ZX-12: launch: lo or hi rpm????

Last Sun nite I finally got back to Houston Raceway after 2 mo waiting on a damn starter clutch.  On the positive side it was my 1st outing with my 12's new StreetSmart system.  On the negative side it was VERY humid, dew on everything.

Before last night I usually launched at 5000-5500 and a normal/good (prestreetsmart) pass was:

60'         330'       1/8       1/8 mph 1000'    1/4   1/4 mph

1.551    3.995    5.954    126.35  7.640    9.078    154.86

 

Last Sun with the dew I couldn't get traction, so I tried launching at 3000 and pinning it as much as possible with the following back to back results:

60'      330'    1/8   1/8 mph   1000'    1/4   1/4 mph

1.557 4.019 5.966 126.65   7.645   9.071 157.54
1.578 4.017 5.956 126.86   7.637   9.068 157.19

I like the consistency and the fact I didn't slip the clutch hardley at all.  I don't like losing time off my 330's fighting wheelies.

 

I'm 230# suited, 762# combo weight, and I am not an experienced drag racer.  Bike is a bigblock/stroked NA Zx12, 6" arm, strapped/lowered, PS3 button shifter, MCR2, running Nutec.  I occaisionally use the bike on the street, mostly strip.

 

OK:  finally the question.  For a charter member of Houston's Team Fat Ass Racing (230# suited), do you guys feel I would be better off:

a - launching at 3000+/-, pinning it and fighting wheelies with the button shifter, shortshifting 1-2, and maybe even 2-3

or

b - launching at 5000 or more, slam/slip the clutch, working into the throttle as fast as I can, 1-2 shift near redline

 

Sorry for such a "newbie" question.  I was planning on taking Rickey's class here in Houston Feb 6-7 but it was cancelled (not enough students).

Any tips would be much appreciated! :D

Brock,

yep it has the power, with nutec it has 222 SAE with a VERY broad peak which really doesn't drop significantly at the limiter (221). 

The addition of the StreetSmart pipe seemed to make a BIG difference, the icing on the cake.  I have Lee's cams, mild porting, etc and as a 1375 it made 204+/- but the curve was lumpy. 

Now as a 1427, same cams/timing, but with yr pipe, its like everything is working together.  VERY smooth curve and plenty o' hp (229 uncorrected).

Less power up to 8000rpm may help keep the f wheel down in 1st. 

I just went from a 50t to a 49t in an attempt to curb wheelies, but it didn't help. I'm doing a 5 gear 1/4 now and have even thought of trying a 4 gear, but from what you say that is the wrong direction.

Thx for the help!

Hey Entropy, you know what man,  I spent all last year saying what you just said:

"I like the consistency and the fact I didn't slip the clutch hardley at all.  I don't like losing time off my 330's fighting wheelies."

Granted, I'm 80lbs lighter than you, and on a stock cc, SWB 12R, but my experience is the same as yours.  Lots of launch RPM = great times on our 12's, but destroys clutches.     Lower RPM launching with WOT sooner (clutch lever all the way out) gives me some great 60' numbers, but ALWAYS a wheelie problem in 1st gear.

I had always thought that it was the Busa's torque down low that allowed them to leave at a lower RPM than I was, but, with your 1427 (wow!) experience, I'm now wondering what the weight bias is front to rear, for the Bus and 12R.

btw, awesome to see you getting 157mph now. 

What kind of rear shock are you running?

 

 

BA,
I've got a Penske.

I yanked oput my clutch after last weekends passes and the plates were PRISTENE! The steels looked perfect, no discoloration whatsoever. I sure like that part of lo rpm launches :D.

I'm gonna fool with shock settings next time out and experimenting with the low rpm launches. But if the 330' keeps suffering, I'll go back to slipping the clutch on Sunday and calling Ron Ayer on Monday!