Launching an Auto/ratchet

CAN3800SC · Post by **CAN3800SC** » Mon Apr 04, 2005 11:09 pm

I tried powerbraking last summer..... holding the brake,I'd rev up to 2500-3000 RPMs, then hammer down on the gas as soon as I let go of the brake.

I can honestly say I felt no positive difference in launch..To be honest I feel like I launch better when I just hammer down without Hiking up my RPMs.

I know a few of you are frequenting tracks in the summer, so what am I doing wrong, or am I wasting my time with this method?

I'm racing my friend's dad's chevelle at the track this summer so every bit of advice counts.

Shaun41178(2) · Post by **Shaun41178(2)** » Tue Apr 05, 2005 6:48 pm

Powerbraking works if done correctly.

You might not feel a difference but there is a difference in time.

Hmm maybe you should recalibrate your ass dyno?

My old 2.8 was about .2 slower int he qtr if I didnt' powerbrake it.

It makes a difference, but its so small your butt won't notice but the clock does.

stimpy · Post by **stimpy** » Tue Apr 05, 2005 8:23 pm

What method produces the least wheelspin? I've tried both of those and I just make Kumho dust on the pavement for a half a second or so.

CAN3800SC · Post by **CAN3800SC** » Wed Apr 06, 2005 6:02 pm

Shaun41178(2) wrote:Powerbraking works if done correctly.

You might not feel a difference but there is a difference in time.

Hmm maybe you should recalibrate your ass dyno?

My old Boat Anchor was about .2 slower int he qtr if I didnt' powerbrake it.

It makes a difference, but its so small your butt won't notice but the clock does.

so what were u bringin your RPMs up to before you launched?

The Dark Side of Will · Sat Apr 16, 2005 8:51 pm

stimpy wrote:What method produces the least wheelspin? I've tried both of those and I just make Kumho dust on the pavement for a half a second or so.

Buying decent tires produces less wheelspin...
What are you running? 712's?

stimpy · Post by **stimpy** » Sat Apr 16, 2005 10:48 pm

711's

The Dark Side of Will · Sat Apr 16, 2005 11:07 pm

Even less sticky.
I went from 712's to Firehawk SZ50 EP's and they are MUCH stickier. You get what you pay for.

stimpy · Post by **stimpy** » Sun Apr 17, 2005 12:27 pm

Yeah, but if I want to keep Christmas nice, I gotta buy what my dad sells at his store. Got any opinion on a Bridgestone that will last longer then a year? I had Turanza Revos on my last Fiero, but it had a boat anchor, no traction problem there.

Post by **eHoward** » Sun Apr 17, 2005 1:38 pm

AFAIK, the Turanza is a non-performance tire. You want something from the Potenza line if you're going bridgestone.

Although, stay away from the Potenza RE-92s. They had very little dry weather traction. And the sidewalls allowed the tires to roll over during hard cornering. That's the only bridgestone I've ever run. And they made LOTS of noise.

Bridgestone RE-050s might last more then a year and give you some traction.

Your father sell Toyos? I loved the T1-Ss I had. Those will give you some life and not break the bank.

stimpy wrote:Yeah, but if I want to keep Christmas nice, I gotta buy what my dad sells at his store. Got any opinion on a Bridgestone that will last longer then a year? I had Turanza Revos on my last Fiero, but it had a boat anchor, no traction problem there.

The Dark Side of Will · Sun Apr 17, 2005 9:31 pm

I love the Firehawk SZ50-EP's I got to replace the 712's. They were $140/tire vs $80/tire, but SOOOO worth it.

Pyrthian · Post by **Pyrthian** » Fri Jun 10, 2005 12:02 pm

at the Fiero 20th at Milan, I tried all different ways to luanch & shift with the auto. I found no powerbraking & letting the auto shift itself was the best way to go. powerbraking may help a already hot motor, but I found the thing that makes the biggest difference is a cool motor. and when you powerbrake, you create ALOT of heat. best time was with not starting the car untill the last minute, run the heater at full hot, no thermostat, nail it just before the last yellow lights, and let the auto do its thing. unless you really screw up a luanch, temp is much more important than the luanch

stimpy · Post by **stimpy** » Fri Jun 10, 2005 12:08 pm

Really?

I don't doubt you, but it would be interesting to see what kind of results 2 identically prepared cars ran, 1 hot, 1 cold.

Pyrthian · Post by **Pyrthian** » Fri Jun 10, 2005 4:19 pm

well, my car was identically prepared all day....

we had LOTS of time, and not alot of people were running, so I could basicly run back to back to back.
first run was ALWAYS the fastest. after 3 runs, I'd go back, park with all the other Fieros, and yack. hour or so later, do it again. again, 1st run the fastest. nothing changed. cold 16.2, hot 16.4. with the auto trans doing the shifting on its own, so no shifting errors or clutching to account for anything. times were rock solid consistant. of course this is just my car, and maybe something else caused the change. maybe I got a crappy O2 sensor, and my car sucks in closed loop mode. I dunno. no, that cant be it - at full throttle ECM goes open loop again.....

Series8217 · Post by **Series8217** » Sat Jun 11, 2005 12:55 am

uhhh... so what time did you get when you tried powerbraking on the 1st run?

groovieguy · Post by **groovieguy** » Sat Jun 11, 2005 7:36 am

The norm is heat produces power, oil is thinner, combustion chambers are hotter etc. This is proven by Nascar, for example, oil and water heaters are hooked up before qualifying.
Now tranny fluid heated up isn't good so that may be what the difference is in your situation.
Also a trick is to Deeeeep stage knock that pre-staged bulb out. Your car doesn't launch the greatest anyway and you fuck with the other driver as they think you will red-light and they will sleep on the line.

Also check you tire pressures sometimes street tires will hook better with more air in them. I know when they first came out with the BF Goodrich Drag radials everyone was screwing up and taking air out when infact you are suppose to put more in it.

Pyrthian · Post by **Pyrthian** » Tue Jun 14, 2005 8:55 am

groovieguy wrote:The norm is heat produces power, oil is thinner, combustion chambers are hotter etc. This is proven by Nascar, for example, oil and water heaters are hooked up before qualifying.
Now tranny fluid heated up isn't good so that may be what the difference is in your situation.
Also a trick is to Deeeeep stage knock that pre-staged bulb out. Your car doesn't launch the greatest anyway and you fuck with the other driver as they think you will red-light and they will sleep on the line.

Also check you tire pressures sometimes street tires will hook better with more air in them. I know when they first came out with the BF Goodrich Drag radials everyone was screwing up and taking air out when infact you are suppose to put more in it.

no. other way around. heat robs power. heat is wasted power. yes, hot oil runs better. thats fine. but, the radiators are ice packed for qualifiying. thats why people go with colder thermostats. thats why people go running for the dragstrip on cool days. thats why turbos like intercoolers.
anyways 100% behind ya on the rest

The Dark Side of Will · Tue Jun 14, 2005 5:50 pm

Hot AIR robs power... hot engines run better. It's the heat of combustion that drives the engine, after all... a hot combustion chamber is an efficient combustion chamber.

Hot AIR brings about detonation and reduces intake charge density.
People pack their radiators with ice and such for drag racing because they don't have a way to separate engine temps from intake temps... Build an LS1 or Northstar or other engine with composite intake and ceramic coat the intake ports. Cooling the engine off will not help performance.

Pyrthian · Post by **Pyrthian** » Wed Jun 15, 2005 8:59 am

well, almost. a engine runs its best at a particular operating temperature. the parts (rings, rods, pistons, etc) are sized expecting a certain amount of expansion. also, the O2 sensor needs to be up to temp to run a computer controlled car.
anyways - just try it. go to the drag strip. let the car sit for an hour. do three back to back runs, without shutting it down. the first will be your best. let it sit again for an hour. do it again. same thing will happen. this is also assuming you can do consistant runs....and have an autotrans (which this thread is actually about). and for more fun, a third set - let the car sit for an hour. then, for your first run, try the power braking. and now you will know. I've done this all already, so I know whats gonna happen. I had all day to see what does what. manually shifting & powerbraking DO NOT HELP - THEY HINDER. at least with a 60*V6 & TH125 based Fiero. just floor it and keep it straight, brake when done. takes all the fun out of it, yes. for a better time out yer car, let an 8 year old drive it. 100# lighter is a good thing. or maybe a frail withered away grandma.

The Dark Side of Will · Wed Jun 15, 2005 7:06 pm

If there's one thing GM does well, it's calibrate powertrains. I think we're coming from different backgrounds when talking about hot engines and hot fluids.

The Northstar lives for heat and the 282 is unaffected by fluid temp and doesn't evolve much heat anyway. The one thing in my setup that doesn't take repeated runs very well is that #@%# Centerfarce dual fiction clutch.