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What would you do C6 LS3 Auto


hpfiend

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Hey all,

 

First time at the track with my dad's 08 C6 Coupe. It is bone stock other than a wireless switch for the NPP exhaust. He has an A6 with performance rear gear option (I think 2.73) and factory runflat tires at 40-42 front and 25-27 rear (hot)... almost 5000 miles.

We ran it 14 times with a MPH range of 110.5 to 114.17 and ET range of 12.649 to 13.391. 60' range of 1.927 to 2.372 (traction control on for latter) Most runs were with traction control off, letting transmission shift itself, sport mode, we varied launch rpm. The traction this car gets on street tires is AMAZING. We were brake launching it at 1400-1500 and it would either dead hook or spin very briefly then pull like a monster. If we left off idle we got some sort of a bog feeling after a light tire spin before the power kicked in... Is this torque management at work? It also seemed like it did this boggy feeling more after a few runs and the car got "heat soaked"? We couldn't figure out how to rig the fans like my c5z and didn't have any ice- coolant temps ranged from 203-223..

 

Here is the best run:

60': 2.082

330: 5.530

1/8: 8.301

MPH: 88.63

1000: 10.668

1/4: 12.649

MPH: 114.17

 

What do you think we can do better? Thoughts? Modification recommendations?

 

I am thinking stall converter to get more rpm off the line without rolling but don't really want to kill the gas mileage.

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The biggest place for improvement I see is off the line as your 60' times need improvement. Maybe swap to a better rear gear ratio like 3.73 and get just a slightly higher stall converter and then do all the typical mods like a cold air intake and so on for more power. A tune would probably free up at least 15-20 HP also.
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+1 for a tune, my car improved 40whp/wtq. Also, I'd see about getting more gear in the rear, i can't believe 2.73's are the performance ratio. Sure its not at least 3.23's? That's how the fbody's were, 2.73 stock, 3.23 performance ratio. Either way, it looks like it picked up real nice on the top end.
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A converter will get you one of the biggest jumps. I have a pretty big stall in my car for the street but also have the 2.73 gears so my it does not eat to much gas on the freeway.

 

Overall a stall will help more than gears in the first 60 feet. I would check around on some of the C6 boards and see what guys are doing.

 

I did headers, stall, and drag radials and picked up about a second at the track and did not touch the gear in the rear.

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runflats aren't racing tires, so swap those out for radials that'll help some with the traction

x2 How high can you stall the car with the stock convertor? Pick up a second hand set of DR's for cheap and full stall it. That will really help it get off the line.

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It's not spinning the stock tires so I dont see how changing that would help without more power somehow or a better launch and about the only way we can launch harder is to rev it up in park or neutral and put it in drive which my dad is not a big fan of- unless there is another way to "stall" the factory converter. I am wondering if "torque management" is shutting it down unnoticeably to us off the line as I don't know how it hooks soo hard on these tires.

 

I will look into aftermarket stalls and tune on corvetteforum.

 

As far as how fast he wants to go- who knows- it just feels like there is a lot more in it right now we just cant launch it harder. Also vette mag claims they got a 12.3 in a 2010 grand sport with the exact same engine/trans/gearing he has...

 

we thought about a line lock but holding it as hard as we can with the left foot should be about the same right? What does a trans brake do?

 

Thanks,

Andrew

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we thought about a line lock but holding it as hard as we can with the left foot should be about the same right? What does a trans brake do?

 

Thanks,

Andrew

 

If you can't hold it with your foot on the brake a line lock won't either. It's essentially just a solenoid that holds pressure in the line after you press the brake and close it.

 

A transbrake essentially locks 1st and reverse together so that you can apply enough power to get full flash stall off the line (You'll never get that footbraking). The car won't move at all while it's engaged. They're not cheap or super simple to install though. If you're going to go that far with it you'd definitely want to go ahead and get a higher stall converter at that time anyway.

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It's not spinning the stock tires so I dont see how changing that would help without more power somehow or a better launch and about the only way we can launch harder is to rev it up in park or neutral and put it in drive which my dad is not a big fan of- unless there is another way to "stall" the factory converter. I am wondering if "torque management" is shutting it down unnoticeably to us off the line as I don't know how it hooks soo hard on these tires.

 

I will look into aftermarket stalls and tune on corvetteforum.

 

As far as how fast he wants to go- who knows- it just feels like there is a lot more in it right now we just cant launch it harder. Also vette mag claims they got a 12.3 in a 2010 grand sport with the exact same engine/trans/gearing he has...

 

we thought about a line lock but holding it as hard as we can with the left foot should be about the same right? What does a trans brake do?

 

Thanks,

Andrew

 

A line lock is basically just for doing burnouts as it holds the front brakes on and lets the rear ones go. I doubt you'd want a trans brake. That is for harcore racers and is pretty hard on a tranny not built for it.

Check out pcmforless for some tuning. They have a excellent track record with C6's to my understanding and can probably disable the torque management system if it has one.

What do you know about the torque managaement? Does it work on every gear shift or just on a launch?

I work on Subaru SVX's for a living and they have a torque control system as well that works on every gear change, so a buddy of mine in Australia built a electronic box that reverses the effects by raising line pressure on the tranny and disabling the torque control at the same time. It makes for some wicked shifts to say the least vs. stock. Maybe something similar has been designed for the Vette or at least could be?

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Hey all,

 

First time at the track with my dad's 08 C6 Coupe. It is bone stock other than a wireless switch for the NPP exhaust. He has an A6 with performance rear gear option (I think 2.73) and factory runflat tires at 40-42 front and 25-27 rear (hot)... almost 5000 miles.

We ran it 14 times with a MPH range of 110.5 to 114.17 and ET range of 12.649 to 13.391. 60' range of 1.927 to 2.372 (traction control on for latter) Most runs were with traction control off, letting transmission shift itself, sport mode, we varied launch rpm. The traction this car gets on street tires is AMAZING. We were brake launching it at 1400-1500 and it would either dead hook or spin very briefly then pull like a monster. If we left off idle we got some sort of a bog feeling after a light tire spin before the power kicked in... Is this torque management at work? It also seemed like it did this boggy feeling more after a few runs and the car got "heat soaked"? We couldn't figure out how to rig the fans like my c5z and didn't have any ice- coolant temps ranged from 203-223..

 

Here is the best run:

60': 2.082

330: 5.530

1/8: 8.301

MPH: 88.63

1000: 10.668

1/4: 12.649

MPH: 114.17

 

What do you think we can do better? Thoughts? Modification recommendations?

 

I am thinking stall converter to get more rpm off the line without rolling but don't really want to kill the gas mileage.

 

Sounds like a good time.

 

As for your modifications, you will have a difficult time getting a converter for that car due to the limited aftermarket currenlty, and the converters that are available for the 6l80 are a FORTUNE, and not worth the price in my opinion.

 

I would consider a air intake (Vararam makes a very good unit) , 160 degree thermostat, then i am not sure your comfort with exhaust modifications, but I would get a set of long tubes and x pipe, and leave the stock axle back, and the car should make around 410-425 rear wheel horsepower after tuning, about a 40-50 horsepower gain from where the car is at now, this should lower the E.T, and make the car much more enjoyable to drive. If you would like I encourage you to stop by our shop, we are very well known in the corvette market and should be able to discuss any option you would like to pursue with the car, and having most items in-stock, and in house tuning is certainly a great benefit to take advantage of.

 

Regards

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