zooguy

iTrader: (1)

i have an A4 with 3.42's in it now ... the car had 2.73's when i got it but changed them and its a long story.

but my question is now that i will be spraying nitrous would the car do better with the 2.73's compared to the 3.42's?

the first time i went to the track the car (bone stock) would trap right as it was shifting into third ... if i put it down to 2 on the shifter it would bounce on the revlimiter maybe 2 times before crossing the line.
i know that boosted applications like the higher gear ratios (2.73s;3.23s) is nitrous the same way?
what do yall think?

Sales@Tick

iTrader: (3)

Leave the 3.42's in it, nitrous likes to be loaded.

TwitchZ28

iTrader: (3)

So with nitrous a 3.23 would be better than a 3.73?

Sales@Tick

iTrader: (3)

It would depend on the entire combination.

Is it a 4l60e or a TH400/350....or does it have a 6 speed.....?

Rear gearing will be determined by first gear ratio, weight of vehicle, rpm range your camshaft makes it's peak power, stall speed, engine size and tire used just to name a few.

Neal@NitrousOutlet

seeing you have a 4l60e i would stay 3.42s

zooguy

iTrader: (1)

thanks guys

zooguy

iTrader: (1)

what do you mean loaded?

twinturbo2

iTrader: (16)

2.73 gears make my shock short block run 5.69 at 124

Pete91

iTrader: (4)

Sorry for the high jack what do you guys think about going from a 3:73 to a 3:42 or even 3:08. BTW I run a th-350 with a fti 5200 nitrous stall. Haven't sprayed the new jy motor yet,but it's a h/c/i 6.0 bottom end. I'd like to hook on the street lol and drive my car a little more.

speedtigger

iTrader: (16)

I like to work backwards from your intended results. Then use the free online drag race calculator to choose the correct gear.

For example. If I am expecting my car to have a maximum top end 1/4 mile speed of 130 MPH, then I want a gear that will put me near my peak HP at the top of the track. So, for my car that is roughly 6500 RPM.

So, I know I am wanting a gear that puts my car at 6500 RPM @ 130 MPH with roughly 5 to 7 % converter slip (automatic guys do not forget to add this).

So using this calculator:
http://www.hotrodpitstop.com/tool.php

I enter my number and get my results. Here is a screen shot:

Sales@Tick

iTrader: (3)

That's all well and good, but an engine being sprayed on nitrous isn't making power like a N/A motor does crossing the stripe and doesn't have to be in it's "peak" power band crossing the stripe to run a good number.

I'm more worried about him using a less than ideal 26" tire most likely, his staggering 3.06 first gear ratio and then combining that with a 3.90 first gear equals spin city every single time. He will never be able to make it consistently hook.

Nitrous likes to be loaded meaning it likes a high gear ratio to pull against, not a lower gear that is going to accelerate very quickly through the rpm range.

speedtigger

iTrader: (16)

Traction is certainly a consideration. I don't have much experience running the 700 based transmissions, so I will default to your experience with those.

I have also read a lot of conversations about "wheel speed" on the bullet which were above my pay grade. So that could play into what you are suggesting too. Although that may be too advanced of a consideration for us street/strip racers.

Sales@Tick

iTrader: (3)

Yea, with the 4L60e that first gear ratio is killer and really creates a lot of trouble from a traction stand point.

If he was going to run a 28" slick or a 28" 275/60 or 315/60 drag radial it might not be as much of a problem, but I figure he will be using a 26" tall 17" rim tire and combined with a 3.90 gear and a 3.06 first gear that is just spelling trouble in the traction department.

You seem to be pretty tech savvy so don't sell yourself short.

StrokerTA

Only problem with that is what RPM are you going to cross the stripe at? Yes you don't need to cross at the "peak" power point, but you don't want to be going through at the bottom of 3rd, or the bottom of OD for that matter.

Any type of 26" tall drag radial I would much rather have a 3.73 gear in the car. Figure the car will trap MAYBE 110ish with a 100 shot? So with a 3.73 it will go through somewhere around 5200-5500? And it will help him accelerate the first 100 feet much better.
Just my opinion.

11.41 SLR with 3.73 gear
10.46 SLR with 3.42 gear

10secZ28

iTrader: (6)

I am taking both sides on this, wheel speed moves a car not RPM, but this is I believe just a bolt on 100 shot car that likely doesn't have enough *** behind it to get his car moving with 3.42's in it, if the car had more motor and/or more nitrous I would agree 100% to stay with the numerically lower gear. I think he would benefit from a 3:73, but if he plans to spray the house down in the future then I retract this statement, he would likely benefit from a lower gear.

StrokerTA

If he is going to build enough motor to pull that low of a gear, I'm thinking it will have a good DR or slick, and would still like a 3.73.. It's just a nice all purpose gear, I probably install 25 or more of those every year.. Everything from street cars to race cars.

10secZ28

iTrader: (6)

yup for what he is trying to do I agree, 3:73 would get my vote. It would also allow him "room to grow"

Pete91

iTrader: (4)

Are you guys talking about my post? I'm spraying this motor till it blows. I will up the shot once I buy a dedicated cell. I'm not gonna be building a big motor but will deff be upping the shot. Best time to date is a 10.30@127 before I pucked the ol ls1. The setup is a little diff now Prc 5.3 2.5 heads ,fast 90/90,244/239 on a 115 lsa. Only things that changed is I gained cubes, weight, and had a ttp cam 234/244 112. Race weight is 3550 with me in it.

WhiteLTone

iTrader: (18)

just let her eat, i would keep the 3.73's.

StrokerTA

Pete what tire do you run now? I would not go with a numerically lower gear, the car wont accelerate as well as it does now.