JMH

Has anyone changed their ratios?

I swear, if I had a little house on the prarie my car would do 160 MPH.

I'll gladly take a 30mph hit if it improves the sad 3rd and 4th gear roll-ons.

Any thoughts?

italstalnprd86

I want to change mine to 4.45 gears like those on the grand am cobalt cars...... i think she would be sick quick with those...... gotta find out where i can get them though

JMH

Good info........thanks. I wondered how those cup cars could compete, afterall they use the stock 5-speed . Perhaps GMP will offer the gear set to the aftermarket.
It's a shame that a powerplant like the LSJ is saddled with "Bonneville" gearing (to please the Ralph Naders of the world).
Why spend thousands of dollars stressing an engine when the culprit is a shitty final drive . Besides, I think the wing would blow off before it hit 130mph anyway .

kenhebe

Actually the wing does just fine at that speed.

Acidangel_5.0

nod.. holds up fine and actually makes sticking to the road better last time i hit 150

wickednick911

Yeah the last time i topped the speedo the wing held up just fine.

italstalnprd86

I got the info from GM tunersource.com, they have a whole list of specs, they actually change the brakes and hubs to pontiac grand am equipment. Really good info, I was thinking of a 4.10 swap, but as I think about it, 4.45's would be a lot faster, the info says that they are acceleration gears...... what would be even more interesting in my opinion is bolting a vauxhaul astra i believe 6 speed to our motors. They have the 2.0 turbo version in their fwd setup, i would think, with the acception of maybe a new machined flywheel that it should bolt right up. Getting the tranny however may pose some difficulty..... Im sure it can be done though. Even a saab motor swap is an option, find a viggen motor, build it up a little, and drop it right in, I would think the ecu is nearly similar to ours as far as wiring and harnesses go. Our tranny is from saab, and the block is from saab, so why would a 2.0 turbo saab motor not bolt right up? With the complete ecu from saab, I dont think there would be too many problems, plus there are some sick parts out there for saab motors as far as tuning programs, and you can always run a bigger turbo with advanced boost controllers and turbo timers to achieve the power you want where you want it. I love having the supercharged motor because the power is there when I need it, however, at higherspeeds, we are not gaining any more boost....... just my 2 cents, what do you guys think?

STI>>>SS/SC

I don't think changing your guys rear end will do much to the gear ratios.

Psykostevo

Stock Body cobalt SS went 243mph and the wing stayed on. It's a FUNCTIONAL body kit, unlike most cosmetic ones out there.

There is no Rear end anyways. LOL. But it is a Final Drive Ratio of 4.05

NKs07CobaltSS

It might stay on but its a chinsey wing it shakes at 55mph let alone 130. I love the look of the wing but its horrible quality!the flex on it is just amazing !

STI>>>SS/SC

I know.

memphisr24

Anyone with the GM build book, do they mention anything about the 4.45 gears used in the cup car? I have the build book somewhere, but I just can't find it, however I remember reading a section on the cup car in that book.

italstalnprd86

you can get it online, there is a whole section dedicated to the cup cars

leviticus88

My only question is, how are you planning on launching with 4.45 gears at the strip? It's going to make first basicly pointless. lol

1gmfanatik

Believe it or not, I think the wing helps hold her to the road a bit better at high speeds, where she will probably stiffen up a bit because of the wind coming over the car. You could always put the Carbon Fiber center section in there. That would help.

As far as 1st being a joke with the 4.45 gears, I may have to agree a bit, but then again..First gear is a joke now. With Stg2 1st is over at around 25ish. and that whole time you have to be weary of massive wheel spin.

italstalnprd86

^^^^he is right, 1st is a joke now..... the drive gears stay the same according to the manual, the end ratio is all that changes, im not sure if that would effect first or not..... with the stage 2 reflash, i would think 1st would last a little longer because you are getting that extra 500rpms or whatever.... i could be wrong i dont know... 4.10's would be very good for the strip i would think, but i dont spend much time at the strip, and most of my races are illegal.... the 4.45's are meant for acceleration, so i would think that what you lose off the line in first you could make up for in 2 and 3

JMH

Hey, it's my first FWD car..........so go easy on me!

How am I to reffer to the diff? The front end?

InfinityzeN

Lets figure out what changing that 4.05 final to 4.45 would do. Basicly, converting your engine RPM to wheel RPM is done by trading engine rpms for wheel torque (or the other way around in higher gears). So lets see 1000 rpm right. Divide that by the engine ratio (and multiply the output torque), divide the result by the gear ratio (again multiplying the torque), and finally divide by the final drive ratio (multi on the torque again).

If the only thing changing is the final drive ratio, you'll end up with about 91% of the wheel rpm at a give engine rpm you would have with the stock ratio. There fore, you would loose about 9% of the top speed in each gear. However, your wheel torque would be about 109.8% of stock.

Ignoring increasing wind resistance, other loses, and increased shift time (you'll actually be shifting to 4th on the 1/4), we are talking about a theoretical 9.6% more acceleration. Of course, real world numbers would be alot lower or you would see stock 13.8 second balts running the 1/4 in about 12.6 seconds. Including the real world elements (I'm figuring you'll see about 1/3 to 1/2 of theoretical, ammount gets lower as speed increase), plus the the shift time (~.25 second shift lose), our 13.8 second balt should run the quarter in about 13.5.

Oh yes, and people who have never done this before or had any experience with it, it does work. It can actually even improve your gas mileage somewhat if you avoid the heavy foot (lower stress on engine due to higher wheel torque = less gas).

STI>>>SS/SC

Transaxle.

an0malous

Have you been in aircraft much?

I could show you some pretty interesting videos of what wings look like during flight.

flexability and movement in your wing is not necessarily a bad thing.

Most high speed aerofoils will have a certain amount of flexability