4.10's, a4, and mpg
 

A friend of mine has an m6 and 4.30's, and can get like 400 miles a tank by driving in a very high gear, well auto's don't really have that luxary, so I was wondering how much of a difference 4.10's make? I usualy stay around the speed limit in the city, and 80 on the highway, if that helps.

If you do that much city driving and go 80 on the highway, for the love of God don't get 4.10s! Do you know how many RPMs you'd be turning at 80 mph?! And they pull like a raped ape, but aren't worth the increased revs and gas loss. Go for the 3.73s.

lol......raped ape


ya bro.. I agree with scotty, 373s are the way to go.

with 410s you will be looking at 4000+ rpm at 80 mph

I got em and its sick if you want a 1/4 mile car and a dd. i love my gears!!!!!!!!

i'm wondering the same thing. But some one said that with 4.10s car will shift to 4th at the track

I find 400 miles/tank hard to believe, unless its a V6 :lol:

go to ringpinion.com and then go to thier calculators and you will be able to figure it out yourself

yes. in my car, i shift into 4th right before crossing the line. and 80 mph in 4th with 4.10s is about 3000 rpms. in 4th your effective gear ratio is 2.87:1.

Don't put 4.10's in an auto if it's a street car. IMO there is just no need for that. That's why they make high stall converters. Gears, either 3.23-3.42-3.73 and a high stall converter, say 4,000, will pull pretty well. :)

damn it. i guess i better take mine out then. with higher gears, you need less converter. less stall, means less heat buildup. trade off, don't see any between the two. high stall, less gear will keep rpms up just like lower stall, hihger gears do. i just see less heat build up in the trans.

High stall, less gear keeps the rpm's down on the interstate or anytime you are cruising while locked up. For me that's ~35 mph in third and ~47 mph in fourth. I wouldn't care to turn 3k rpm down the interstate, either. That's why I rebuilt my 60E instead of getting a Turbo 400.
I doubt there is much of a heat difference between a 3500 and 4k stall converter, and with a good trans cooler heat buildup isn't much to worry about regardless.



You have 4.10's in the heads/cam car that runs 11.67? Is that the one you are referring to?

well, i do agree with the interstate deal.

no, i have 4.10 in the 00 formula that runs 11.664 @ 117.67. all stock motor from TB to CATS. pulls a disappointing 1.709 60ft. yeah, i liked the 2300 rpms @ 90 mph better than 3000 rpms @ 80 mph. but, my car is more strip action. hers is more street action.

slp airlid
k/n filter
200 n2o motor rating
yank py3400e
4.10 gears
315/35-17 nitto DRs

the wife's car has stock cam just to let you know. her's still has the stock converter and 3.23 gears as well.

never did answer the mpg question. i get about 1 less mpg with the 4.10 vs 3.23 in town. never did check long distance.

I'd bet the majority of mpg loss is on the highway/interstate. Some nice time for the mods on that one. :cheers:

You may not find somebody with 4.10's in an A4 that has a before/after mpg on the interstate. Most street cars/daily drivers go with bigger stall and more mild gears. Only time will tell.......

thanks for the compliment. one of the few that actually see that mid 11s on stock motor and fuel system is pretty good. and that time was done in june about 1:00pm in the after noon.

did some driving last night.

80 mph = about 3100 rpms
90 mph = about 3500 rpms
100 mph = about 3800 rpms
all were 4th gear converter locked.

This link will help. http://www.f-body.org/gears/

a 3.23 or 3.42 should be plenty, match that up with at least a 3500 stall and you'll be good to go.

:werd: I'm staying with my 2.73s until a 12 bolt becomes affordable. Aslo easier on the 10 bolt.

What may help the 4.10+ A4 delimma, is a little thing called Gear Vendors that I first saw featured on Trucks (copperhead has one)

http://www.gearvendors.com/hrgm4s.html

This thing gives you 8 forward gear ratios, including an overdrive for your overdrive :jest: As you can see, the end gear ratio of 4/OD OD on 4.10 gears is 2.24, slightly BELOW the normal 4th/OD with 3.23s @ 2.26. That'll give you back your gas mileage.

Only downside, $2k+ :(