hello

First about the car. its a 1997, 3800 II 3.8L Turbo Camaro. with a best Dyno of 456 RWHP and 509 RWTQ. so far i only have 9 track runs in the 1/8 mile. best of 8.05 @ 87MPH with 10.5 psi (can hold 16-18 on pump gas)

Drivetrain is: PI Vigalent 3800 Stall, Rossler stage II 4L60E tranny and 10 bolt rear with 3.23's/LSD.

The clutches in the rear are about gone. so i have to rebiuld.
i was going to upgrade to a EATON carrier and possibly up the gears.

However i have gotten some mixed info.

being a V6 i dont have tons of low end TQ to get off the line so i was going to go with 3.73 gears. then i was told that was to much gear for a turbo and to stay with 3.42 and no more. i have heard different things from different poeple, And i'm really confused.
can someone please explane to me why i can/can't go with the 3.73's? or why the 3.42's are better?
i know my max 1/4 mile with the 3.73 will be about 10.7 or so.... but my goal is only 10.99 (with 26" tires)

i know the GN's came with 3.42's does anyone ever upgrade those ?

 

i would stay with the 3.42's turbo's love the extra load on the motor. i ve had 4.56's in my truck with a turbo and swapped them down to 3.73's and i might even put less gear. I've noticed very little difference in accleration from the bigger gears with a turbo. 3.42 to 3.73 isn't much of a difference as well. the only noticeable difference was right off the line but that was very minimal.

 

so in an NA car 3.23-3.73 would be big diff but in turbo cars would not notice as much !?!?!!?!?

 

yup my truck is just a little 4.3L v6 its seen everything almost

n/a it had 3.08,3.42
supercharged 3.42,4.56
turbocharged 4.56, 3.73

i ve always had a manual tranny in the truck, in high gears 5 th or 6 th i can build boost around 1800-1900 rpms where as in the lower gears i don t see boost till around 2400 rpms give or take. becuase of the extra load on the motor., when i went from the 4.56's down to 3.73's i noticed almost no difference except a little off the line but no so much that i would worry about it.

 

i have been on the Turbo GNX site too and they are saying the same thing not over 3.42

 

TTT any others?

 

Back when I had my turbo'd Z28. IT had a 355" V8 and a GT76 single turbo. THe V8 still had enough torque off the line to get the car moving respectively. Once moving the turbo would hit full stride and WHOOSH.!! That was with a Manual. Now,you are an automatic V6 with a big stall. You shouldn't have a problem stalling up the car and loading the turbo to make some big boost before you drop the brake? If you are in fact making those numbers you should be running better than 8 secs?

When I had the car, it initially had a 4.10 gear in it. I blew that stock rear out! I quickly changed to a 3.42 when I ordered the 12 bolt..... I later lamented not going with a 3.23 or less. WHy? because when that "Biotch" spools its quick shift time and too much( 4.10) gear made my car hard to launch cause it blows the tires off and it never took advantage of the turbo's stump pulling power/torque. So like mentioned, a turbo LOVES load on the engine! It spools harder, faster and makes more power than having the load "lightened" by a gear. You'll watch your MPH go up for sure with a lower numerical gear and maybe down with a higher gear. HOWEVER, I'd stick with a 3.42 in your car. IT should be the best compromise of load vs mph that you need.

Cruising down Memory lane,
STEW

 

i'm still working on my lanch and at 10psi I'm not at 456....... now when i turn up the boost to 16 psi watch out MR. track

 

hes a scan from the track and my 90 MPH run.... the shift point MPH and RPM...

www.turbov6camaro.com/track8.htm

does this tell you anyhting?

 

Stew's right. A more succinct way to put it would be to say that a shallow gear will load the turbo better.

-Chris

 

here is the thing,

with 3:42s or lower, you are spreading out the gears through higher speeds.

In turn this means you are in gear longer, and most Turbos spool up at 2500 or higher. So your launch with 4:56's may seem a little better, but your shifting right after getting into the power. As opposed to the 3:42s where you launch at 2000 rpm and go into boost quickly, then stay in gear longer.

We put 3:42s in a turbo Regal and it was a great combo.

I'd love to see pics of your car, I always wanted to build one like that.

 

http://www.turbov6camaro.com/photo.htm

http://www.turbov6camaro.com/mod.htm

http://www.turbov6camaro.com/dyno/437.MPG << dont mind any NOOB questions i asked the dyno guy, i was still learing how to tune the AFR (kind hard when the MAF AND the MAP max out )
also this dyno was with the broken T-5 tranny.... notice the 2-4 shift !!! lol
now auto and stalled of course

http://www.turbov6camaro.com/dyno.htm

 

nice ride....

no problem with the question. I hated turbo cars and thought they were stupid and "gimicky" until I drove one that was set up right.

THen I ended up building a monster turbo regal, go figure.