First time at the dragstrip with my GXP

[Lithium Lotus]

I took my GXP [auto] down the strip for the first time this weekend. Only mod is the GMPP intake. All three runs were with no powerbraking.

1) 14.593 @ 96.04 / 60': 2.41 / TC&ECS Off
2) 14.587 @ 96.03 / 60': 2.37 / Competition Mode
3) 14.606 @ 95.27 / 60': 2.39 / TC&ECS Off

The track is 1500ft above sealevel, so with NHRA altitutde corrections, the times are
1) 14.38 @ 97.41
2) 14.37 @ 97.40
3) 14.39 @ 96.63

I really need to work on my launches to lower my 60' time.

[Bogie]

Originally Posted by Lithium Lotus

I really need to work on my launches to lower my 60' time.

Everyone says that. Turbo lag?

[RedSkyWV]

No one is seeing good numbers without powerbraking in the autos. The manuals see a lot better 60' times but rarely beat the autos for the whole quarter. You have to be fast with the clutch to beat the automatics all the way down the track.

[Lithium Lotus]

How high are you able to powerbrake it until the wheels start spinning?

[SCVanguard]

I tried powerbraking yesterday for the first time in my RL. With all my mods, it was REALLY trying to lurch forward right around 1500rpm, but got a good launch . I wasn't sure how much boost I had at that point, but I think any more throttle would have sent the tires spinning.

[R3DLIN3]

I stand on the brake, and get a good launch around 2200 RPM. 2500 RPM and she blows the tires on asphalt. I hope to get 2500-2600 on the launch pad covered in vht.

Kendall

[sidejam]

Anyone else notice that in the last gear during the quarter mile, the car really feels a lot weaker??? I can't remember if this is third or fourth gear. Either way, after the last shift, the car seems to really run out of power.

[SCVanguard]

Well, it is a 4 cylinder...

I had a friend who owned a SRT-4 and it was the same way. It would run pretty hard from 1st gear until top gear, but once it got there it was very slow acceleration.

[Bogie]

Originally Posted by sidejam

Anyone else notice that in the last gear during the quarter mile, the car really feels a lot weaker??? I can't remember if this is third or fourth gear. Either way, after the last shift, the car seems to really run out of power.

Torque delivered as a function of the previous gear for automatics:

2: 64.6%
3: 72.4%
4: 62.5%

Gearing alone will drop you by almost 38% when going to fourth. You get this drop at the same time drag begins to bite into your horsepower. What do you feel? On shift, you notice a 38% drop in acceleration, which will then continue to slide 20% (relative to the current gear, due to drag) to the trap.
This is the reality of a 260HP vehicle.

Contrast with a 420HP vehicle, such as a base Vette. It will hit the final trap in third. Not only will the gearing be almost 20% stronger than a SKY at the same point, but the engine will be delivering significantly more torque at the additional multiplicative gearing factor. And lastly, while drag will also increase over that final period, when factored as a percentage of power delivered, it will impact acceleration by less than 10%.

[sidejam]

Originally Posted by Bogie

Torque delivered as a function of the previous gear for automatics:

2: 64.6%
3: 72.4%
4: 62.5%

Gearing alone will drop you by almost 38% when going to fourth. You get this drop at the same time drag begins to bite into your horsepower. What do you feel? On shift, you notice a 38% drop in acceleration, which will then continue to slide 20% (relative to the current gear, due to drag) to the trap.
This is the reality of a 260HP vehicle.

Contrast with a 420HP vehicle, such as a base Vette. It will hit the final trap in third. Not only will the gearing be almost 20% stronger than a SKY at the same point, but the engine will be delivering significantly more torque at the additional multiplicative gearing factor. And lastly, while drag will also increase over that final period, when factored as a percentage of power delivered, it will impact acceleration by less than 10%.

So what you're saying is this is not that surprising.
I guess this is also why our mph is a bit low for our times too?

[Bogie]

Originally Posted by sidejam

So what you're saying is this is not that surprising.

Anlaytically speaking, it's not surprising.

Also keep in mind there is a perception difference between going up a gear on a track acceleration profile and droping a gear from a constant road cruise. In both cases the acceleration at the gear you enter into will be approximately the same, but the perception can be significantly different. On the track you will experience a dissapointing drop in rate of acceleration, feeding a perception that you are running out of power. On the road from cruise you will experience a lurch in the rate of acceleration feeding a perception of power.

The acceleration on the body is the same, but on the track it can be dissapointing while on the roadway it can be downright exhilarating.

[Antonio]

higher hp levels should change this.

Heck, my car pulls pretty strong in 4th coming up to the line. My trap speeds have increased about 8 mph over stock

[RedHeaded RedLine]

Originally Posted by Lithium Lotus

I took my GXP [auto] down the strip for the first time this weekend. Only mod is the GMPP intake. All three runs were with no powerbraking.

1) 14.593 @ 96.04 / 60': 2.41 / TC&ECS Off
2) 14.587 @ 96.03 / 60': 2.37 / Competition Mode
3) 14.606 @ 95.27 / 60': 2.39 / TC&ECS Off

The track is 1500ft above sealevel, so with NHRA altitutde corrections, the times are
1) 14.38 @ 97.41
2) 14.37 @ 97.40
3) 14.39 @ 96.63

I really need to work on my launches to lower my 60' time.

With some practice you can loose a 1/2 second.
He averages a 2.0x 60' in the Volvo & I am quicker than him, off the lights.
I would think with my auto I am ~1.90. Take all the nannys off. -Joyce

[R3DLIN3]

I finally got to the track tonight(more on that in a different post).

I was getting consistent low 1.9 60ft and managed one 1.89 on the stock tires.

[|V3nom|]

14.55 @ 98mph
60': 2.2 tcs and esc off

i had HORRIBLE launches. with a better launch i wouldve hit low 14s. i launched at 4500 and just spun off the line and started going sideways but it keep the rpms up the whole time and the turbo spooling so when it gripped it just went which is why my trap is so high.