First impression? I hated it. My first run showed I had 550 HP or something like that and a 0-60 in 5.1 seconds. I wish! This goes to show what can happen when you try to rush a very precision instrument. I was uphill, incorrectly entered rollout time, etc. and it really through everything off. I was so anxious to play with it so I took a lot of shortcuts and it was just a big POS.

Anyway, spent all night Friday and all day Saturday studying, calibrating, ciphering, researching etc. and took her out this morning for a 45 minute trial and got some very very reasonable numbers.

If anyone near Memphis wants to know a good place to go play with your car, I found it. It's a 1 mile stretch of road with just about a 5 feet of difference in altitude from beginning to end. A level surface is mandatory for this thing to work. The first time I did it I was pulling .09 G's just sitting there. That really screws up the calculations so you need flat ground.

I recommend this little toy. If you take the time to calibrate and have procedural discipline, this will be invaluable for evaluating mods and shifting technique. I'm uplaoding runs now and will publish results shortly. Although here are some initial findings/impressions:

1) I couldn't get a statistically significant difference between Manumatic and Automatic.

2) Spinning wheels is bad for a 0-60, but will improve your top speed on a quarter mile, depending on what your rollout distance is.

3) My wheels barely spun loading 1800 RPMs at launch, and spun for 1 second at 2200 RPMs at launch. This was with stock 18" wheels on standard asphalt, at 56 degrees F.

4) While in full auto mode, my G shifted into 5th a second before 1/4 mile. In MM I left her in 4th. I haven't made enough runs for analysis yet, but for the pros who race at the track frequently with 5AT, what's the technique I should be shooting for here? Where do you shift at? I was hitting the **** at around 6400 but that needle was moving pretty fast in the lower gears so by the time it actually shifted it may have been higher.

5) I was getting HP readings around 192 HP. Remember this is NET HP, not RW HP. Drag is a biggie the faster you go and I estimated my weight at around 3650 with me (185) and 1/4 tank of fuel (6 pounds at 5 gallons?=30 pounds). I figured 20 pounds for all my options (I have everything but the front spoiler). This was probably light, thus my HP readings would have been higher.

6) There seemed to be NO DIFFERENCE between VDC on, and VDC off! Actually this makes sense. The name of the game is getting HP to the ground and the computer can do that better than I can. You waste time spinning wheels and VDC corrects this. At least for an automatic, VDC on may be the way to go unless you're trying to spin your wheels for a cute trailer trash girl. I shall conduct more runs both ways, but these were my first impressions, so please no hatin or flamin on this comment.

I found it on southwestautoworks.com, latest firmware version, new in box, for $249 out the door! Shipping was included, got it in 3 days after order. In 5 months when I'm done with my mods, mine will be for sale .

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

If your VDC doesn't drastically reduce power and apply brakes, you got a much better one than the one in my MT.



2004 G35C 6MT Black. Yes Honey, I promise no mods. I love it just the way it is.

 

Ok, here's my first comparison. The first is a run at heading 090, winds 360 at 9 knots with the VDC on. The second is a run at 090, winds 360 at 9 knots with the VDC off. Both times I revved to 1800 then let off the gas. When VDC was off, I did notice a split second of wheel spin.

I ran duplicates at heading 270 and at that heading both 270 runs were 1/10th of a second worse on 1/4 mile, most likely due to the fact that at slight uphill gradient was present at that heading. The fact that the times were consistently 1/10th off in that direction is enough reliability for me to confirm that they were valid readings, and not due to wind or gradient.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

On the left is VDC on. On right is VDC off. All variables controlled. Slight wheel spin with VDC off. Results may vary with 6MT .

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

243874-VDConVDCoff.jpg

 

Here I'm manumaticing around 6400. The numbers on the right is at opposite heading. Looks like the TCU/ECU does a better job than I do. Because I'm human, my shifts will always be inconsistent. I see no appreciable difference between letting the car shift for me, when comparing these times to the previous set of times. What this tells me is that next time I'm going for a kill I'm going to just leave the VDC on and leave it in full auto mode. Results may vary with 6MT. (Sorry Neff, if I'm plagarising your sig )

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

Whoops, no attachment, try again.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

3rd times a charm?

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

243882-ManuMaticEastWest.jpg

 

My experience with the G-Tech Competition Pro (and comparing it to 25 or so runs on a drag strip) is that the 60 ft and 330 ft times are reasonably accurate but the 1/8th mile and especially 1/4 mile times are optimistic.

For example, I mean no offense to catatafish but I'm extremely skeptical that you could run a 14.2 second 1/4 mile with a 60ft time of over 2.3 seconds. The trap speeds are also way out of whack IMO (ie. too high).

The good news is that GTech is coming out with a new firmware that should increase the accuracy of the device. I can't wait until it's out.

--Steve

 

Zimbo,
I've heard the new firmware will compensate for the hood rising on launch.

Regarding your other comments, I don't know I've never been to a track but from my extensive (I've read for hours believe me) the biggest factor in the differences is a few things:

1) The GTech requires you to input the rollout. I had mine set at 6 inches. They say that if you program your rollout correctly, your times will be within thousandsths of a second. I've seen other posters run this neck and neck at the track and confirmed this. I don't know if I'm a "shallow" or "deep" stager so I just set mine at 6".

2) If the tach isn't calibrated right, it will throw off some readings, but I can't remember which.

3) If the road is not perfectly flat, like many tracks, the times will be skewed. For instance, if the 1st 60 feet is uphill, even the slightest, and after that, it's ever so slightly downhill, that would explain things. What should my 1/4 time be with those 60' times?

In any case, I'm doing this mainly to test mods. Thus, so long as I keep my parameters consistent, I will have great reliability, but maybe not so great validity. I'm shooting mainly for reliability/repeatability here, so I'm not going to attempt any more tweaking of the parameters. This is "close enough" no?

BTW, the 1/4 mile thing is pretty new to me, what do you mean by comparing the 60 ft times and the 1/4 times? What, in drag racing, is the 60 ft time supposed to indicate and what does one infer when comparing it to the 1/4 mile time and trap speed? A little drag racing 101 if you don't mind. I'm always looking to pick up some new info.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

Zimbo,
Hey, also keep in mind that I was at a -10 foot density altitude...high pressure, cold air, nice cool road. Is that speed out of the question? Remember, I had a slight downhill gradient. 5 or 10 feet lower at the finish line. Does that make it seem more reasonable? This summer I'll try to get the lowdown on our local track and do an actual run, but if my plenum gets here before I do, I'll never know what my time "would have been" .

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

Unless you misshift, if you know the HP of the car and the 60 foot time (i.e. the quality of the launch) then you can pretty accurately guess how fast the 1/4 mile time will be.

--Steve

 

Zimbo,
I have a feeling that the longer you are dragging, the more pronounced the error will be. For instance, at 60 ft, if the error is 1/100th of a second, if you keep going that error will eventually be 1 second. I bet the combination of that, and possible gradients in the road were making my times a bit optimistic perhaps, but given my density altitude is that quarter mile time out of the question?

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way