technique info requested

[Echoman]

Hey guys I was at the strip on Sunday and I'm a little frustrated. I've run a dozen times now and I'm not totally satisfied. My inclination is that it's my driving, but I'm struggling to be in the 14's with my build. The dyno plots for my car are pretty good, but I'm just not putting that power down for some reason. I launched at about 3700 and I'm a quick shift. It goes like this for me: I rev to about 3700, come close to just dropping the clutch, I don't know if I'm bogging the car down maybe, but I have my foot to the floor from start to finish between shifts. I'm a pretty fast shifter and I haven't missed at the track. I , don't think it's my shifting, but let me know what you guys think. Maybe my flooring the whole time is actually bogging me down. Never did get a chance to use my N2O before I broke my stock diff. I'm updating my whole tranny and adding an Torsen this week. I should have done that in the first place...I know.

[RodneyBur]

It will help if you post more info on your runs:

R/T
60
330
1/8
MPH
1000
¼
MPH

Also you mention something about your dyno plots. What did your car dyno at?

My guess is without seeing more info is that your 60ft times are bad and need improvement on launching. Did you have a lot of wheel hop and tire spin at the start? I'm sure not having the LSD was also an issue in this. Breaking the stock diff also points toward bad launching IMO.

[Echoman]

I think this is what you needed this is the line with my max values off of the spreadsheet
EngRPM Torq Power Temp MAP Lambda AFR PCRatio Time Baro T.Effort Torque
lbft HP ｰF PSI P/PC sec InHg lb lb-ft
6034 1020.713 205.017 62.4 0.63 0.84 12.35 1.05011 8.471 28.891 979.88 178.4463287


I don't have my slip with me, but I had a 60ft of 2.23, and max mph of 93. I remember from an earlier post that bbox said he was in the 14's with a bad tune, bad launch, and on street tires. My car dyno'd slightly better than his last build did at Logan. I know my 60ft times need work, but I didn't think that mine was absolutely horrible. I've tried launching like the elderly as well as hard launches and it doesn't seem to make MUCH of a difference in my 60ft. I don't hop at all and if my tires slipped it was just a chirp. I know we're talking tenths of a second and they make a difference, but I didn't think I sucked THAT bad (probably do though). I've gone down the track about a dozen times trying different launches and only broke into the 14's once...then broke my differential!

[RodneyBur]

Here's my info from my best run:

R/T .322
60 2.265
330 6.191
1/8 9.406
MPH 77.22
1000 12.160
¼ 14.509
MPH 96.09

As you can see your 60' mark is right where it should be. The best 60' I've seen is just over a 2.0 and was Blackcoog IIRC. Here's his stats:

Blackcoog 1999 MTX 3L Hybrid
Many mods
R/T: 1.065
60': 2.098
330: 6.036
1/8: 9.244
MPH: 77.91
1000: 12.002
1/4: 14.341
MPH: 96.42

I've seen one or two others with a near 2.0 60 foot time but most good runs are around the 2.25 mark so thats a good time. 2.0 is near perfect for the coug IMO. It takes some near perfect conditions to get that time, especially without good tires and good suspension set up.

Your top speed seems to be lacking though and is probably what is causing the higher times. Without seeing the rest of your slip its hard to judge why the end MPH is slow. Compare my time and black coogs time and you will see the major difference is his 60' time which is where he made his 1/4 pass .2 faster than mine. If I'd had his 60' time then I think my overall time would have been a little faster since I made up some of that loss up top. Its hard to say really but looking at the numbers you can kinda see that.

Your 60' time is close to mine and most others but your over all speed is what is hurting the run. My guess is that you are shifting too soon and not taking full advantage of every gear. It be nice to see the rest of your slip and compare the other marks too.

Here's my suggestion:

If you have good grip in first gear don't shift until 6500 rpms, if its slipping/spinning/bouncing/squelling/smoking/gurgling/or people are pointing and laughing don't prematurely shift to second....left off the gas and reposition throttle

Shift the rest of the gears around 6500 or you can examine your h/p torque curve and adjust to shift when they begin to drop off as long as it puts you in a good spot on the curve after you shift to the higher gear.

Since you were running without a LSD you should have pulled off the line slowly with more slipping clutch then gunned it after you were rolling a little.

What was your max HP and torque again? THe info you posted I got torque of about 178 but not sure if I read it right.


Look here and compare your times to others and it may help you understand what was going on on your run a little: 1/4 times (http://www.newcougar.org/forums/showthread.php?t=1391)

[Echoman]

I'll post my slips as soon as I get back to the car tomorrow. I'll take a look at my plots that I have to see where I drop off. The dyno info the I provided was a little outdated (copied from dewaynes response from my first dyno). My most recent one has my hp at 210. I'm glad that my 60ft times aren't totally off. I agree that my top speed is a little low. I set my shift light to 6500 where my peak hp is, but I didn't notice where it dropped off since it did plateau for a while. It almost seemed to me that my car lacked a little something in third. I know it's a "longer" gear but it just feels like most of my time on the track is spent in third and then fourth for what seems like just a fraction of a second.

[Dat1BlueCat]

Do you think the IMRC in third is bad?

[Echoman]

Is it even possible for the imrc to not function properly in third, but fine in others? I know it works in 1st, 2nd, and it was dyno'd functioning properly in 4th. I suppose I could put it in third with the clutch in and have someone watch the control arm from the side...with their feet out of the way just in case! If that's possible it might be the problem because that would be the best way to describe the feeling. I had my imrc out before and the lack of power past 4k is like the feeling I get in third. Kind of like there's no extra oomph through third. Like I said before..it might just be because you don't run through third as fast one or two.

[J-Man]

If the IMRC is working in first, second and fourth then it is defenitely working in third as well. Don't listen to nos-cougars comments.

Were you by chance running on your heavy 18's?

[RodneyBur]

yeah the IMRC is based on engine RPMS and doesn't matter what gear you are in. It could be opening sometimes if it is having issues, but it would happen in more than one gear and you would most definately notice.

If you're running 18's it will make a difference, but I don't know how much. Try putting on your stock rims and give it a try.

[Drewmanfu0]

I had an intermittent IMRC, never gear specific though, sorry NONO'S_cougar.

[Echoman]

I was on my 18's though they're pretty light. Here are my times

R/T....726
60'....2.35
330...6.387
1/8...9.692
mph...76.06
1000..12.513
1/4...14.923
mph...93.23

[BigBalledOX]

Your 60' time is bloody murdering you dude. If you can take two-tenths off that, you'll knock four-tenths off your run.

[Echoman]

Well it turned out that I was running rich after I fixed my vacuum leak. A retune boosted my torque and hopefully this should help my times. The extra 12ft/lbs with less timing taken out than before really seem to make the car pull.