StealDads67

Hey Guys.... For some reason (most likley being bored) I was looking through some members websites and I came across -=Jeff=- site..... I downloaded his gear/tranny/mph indicator.... And I was messing around with it and started to realize, Wait.... my car it at that rpm at that speed.......... so.. i copied down speeds at 3000 and 4000 rpms for 3rd and 4th gear for 3.45 rear and 3.73 rearend and 4.10...... Ends up.. I have 3.73s in the rear!!!!.....

I found that pretty cool.... No wonder my car takes off so damn fast down low.... The torque and teh gears is the answer...... Great Light to light car.... :yesnod: This explains a lot! like beating everyone to atleast 60, lol

65Z01

You should bring that "bad girl" down to Raceway Park on Mar 1 to see how she likes the cold weather.

StealDads67

i would love to... but..... she will probably be in pieces at that point..... :yesnod:

Preacher

I had the same revelation not long ago. I bought this car not knowing that the gears had been changed. After I did the calcs, I figured out that I have 4.11's.... it sure explained the sore neck.. :thumbs:

93aqua

is there a way to check if its an automatic?

hz900

One way to check is to mark the drive shaft and half shaft and see how many turns it takes the drive shaft to go around to turn the half shaft one turn. I forget exactly what you do with those numbers. I think it is like if the DS turns 3 times to HS 1 time it is 3.07. 4 times to 1 time would be 4.11 gears. And so on you get the picture. I think I explained that right.

J Z06

The six speeds really like a lower ratio gear. 3.45's seem to lug the car off the line(when launched with DR's or stickier)

Glad to hear your find was a good one!!

StealDads67

Shoot... Gusy, now Im confused... I was thinking, my tach is off a little bit, like 100 rpms..... So i then realized, I have a 2 stage rev limiter .... DUH....

Set it at 3000rpm..... and now I dont know whats going on.... I need to look this over again when I get on a highway or something so I have time to figure it out..... Its like halfway between the numbers it should be for 3.73 and 3.45..... The numbers are to close together at the low speeds.... Which calls for a high speed run later and use 5th gear to anylisis this.... I think this was false hope though..... (which is cool to, more room for improvement and faster get up and go if I decide to change them) Matter which way you look at it...... Im gonna say right now, Who knows.. Ill give it another shot tonight when I am going to my friends house.....

USAsOnlyWay

So where did you find that program?
TIA

85vettelovin

Yes where did you find this info? Post a link please!

ConeKLR

Easy. He said -=Jeff=- . Do a search for a post started by -=Jeff=-
then look at -=Jeff=- signature. He has a link to his web site. From there look at the link called GEAR PROGRAM. :yawn:

Raistlin

i think you'll find that your tach is off, just like the rest of us :sad:

if you have scanning software, you can check your rpm out that way. or, jack it up and turn the wheel, counting how many times the driveshaft spins.

there's a rpm/mph calculator here, as well http://www.f-body.org/gears/ it's set up for zf6's, too

StealDads67

Well... I just got back from a testing session, lol

I used the MSD rev limiter to do the testing...

4th gear
2000rpm ~ 41 mph
3000rpm ~ 61 mph
4000rpm ~ 82 mph

5th gear
2000rpm ~ 52mph
3000rpm ~ 81mph
4000rpm ~ 108mph

~ = +- 1mph

That shows me 3.73.... Unless Im doing something wrong :yesnod: :yesnod:

Well, Its prob going on the lift tomorrow anyways.... Need pull the cover and change the Rearend oil anyways... So If I bring it in Ill check it out... Sounds like 3.73s to me though.... My one skeptical thing is, Why would you only go from a 3.45 to a 3.73??? What a waste of $300 bucks, go to 4.10s :yesnod:


[Modified by StealDads67, 7:16 AM 2/15/2003]

Jeffvette

Never liked that website. I cruise at 2,000 rpms in sixth gear doing 80 MPH, based on the chart, I should be doing 89 mph at that RPM. It's saying I should have 3:73's in it.

RichS

You need to do more than just pull the cover. There is no"cover" to pull. You need to putt the whole rear end apart to change the lube totally or suck it out the fill plug the best you can.

Raistlin

kevin, your math looks right to me, and i can't see why i wouldn't truns the msd for rpm. nice find!! :cool:


jeffvette, what are you using to figure out the speed of the engine? i can bury the tach on my dash (6k+rpm) and still only be spinning ~4k rpm according to tts datamaster. plus, i have an l98 and you can absolutly tell when you hit 4800rpm, it just stops accelerating.

hngacurv

I just did a lot of checking of speeds/rpms for different gears while driving and according to the program either my tach is off or I'm running 2.73s intstead of the 2.59s like my RPO code lists. Either way, I have 3.07s that I'll put in sometime in May.

ZAD54

:yesnod:

Light84vette

Same here, I'm doing 60 at 2000rpms and with my tire size I have to have 3.54 gears in 4th gear which is .7 ratio on my Auto

Darkness

Its quite simple, you'll have to get on all fours and look at the tranny and ask if she has 4 or 6 gears, if she says 4 its an auto if 6 its a manual, but sometimes they get moody and wont answer so better check some other way, maybe build sheet will say :thumbs: