Drag Racing Tech - I need those 4.56 guys in here, please...

John (gator's 99TA), you said I'd cross the traps at the right RPM with the 28" x 9" ET Drags...looking at the gear calculator, I'm not sure about that. Looking at trapping in the 123-125-MPH range. That's like 6800-6900 RPM's. Isn't that a little high?

[Edit: And that was figuring a tire height of 27.8", which is allowing for .5" tire growth]

<small>[ October 12, 2002, 02:42 AM: Message edited by: RAGEman ]</small>

Where is your peak HP? Rule of thumb is you want to cross the finish line about 800 rpm above peak HP.

Bob, I figger my peak to be somewhere in the realm of 6600 or so. That's just a guesstimate because my cam hasn't been selected yet. 800 RPM's? Good night! I haven't heard that. That means with my stock motor setup, I should have been crossing the beams @ 6500. Ouch. Stock rev. limit is 6250. Rule of thumb for LS1 bottom end is set the rev limiter @ 7000. That would mean I'd need a cam that peaks @ 6200. I don't think that's gonna happen.

What a crazy, mixed-up world we live in.

if you want to cross the line right at your peak HP go ahead, but youll be wasting ET unless you have a VERY flat HP curve for a long ways below the peak.

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by chevyguy3:
<strong>if you want to cross the line right at your peak HP go ahead</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I don't recall saying that.

<small>[ October 12, 2002, 10:07 AM: Message edited by: RAGEman ]</small>

LOL. Do you have a dyno graph handy? That might lend a bit more info. However, if your peak is 6600, then you likely need to be shifting @ 7000+ to get the max ET, and your finish line rpm should be somewhere up there too.

Hell I spin my car to 7000+ rpm all the time...what's the problem! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Seriously, if you have a dyno graph - or better yet, a tabular output of your dyno run - it would be easier to figure optimum shift points and finish line rpm.

Bob

well, you said you plan to have peak hp at 6600, and you said that you thought 68-6900 was a bit high....

Dang it! Well, my problem is that I don't think the motor will live long past 7000. I just don't think it would be safe to set the rev limit any higher than that. I guess I'll get back to you after my cam has been picked out. I've asked you this before, but, when are you coming to Texas?

chevyguy3, I know, but I was saying it was a little high for my weak, inferior, non-Ford LS1 motor to handle for very long. However, the reason I am posting is because I truly don't know. So, this is very much open for discussion. So convince me!

When am I coming to Texas? Oh jeezum dude, I live in Va Beach! LOL. I was there this past July visiting family, but it was a 'family trip', so we were in the Van. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> I retire from the USN in about 4 years, and then should go back to Texas...permanently.

If your shortblock won't live past 7000 rpm - then stay under that. Pick a cam that will give you the best average power at the highest rpm you can safely run the shortblock to (your heads obviously can support plenty of rpm/power).

</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>When am I coming to Texas? Oh jeezum dude, I live in Va Beach! LOL. I was there this past July visiting family, but it was a 'family trip', so we were in the Van.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Excuses, excuses. That's the same old excuse you gave me last time! At least try to come up with some better ones!

<img border="0" alt="[pimp]" title="" src="graemlins/gr_pimp.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

<small>[ October 12, 2002, 02:33 PM: Message edited by: RAGEman ]</small>

Bob, doesnt make excuses. he is a very helpful person around our parts. even if he does drive a mustang. just messin with ya Bob.

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by RAGEman:
<strong>John (gator's 99TA), you said I'd cross the traps at the right RPM with the 28" x 9" ET Drags...looking at the gear calculator, I'm not sure about that. Looking at trapping in the 123-125-MPH range. That's like 6800-6900 RPM's. Isn't that a little high?

[Edit: And that was figuring a tire height of 27.8", which is allowing for .5" tire growth]</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Your talking about the 28x9 ET DRAGS right?
They will be 27.3 at FULL GROWTH.
They measure around 26.5ish as they sit.
Good Luck!

Dude, Summit Racing lists them as 27.3", and I just assumed they meant cold...if 27.3" is as tall as they get, then that simply won't work. <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

Me-4.30 gears,Et Drags trapping a mid 117's.
6100 rpms.

At 123mph would be,what 6500?6600?(4.30 gears)
I looked at 4.56 gears and I figured they wouldn't work.
But check with the guys who are RUNNING them.(on 28x9 ET dragsthat have made
ACTUAL passes,not 'should' or 'I think')
I could be wrong.

If worse comes to worse, I still think I could get some killer times with 4.33's...

Sean, that's what I'm trying to do is get some testimonials from people that have done it.

28" tire with 4.30 gears:
117 is at 6050 rpm