car info 01 c5z h/c/i full bolt'ons 475rwhp 415rwtq N/A 600rwhp 599rwtq spray


took my car down to RPM to have the clutch changed, the trans & diff gone true while it was all open i decided to upgrade the trans output shaft to 30 spline and the only 30 spline ring and pinion they had in stock was a 3.90 & 3.42 gear, I had a 3.73 in the car and really liked it wanted to stick with it but sort notice unplanned swap i said the hell with it put the 3.90 in

so wondering if i done the right thing? the car sees the the strip usually after modding to see the results and some nights in Mexico with some friends

last track passes with 3.73 gear n/a no spray

#Q9

 

I have been running a 390 gear on the street since 2009. Great for the track (some say the 410 is a better move). However, it is a lot for the street. Hard to get any traction in first and second...and sometimes third will get loose in the upper rpm range. No regrets though !

 

I also have the 390, I enjoy it and it is at 2200 rpm at 70 in 6th. However with my current power level and tire setup 1st and 2nd are pretty useless. Btw 692/590

 

Great info. I have 3.15's and the car is a little slugglish even with the supercharger. ECS said the next move would be the gears. Do you notice any gear whine with the lower rear? (Use to have a 4th gen Z28 with 3.73's that would whine around sharp curves.)

 

i have about 500 miles on the car now, car feels a little better then when it had the 3.73 but for such a small jump in gear ratio its a huge change in that car i think i need to retune mileage is really low about 15mph mix and thats keeping my foot out of it, cam surge is annoying at times and to keep the rpm under 2500 i need to be in 5th gear by like 40mph

at this point i was much happier with the 3.73 on the street, this feels like a 4.10 gear to me

 

Changing gears should not cause any gear noise, not that it doesn't sometimes happen, but it never should.

 

I'm no expert, but from three "personal ownership" cars and everything I've ever read, what Doug said. They should never whine.

Stroker, I've followed your posts in these "performance" threads for a couple years. You've helped me with your advice; I think you've got a lot more bolt-on and mod experience than I do, but your description of your dissatisfaction seems an accurate evaluation of your set up. (what I see as H/C/I vs. "too much" gear)

I don't have any engine mods; long-tube headers, Callaway CAI, lightweight flywheel, a Chuck CoW tune and 4.10s. Everything I read said that I shouldn't consider H/C/I for additional street performance if I went to 4.10s because of reduced street practicality and gear-shifting issues. I know that 3.90 ain't 4.10, but from your description, it sure sounds too close to 'the same thing'.

Cruisin' on a flat highway I can barely keep to 22mpg on a bone-stock engine at 73mph (my "combined" is ~18+), so 15 "EPA combined" doesn't sound outrageous. Like you, I'm in 5th in residential neighborhoods just to conserve gas at 40mph; prolly revving at 13-1500 though.

Did you booboo? (I love that usage; it's soo funny) "Booboo"? I guess it depends on what you want out of the car. It sure should scream down the track... is that worth it all?

 

4.10s in a Vette ONLY make noise when they are....

A) Installed Wrong..

B) NOT BROKEN IN PROPERLY (or wrong fluis is used)

C) ABUSED and OVERHEATED and/or not maintained regularly.


In my opinion, NOT HAVING 4.10s is SILLY.

THERE IS NO PRACTICAL DIFFERENCE between 3.90 and 4.10 for what it's worth. Why not go with the steeper gear.

There are ZERO ISSUES with highway driving and or mileage or reliability or whatever

FANTASY FOBIAS that many have regarding 4.10s but I can assure you that they are all TOTALLY UNFOUNDED.

The fact is that your car will ALWAYS run better and drive better on the highway at cruise and will always have better

part throttle, and most importantly.... Stop and go city traffic is GREATLY ENHANCED with 4.10s in a stick car.


If you don't put 4.10s..... you're out of your mind. 3.73's.... Nah...... Hardly warrants the money spent when coming

up from 3.42. Auto car with 3.73s is nice and fun just like a stick with 4.10s... Only, we prefer 3.90s in A4 cars.

Steer clear of people that tell you that 4.10s are not the PERFECT COMPLIMENT for your stick Vette... Not matter if it's

C2, C3, C4, C5, or C6...... C7 coming soon!

Take that to the bank.
Chuck CoW

 

thanks! ive been playing with bolt'on & grear mods for the last 25+ years and for the last 13 or so heads and cams ive learned a lot had lots of fun along the way too

well the main reason we mod is for performance right? I guess maybe once i take the car to the drag strip it might all make sense to me then? (I hope!) 10's n/a would be cool bragging rights with my buddy's since they have blower cars in 10's

on the street im still really not liking all the surging car needs to be at or above 2k rpms to avoid it so traffic or just cruising between 25 to 35mph sucks i thinks it needs a tune for 3.90 to be more driver friendly if not i'll be going back to 3.73 at some point honestly

i have to disagree with you! i loved that 3.73 gear even though it was a small jump from 3.42 my car came ALIVE best bang for the buck mod i've done to the car honestly and right now my gas mileage just plan out sucks i was getting 23+ mpg with the 3.73 cruising 80+ mph on the interstate and around 17 to 18mpg around town with my driving style. now im down to 14.5/15mpg on the interstate and 13ish around town, i didnt go 4.10 since i drive A LOT on the highway so wanted to keep some of my mpg plus every time i had a 4.10 (had a few) on the highway the engine always feels like its screaming when you cruise 80 - 85mph like my last 4.10 80mph was 2900ish rpm (lq4/4l80e/4.10 combo) this is not 100% track car its more like 80% street pleasure 20% track duty and street beast

i guess if your really not on the highway a lot or cruise under maybe 70mph 4.10 would not be a bad match? 65% of my driving is highway tho usually 75+ mph

 

A-4 with 3.73's here, I would run out of gear in third running a quarter mile... Now, if I had less power, I'd totally agree.

 

I dont agree with the 4:10 3:90 being better, if you dont have any power, then 3:90-4:10 would help. If you have power, you dont need all that gear. I wouldn't even run 3:73's. In my car, I keep the 3:42 but switch out the MN12 for a 6060 with ZR1 gearing

 

4.10 isnt as low as some would make it out to be

Will say if one is the type to want to always lug the engine (which is bad for it) then those will complain they "have to shift all the time".
Like chuck said very little difference jumping from 3.90 to 4.10

In a span of one month (different car) went from 3.08 to 3.73, a week later 4.11s. 6 spd, 26 in tire is perfect if you like to run it up once in awhile and 6th still feels super tall.

 

Your car is bucking and surging because the gears put a different load on the engine a low speeds and your car probably never hit those cells in the ve table with the taller gears. Your issue should be fixed pretty easily with a touch up to your tune.

 

It's not really low at all...... I'd put 4.30s if they made them....

ANY stick with a 5 or 6 speed NEEDS 4.10s.

Chuck CoW