WheelsUp84z

iTrader: (14)

2 step will exponentially help your launches.

Gary Z

Oh, and thanks for the data log. I've heard guys talk about power shifting but this is the first proof I've seen.
-Gary

Gary Z

Good to hear. I've resisted because I thought I could learn to recognize the sound of 6000 rpm. Also, I don't know anyone who has a 2-step. People around here think they're sophisticated but most don't know squat about drag racing.

Gary Z

I hate the sound and hesitation but bogging sometimes works for me. Bogging is certainly much better than wildly spinning. I classify my launches into three categories: a deep bog, a no-hook spin, and in-between, which I call a hooking-spin. The attached chart shows my five lowest ET runs superimposed on one another. In the five launches I have two bogs (blue, green), and three hooking-spins (red purple, turquoise).

The numeric data for these runs is:

Sixty ET Speed TirePSI LaunchRPM
1.559 11.534 118.56 19.0 6069
1.612 11.541 119.39 18.0 5697
1.604 11.577 120.34 19.5 5762
1.568 11.577 119.53 19.5 6735
1.653 11.582 119.02 19.0 4907

nmass399

Bogging the car is good for bracket racing as long as it consistenly bogs the same amount each time. I tried to get the car to bog at the race in Commerce, Ga to slow it down some but it had way much effect on 60ft. As long as i launch around 4500 to 5500 rpm with 11psi cold tires and around 12 to 13 hot, the data log will look like i posted. I can usually get my car to run within .025 quicker and slower with the exact same tune as long as the density altitude does not make a big change.

That track outing from that graph i posted, i ran from 11.74 to 11.82 as long as i did not miss a shift. It would be from 11.74 to 11.79 if that 11.82 run was not in there, i did not have to much air in the tires or the track wasn't as sticky, not sure which one. It would have been even more consistent if i wasn't changing the tune up.

Those runs you posted were on separate track outings right? Is your car more likely to hookspin or bog? How consistent during a track outing is your car?

nmass399

Also from the looks of that graph that you might be able to get the car more consistent with a 2 step. Not sure tho but i know it makes it easier on me to have one rather than searching for rpm while trying to consentrate on the tree. If you can get your car to either just bog, or just hookspin and not both during a track outing it should get more consistent also, at least i would like to think it would.

223HAWK

iTrader: (11)

This!! It is one less thing you will have to really think abotu on the line. Set an RPM your car likes and then make suspension and tire work with it. The less things you change it will be easyer to make the car work. Changing Launch, Tires, Shocks all at once you wont ever learn what works and what doesnt. At 6300 my car cuts 1.47-1.49 60s all day on a decent track. Go to a better track I gotta leave higher.. I really hated the thought of it at first but once you get it and learn what the car likes its priceless..

Gary Z

LS1Tech is still great. I started this thread thinking my launch data might help a few beginners. It turns out I’ve learned a few things myself. Somehow I wasn’t fully aware that consistent, low sixties are possible with a manual transmission. We all know the easy way is with an auto but what fun is that? Thanks everyone.

Gary Z

Yes - the graph of my five lowest motor ETs shows runs from three different days - two runs one day, two another day, and a lone good run the third day. So I am able to achieve some consistency although not the kind of consistency you and others have described. I do believe a 2-step will help. One reason I run higher tire pressure than you (aside from the fact that higher pressures work better for me) is that I want never to bog. I usually air the ET Streets to 20 psi cold before my first run and lower the pressure if I get too much wheelspin. I'm always trying to find the sweet spot between useless spinning and dead-hook bogging. Some days the track is super good and I bog from a 7000 rpm launch with 19-20 psi in the tires. A bog can give me a 1.5x sixty but I still won't like it. Bogging from a 7k launch is brutal clutch punishment.

Gary Z

Beginners sometimes ask what type of tire works best with a manual transmission. The attached graph shows my sixty experience with drag radials. I have relatively few data points for DRs because I soon discovered that bias-ply ET Streets work much better. My best result with DRs was a 1.786 sixty, launching at 2500-3000 rpm on BFG 255/50/R16s @ 22psi. I toasted a clutch trying to repeat that launch.

nmass399

One reason i have good consistency i think is also running speed density. Which has to be tuned with different density altitude.

WheelsUp84z

iTrader: (14)

On a set of 295/55/15 MT DR's i've gotten a 1.72 NA, but could only keep the 2 step at around 3200 and had to slip the clutch vs either a dump or very quick slip around 5k on the bias plies. DRs are really tricky on marginal tracks and still require a lot of adjustment to the suspension on good tracks with a manual. Takes a lot of passes/seat time to get it right. Lighter cars help out as well

Nemesis350

iTrader: (11)

kinda deviating off topic, but are you guys launching on a build t56?? All this info makes me realize i need to make some changes at my next track visit, but i'm sure my t56 is pretty much stock (other than clutch/cmc)

96onele

Nobody has mentioned front shock settings in this thread. Any thoughts?

Gary Z

My T-56 has all stock innards with the exception of billet keys and a steel 3-4 shift fork. My hydraulics are stock except for the “drill mod”. A more or less stock T-56 is sweet up to at least 550 rwhp if you have a good, properly installed clutch.

Gary Z

The general rule for front shock settings is stiff compression and loose rebound but you really need to experiment to find what works on your car. Be careful with front shock settings, especially if you have skinnies and no front swaybar.

96onele

Agreed. With my Strange DAs upfront, adjusting them close to full loose on rebound (extention) seems to affect the compression in a negative way. In other words, with compression set to close to full stiff, rebound full loose, the shocks seem to be way to soft on compression. It feels like they may bottom out real easy and of course the front end does lift real easy as well, which I expect. So, I was courious what you guys had for your settings.......may help me with a baseline setting.

nmass399

Stock bilsteins here. Not sure what mine could pick up on 60 ft with some double adjustables and a different spring up front. If you watch in some of my video's the front suspension is fully extended but does not lift a tire. I am thinking mine would raise up a little quicker getting more weight to the rear tires earlier.

Right now i am interested in changing the instant center on the car, basically to see if what hitting the tires harder will do vs lessining the hit. I know i need a drag bar badly tho.

Also running a stock gto t56 for the other guy who was wondering. Mine is only a bolt on car so not much power to break it here. The gto t56 has a few better internals than the fbody t56.

Nemesis350

iTrader: (11)

i'm just a little worried about launching the car on what i'm assuming is a stock t56. I don't power shift, and i'm only putting 405rwhp, but i've heard of people destroying output shafts and other stuff with less.

Nemesis350

iTrader: (11)

yeah apparently the mn12 is stonger, and the guy i bought my moser 12 from was putting 740hp through a stock mn12 without a problem.

Anyone else here clutch dumping over 4k and cutting < 1.8 60 fts on a stockish t56?? (without breaking?)