Hello everyone! I recently joined the ranks of Corvette ownership. I purchased a used 1 owner 2007 C6 with 46,500 miles on it.

I LOVE the car. It has every option I wanted - Yellow, Nav, T top, Z51, etc...

Anyway, the reason I am posting is because although it has a TON of power, it doesn't quite seem to be "Corvette fast". (Or at least how fast I anticipated a 400HP/400tq car to be)

I have done some basic maintenance on it (Replaced front tires (rear were ok), oil change, new air filters, checked tranny fluid, new brake pads) The only basic component that I haven't checked is the spark plugs, but again the car is a completely stock LS2 and only has 46,500 miles - so I didn't think it should need it.

The car had no DTC codes stored when I bought it and had not tripped any since driving it about 500 miles.

However my problem is that it still seems a little light on power for what I expected a Corvette to be. Even with traction control turned completely OFF, the tires don't break loose at all. I don't ever rev the engine while holding the break before launching (it's auto, so I can't dump the clutch) but I would think that the car would have enough power to spin the tires even from a 2-3 MPH crawl launch with traction control turned off.

I have not been to the track with it, but I have had a chance to use the "Dynolicious" app for the iPhone. I know that these things can be slightly inaccurate, but from what I hear they are usually accurate to within +/- 5%.

My Dynolicious numbers are:
0-60: 5.4 sec
Max acceleration: 0.66G's
Even with 0% drivetrain loss, it estimates the car to only have about 280HP

To me between those numbers, and the tires not ever breaking loose even with traction off, it would seem as though something is wrong. Any thoughts? What should I check next? I don't really want to pay for an official dyno yet since I'm pretty sure it will just confirm the low numbers, and I'll still have to hunt down the problem anyway.


Just for reference, here is a short video clip of me punching it at WOT:
http://www.youtube.com/watch?v=ZpGeGNoANXM


Thanks for your help! Again - I love the car, I use want to make sure I'm getting the "full Corvette experience" :-)




*********UPDATE**********
I replaced the spark plugs. Helped a little, but the tires still don't spin. It's not that I'm trying to burn off two $400 tires, I just want to make sure the car is making as much power as it should. I'll post again once I have some track numbers.

 

I think all you numbers are low. HP should be 310 or so at the wheels, 0 to 60 should be under 5 and the Gs look low as well.

 

Agreed. Any idea what I should check with the car?

 

Please don't take offense, maybe the driver. My car is much more capable than I am.

The older I get, the faster I was...

 

No offense taken. I'm pretty sure I'm not the issue though. I'm really getting on the throttle. I'm pushing it as far as it'll go.

Additionally, I have been very blessed with my career straight out of college. I'm still in my mid 20's, so I don't think we can chalk it up to "old age" ;-)

 

Probably more than just +/- 5%.




Well, THAT would do it.
But if your C6 is really only making 280hp then your motor is having some serious internal problems or it could even be something binding in the torque tube and/or rear as well.
But I highly doubt that's what it is. I really think it's just the combination of a hot day, high coolants temps, hot tires and a hot road surface.

What state are you located in, how hot out was it and how much fuel was in your tank at the time?

I would change the spark plugs, throw in some fresh name brand premium fuel and wait for a cooler night to take it out and jump on it.

 

Also, the C6 is very quiet/well sound deadened inside and is quite smooth. That can give the illusion or feel of moving slower than one actually is, the cars are deceivingly fast at times.

 

Mid 20's? Maybe we can chalk it up to inexperience.

Your numbers do sound low. However, my experience with a GTech is the numbers are not that accurate. Also, is it a manual or auto? With the manual you should be able to spin it very easily. Also, these cars do put out a lot less power when it's really hot. The ECM pulls tons of timing.

If it's a manual, then it's typically a tap dance between spinning the tires and bogging. You have to slip the clutch a little to get a really good launch.

Last thing, is there a setting on your dynolicious that allows you to nail it from a roll, say 30 to 60 mph? That would take the launch out of the equation. Best thing is to wait for it to cool off and head to a 1/4 mile track.

Good luck.

 

The 280HP number is at the wheels. 330 was what it came up with for flywheel. Either way, it's a phone app and I'm willing to believe it's off by a bit, but between what I'm feeling and the app I don't think it's making as much HP as other stock LS2s.

I am in a very hot state (FL) and it is August, so I will try again at night. Still not sure that will make the difference, but we will see :-)

Thanks for your suggestions :-)

 

Well, I've heard that Dynolicious is actually more accurate then GTech, but I'm willing to act under the assumption that neither are as accurate as a real dyno or track run to go on.

The runs I did were performed on a hot day in FL, so I guess we can try again with no A/C and when it's cooler. Doesn't the ECU turn off the A/C at WOT anyway?

Lastly, I did not know about that setting in Dynolicious. Thanks. I'll test that out too.

I guess I really won't be able to say anything definitively until I get some track runs.

 

Sir,

Do you plan on having your Vet dyno tune later on?

 

Weird... I have the opposite "problem". With a manual and the rock-hard runflats, I can't hardly keep my tires from spinning when I punch it... even with traction control engaged... hot day or not (yes, it occassionally gets hot -- and very humid -- in Minnesota).

I don't know about that phone app, but I'd think you could break 'em loose no problem. You said you replaced the fronts... what do the rears look like? Are they runflats?

 

How hot is it where you are? Heat can rob power.

 

I have that app. I'm not sure how accurate it is, but I can always get my 0-60 below 5 seconds. On the other hand, I've also saw how long it would take if I turned the traction control off and just spun the tires. I think it's a fun app but it has to be planted to something that won't allow it to move!! Otherwise your numbers will be all over the place!!

 

I would definitely check, or replace the plugs. If you can get it to a track that should answer your question. If your e/t isn't that great your trap speed can still see how far off the car is, if at all.

 

I'm in no way shape or form a mechanic but is it possible the exhaust is partially plugged or the intake is starving for air? I've heard bad cat converters can plug up and do what you describe. Also, is it possible your drive by wire throttle body is not fully opening up?

 

Rears are run flat. They have pretty good tread left on them. :-/
When you launch, are you dumping the clutch? Do you have the z-51 package? LS2 or LS3?

Thanks for your help.

 

I do, but if something is mechanically wrong, I don't want to pay for the dyno twice.

 

It's secured to the car when I use it.

 

I replaced the plugs yesterday. The old ones didn't look too bad when I pulled them out though. It does run a bit better now, but only slightly. I think I may call up the corvette specialty shop around me.