faris13

hey guys i just recently put on the 3.9 final drive and was wondering if this in addition to the aps single turbo kit would be too much. Im looking at a milder setup at about 370 whp... well at least "milder" in comparison to some other beasts on here lol. Well just wanted to know if id just be spinning through most my gears with this setup, any info would be appreciated.

bullseye

The 3.5 to 3.9 swap seems to be optimal for N/A applications only.

From what I've read here and elsewhere, many F/I guys are swapping out their 3.5 or 3.9 FDs in favor of a 3.3. The taller (3.3 FD) gearing improves traction in the lower gears, which would otherwise be hard to come by. The 3.3 FD also obviates the need to shift so soon in each gear, most notably under hard acceleration. Of course, the 3.3 FD will also provide improved gas mileage while cruising on the highway.

The 3.9 FD with F/I will make traction an issue in gears 1-3. You may even chirp the tires on the 3-4 shift. During hard acceleration, you will have to shift like a madman to keep from bouncing off the limiter. (Maybe you do that already?) Your gas mileage with the 3.9 FD will suck even worse than it did with the 3.5...

Don't feel too bad. I read a post from a guy who, at no small expense, bought and installed aftermarket headers, thinking that installation would be a great intermediate step on his way to a future twin turbo install! Of course, his twin turbos replace the headers with their own manifolds...

faris13

yea i figured that was the case... I was just messing around this morning and that rev limit comes up so fast now its hard to time the 1st- 2nd shift... i couldnt imagine how it would be with FI. well i guess if i go this route ill end up swapping with someone. Thanks for the feedback

xxlbeerZ

iTrader: (8)

faris13 are you in the APS ST group buy?

Only a few days left, it's $600 off plus a free APS plenum if enough people sign up.

InternetABYSS

we are at 18 paid deposits on the ST GB 7 more and we get the free plenium.

faris13

i wish i was, the turbo project is for the future... dont have the funds right now otherwise I'd sign up in a heartbeat.