How do you go faster than 120mph?

[Under Par]

I just got my '97 six speed. I have tried a few times to test the top end capability of the car, but have not been able to get much faster than 120mph. I have been trying this in normal stretches of highway where there's about a 1/2 mile straight away, but because of my fear of getting picked up for "wreckless driving", I back off the gas when I can't see what vehicles are coming the other way. I have gotten up to about 120 in 5th gear (roughly 4500 - 5000rpms), but when I switch to 6th, I don't accelerate any more, just lower RPMs. Is it just a matter of needing more time and distance to get to the published 174mph top speed?

 

[6 Shooter]

Stay out of 6th Gear . . .

If I want top speeds out of my LT4 , 6th gear is not the 1 for the job, I get the R's/Speed from 5th gear.

Run each gear up toward it's redline to obtain your vette's top speed and acheive it faster.

 

[Roadster Fan]

Top speed is in 5th gear

6 Shooter's right. Doesn't seem like you're getting the rev's as high as you think. Understandable as you're concentration is focused on the road. I've had my 6 speed over 130 mph at least 6 times this summer with a top speed of 153 mph to date :cool

I've posted this pic before of my run. Notice the tach is at 5000 rpm for the 153 mph speed. I was in 5th gear and had plenty of peddle left too. Next summer my goal is 165 mph



Brett

 

[Roadster Fan]

hmmmmmm......... won't let me post a pic that's been posted before. If you're interested in seeing it, let me know and I'll email it to you.

Brett

 

[Wegone]

I would think you should be able to get 120mph in 4th, if I wind mine up I can get 118mph in 3rd and 150+mph in 5th in about 30sec...but than it is a C4

 

[DRTH VTR]

top speed

Do you have the stock rear end, or something else?
Does the six speed come with an optional "performance" rear end?

 

[twiget]

The key to getting the most top end out of your car is to run out each gear to redline. I my GS 1st tops out at a little over 30mph, 2nd at about 68mph, 3rd is 115-120mph. I've not topped out 4th yet, but I've easliy reached 135 in 4th with a lot of pedal left. LT4's are supposed to top out at the mid 170's in 5th gear. 6th gear is too long to get any more acceleration out of the car. As a matter of fact, you actually loose speed in 6th.

As far as I know the same holds true for C5's. The top end gear is 5th gear, and the top speed is also the mid 170's.

Jason

 

[Mongoose400SS]

On a stock C5 you can hold 4th until about 140 mph without any issueand the same holds true on a Z06 5th gear is good above that speed for a little more.I have had 01 Z06 Delco/Mongoose 425ZS to 165 while racing a Suzuki 1200 rice rocket last year in Carlisle, kind of feels like your hovering at that speed so I decided to SLOW down. But back to the subject just hold 4th don't shift and you will be happy with your C5.

 

[Under Par]

Since I just got it...i've been afraid to throttle it much over 4000 - 4500rpms. I'll try to stretch it out a little more in 4th and 5th. Thanks for all the advice.

 

[Under Par]

I just noticed Drth Vtr asked about the "rear end". I'm not sure how to tell if there's anything different. I think the only difference is the previous owner put some type of Borla exhaust on it, as well as a shorter, graphite shifter.

Would this make any difference? Also, what is the "performance rear end"?

 

[DRTH VTR]

"rear end"

What I was asking about concerns the gear ratio in the differential. The stock automatic transmission differential gearing is 2.73:1 That is, the drive shaft (or torque tube) turns 2.73 times for every time the axles (or tires) turn one time. There is a "performance" gear ratio available. I don't remember exactly what it is- maybe 3.42:1 or similar. Having a larger number in the gear ratio often gives better acceleration, but can take away from the top speed. I didn't know if such an option is available with the six speed.

 

[HOTMOTORSPORTS]

Under Par has a six speed car. They only had 3.42 from the factory. Automatics have 2.73 ratio as standard equipment with an optional 3.15 ratio.

Chuck

 

[DRTH VTR]

gear ratio

Thanks for the information

 

[C5_CHICK]

how do you get to 120?

easy very easy

if you can see pic go to my web site pic is a bottom on front page 180 lol

 

[Karl Snedeger]

120

Just come out here to Vegas. There are several roads where you can see 15 to 20 miles ahead and no one coming. As far as 174 mph, the best I've been able to do was 158 going uphill with a A4.

 

[Under Par]

Actually, I just moved from vegas a couple of years ago. Yeah, there's lot's of places to "air it out" in the surrounding areas. I-15 to Mesquite / St. George is probably the best bet I would imagine. The roads here in Texas are too windy (still a lot of fun to drive on...you just can't push the top end). Enjoy those open roads!