glass slipper

Also, the C6 Z51 manual cars use the MZ6 while the C5 Z06 uses the MN12...they have different 5th and 6th gear ratios. The MZ6 has a .71/.57 5th/6th while the MN12 has a .84/.56 5th/6th.

Joe_G

Correct you are...I can't believe I forgot about that. I used that gearing advantage to great effect racing my c5z buddy at the Miami Mile event. My 5th topped out at 185 and his topped out at 160 or so iirc.

There is a great article on the difference between the t56 and the 6060 with comparison pics in this months GM High Tech Performance for those interested.

JoesC5

Not quite the spread in MPH in 5th gear as you are showing.

2004 Z06 redlines at 6,500 RPM and with a .84:1 5th gear = 175 MPH.

2004 base C5 redlines at 6,000 RPM and with a .74:1 5th gear = 188 MPH. (MN6 transmissions in C5's have a .74 5th gear, not a .71)

But a stock base C5 couldn't hit 188 MPH in 5th gear, more like 175-176 MPH due to too much areo drag and not enough horsepower.

I guessing you are speaking about your 2005 C6 Z51 that does have a .71 5th gear. That would allow a little more speed in 5th, but the poorer aero in your vert would hold the top speed down somewhat. I see that you also have 4.10's. That would hold the top speed in 5th gear down to 177 MPH, even with a 6,500 redline.

JCtx

Just remember folks that indicated speed is VERY different from real speed. Haven't checked the Vette against radar, but it's a good bet it's a good 9 MPH off at the top, with the typical 5% speedo error built into most cars. By the way, the odometer is almost always dead on accurate. Manufacturers reportedly do it to avoid lawsuits; who knows.

JoesC5

You're correct. I don't have all the information. I only have what you said in your original post....that your friend's C5 Z06 topped out in 5th gear at 160 MPH.

A C5 Z06 with 295/35-18 tires and the 3.42 rear gear and hitting 6800 RPM in 5th gear(.84:1) will be doing 184 MPH, not 160 MPH. If he only hit 162 in the mile he would have been at 6000 RPM in 5th gear, with no reason to have shifted into 6th gear as he would still have plenty of RPM left(another 800 revs) before he needed to shift. Your numbers don't add up.

GM rated the 405 HP C5 Z06 at 171 MPH(6300 RPM in 5th gear). You don't say if your friend's Z06 is stock or not. Even if 100% stock, he should hit his top speed of 171 in 5th gear at 6300 RPM(way shy of his 6800 RPM redline that you said he has, so I'm guessing it's not showroom stock).

Joe_G

No stock z06 does 11.2.

He had 4.10 gears too.

Sorry OP for the hijack arguing with this guy on something unrelated to your question.

JoesC5

Why didn't you say your friend's C5 Z06 had 4.10 gears in the first place. Your post made it sound as if the only difference was in the transmission's gears. Talking about hijacking, you are the one that brought up the C5 in a c6 forum.

That's like some one asking what the maximum speed in first gear is in a C6 Z06 and me making a post claiming I can hit 81 MPH in first gear in my C6 Z06, but not telling the person asking that I have replaced the stock 3.42 rear gear with a 2.56 rear gear. Of course I don't have 2.56 rear gears, but my point is that I would have just thrown a bunch of BS into the post about the person asking about the top speed in first gear, as a stock C6Z06 won't hit 81 MPH in first gear.

Joe_G

Dude please quit busting my chops and hijacking this guy's thread.

Our cars are equal gearing. 4.10's. We run the same quarter mile times thus our horsepower is roughly equal as are our driving capabilities.

He had to shift to 6th before the standing mile was up and his acceleration was over when he shifted to 6th. If you want to see for yourself watch this video and fast forward to about 45 seconds in.




Because my car's 5th gear is longer, I continued to accelerate in 5th through the mile finish and beyond... going up to 185 mph vs his car topping out at 162 mph. He let off after the mile because his car stopped accelerating as you can see from the video above.

To the other guy's post that we cannot trust speedometers, my speedometer is accurate compared to my GPS.

The point of my very short post above was to agree with Glass Slipper that my original post saying the c6 z51 trans was the same as the c5z was incorrect.

And I thought it salient to add that that taller 5th has a demonstrable advantage in certain circumstances, such as a mile race or a roll race. I mentioned that my car went a lot faster in 5th than my friends c5z in actual racing conditions, due to the better gearing in 5th that my c5z51 car has.

I should have mentioned that we both had 4.10 gears, you are right about that. Your tone in your rebuttal post offended me so I replied in kind and I was in a hurry posting at work.

OP I'm sorry to hack up your thread. I was hoping to add salient information to you since you have a c5z pointing out the advantages the c6z51 trans has in case you are considering switching and like to do mile racing or roll racing. I was at work and did not have time to type out a diatribe as I've now done.

Here is a great gear ratio calculator that will allow you to play with gearing and redline and tire sizes and see what effects they have. I have provided real world results in my videos and comments above.

http://xse.com/leres/ss/calculator.html

I'm unsubscribing so I won't get updates as I do not wish to argue further and have nothing more to say on the topic.