One of the guys at work has a stock 99 Grand Am GT. It's a 3.4l, so 160hp and 200 tq I beleive. Car weighs 2950, so it's about 400lbs lighter, auto, stock, and he destroys me off the line like he's got a 350 in it. I'm talking destroys me, I can't come close to keeping up and I got some minor crap done to my car. I'm wondering what the frig. Car is also having some horrid gas milage, 106miles on 12gallons of gas which the racing isn't helping. Just wondering if there's a connection between the 2 and also why the frig this Grand Am is killing me off the line like this.

 

if its front wheel drive it has less travel time between the motor revving and the wheels turning.

plus its much newer ,and probably has a newer suspension design.

and the 400pound diffrence is kind of alot.

it takes 15 hp per 100 pounds to go the same speed.

try putting a few people in his car THEN racing him.

 

GEARING!!!!

You probably have a 2.73 or 3.08 gear combined with a 700r4.
2.73x3.06=8.354
3.08x3.06=9.425


The 4T60E has a first gear of 2.96:1 and a final drive IIRC, 3.63:1. Makes for a overall gear ratio of

3.63x2.96=10.748

That is over 1 full point more gear reduction and gives roughly 10% more torque to the wheels in first gear.

Then lets just say the Redline is about 6,300-6,500 on the 3.4 and the transmission shifts there @ WOT.

Lets also say the generation 2 engines have a broader power band, more bottem end torque, and more HP.

On top of that he is lighter and loses less power to the wheels than you do.

See why he beat you.

 

yeah, his motor has the gen III aluminum heads, its making 185/210, not 160/200. hes got 50 more hp and 400 fewer lbs, you can bet your *** he's gonna beat you.

all the v6's come with 3.42 rear gears, so its not gearing, but there is plenty just in weight and hp.

 

having said those numbers, it makes me wonder why the hell we arent all putting the gen III **** on our motors. i know why im not, and it starts with cali and ends with sucks, but seriously, 50 STOCK bolt on hp? . . . wtf, we're talking like a 40% increase in power for what . . .$300? thats the kind of gains you'd see from forced induction on our stock motors!

 

As for the mileage, have you tried a major tuneup lately?

But Fast355's correct... if you want off-the-line performance, go with better gears.

I "think" you have 3.23 gears in that '91? (Someone correct me if I'm wrong) But, 85-89 2.8's with automatics have 3.42 gears in the back. So if you wanted an on-the-cheap swap, pick up a complete rear axle from an 85-89 2.8 out of a junkyard (probably $100).

Then if your brakes currently work great, move all your brake parts onto the junkyard axle.

Oh- if you go with the junkyard axle, pop the rear cover off and check those gears!! Make sure they're not missing pieces. Tip- bring an old antifreeze container with you. keep the cap on, and use a blade knife to cut the side out. Then, you can lay the container on its side under the junkyard car, and drain the rear axle oil right into it.

Then you just carry it over to the junkyard's oil containers, remove the cap from the antifreeze bottle, and pour that old oil into their recycle containers.

Of course some yards might not care about dumping oil on the ground, but that rear gear oil smells so bad, its not something you want to be laying in on the junkyard's ground.

 

ALL 3rd gen Stick Shifts get a 3.42 gear.

90-92 3.1L Automagics get 3.23 gear.

 

I have a 94 firebird rear end sitting outside 3.42 posi disc brakes, just gotta get a prop valve and wait for the damn ice to melt to put it in....might get sped up though cause I think my drum rears are about to crap out on me. There is something seriously seriously wrong with my car, was racing on an empty highway this morning against some buddies from work and my car wouldn't go past 90mph, used to go to 119mph no problem. Not that I need to be going that fast but it still tells me something is wrong. Gonna change plugs and O2 this weekend probably, all that stuff is pretty new though, plugs aren't a year old, neither are the wires, cap, rotor, coil, O2, air filter, tranny filter/fluid, fuel filter, PCV valve... think that's everything.

 

also, the 700r4 has a better (lower) first gear than the 4T60E that was mentioned. I don't remember the exact ratio off hand but its numerically higher than 2.96:1.

 

The first in the 700r4 is 3.06:1. The 4T60E take less power to drive than a 700r4 and then the rest of the driveline losses are higher as well.

As a side note, I brake stalled my grandma's 1995 olds achieva 3.1 Auto trying to find a fuel system problem, and it brake stalls up to 2,800, then starts spinning. The FWD cars have a HIGH stall converter in them which also helps them get off the line. If you floor it right off the line, the car JUMPs to 3,500-4,000 and just flat takes off. Hers is just the Gen II.

 

how did you brake stall a FWD car and get the tires spinning? were you using the parking break??

 

I would love to know that myself, the parking brake was set though. That is SOP when you are doing a brake stall test. Slick concrete, parking brake set, WOT in drive= tires spinning.

That 3100 in a FWD car will spin the tires easily. The car has close to 275,000 on it, so it just doesn't get driven ***** to the wall anymore.

 

Hehe, I was at a burnout contest once where a kid powerbraked his front wheel drive import... he didn't do too well because he just dragged the back tires around the place- they had no bite. He had no burnout and finally just drove away.

 

I gotta get new tires as well, everytime I hit the gas more then 1/4 the rear tires just spin.

 

back in the day when the local street racing scene was huge, we used to grab a couple trays from jack in the box and stick 'em under the rear wheels of imports, put the e brake up and slide everywhere. No burnout but it was fun watching friends be idiots til the trays wore thru.