I don't know guys. I just traded in my 99 Z51 hardtop for a C6. Both cars are 6 speed. The only thing I did to the 99 was a Vararam intake and ported MAF.

Now here's where I'm concerned. I've only had the C6 two days and have only been able to drive it on dry roads for maybe 10 miles so far, but the C6 doesn't seem to have the "grunt" that my C5 had. I'm probably judging too soon since there are only 185 miles on the car and I'm not getting into it all the way, other than to press it to the floor momentarily a couple of times, not taking it past 4,000 RPM.

All I know is that with traction control off, you couldn't go more than 3/4 throttle in 1st without the tires coming loose on the 99. On the C6, I tried twice pressing it to the floor just for a couple of seconds and where the 99 would definitly have lost traction, the C6 never did, and seemed to have less acceleration. And yes, traction control was off on the C6 when I tried it.

I'm hoping that maybe my perception is a few things combined, like not wanting to stay in it up to redline, the new engine developing its power higher in RPM, the new tires being a little stickier, the new engine running smoother, and maybe the dealer put in 87 octane since they filled the tank before I picked it up.

Anyone have any experience here? I love the car, but something about this new engine feels more like a Japanese turbocharged 6 than a good ol' pushrod V8. Either this thing is slower than my C5 or the feel is just so different that my SOTP meter is all out of whack.



Mike

 

Well, according to the road test results, it isn't a whole lot faster in a straight line and the tires certainly are stickier, so that's my guess.

Hopefully you've found it to be a better car overall, though. How is it in the twisties?

 

Very good! My C6 is not a Z51 yet it seems to handle better than the 99 with Z51 package. Not surprising I guess. Both are great handling machines, but the C6 just seems more "refined" with higher limits.

I wonder if my old one being a Z51 and the new one not has anything to do with speed. Is the gearing or rear ratio any different between a 99 Z51 and a 2005 non-Z51? I know the gearing is a little different in the 2005 Z51's versus the regular 2005.

Mike

 

Don't know what the 99 Z51 gear ratios were, but here are the C6 6-spd ratios. First number is gear, 2nd is ratio w/o Z51, 3rd is w Z51.
1st - 2.66 - 2.97
2nd - 1.78 - 2.07
3rd - 1.30 - 1.43
4th - 1.00 - 1.00
5th - 0.74 - 0.71
6th - 0.50 - 0.57

Rear axle is 3.42 for 6-sp C6, no matter whether you have Z51 or not.

 

You may know this already but on the C6 you have to push the traction control buttom twice to turn it off. If you don't push it twice it is still active.

 

I saw a C6 A4 get beat at a 1/8 mile track this summer by several lightly modded C5 A4's . I don't no what the gear ratio was in it and it only had 300 miles on it.

 

If you are really worried go weigh your car and get it dynoed.

I have seen several C6 6 spds dyno around 350 rwhp so far and they seem to weigh in around 3200-3260 gassed up . After that it is simple math to some degree. Yea gearing traction and other factors weigh in but bottom line is that your 99 should have weighed around 3180 or so stock (hardtop , right?) and should have dynoed around 300+ or so stock . Those few pounds advantage is more than outweighed by the C6's much greater horsepower.

It may not FEEL that fast yet but you really have not given it the chance yet.....how well they break the tires on a particular car loose is really not the best way to tell how quick and fast they are and neither is the ole butt dyno .......

 

I don't know about your car, but my C6 (Z51, 6 speed) feels a whole lot faster than my '02. Part of it is the lower gears on the Z51, but the rest is just the extra power and torque. My C6 accelerates a lot better in 6th gear than my C5. And first gear is amazing. A good buddy took his C6 automatic to Fontana on Friday and turned a 13.10 quarter at 106 mph. Not bad for a bone stock ride.

 

Dude thats slow for a c6 13:1 in the quarter they tested doing 12.5 12.2 in the quarter

 

Are the 12.2 12.5 you're quoting with manual tranny?

 

After a few more days driving it, it is starting to feel just a hint faster than my 99 now. I think when I first drove it, the weather was warm and very muggy and I'm still on my first tank of gas which the dealer put in. I think it was "dealer gas" so who knows what they put in it. It could be 87 octane! I'll hold out final judgement until after the breakin, but it does feel a lot better on a cooler, drier day.

Mike

 

Give it some time

 

My impression upon first driving a C6 was that it didn't feel any faster than my C5. However, when you get on it and stay on it, it gets up to speed noticeably quicker, it just doesn't feel that way because it's so tight and quiet and smooth. Both cars are Z51 A4s.

 

I noticed mine feeling slower at first. But as it is breaking in it is feeling really good. Also if you were used to Z51 C5 and are now on base suspension you are gonna get a lot softer ride which could result in the sensation of it not being as fast when it actually is faster.

 

When the LS1 Camaro came out, people didn't think that it felt faster than the old LT1, but at the strip it was... I love my C5 Z06, but you have to give the C6 a chance, it's only been out 6 weeks at most, and alot of non-owners are giving it a bad rap....

 

Update:

I originally posted this subject when I had only driven the car about 50 miles, only a portion of that on dry roads on a hot/muggy day with "dealer gas". Now that I've run almost a tank through it, replaced the gas with Mobil 93, and gotten a few more miles on it, it is tearing up the road like a scalded ape!

It's definitely faster than my old 99 w/Vararam now. I really think these things will be slipping past the 2002+ Z06's at the track once they've been driven a few thousand miles and properly broken in.

Mike

 

I've have driven a c6 and it has more "grunt" than a ls1 by far. The ls2 has more grunt just like the lt1 does. The ls1 isn't too great off the line but after 100mph it gets it done.

so maybe you need to break it in more.

 

I don't know if that's going to help, but the one thing I would be curious about is the torque curve. Generally to get more HP you have to give up torque. Even though the C6 has more OVERALL torque, the C5 might have more lower RPM torque which is where you feel the "grunt" you're referring too.

Anyone have a dyno graph of a stock C5 and C6 showing the curve differences?

 

I have driven all the C-6 Corvettes 6 spd., automatic with 2.73 gears and 3.15 gears , F-55 suspension, base suspension, but I haven't driven any C-6 Corvette with the Z-51 package ..Then I drove a Z-16. I can tell you in straight line acceleration on the Z-16 in the SOTP feelin was very AWESOME and a very big difference in feeling compared to the C-6's.

 

On the C-6 which suspension do you have as you know there are 3 of them: Z-51, Base, and F-55.