john563

iTrader: (17)

Anyone here have 3:90gear in an A4? Im thinking of swapping gears and thought abuot 3:90 gears.I originally was gonna go 3:73,but some one mentioned I should ask about a 3:90 gear.Right now i have 3:23 and a 3500 stall.Im H/C/I and put down 417rwhp and 407rwt.Not that it matters or anything,but how much Rwhp would it lose if i whent to 3:90 from the 3:23 I have now.Am I just better off going with 3:73 or stay with what i have
thanks
john

john563

iTrader: (17)

Anyone?

mzoomora

iTrader: (36)

I just installed a 3.90 in mine. Drives fine, not a lot of extra RPM's over the 3.23. Not a drastic improvement on the street due to the extra traction loss. I was going to post earlier but seeing as how I havent been to the track I dont have any real hard facts. You are really talking about approx. a 6% difference in RPM, so the difference between a 3.73 and a 3.90 is negligible. If you think the extra RPM's are needed or you might go with a taller tire, you should do it.

john563

iTrader: (17)

so there isnt a whole lot off difference with these and a 3:73. I have 3:23 right now. If there is not whole lot of diff. I may stay with what i got the main reason is tha Just in case i go with a bigger cam I dont wanta soggy bottom end.I heard the If I go with a 373 it would help the bottom end if i do go with a larger cam,then a friend of mine mentioned 390 gear thats why i made this post if swapping to a 373 or 390 is worth it over a 323 I started with a 373 in mind,but thought i would ask about the 390
let me know what you think and thanks again
john

Jefro6996

iTrader: (21)

with the 3.90 gear you would max out at 129mph in 3rd geara nd going 70mph on the freeway you be at 2500rpms. Now with the 3.73 you would max out at 135mph in 3rd gear and run 2400rpms. This is based on a 6600rpm redline. So if your not going to be trapping over 129mph i say go for the 3.90 especially since there is a 100rpm difference with freeway driving.

gillbot

iTrader: (27)

go with the 390's john and call it done