Previous best was 1.76 60, 8.34 @ 80.98 1/8th. I moved and finally got a chance to head to the local track. I ran a few 8.3s. I added an EWP and cutout. The EWP made no difference in times that I could tell..similiar elevation and weather, but different track. The cutout was worth about a .10 and 1 mph in the 1/4 (back to back runs).
New best is in sig, along with mods. I usually run an 1/8, so this was the first real time I got to run the 1/4 with this car. I was dissapointed to see the car falling off so much on the top end. I think Im getting every ounce of pwr Im making to the pavement, it just seems like the mph is a little low. I was ecpecting a 12.9 or so and the best I could muster was a 13.12. Any suggestions? Im not spinning, there is no spark retard, tuning is spot on as far as A/F and timing.

 

That's why I normally don't give 1/8 mile times much credence.

Do you have any suspension mods? If not, it is time. Any weight reduction? What are you running for rear end gear ratio? A set of 373's would do you some good too.

Keep us posted. You have a great start!!

 

The suspension is all stock, but its hooking great. I did remove the sway bar. No weight reduction either. I drive it everyday and dont want to get rid of any of the stuff in the car. Gears are looking good, but I think Ill settle for some 3.42s or 3.55s(if I get a 9"). The 3.73s might be too much for me.

 

Typically, a car like your's (N/A) makes 64% of their 1/4 mile ET in the 1/8 mile. Therefore, your recent 13.12 in the 1/4 cooresponds directly to your previous 8.34 1/8 mile ET.

So, when you can make some improvement in your 1/8 mile ETs, you'll also see an improvement in the 1/4. Providing you don't have any major problems (running out of gear, Etc.).

The bottom-line is, you can use your 1/8 times to assess potential performance improvement for the 1/4. Just multiply your 1/8 mile ET by a factor of 1.5625.

For example: 8.34 X 1.5624 = 13.03

WD

 

Engineer, Thats why I think Im losing a little on the top end. a 8.28 1/8 and 13.12 1/4 on same pass (see sig). Previous runs had 8.3s/12.2s consistently. Thanks for the reponse.

 

Seems like the ET matches those mods. My friend's 97' had: Pacesetter LT's & ORY, cut out, BBK UD pulley, 3400 2.1 STR fuddle, tune, LT4 KM, MSD 6A & coil, K&N CAI, SFC's, LCA's, !sway bar, !EGR & !AIR, !rear seats.

His car went 13.094 @ 104.02 on a weak 1.92 60'. The air was great that night though. When his car was falling off on the top end, we found it to be a weak factory fuel pump. But, if your a/f is rock solid through the entire band, I doubt that's it. All I can think of now is that your converter isn't very efficient on the big end.

 

awesome times man...mine are similar

 

I didnt think about the converter...hmm. What would my data logging indications be of a converter or even a valve float problem on the top end? Thanks for the replies

 

If you logging software has the trans values like Autotap does then you could make a pass logging rpm vs trans input speed vs trans output shaft speed. In 3rd gear the difference between input rpm and output rpm is the amount of slippage in the trans and converter.

 

awesome info. Ill get the laptop out and check it out. Thanks

 

ok, datamaster doesnt have the input vs output but does list "slip rpm". Im not sure where they get the figure, but mine is listed as 700ish rpm in 3rd on all the runs. BTW, I have logs from every pass since Ive had the car, and even with a stock converter, it was around 200rpm. Here are 2 other things that I should mention...
1. I did notice my injector duty cycle getting into the 91-92 percentage. At what point is the atomization/spray pattern effected by duty cycle?
2. My O2 mv has a consistent 100mv gap between the two. Its like parallel lines on the plots, but all other data virtually matches between left and right.

 

700 rpm slip at what engine rpm? That's way over 10% and IMHO too much. Could be 3rd gear or the converter. Can you look up slip rpm at the very top of second gear?

 

700 at about 5000rpm. I am using datamaster, and it shows consistent jumps in slip rpm at5200-5500rpm (slips about 2krpms), then after the shift it drops to 1000 slip rpm and then consistently trails off until the next shift point. Its hard to explain, but it looks the same relatively on all my runs in the past 2 years. Do you have datamaster? If so, would you mind looking at the file?
A side note- I compared my finish line rpm with the f-body gear calc and it shows about a 800rpm difference too. I am hitting 100mph in 3rd at 5000rpm, but the calculator says 4200rpm (a4-3.23) I then rechecked the runs and noticed that the TCC enganged indicator shows it does not engage in any of my runs. But driving around normally it locks up fine.

 

Don't have Datamaster but from your sleuthing I can deduct that your TC is not very efficient and that a better TC would improve your 1/4 ET and MPH. Some get around this by installing a manual TC lockup switch and lock the converter in the middle of 3rd gear to make the car pull like a stick car. But that is hard on the clutch and could cause it to fail. It will not lock on it's own because the PCM is programmed not to lock it at WOT.

 

Thanks Al. I guess Ill be looking for a new stall then. Probably Edge or Fuddle since the vig is too expensive for me. What would you recommend?