jayz28

iTrader: (3)

Here's the thing. My buddy bought a relatively stock LT1 Z last year and planned on doing mods to it one at a time to see the gain. The car came with Long Tube Pacesetter headers and a shift kit. Baseline runs last year was 14.20s. Then after barrowing my slicks and cold air he managed a 13.95 mph.

This winter or early spring rather we completed a gear swap from 273s to 373s. The car feels a lot better! Runs amazingly better. We noticed the car shifted too high and I tried to adjust it down some. But I don't have alot of experience using Tunercat.

We took the car to the track last night and was expecting alot better times. I was really expecting several tenths quicker et. Well the car ran 13.92 at 98mph.

So my questions to you guys is WTF is wrong? LOL

Where should the car shift?
Should we have ran quicker with a gear swap?
Do the slicks hurt it any?

Bowtie Boy

What kind of slicks? Slicks should help not hurt except if he launches hard and destroys the rearend...

Gears swap will always make you run faster.

Compare time slips could be something that differs, for example the 60'
Weather could have been different etc.

Slow94Formula

iTrader: (18)

I'm guessing weather had something to do with it.

jayz28

iTrader: (3)

Weather was good. 65 degrees. Slicks are from Micky Thompson. I got em on trade, never used em. He stole em with my draglites and been using them since last year as my car is still a work in progress.

I don't have the numbers with me at the moment but I do remember the 60' dropped a tenth. I need to to study it a little more. I'm working on a better wot shift table right now. I think the car is over revving.

SS RRR

iTrader: (2)

I would tend to agree. If you are running past your power peak it will only slow you down. Stock power peak on a LT1 is 5700 if I recall?
Here's a great sight to figure **** like that out:
www.f-body.org/gears

jayz28

iTrader: (3)

Datalog shows the car is shifting at 57-5800 rpm. But I've been researching online and stock cars shift at 5300. Should I lower the shift points to 5300 and try it out????

Nastyc4

iTrader: (13)

FInd out how tall the tires are and add that into the calculations on that site. I will admit I am NOT a fan at all for gears. they suck. all they do is give you a shorter first gear. They are good for dump trucks and garbage trucks.

Now, they will NOT always make you faster. they will sometimes make you quicker. all depends on what rpm and gear you are trapping in. When you are using a slick they are beneficial because you want as MUCH torque possible at the wheels since the slick will help it go to the ground. this is why gears usually help e.t. after first gear your 2nd gear is almost the same as the old 1st and so on so theres not much improvement elsewhere.

Go ask the guys on viper alley why their cars go slower with gears. They have truck motors that are designed to pull heavy trucks and loads. when you ad that to a light car you get a car that needs a lower gear to help it go fast. Hence the very low 3 series rear end gear in it from the factory.

Slow94Formula

iTrader: (18)

Isn't it true that the fastest stock auto lt1s have 2:73's, and the 3:23's were slower? I just remember seeing something like that in another thread on here. I know it is strange, but I am curious if keeping the engine under a heavier load makes it faster. ???????

1dirtybird

iTrader: (7)

my old lt1 car was a 2.73.... the best stock was a 14.5 @ 94 ish
my buddys was a 3.23... best stock was a 14.4 @ 95 ish

I did a cai, slp dual dual cat back and 3.42's i went 13.7@102.5 W/ 2.19 60ft(no tuning, but mine was a 93)

Best before gears W/cai & cb was 14.0 @ 99.5... 2.2 60 ft


my buddies had cai, bbk shorties, flow master cb, and 2400 verter best was 13.8@ 98 W/ 1.9X 60 ft ( no tuning and was a 94)

So gears made a huge differance in my car.

Wicked94Z

iTrader: (26)

lol at this thread, so much misinformation it should be deleted.

1dirtybird

iTrader: (7)

Dude you have to remember most lt1 cars are in th hands of kids. Around here a beater LT1 can be had for 1500~2000 and a nice one is 3500. They are just new at the game and learning.

SS RRR

iTrader: (2)

You should dyno it to see where your power peak is, however yeah if it's easy enough to change then play with your shift points.

Wicked94Z

iTrader: (26)

I am a kid, I'm only 22. somehow I figured out how not to be a moron

nighthawk15

Not to sound like a dick, but that makes absolutely zero sense. I know what you're talking about though with the 2.73s sometimes getting good stock e/ts. I don't really know the exact reason, but I'd be inclined to think it has more to do with traction. That's really only if we're talking street tires though.

MickT/AWS6

i agree, im about to turn 21 and i've been tearing apart f-body's for ten years now, some guys just think a v8 and exhaust is the ultimate recipe for badassness, just like a ricer thinks a turbo is all you need for a stocker to go to rocker. I have 4.10's and i love them but i have a 6 speed. My 3rd gen had 2.73's and i swapped in 3.73's and saw a world of difference, that was my only mod besides exhaust. Those shift points sound like the culprit, dont go straight to 5300 rpm find a happy medium attempt to lower it from 57-5800 to like 5500 then give that a shot and work your way down if necessary, it still has a stock stall correct?

97Z28SS

iTrader: (5)

Anytime you change gears in an auto powered f-body you need to get the computer recalibrated for shift points,firmness and speedo accuracy. I brought a 97 Z a4 some years ago and the previous owner had installed 3.73s but didn't get the computer done and it ended up costing me a tranny rebuild because the trans shifts based on mph and with different gears the computer was shifting up and down at the wrong times and burned up the trans. I got a mail order tune from Mad Z and had the tranny rebuilt with a Trans-Go shift kit and all of the billet internals and added a 2800 stall and external cooler and man did that wake up the car.

jayz28

iTrader: (3)

Yes, it still has the stock stall. We have a stall converter and cam waiting on the side.

jayz28

iTrader: (3)

Misinformation or not. I'm just trying to figure out why the car ran slower. It feels like a world of difference on the street but at the track it under performed.

BTW your rims look badass. What are those? Kinda look like Billet Specialties...

Slow94Formula

iTrader: (18)

Or the fact that the torque is made down lower in the RPM range on a stock cam, and with 2:73's you stay in the torque band longer. I don't mean to sound like a retard, I just wanted to throw that info out there. I have two friends with A4 LT1's and one has the 2:73's the other has 3:23's (both stock besides a CAI). Neither of them spin off the line, but the 2:73 car runs faster by about a tenth. and gets a slightly better 60 ft. Could just be the driver I guess.

Wicked94Z

iTrader: (26)

billet specialties street lites in 15x4 and 15x10