Quarter mile times for bone stock LS1/A4

[MagikDraggin]

I can't seem to find any performance info on the Automatic equipped 2004 stock 2.73 geared LS1 coupe.

Anyone know what it may be.....0-60 and 1/4 mile times?

I'd like some kind of an idea where I am "starting from", before the mods begin.

Thanks

 

[Skull One]

I can't seem to find any performance info on the Automatic equipped 2004 stock 2.73 geared LS1 coupe.

Anyone know what it may be.....0-60 and 1/4 mile times?

I'd like some kind of an idea where I am "starting from", before the mods begin.

Thanks

I believe it is 5.3 for 0 to 60 and roughly 13.5 to 13.7 for 1/4 mile. But I have only had my coupe for 10 months so I am still learning

 

[STRAYDOG]

I can't seem to find any performance info on the Automatic equipped 2004 stock 2.73 geared LS1 coupe.

Anyone know what it may be.....0-60 and 1/4 mile times?

I'd like some kind of an idea where I am "starting from", before the mods begin.

Thanks

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> My 2001 convertable has 3.15 rear gears & Z51 Suspension ...best ET 13.13 >>> Ran in October , temp was 55 Deg F.............Stock except for cold air nbox & K&N filter........The Dog.

 

[DRTH VTR]

The times will decrease with increases in elevation. The amount of wheelspin that you get will depend on the tires that you have and the launch technique. Stock C5's run about 13.9-14.1 at my local track at 2600'. The times quoted in magazines could be done at low elevation by a driver who knew what he was doing.

 

[MagikDraggin]

The times will decrease with increases in elevation. The amount of wheelspin that you get will depend on the tires that you have and the launch technique. Stock C5's run about 13.9-14.1 at my local track at 2600'. The times quoted in magazines could be done at low elevation by a driver who knew what he was doing.

I can appreciate that. My new C5 A4 coupe is really dog-earred up until it gets into the 3k rpm range, then it almost feels like a turbo kicking in as it really accelerates strong from there.

I realize I didn't buy it equipped the way it was for its performance.....knowing full well from my LT1 experience with 2.59 gears, that it wasn't going to be a screamer out of the hole.

I was simply curious what it is SUPPOSED to be capable of, but nowhere can I find acceleration times done with an automatic transmission.

I was considering doing an intake upgrade and then looking into a higher stall converter to get those "R's" up higher off the line, and maybe a shift kit, before doing anything else.

I do NOT want to change rear end gears anytime in the near future, as I am not really interested in "racing" the new C5.....just make it a little more "spirited" than it is now, without sacrificing any of the ride, idle and fuel economy, if you get my drift.

Thanks to ALL who responded so far.

 

[C5Richard]

I can't seem to find any performance info on the Automatic equipped 2004 stock 2.73 geared LS1 coupe.

Anyone know what it may be.....0-60 and 1/4 mile times?

I'd like some kind of an idea where I am "starting from", before the mods begin.

Thanks

Just my opinion but I think you're starting off at a disadvantage with the stock 2.73 gears. It will take a ton of additional hp to overcome that alone. There's a noticable different in G92 option autos.

Richard.

 

[C5Richard]

I can appreciate that. My new C5 A4 coupe is really dog-earred up until it gets into the 3k rpm range, then it almost feels like a turbo kicking in as it really accelerates strong from there.

I realize I didn't buy it equipped the way it was for its performance.....knowing full well from my LT1 experience with 2.59 gears, that it wasn't going to be a screamer out of the hole.

I was simply curious what it is SUPPOSED to be capable of, but nowhere can I find acceleration times done with an automatic transmission.

I was considering doing an intake upgrade and then looking into a higher stall converter to get those "R's" up higher off the line, and maybe a shift kit, before doing anything else.

I do NOT want to change rear end gears anytime in the near future, as I am not really interested in "racing" the new C5.....just make it a little more "spirited" than it is now, without sacrificing any of the ride, idle and fuel economy, if you get my drift.

Thanks to ALL who responded so far.

Changing the intake and stall converter will cost more than rear end gears. I wouldn't call G92 gears racing gears by any stretch. Just noticably more accelleration and better gas mileage. Even with a different intake and stall converter I don't think it will perform better than a stock corvette with G92.

Richard.

 

[MagikDraggin]

Changing the intake and stall converter will cost more than rear end gears. I wouldn't call G92 gears racing gears by any stretch. Just noticably more accelleration and better gas mileage. Even with a different intake and stall converter I don't think it will perform better than a stock corvette with G92.

Richard.

How do you figure, "better gas mileage" with the 3.15's? It would seem to me that the more times the motor turns over at a given speed, the more fuel it is going to use, all things otherwise being equal.

A 3.15 equipped LS1 is certainly going to have more rpm's at 70mph that a 2.73 equipped LS1 at the same speed.

 

[C5Richard]

How do you figure, "better gas mileage" with the 3.15's? It would seem to me that the more times the motor turns over at a given speed, the more fuel it is going to use, all things otherwise being equal.

A 3.15 equipped LS1 is certainly going to have more rpm's at 70mph that a 2.73 equipped LS1 at the same speed.

The 2.73 is harder to turn thus loads the engine more.

Richard.

 

[cavettefan]

For what it is worth in this discussion regarding mileage, I have the 3.15 rear end in my coupe, and at 2,500 rpm on level ground with no head or tail wind, I have been getting 34 instantaneous mpg. The first time I checked, I though I was benefiting from a tail wind. I then exited the freeway and retraced my path in the opposite direction and still came up with 34 mpg instantaneous at 2,500 rpm. I would tend to agree with C5Richard that the 3.15 rear end puts less load on the engine which results in higher gas mileage at a given speed. I would be curious what MagikDraggin (or anyone else with an A4 and 2.73 rear end) is observing for instantaneous mileage at 2,500 rpm on level ground with no wind.

In any event, if you are looking for faster quarter mile times, you are going to get better performance by looking at the rear end first.

 

[MagikDraggin]

I would be curious what MagikDraggin (or anyone else with an A4 and 2.73 rear end) is observing for instantaneous mileage at 2,500 rpm on level ground with no wind.

2500 rpm? Surely you jest! I'd have to be traveling about 100 mph to get to 2500 rpm with my A4 and 2.73 gears. These Iowa "Smokies" around here would have me for dinner for certain, if I attempted that for any length of time.

At 1700 rpm, which is about 70 mph, mine reads 31 mpg

I'm not sure I understand your logic here, though. If I were to extrapolate what you suggest further, then 3.54 gears should provide even better gas mileage than the 3.15's, since the "rolling resistance" would be even less.

With my 96 A4 however, when I went from the 2.59 stock gears to 3.54's, the fuel economy dropped dramatically from 29-30, down to 24-25 mpg at 70mph.

Your statement that 3.15's give better gas mileage than 2.73's seems to defeat the whole purpose behind OD gearing in the first place.

 

[Edmond]

IMO, you gotta do the exhuast because the stock C5 exhaust is kind of wimpy. It'll give you a few horsepower but the audio difference will bring a to your face.

 

[C5Richard]

2500 rpm? Surely you jest! I'd have to be traveling about 100 mph to get to 2500 rpm with my A4 and 2.73 gears. These Iowa "Smokies" around here would have me for dinner for certain, if I attempted that for any length of time.

At 1700 rpm, which is about 70 mph, mine reads 31 mpg

I'm not sure I understand your logic here, though. If I were to extrapolate what you suggest further, then 3.54 gears should provide even better gas mileage than the 3.15's, since the "rolling resistance" would be even less.

With my 96 A4 however, when I went from the 2.59 stock gears to 3.54's, the fuel economy dropped dramatically from 29-30, down to 24-25 mpg at 70mph.

You statement that 3.15's give better gas mileage than 2.73's defeats the whole purpose behind OD gearing in the first place.

Specifically in this car comparing these two options, the car gets better gas mileage with the 3.15 gears.
You did a much more drastic change in your 96 A4 where 70 mph was likely not the optimum speed for the best gas mileage.

Richard.

 

[invinceablevett]

I would seriously look at the rear gears.I think(because of past experience) that it's the best mod for the money.My vette is not a daily driver and I don't usually drive way over the speed limit so fuel consumption is of no concern to me.

 

[DRTH VTR]

Your statement that 3.15's give better gas mileage than 2.73's seems to defeat the whole purpose behind OD gearing in the first place.

I would agree with this. In general, slower engine speed at a given rate of travel will result in better fuel economy. That is why overdrives work. I would need to see this mileage issue settled with something more scientific than an instantaneous DIC reading on one car.

 

[C5Richard]

I would agree with this. In general, slower engine speed at a given rate of travel will result in better fuel economy. That is why overdrives work. I would need to see this mileage issue settled with something more scientific than an instantaneous DIC reading on one car.

You have to consider some loss of efficientcy with an automatic to begin with. OD wasn't really designed as much for better gas mileage as it was for increased highway performance and actually even more so to increase engine life. The less rpm's an engine turns the longer it's life. Extended highway use where the engine does 2500 rpm just to maintain 70 mph will wear the engine significantly more than an auto equiped with OD that will do 70 at 1500 rpm.

Richard.

 

[DRTH VTR]

You have to consider some loss of efficientcy with an automatic to begin with. OD wasn't really designed as much for better gas mileage as it was for increased highway performance and actually even more so to increase engine life. The less rpm's an engine turns the longer it's life. Extended highway use where the engine does 2500 rpm just to maintain 70 mph will wear the engine significantly more than an auto equiped with OD that will do 70 at 1500 rpm.

Richard.

It is interesting that we see this so differently. I have to admit that I was thinking in terms of my manual 6 speed transmission. However, the Corvette A4 does have a lock-up torque converter, so at highway speeds, the torque converter has locked up. This is pretty similar to the 6 speed, in that there is a direct relationship between car speed and engine speed. I always thought that the reason for the increased fuel economy due to lower engine speed had to do with the internal friction of the engine itself. Fewer revolutions per unit distance means less loss to friction.

I would like to have a professional engineer or a knowledgeable mechanic (c4c5?) address this issue.

 

[1g1yy]

Come on guys -- this is not rocket science!! At highway speeds the 2.73s use less fuel -- not because of less engine friction from lower RPMs, but because it has enough torque at that lower RPM to maintain the cars speed while the accelerator pedal is not having to be depressed as far (in other words the injectors are giving it less fuel). It takes very little power to maintain an aerodynamic C5s speed at seventy. At highway speeds with 3.15s the throttle is open a bit further because RPMs are higher, so it uses a bit more fuel -- though only about 2 or 3 MPGs.

At low "around town" speeds the 3.15s can get slightly better MPG because it takes less effort (less depression of the accelerator, therefore less fuel) for the engine to get the car moving.

Why do you think the general fixed the M6 tranny as he did!!? He gave you a low gear to takeoff, and high gears for cruising. Trust me -- he did some MPG testing!

As to the original question -- GET 3.15s AND A MILD T/C! The difference will amaze you, and you won't notice much difference in MPG at all! It will still feel stock in normal driving.

 

[DRTH VTR]

the throttle is open a bit further because RPMs are higher, so it uses a bit more fuel.

Why? Why does it take more fuel at higher RPM? Clearly it does take more fuel. What is the physics of it? Internal engine friction is a very large factor. Try and turn an engine by hand. It is a serious grunt to do it. Rolling resistance and air resistance are independent of engine speed, so the extra energy needed to propel the car using lower gears and higher engine speed must be due to a condition within the engine itself.

If having higher RPM's requires more fuel, why doesn't that apply around town? The same rules should apply. It may not be rocket science, but it is still science. I simply don't buy the idea that lower gears result in higher gas mileage. If you get better acceleration, it means that you used more energy. More energy out means more energy utilized. More energy utilized means more fuel burned.

I totally agree with you that lower gears are a performance improvement. I just don't see how you can have your cake and eat it too. I don't mean this to be argumentative or unfriendly. I mean this to be a friendly discussion/debate.
Jim

 

[1g1yy]

Why? Why does it take more fuel at higher RPM? Clearly it does take more fuel. What is the physics of it? Internal engine friction is a very large factor. Try and turn an engine by hand. It is a serious grunt to do it. Rolling resistance and air resistance are independent of engine speed, so the extra energy needed to propel the car using lower gears and higher engine speed must be due to a condition within the engine itself.

If having higher RPM's requires more fuel, why doesn't that apply around town? The same rules should apply. It may not be rocket science, but it is still science. I simply don't buy the idea that lower gears result in higher gas mileage. If you get better acceleration, it means that you used more energy. More energy out means more energy utilized. More energy utilized means more fuel burned.

I totally agree with you that lower gears are a performance improvement. I just don't see how you can have your cake and eat it too. I don't mean this to be argumentative or unfriendly. I mean this to be a friendly discussion/debate.
Jim

Yes, higher RPM requires more energy, ie. more fuel. With your car in park it requires more fuel/oxygen to continue bringing the RPMs higher. Why? Engine friction? Sure. If there were no friction then once the first cylinder fired the engine RPMs would quickly accelerate -- and continue accelerating! But, in a sense, engine friction might be considered a constant apart from any external load. Around town driving requires acceleration from stops for the most part. Gearing that multiplies torque best reduces the engines effort, ie. the "external load" and therefore the need for greater combustion pressure, and hence, less fuel/oxygen. With 3.15s torque is multiplied more than with 2.73s, so this lessens the "external" load on the engine, and so does not require as wide open a throttle. On the other hand, for highway driving all that is needed is to maintain speed (as opposed to acceleration). It requires very little torque to maintain 70 MPH (low "external load") in a C5 so high torque multiplication is not required, and gearing that brings RPMs very low can be utilized. Now, as with most things in life, moderation is the key. You could gear a C5 so high (low numerically) that it would be at the point of bogging down at 70 and require WOT just to maintain speed. Then it would really get poor MPG!

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