verbs

Here is the low down.

Mods are in the sig (m6 tranny), I have a 7000rpm rev limiter, 3.73 gears, and will be running slicks. I'm at 1500ft elevation, and don't think I'll be able to trap much more than 117mph or so on 26.2" slicks (maybe I'm just being conservative) I hit my peak horsepower at about 6300rpms, and shift at 6800rpms on average.

As it stands, if I were to cross the finish line in 4th gear on slicks at around 117mph, I'd be at about 5600rpms making about 410rwhp on the dyno graph. Definately not optimal.

If I were to add 4.30's to the car, assuming my trap speed didn't increase any, I'd cross the finish line at 6400rpm's or so making 435rwhp, which is almost exactly where I make peak power.

So my question is, how many tenths/mph am I leaving on the table by running 3.73 gears vs. 4.30 gears, which seem to be optimal for my setup?

I'm trying to justify the switch.

<small>[ October 01, 2002, 01:29 PM: Message edited by: verbs ]</small>

CHRISPY

If you can hook you will probably go .2 faster and 2mph faster with the 4.30 IMO <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Cheers,
Chris

<small>[ October 01, 2002, 04:52 PM: Message edited by: Chris ARE 360 ]</small>

SPANKY LS1

iTrader: (24)

Can't really help you any, but I'm really really interested in your track times. FWIW, I'm going with 4.30s. Good luck, Shawn

Terry Burger

iTrader: (4)

Hard to say, but 0-.1th max.

CHRISPY

He is a 6 speed Terry not an A4 with loose converter. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
With traction he will drop .2 easy. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
cheers,
Chris

verbs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SPANKY LS1:
<strong>Can't really help you any, but I'm really really interested in your track times. FWIW, I'm going with 4.30s. Good luck, Shawn</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">As soon as I can get my 2nd gear rpm limiter to stop kicking in at 6300rpms, I'm going. For some reason, LS1 edit isn't able to reprogram my 2nd gear, but every other gear is setup for 7000rpms. Wierd.

AlienDroid

With traction you're going to blow your clutch easy. <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />

My bro's near stock car with 4.10 gears is having some clutch issues. What clutch are you useing?

Ebbsnflows

iTrader: (15)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by AlienDroid:
<strong>With traction you're going to blow your clutch easy. <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />

My bro's near stock car with 4.10 gears is having some clutch issues. What clutch are you useing?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">In his sig it says McLeod single disc. It's the same clutch I run. Trust me....based on his mods, it'll take anything he can throw at it.

John B

iTrader: (10)

I think you are way too conservative in your trap speed estimate based on your power! I would venture to say unless your car is a pig (weighing in over 3700+ lbs!) that your traps should be in the 119-120 MPH range. At any rate, I think 4.10's would be your best bet with a 26" tire because this should send you through the traps at roughly 6300-6400RPM.

verbs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by John B:
<strong>I think you are way too conservative in your trap speed estimate based on your power! I would venture to say unless your car is a pig (weighing in over 3700+ lbs!) that your traps should be in the 119-120 MPH range. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Remember, I'm racing at 1500 ft, where density altitudes are never below 2000ft. That is why my numbers may seem a bit low.

My raceweight is between 3550 and 3600.

Got Me SOM

iTrader: (2)

For the time, labor and energy spent changing the gears it just doesn't seem worth it for 1-2 tenths.

Ebbsnflows

iTrader: (15)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by verbs:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by John B:
<strong>I think you are way too conservative in your trap speed estimate based on your power! I would venture to say unless your car is a pig (weighing in over 3700+ lbs!) that your traps should be in the 119-120 MPH range. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Remember, I'm racing at 1500 ft, where density altitudes are never below 2000ft. That is why my numbers may seem a bit low.

My raceweight is between 3550 and 3600.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Despite your elevation...you should still see much higher Trap speeds. I'm making MUCH less hp than you, and I trap around 121 (w/ Density Alt. of 1600 ft). So with 430+ hp on tap, even at 2k ft. elev. you should see 121 mph or better.

BTW...I think you should do the gears (at least 4.10's)

verbs

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Ebbsnflows:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by verbs:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by John B:
<strong>I think you are way too conservative in your trap speed estimate based on your power! I would venture to say unless your car is a pig (weighing in over 3700+ lbs!) that your traps should be in the 119-120 MPH range. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Remember, I'm racing at 1500 ft, where density altitudes are never below 2000ft. That is why my numbers may seem a bit low.

My raceweight is between 3550 and 3600.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Despite your elevation...you should still see much higher Trap speeds. I'm making MUCH less hp than you, and I trap around 121 (w/ Density Alt. of 1600 ft). So with 430+ hp on tap, even at 2k ft. elev. you should see 121 mph or better.

BTW...I think you should do the gears (at least 4.10's)</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I hope you are right on this one....I don't want to get my hopes up too high, so I guess I'm trying to be conservative.

Hopefully I'll be able to trap in the 120's. That would kick *** <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Damian

iTrader: (89)

I agree with the posts above, you should definately be trapping higher despite your altitude. There are guys trapping higher, with less power, in similar or slightly more altitude. With your race weight, I definately see 120-121 coming out of that car...

Josh

MARKSZ71

iTrader: (3)

I went exactly 2 tenths faster with 430s than my 373s

The Juggernaut

iTrader: (7)

Is this all speculation?
Have you ran with the new setup?
If not- run the car and SEE what it traps at(MPH and RPM)
How it hooks and how it feels.

But for the record-throw the 4.30's in.

If you want to'justify' it. Run it with 3.73's and then run it with 4.30's.

You'll feel the difference.

4.30's should be a no-brainer. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

verbs

</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>Is this all speculation?
Have you ran with the new setup?
If not- run the car and SEE what it traps at(MPH and RPM)
How it hooks and how it feels.

</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">How could you ask a bench racing expert if he speculates? <img border="0" alt="[jester]" title="" src="graemlins/gr_jest.gif" />

No runs yet....It had been way to hot recently, and now that it cooled down, I just broke my driveshaft. <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" />

Car should be up and running in about a week, and hopefully I'll have a better idea by then.