Thread: need gears

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i need a new set of gears for my camaro i think i have some 2.73 and there killing me. i went to the track the other day and didnt do so well my 60" suck 2.15. i can acually go threw the finish at 6200rpm in second. the trans shifted by itself to second at 5000rpm but the other day i put some lighter weights in the trans govoner and took it out on the road and it shifted at 6600rpm and it was still pulling so i got the set up havent had it to the track yet. the fastest time i pulled of was 13.75 at 104.65mph how much more do you think i can get out of it from the shift point i have made. also i have 26" tall tires do you think i should go for 4.11 or 4.56. this is a race only car. looking to get in the 12's thanks

1987 iroc camaro gutted, 4" harwood cowl lift off, lakewood 90/10 struts lakewood 50/50 shocks, battery relocated to rear, b@m pro stick shifter, weld pro stars 15x6 in front 15x8 in rear, hoosier quick time pro 26/11.5/15,

355ci
dart iron eagle 215cc platinum heads with 64 cc chambers with guide plates, isky 507/507 lift 247/247
.50 lift with 108 lsa, victor jr intake ,holley 650dp choke horn milled, 1.5 roller rockers, moroso tall valve covers, hyper flat top pistons with 4 valve relief, stock rods, eagle crank, 1 5/8 longtube headers with 2 1/2 pipe and dynomax race bullets, turbo 400 trans with b@m shift kit and unknown 3500 stall

Hard to say without the weight of the vehicle but I think 4.11:1 is about where you want to be for that setup. That should put you through the traps at about 110mph at 6600rpm which should equate to mid 12s for a 3400lb car (more or less). You may even get away with 3.90 gears depending what power you're packing.

This is my best guess, I'm sure there will be other/better opinions...

Check out these calculators:

http://www.tciauto.com/Products/Tech...alculators.asp

-Chris

I like 3:73 - 4:11s for street and strip. 4:56s give a great launch, but they're a little steep for highway driving (especially without an overdrive or tall tire).

-Lee
www.atomicpinup.com

I hear that, Lee... 4.56 is still too short with a tall (31") tire... buzzing along at 3400 for 20 miles or so is enough to loosen your fillings and impair your hearing, but that's the price we pay. Great for good short times and smoking fat tires on the street, tho

I agree.....my pro-street '64 Chevy II has 4:86s on 33" tall tires. It's great at the strip, but pretty annoying at 60 mph on the highway (the motor's turning around 3,000).

-Lee
www.atomicpinup.com

the carb jetting is 68 and 72 timing is 34* advanced no tire spin i just baught a 4000 stall for it beacuse the stall i baught before from a guy was supposed to be a 3500 but only stalled about 2200. and i got the trans to shift out of 1st at 6700 now insted of 5000 hopefully i will pick up some do you think i should change jetting on carb. and what do you think i will pick up with the new shift point and stall with out the gears for now.

You will still be slow as a slug off the line with those gears... the 4000 stall will be better though.

If your rear gearing makes use of all the gears in the tranny, you will get significantly better ET's.

Jetting depends on way too many variables to make a guess from 1000 miles away... read the spark plugs to tell whether you are too lean or too rich... there have been a number of threads on here dealing with plug reading and I've found some good articles elsewhere on the net (google read spark plug). Try a forum search here or google to learn how to read a spark plug for both a/f mix (at idle, part throttle, and wide open) and timing advance. My guess is you could be running at least another 2* timing but I can't know for sure without figuring your compression ratio, fuel octane, etc... if you're running something like 100 octane a few more degrees timing can make a big difference.

You can try increasing timing advance in 2* increments until you stop improving mph and back off a little from there. You can use the same technique with jetting... increase jets 2 sizes at a time until you pass peak hp (if increasing jet size slows you down, go the other way). Use mph as your metric as it will be more consistent than ET because of variability in the first several feet of the run.

I know these aren't the quick easy answers you're looking for but I hope it helps...

-Chris

5:13's are fun on the highway LOL <wink wink>

After you get some gears that will actually launch the car, might want to get some frame ties and a 6 point bar to get the car tied up a bit....Unibodies eat up a lot of torque before it finally makes it's way to the tires. Horsepower is nice, but doesn't do a lot of good if you can't hook it up!

i just found out that i had a broken pushrod when i ran the 13.75. I went to the track tonight with all the cylinders and ran a

60ft. 1.771
1/8. 7.721 88mph
1/4 12.10 113mph

still shifting at 6700 out of first and going through the trap at 6600rpm in second.
second and third runs the car was breaking up down the track not sure why yet think its electrical. tires hooked alot better this time. girlfreinds first time running the camera lol NEED GEARS!!! think i scan hit mid 11's also installed 8 point cage

http://www.youtube.com/watch?v=ps6rBqJeeZU