would a 4:10 rearend gear be to high for a borg warner t5?

 

For me, I really enjoy the 3:42 set up, I have an auto.
BUT, if ya in congested traffic in town, 4:10 may be to low.
Compromise at 3:73 & WIN!
Can your engine handle the extreme jump to instant high RPMS every shift!

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

I have 3,73's and like the better acceleration it gives. I could only imagine 4.10's must be an even greater improvement. THe only bad thing about 4.10's would be your gas mileage. GOing 65mph with my 3.73' I have the RPM;s at 2500-2600. At 75 mph my rpms seem to be up around 2800. I would think 4.10's would put you right around 3000 rpm's at 75 and 2700-2800 at 65mph.

 

I am gear dumb ya'll lol ...Someone give me a little education on gears .Whats the difference in 3.73 and 4.11 ? I know ones higher , but how to you always know whats the best to use and such ....Thanx guys , Wayne

 

Numerically, the higher number equals (the term) a "lower gear ratio".
You are just turning the rear wheels, for every 1 complete engine revolution, the rear wheels turn 4 + times.
For the number 3.73, ALMOST four times, a little under.
My 3:42 example, basically 3 1/2 times the rear wheels turn.
Kinda help?
Truck use these lower numbered gears alot.
They use them to get moving, for the torque produced, with the weight in the truck bed.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

If your not going to do a lot of highway driving go with 4.10's.. I will go with 4.10's because the best I think the camaro will ever run is 100 in the 1/4 so I reall y do not need to worry about running out of RPM...

 

I would personaly go for the 3:73's with a 6. Here are some things you might want to consider.
Fuel economy decrease.
Highway and city.
Is you engine capible of sustaining higher RPM? Is it in good ruuning order low miles ext, ext.
Can you get the proper spedo gear? This may put you in a bind because most if not all t5's dident come with 3:73's. Imagine fiding the right gear for a 4:10.
SSC

 

for my auto ill go with a 3:73 gear. but if i do a t5 swap ill go with the 4:10 gear. Thanks for the help.

 

i just got my car back from the shop(had the rearend replaced) with the new rearend out of a doner firebird i found in a yard in excellent condition, the thing is i dont know what gears were in the firebird rearend i swapped out..so i dediced to keep my old rearend they yanked out so i could gut it and cram some 3.73's in it, which leads me to my question, how do i go about finding some 3.73's to put in there and how hard is it to do myself??

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91 Blue RS with ASCD SS hood w/hood pins, Flowmaster 80 series, K&N, Bosch Platinum wires and plugs, rebuilt transmission with shift kit.

Soon to be added:
Z28 spoiler.
New paint.(black with orange stripes)
A 3.4L V6.(WOOHOO!!)

Official Kills:
80something Monte Carlo SS
New Civic
Ford Splash(Souped up somehow, he was chirpin every shift)
Late 90's Crustang
Early 90's Crustang(at the strip)
Older Eclipse(at the strip)
CRX(at the strip)

 

Go back to the yard, and give us the specs on the firebird....VIN, and we'll let you know (also check for standard or auto).

OR, it should be on a tag or something stamped on the rear diff IIRC.

 

3.73's were an option on our cars. One could procure a posi/disc/3.73 rear for a decent deal if he was to look around. I'd start with L69 and IROC's.

For a T-5 4.10's would be a bit low. 3.73's would be a better choice for an all-around application. If I could find them I would be looking at 3.90's.

 

Gears will be tricky to install if you've never done 'em before; plus, you need to buy all the tools for setting lash & preload & etc. One drive with incorrectly-set gears will destroy them!

You can turn the pinion yoke on the axle, and count how many times the wheel turns. If you can only get one wheel to turn, remember to divide the ratio by two. Ex: A 3.42:1 gear, with one tire spinning, will seem like a 6.84:1 gear.

Or, you can do it the exact way- pop off the rear cover, and count ring gear teeth & pinion teeth. Your gears might even have the ratio stamped on them- the 3.73/posi/disc axle I put in had "41:11" stamped on it- divide them and you get 3.7272727272...


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-Tom P (Hot rodded 1986 Firebird 2.8l)

 

i woulndt be able to make it to the yard till thurdsday but if i got the number stamped on the back of the diff. you could tell what gears on in it? I feel like i have a little better acceleration now with that "new" rearend

 

Uhh.. since noone's pointed this out, Karl explained that bass-ackwards.

The larger the rear end gear, the more times the driveshaft spins to generate a full revolution of the wheels..
Let's start with our usual stock 3.42 gears, in first with a 3.06 first gear:
1 wheel revolution = 3.42 driveshaft/transmission revolutions = 10.4652 engine revolutions (per rear wheel revolution).
Now a car with 3.73 gears, again in first with a 3.06 first gear:
1 wheel revolution = 3.73 driveshaft/transmission revolutions = 11.4138 engine revolutions.
Or a car with 4.11 gears, again in first with a 3.06 first gear:
1 wheel revolution = 4.11 driveshaft/transmission revolutions = 12.5766 engine revolutions.

Notice how quickly the engine revs climb even with seemingly small changes to the rear end ratio.. 4.11's are great on the track, but forget the highway.

Hope this helps out those who don't understand gearing.

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'86 Camaro SC, black /w silver racing stripes
2.8l MPFI/700r4 /w special 2nd gear delete option
In search of new v8 engine & transmission, now contemplating t5 swap to get me out of this mess.
Misc Mods: Cut air box, '83 Firebird spoiler.
Performance Parts: MSD coil, Accel 8mm wires, SplitFire plugs, Gabriel hijackers.
Audio Mods: Pioneer DEH-P3000, two 12" Optimus Pro Audio subs in hand-made enclosure each powered by a 260 watt Optimus amp. Working on shaving the box for weight.
My Homepage, with pics.

 

THANKS FOR HELPING MAKE MY ANSWER BETTER UNDERSTOOD, (even to me! )!
I was dealing with just the rear gear action, not the whole drivetrain/tranny issue.
With 3:42 gears 55 MPH, ya looking at about 22-2400 rpms.
W/4:11 its much higher. About closer to 3K RPM's?

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA

 

You can use my favorite tire/wheel/gearing calculator to figure out your engine rpm's... the website is: http://www.tolan-hoechst.com/cars/tirecalc.htm

Put your tire size in at the top (I never put in the offset) as the "current" tire. Then go to the bottom of the page, under Effective Gearing. Change the first item ("Wheel RPM at MPH") for the speed you want. Then, change the differential gear. (You can also change the tranny gear; Drive is 1.00 on the 700r4.) Click to another field; the page recalculates every time you move to another text area. Look at the "engine rpm's, current". Change the differential gear again, click somewhere else, and watch the RPM's change.


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-Tom P (Hot rodded 1986 Firebird 2.8l)