MelloYellow

What would the best gear ratio be for the MN6?
Price?
Source?

Thx!




[Modified by MelloYellow, 11:43 PM 10/9/2002]

MitchAlsup

Well, 140 is above 4th gear with stock rear end, so:

If your question is: "What gear allows me to drive any velocity between 60 and 140" there are only 2 choices 5th and 6th.
Price: nada
Source: your car

If your question is: "What rear gear ratio allows me to get maximum performence out of 5th in the 60 to 140 range?" Even 4.10 allow more than 140 in 5th.

Could you restate the question in a form that asks what you are really trying to get at?

EuG

I’m a bit confused too :confused:
Do you mean 60-140mph race?? In that case you better stay with stock 3.42s or you’ll have to shift to 5th gear….

MelloYellow

Ok, let's say I want better acceleration off the line.
That would leave me with going from 3.42's to either 3.90 or 4.10's.

I like highway driving. In my language that means good performance between 60->130. You know, highway driving. ;)

Are the taller gears 'laggy' or unresponsive on the highway at higher speeds? What am I giving up by going to taller gears?

I want better acceleration at lower gears and speeds. But I also don't want traction problems.

Should I consider 3.90's?
Do you only give up top end speed?
I'd like the gears to take me to 170mph on the top end. I don't plan to go faster than that.

Is having to shift gears really that bad of a trade off?
5th and 6th seem pretty weak right now. 1st could use a bit more Oomph too.

Thx!

Untouchable00

You don't plan on going faster than 170MPH!!??? Wow, live on the edge a little, Mr. Conservative. :lol:

EuG

Mellow, the problem with shifting to 5th is not so much the shift itself (although the 5th gear IS always a bit notchy :rolleyes: )
The problem is the rpm drop between 4th & overdrive 5th is too much :(

Let say you put 3.90s. Let’s say you shift at ~6K rpm (~120MPH) in 4th. That will put you at ~4450rpm in 5th gear. That’s a bit too low plus 5th is very tall, so you’ll have a bit of a “lag” until you’ll get into the “meat of your powerband” (5Krpm +)

Check out some mag tests of 0-150 runs of C5s vs. some other cars and you’ll see how C5 is kicking butt in say 60-100, but 100-150 is always weirdly slower than it “should” be (and keep in mind that aero is most of the time superior to the competitor)
Why is that? I bet because they have to shift to 5th passed 140MPH.


Finally, you really need to match the gears to the rest of your setup. What do you got now? Aren’t you considering CERA single turbo?

Oh and btw: Taller gears means higher (numerically) e.g. 3.42 is taller than 3.73 :)
My $.2

MelloYellow

Thx guys! Ya, leaning towards a FI setup around 9-10#. Guess I'll just focus on that. Was thinking gears might be a less expensive way to fill in some gaps, but sounds like I'd give up some performance from 100-150. 5th gear really is a dog. Why is that again?? ;)

Maybe I'll just save the gears and add a small 35-50 shot if the FI isn't enough.

P.S. I see 120 all the time, 135 is a weekly thing. 140 a monthly thing. Only been to 165 once. 170 is the most I would ever want from this car on a rare occasion.


[Modified by MelloYellow, 11:40 PM 9/30/2002]

vetterdstr

It may be best to swap trannys than gears for your situation. :yesnod: This is what I am thinking about doing too.

vetterdstr :cheers:

4DCYKEY

It appears to me that from what you state that a set of 3.73s would be a good change. That would give you the oomph you wanted from a standstill and still give you good power up to 140. Going from the stock C5 tires to a 295/35/18 tire setup would also help reduce the rear gear ratio.

A change to an M12, as Steve suggests, might be another alternative. Would be interesting to see a side-by-side comparison of overall gear ratios (and speeds) from first to sixth with a M6 and 3.73s versus the Z06 with the M12 and the 3.42s. I would think they are pretty close.

Herb

Quick Brick

Try my old threadon this. I am concerned with diff reliability since Getrag only suggests up to 3:73. Maybe add a cooler above that. :seeya

vetterdstr

Herb, I like the new Sig pic. :)

With all the gears, transmissions and tire sizes available one can come up with a good selection of speed/rpm in each gear. One good web site I have used in the past is http://www.f-body.org/gears/

You can adjust the variables within the spread sheet and come up with a whole lot of info. You can also input the info for the comparison between the M6/3.73 and M12/3.42's while using different tire sizes too.

vetterdstr :cheers:


[Modified by vetterdstr, 9:53 PM 9/30/2002]

4DCYKEY

Quick Brick,

Thanx for the info...it looks like 3.90s and the M6 match up better to a Z06 than the 3.73s. I'd probably stick to the 3.73s for reliability, although just changing out the tranny seems to be the real ticket. I'm always amazed at the amount of information readily available on this forum. :cheers:

Steve,

Thanx for the compliment... :)

Herb


[Modified by 4DCYKEY, 12:23 AM 10/1/2002]

MelloYellow

Thx guys. Think I finally understand the gear thing!!

Ya, looks like the 3.90's will trap the 1/4 in 4th at 130mph @ 6500rpm.
Think I'm going with the 3.90's! :D

3.90 gears become just a touch better than the M12 in 1-3, then really kick in 4th vs Z06.




[Modified by MelloYellow, 1:06 AM 10/10/2002]

robiferretti

i got teh 3.90's waiting to go in happy with my decision, and i raec on the roads too ;)