 3.80's it should be a lil easier on you pm first gear... yes this is my daily driver too and it gets a lot of highway miles and street miles...
Something never mentioned is how much power are you making?? It's going to make a difference in how fast you use up 1st... A steep gear isn't going to make up for a lazy engine..
Stock 302 block/heads, mild cam, 650cfm vacuum secondaries. Never had it dyno'd. 1st gear ratio is 3.35....lots of folks saying 3.8 way to steep and 1st gear will be useless
you need to also consider your rear tire height. a taller tire effectively lowers the rear gear ratio. i really like 3.80s with a t5. i usually run a 28" tire but ive dont have any problems when ive had 26" tires also.
you do realize that 3.55's and 3.73's are the bread and butter for the 5.0 crowd, right? Because if you look around at the guys with hotter cams with extended rpm ranges?.. they certianly aren't sticking with stock gear ratio's(3.08/3.27). In fact.. you'll be hard pressed to find a limited edition model(Cobra's, Steeda's, Roush's, etc) using taller factory rear gears like that from the assembly line. Engines that like to rev need the gear to maximize accelleration by staying in the extended power bands "sweet spot". Engines that have more lowend torque can use taller gear simply because the engine can pull it and prefer to live in that range anyways. Which is why putting a massively sized cam behind stock gears will turn it into a pig off the line and increase rpm lag(recovery) between shifts. Now.. that being said.. it doesn't necessarily mean that you "NEED" steeper gears in the rear with a milder cam. Like was said above.. extra gear will not usually make the car faster(even though it will feel faster/break tires quicker from the extra torque multiplication gain).. and can actually slow you down when the motor can't carry the extra rpm(runs ouit of breath too quickly) that the gears/engine combo would like for best effect. With a 3.80 rear gear on a shorter cam like yours.. I'd use 3.55's max for a nice stout daily driver. Which would end up being similar to running a 2.95 first gear ratio combined with a 3.73 rear gear. As was also said.. it really depends on what you like to do with the car and your personal preference. I absolutely LOVE steeper gears in any of my toys.. and after all it's a toy, not a pickup truck used for work duty.. so I deal with the necessary evil's invloved with having a shorter first gear ratio(who really stays on first gear all that long anyways, so wether it's 3 seconds or 1.5.. won't have major impact on the rest of your day). Luckily I don't drive in downtown "stoplight to stoplight traffic" every day of my life for hours on end, and it's a really small price to pay when you do get into open spaces to play. Plus, I build all my engines to rev, so it works best with the overall combo.
Thanks everyone for rapid and clear advice. I am going with the 3.55's as overall that seems to be the best fit. I do drive the car frequently and a few times a year take 300 mile round trip jaunts. Although even with the 3.80 gears I would only be taching 2400 at 60 mph in 5th, it is the 1st gear that I was concerned about. I spoke to Larry at D&L Transmissions in Long Island (he specializes in Borg Warner and Muncie) and he strongly recommended the 3.55. That is primarily because with the 3.8's combined with the 3.35 1st gear ratio, there could be driveshaft vibration issues during 1st gear launches due to the high rpms not to mention an almost creeper gear functionality to the 1st. I am currently running a 2.8 open rear that came with the car from OEM so the 3.55's should be a major improvement for low/mid range jaunts.
LOL.. there's the understatement of the week right there! Good luck with it all and keep us posted on how everything turns out. PS.. you better have some decent tires under the rear of that thing after that gear swap. And even then.. good luck keeping them that way even if you do.
Running 215 60's.......as you indicate....might need to have some more rubber meeting the road than that...or traction bars. On my previous Fairmont many moons ago (which is only 100 pds more street weight) with 3.55 and T5 I had ridiculous wheel hop and traction issues....which traction bars helped tremendously.
My old daily driver was a 69 Mustang, 302 with a mild cam, 4 barrel Motorcraft carb and headers with a T5 and 3.73 gears. I personally wouldn't go any smaller than 3.73! The car was my daily driver, driven to California once, and driven to Oklahoma more times than I care to remember! Since you are used to 2.8s, 3.55s are going to feel amazing! Have fun with it!
I have been driving mine around last couple days: with the 25" tire, first gear is as said, like a dump truck. BUT I can shift at 6500rpm+ as my motor really likes to rev. Unfortunately with 225 tires I get ZERO traction in first or second. Around town cruising it is easy; just use first gear with light acceleration and rev up to 3-4k rpm "easy" then shift into second and get going. I shift just after the intersection and it is fairly smoothe. Or just put it in second and take off if I am feeling lazy. on a 30-45mph road I actually just shove it in 4th and barely any throttle it cruises at about 1500-2000 rpm (no speedo). The only problem with 4.11's is it is WAY too easy to blast off the tires in first. You really will need some serious tire on the street. I have a T-5Z which has even taller gears. My motor is not even that hot imagine if you had a big block
I use a T5 with a 3.35 first gear, 3.50:1 ring and pinion, tru-trac locker, 26" tire and stock 5.0l HO EFI with no mods but headers and a 65mm throttle body. For my preference, it's perfect. I have no issues with 1st gear or tire blow out unless you want to.
