I was watching some old videos that I recorded of my car along with some new ones and noticed that the car was shifting different back in 2004 than it does today. The tachometer is off by about 200rpms on average at higher throttle levels. Driving normal, the tach was pretty close to what the computer was seeing(my speedometer is the same way, it gets worse the higher speed you get to, the HUD w/ it's separate input from the ECM is dead-on though).
2004 Videos: I did a few WOT runs on video around Feb-March 2004. It was very cold out and the car was running strong. In the best video I took of it, I started around a 20mph roll and took the car to around 110mph on a road that was sloping uphill a bit. During the video, the 1st to 2nd shift occured at an indicated 5500rpms(~5300 actual). 2nd to 3rd also occured at 5500pms indicated(~5300 actual). One other thing that I noticed is that the rpms fluttered for a split-second around 90mph or so on my first run.
November 2007: Weather conditions were close to what they were in the original video, it was very cold out and not humid at all. Anyways, I have one video that is a bit blurred, but I can make out where the shiftpoints occured. I started from a 20mph roll the same as the old video and 1st to 2nd occured at what I would say was 5450rpms(~5250rpms)...the tach needle was just shy of the 5500rpm mark a bit. 2nd to 3rd occured at right about the same 5450rpm(~5250 actual).
Now for the differences I noticed between the two runs. I'll be using my "actual rpms" to state my findings below....
2004: 1st to 2nd shift drops me from 5300 rpms down to ~4,050rpms. 2nd to 3rd shift drops me from 5300rpms down to 4250rpms. So, 1st to 2nd netted a 1250rpm drop, and 2nd to 3rd netted a 1,000rpm drop in speed.
2007: 1st to 2nd shift drops me from 5250rpms to 4200rpms. 2nd to 3rd dropped me down from 5250rpms to 4400rpms. So, 1st to 2nd netted a 1050rpm drop and 2nd to 3rd netted a 850rpm drop in speed. The current shifts occur a good bit quicker than in the old video.
Changes made between '04 and '07
-Current TV cable is off of a naturally aspirated 1990 Grand Prix with very low miles on it. I broke the hook off my original cable, but will be repairing it and reinstalling it as it's not stretched at all.
-Pan/drop filter change on the transaxle.
-New check valve at the vacuum modulator.
-New spark plugs
-Ford yellow top injectors
I'm planning on datalogging the car to get specific rpms at shiftpoints. Going by scanning the car in the past, I know the numbers I listed above are VERY close already.
PS: I was looking at futuretgper's dyno chart from a dyno dynamics dyno(his car had a K&N and topgun chip) and calculating shiftpoints from his chart along with the information on how shiftpoints occur from MY car, it appears to me that 5200-5300rpms is an optimal shiftpoint for a Topgun equipped TGP. At 5200rpms on his dyno chart, approximately 170whp was available. At the rpms I listed above that my car drops off to(2007), almost exactly the same amount of power(170whp) is available after the shifts indicating that this is an optimal shiftpoint. I know using his dyno chart isn't exactly ideal for my particular car, but his chart gives me a great idea of where shiftpoints should occur. *I still plan on trying to keep the car at lower rpms like Kenny suggested to see if it makes my car any quicker. Kenny reported that his car went quicker in the 1/4 mile in this manner. That post can be found in the 1/4 mile section in 93luminaz34's thread.
If any of you have paid close attention to how your shiftpoints occur, please add your information below for comparison purposes.
Sorry I did not read your entire post...more of a breeze by.
Once again I will say...on a vehicle that produces more torque than HP you need to keep the vehicle in the torque curve. Torque turns your wheels...not HP! HP only carries the vehicle once the torque has faded off.
Alright Kenny, I did some more figuring and see why keeping in the torque curve on this car is better. I calculated some shiftpoints for the torque curve.. Going by my knowledge of how my car shifted above at those higher rpms, I assumed the same 25% drop in rpms shifting 1st to 2nd and the same ~19.3% drop in rpms from 2nd to 3rd. I plan on trying out these shift points and seeing if the rpms drop off to where I think they do, if not, I'll recalculate to reflect proper shiftpoints. I'm still going by futuretgp'ers dyno dynamics chart by the way.
I came up with following shifts for torque
1st to 2nd @ 4950rpms
2nd to 3rd @ 4670rpms
These are approximations of course. 1st to to 2nd @ 4950rpms will drop rpms down to approximately 3713rpms. At 4950rpms, 225 ft-lbs is available. At 3713, the same 225 ft-lbs is available and then you're in the meat of the torque curve and hit peak torque shortly after this shift. 2nd to 3rd @ 4670rpms will drop you down to approximately 3770rpms. At 4670rpms, 240 ft-lbs of torque is available, the same 240 ft-lbs at 3770 after the shift. Going by the dyno chart I'm using, these shifts will put you just shy of peak torque and the car should pull pretty hard.
Kenny, in that track information you posted, you said your car would only drop down to ~3800rpms when modulating the throttle to get it to shift lower. My shiftpoints above are dropping very close to that and I'm sure modulating the throttle like you said will be even better.
PS: I can modulate the throttle to around 80% in my 140hp '93 GP and even it's faster with a bit lower than factory shifts! :laugh: