Lethal

I have a near stock (just a lid and muffler) '01 WS6 M6, and people tell me that I should be shifting at 6000. But just about anything I see from magazines have them shifting about ~5500, and they are getting really low 13's, where my best is 13.41 WITH drag radials. With the power I'm putting down (331/350) shouldn't I be low 13/high 12 territory? Everyone tells me that my shifting is quite fast, so the only thing I can think of is shift RPM. Any suggestions? Thanx. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

AlonzoVersion 1.0

I would try both and see which one nets you the better et.

The Juggernaut

iTrader: (7)

I have always shifted at 5900 to 6100 RPMs.
Weight,elevation and air quality will effect ET also.
Your dyno is probably a corrected number,so it may not be applicable.
Don't look to pick up .5 from shifting 500 rpm's earlier. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
What's your 60' time?

Lethal

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 01-Z:
<strong>I have always shifted at 5900 to 6100 RPMs.
Weight,elevation and air quality will effect ET also.
Your dyno is probably a corrected number,so it may not be applicable.
Don't look to pick up .5 from shifting 500 rpm's earlier. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
What's your 60' time?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The best I've had is a 2.1.

The Juggernaut

iTrader: (7)

2.1 on drag radials?!
What size and pressure do you run them at?
You should be consistant 1.97-1.99 with an occasional 1.89-1.94.

Lethal

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 01-Z:
<strong>2.1 on drag radials?!
What size and pressure do you run them at?
You should be consistant 1.97-1.99 with an occasional 1.89-1.94.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No, that was with street tires. <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" /> I did a 2.1 with DR's too though.

Lethal

Talked to my roommate (Saladbar) last night, and after looking at my dyno sheet, he believes that I should be shifting around 5700-5800. I still need to hook up my shift light, but I'll have to work on a finding a pill (the lowest pill in the kit is 6K).

Bob Cosby

An LS1 - even an internally stock LS1 - makes very good power right up to its factory rev-limiter. I'd shift that thing as high as possible - I did when I owned my old 99 T/A.

Do you have a dyno printout or graph by chance? If so, please post and I'll show you how I get optimum shift rpm. A torque printout is best, if you have it - next best is a graphical HP curve. If you don't, I'm sure you could find a representative dyno output from a similar car.

Lethal

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Bob Cosby:
<strong>An LS1 - even an internally stock LS1 - makes very good power right up to its factory rev-limiter. I'd shift that thing as high as possible - I did when I owned my old 99 T/A.

Do you have a dyno printout or graph by chance? If so, please post and I'll show you how I get optimum shift rpm. A torque printout is best, if you have it - next best is a graphical HP curve. If you don't, I'm sure you could find a representative dyno output from a similar car.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The sheet is at home, and I'll scan it at work tomorrow (no scanner at home). The power seems to drop off a bit at 5800, so wouldn't make since to shift there? Wouldn't that make it fall back to about peak torque?

Lethal

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Colonel:
<strong>You'll go faster shifting at 6200+. It's all about putting most average HP to the ground over the course of the 1/4 mile. Sure, you power starts dropping off well before 6200 but because of the gearing advantage of staying in a lower gear for longer, you'll be putting more force to the ground.

Try it at 5700 several times and then at 6200. You'll see. <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I'll try it. Hopefully tomorrow night. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

Colonel

You'll go faster shifting at 6200+. It's all about putting most average HP to the ground over the course of the 1/4 mile. Sure, you power starts dropping off well before 6200 but because of the gearing advantage of staying in a lower gear for longer, you'll be putting more force to the ground.

Try it at 5700 several times and then at 6200. You'll see. <img border="0" alt="[Burnout]" title="" src="graemlins/burnout.gif" />

Lethal

Here's my dyno sheet.

<img src="http://www.dfwstangs.net/hosting/Lethal/dyno.gif" alt=" - " />

Bob Cosby

Ok. If you have the torque numbers from the dyno run, use the following link to get optimum shift points: prestage.com/carmath/dynochart.asp.

If you do not, you can use your graph and take your best guestimate of the torque values at the needed rpm. This is what I did...here are the guestimated numbers that I used...

RPM Torque

3000 330
3200 333
3400 336
3600 339
3800 342
4000 345
4200 348
4400 350
4600 347
4800 344
5000 336
5200 328
5400 316
5600 304
5800 292
6000 280
6200 263

Plugging those into that calculator gives the following shift points:

1/2: 6200
2/3: 6200
3/4: 6200

Don't get wound around the fact that this particular calculator uses torque vice HP - it is simply doing math to figure the power.

Anyways, the reason you need to shift so high can be readily seen simply by looking at your HP curve. Shifting from 1/2 @ 5500 rpm brings you all the way down to a calculated 3690 rpm (using the RPM and MPH calculator at www.camaroz28.com/calcs/rpmmph.html). At that rpm, you are making on only ~230 HP. Shifting at 6000 rpm nets 4000 rpm when you hit 2nd, at which point your making ~265 HP. Quite a difference, huh? Would you rather start 2nd gear with 230 HP or 265 HP? Don't answer that. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

The next obvious question is "what about the difference in HP between 5500 rpm (my previous shift point) and 6000 rpm? Look at your graph....the difference - at most - is 10 HP, which is more than made up by the 35 HP you gain on the bottom of your rpm range. Additionally, your HP is climbing very, very rapidly from 3600 to 4000, while it is only gradually declining between 5500 and 6000.

Does all this makes sense? I like to keep things simple (likely cause I don't understand them when they get complex). However, sometimes my explanations only make sense to myself. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Best of luck to you.
Bob

Lethal

Wow. That's some good info. Guess I can try it at 6200, but won't I bang the rev limiter?

Bob Cosby

If the limiter is at 6200, then you'll need to shift a bit lower...perhaps 6000. It all depends on how accurate your tach is, your shifting style, how well you shift, etc.

Practice, practice, practice. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Norm

On my '01 TA thats an auto, it shifts at 5500rpm from 1'st to 2'nd. Then everything after that is 6000rpm. I was able to get 13.40 like that... with my spare tire and two friends in the car...

Bob Cosby

An A4 will behave quite differently from an M6 - whole different strategy.

Lethal

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Bob Cosby:
<strong>If the limiter is at 6200, then you'll need to shift a bit lower...perhaps 6000. It all depends on how accurate your tach is, your shifting style, how well you shift, etc.

Practice, practice, practice. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I heard the tachs are pretty slow. People say that I shift pretty fast, but that doesn't mean I'm shifting right. Could you explain?

Colonel

Shift just as close to the stock rev limiter as possible. That should have you right on 6200. Yes, this may read 6000 on the tach in 1st gear due to the tach not being able to keep up.

ed f

thanks for all the info i,m shifting around 6200 i moved my rev limmiter to 6600 it just seems that i have a dead spot from 94 mph-100 mph.i thought mabey by moving my shift points might help. thanks efriedhoff@fuse.net