Whats for Launch?

[SYCLONE#1531]

Re: Whats for Launch?

phil long (turbo6) was using caltracs, suspension limiters, and green dot tires at all corners cutting 1.4s n the 60s. He launched at 3000 and 10lbs to achieve this.. nothing special!!

 

[0966Sy]

Re: Whats for Launch?

I was footbreaking 2800+ on the 2800. Just wouldnt spool. This was a cheap generic conv off of ebay. The precision I launch at aprox 3200 and 8 to 10lbs. With the precision, boost comes on pretty fast! Precision says they use a special designed stator for faster spool up for turbo applications.

I used a restalled 12" 2800 with my PTE52 on a stock long block, and it spooled fast but was just as fast as my stock TY in the 60ft. I hit 1.60 with that combo untill the TC blew up. I could say I would never use a generic off ebay. Maybe thats why it didnt spool, so what are you realy comparing too? So you gained 3 10th's from using a converter that didnt work to one that does?

 

[SYCLONE#1531]

Re: Whats for Launch?

Heres ya some good information!
http://www.syty.net/forums/showthread.php?t=19577

How to get a killer 60'

--------------------------------------------------------------------------------

Lots of people have asking me about my 60 ' so I thought I would make this post on what I have and do.


These are the parts I have:

1) green dot tires
2) HD Bilstein shocks
3) Caltracs
4) Suspension travel limiters through both upper control arms.
5) Digital 6 MSD using the 2step on the launch.
6) Pressure switch set at 6 psi in series with the 2step trigger wire. This makes it build boost faster.

What to do with that stuff:

1) Let the tires down to 20-22 psi on all 4
2) Load the rear springs with 1/2 turn on each side with the caltracs.
3) Turn the travel limiters where the end of the stop is 1/4 inch from bottoming.
4) Set the 2step on 2900-3200 depending on track conditions. (The 1.47 was at 3100) you will have to play with this some. I have a 3500 stall.

The fun part:

1) I cool the truck down to 145-150 deg before I go to the lanes leaving the hood open in the lanes to keep it cool.
2) Flip the tq converter lockup switch.
3) Drive around the water and backup close to the water but dont get in it while making sure I am lined up straight.
4) Mash the brake as hard as I can and put the throttle to the floor. When I see 15psi on the boost gauge let off the brake and let the tires spin to clean em off.
5) Start pulling up to get pre staged making sure of being straight and in the groove. If it is not I back up and correct it.
6) Creep up very slowy to the staged beam and stop just as it turns on to stage as shallow as possible.
7) Mash the brake hard and put the throttle to the floorand hit the 2step button.
8 Let off the brake and step button on or maybe a little after the last amber.
9) If it starts spinning I am ready to lift some and then go back down with it. I have not had a spinning problem lately tho.
10) Keep it in the groove and as straight as possible going down the track.

I hope this helps someone. This is the longest post I have ever made I think :fadein:
__________________
Phillip Long

 

[0966Sy]

Re: Whats for Launch?

phil long (turbo6) was using caltracs, suspension limiters, and green dot tires at all corners cutting 1.4s n the 60s. He launched at 3000 and 10lbs to achieve this.. nothing special!!

EXACTLY! he launched at 3k, It is somthing speacial. He was running a stock long block also right? Even if he was using vortecs his 1.4 60's show him taking advantage of that 10psi at 3k.

Just because he used caltracs, limiter's and green dots doesnt mean he needed to launch at 3600 rpm at 15psi. There is probably a reason he didnt

 

[Beavis]

Re: Whats for Launch?

and im launching at 5-6psi at roughly 2800-3000 on a stock TC.

On my stock shit, 20g 12cm2 turbo, i couldnt get to 6 psi without pushing through the brakes. I couldn't get to 2800 rpm on the brake if life depended on it. The best rpm i could get was 23-2400. Now, same turbo, same tune, same brakes, same everything but trans and converter, I can get 12+ psi on the brakes at 3200 rpm and launch like a bitch. The last time I let her rip, i thought the front end came off the ground. It never left that hard before.

 

[0966Sy]

Re: Whats for Launch?

Digital 6 MSD using the 2step on the launch.
Pressure switch set at 6 psi in series with the 2step trigger wire. This makes it build boost faster

Set the 2step on 2900-3200 depending on track conditions. (The 1.47 was at 3100) you will have to play with this some. I have a 3500 stall

Here is the evidence i am looking for! He was using a 3500 stall TC and launching below his stall speed with 10psi! Now phill was just using a 2 step. Could you amagine if he added a TB. And people think it probably doesnt get any better than 1.47

 

[0966Sy]

Re: Whats for Launch?

On my stock shit, 20g 12cm2 turbo, i couldnt get to 6 psi without pushing through the brakes. I couldn't get to 2800 rpm on the brake if life depended on it. The best rpm i could get was 23-2400. Now, same turbo, same tune, same brakes, same everything but trans and converter, I can get 12+ psi on the brakes at 3200 rpm and launch like a bitch. The last time I let her rip, i thought the front end came off the ground. It never left that hard before.

Kinda off subject, Im using a 14cm 20g. What wastegate are you using? I start to push though at 5-6psi also, makes it real hard to launch.

Why do you want to change TC's?

 

[Beavis]

Re: Whats for Launch?

The problem with a trans brake is it is a hard shock to the driveline. On the brakes or on a line lock, your are slowly putting the pressure on and that isnt as hard on them. Tap a peice of glass with a hammer and it brakes, slowly push the hammer against the glass and it takes more effort to brake.

Another thing, what was Phill shifting at? He left lower than his rated stall, on a 700, so he wouldn't spin, and to control the boost on the line. He had a 3500, he could of had enough cam to shift at 5500+. What he was doing sounds about right, if I put in a 2 step and set it to 3000ish, I also would be at about 10psi.

With an 80e, you can leave higher and harder because of the gearing and worry less if at all about spinning.

 

[SYCLONE#1531]

Re: Whats for Launch?

He was shifting at stock shift points / stock cam.

 

[Beavis]

Re: Whats for Launch?

Kinda off subject, Im using a 14cm 20g. What wastegate are you using? I start to push though at 5-6psi also, makes it real hard to launch.

Why do you want to change TC's?

I'm using a tial external on the crossover. My 700 would slip at the 3-4 shift, so I know it was a time bomb. I started getting my 80e conversion together as soon as it started doing that. I collected all my stuff during Group Buys, and stumbled on a few really good deals and shoped around to try to get good/great parts at fair/good prices. It took me 2 years to get it mostly together, and then I blew a trans line. Told the wife "I'm not fixing something just to rip it out and replace it with AN anyways. It's done and I'm not waiting any longer, get ready for the credit card bill for the converter and the shafts, they are the last pieces." :rant: I wasnt gonna put a dime into a 700. When i got it all done, I don't push through the brakes anymore and it leaves real hard.

 

[Beavis]

Re: Whats for Launch?

He was shifting at stock shift points / stock cam.

He might of had a converter rated at different hp/tq than has was at, making it act different at lower rpm

 

[0966Sy]

Re: Whats for Launch?

3 Type's of stall rating's, companies rate there TC's to flash stall. If phil long was using a 3500 i wonder if that is what he rated it at on the footbrake or if he bought from someone rating it at 3500 flash stall. Becuase 3500 brake stall could actually be 3000 true stall in our high torque application.

The Hows And Whys of Stall

Converters are rated to stall within a certain rpm range. That’s not because the converter companies don’t know their product; it’s just that your individual engine characteristics and vehicle specs influence stall speed and make a precise number nearly impossible to predict. Even the term “stall speed” itself isn’t perfectly defined. Here are the three distinctions you’re likely to encounter.

True Stall: The rpm the engine cannot exceed when the driveline is locked. The most accurate way to determine true stall is by locking First gear and Reverse with a transbrake and observing engine rpm at wide open throttle (WOT).

Flash Stall: The rpm the engine “flashes” to when launched from rest at WOT. A converter will often briefly flash to a higher rpm than its true stall speed.

Brake Stall: The rpm the engine cannot exceed with the brakes locked and the driveshaft not spinning. Brake stall isn’t usually an accurate measuring tool since the engine often overpowers the wheels before the true stall speed is reached.

 

[0966Sy]

Re: Whats for Launch?

So the 2 step allows the turbo to spool faster to launch RPM by retarding ignition timing, while holding the throttle to the floor. If phil long and others are using a 2 step launching at 3000rpm at 10psi on a 3500 stall speed TC.

What results would be had with a transbrake vs a 2 step as im not sure if i like the idea of using a 2 step/rev limiter yet? Could a transbrake accomplish the same effect as a 2 step/rev limiter by building boost before your stall speed?

If so what is the need of the higher stall speed?

 

[RealFastV6]

Re: Whats for Launch?

So the 2 step allows the turbo to spool faster to launch RPM by retarding ignition timing, while holding the throttle to the floor. If phil long and others are using a 2 step launching at 3000rpm at 10psi on a 3500 stall speed TC.

What results would be had with a transbrake vs a 2 step as im not sure if i like the idea of using a 2 step/rev limiter yet? Could a transbrake accomplish the same effect as a 2 step/rev limiter by building boost before your stall speed?

If so what is the need of the higher stall speed?

A transbrake just holds the transmission- you're still relying on the stall speed of your converter to build boost.

A 2step retards the ignition timing so much that you're basically blowing the burning air right out your exhaust valves which spools the turbo.

Completely different concepts.

 

[Quickstop [UK]]

Re: Whats for Launch?

Correct - The gear ratio of the 80e means less torque at x RPM so the wheels are less likely to break loose but the limit is still traction hence the near identical times.

 

[bezerk]

Re: Whats for Launch?

a 2 step retards timing? i though it was just a Rev limiter?

 

[dgoodhue]

Re: Whats for Launch?

i though it was just a Rev limiter?

It's a rev limiter, it actually cutting cylinders out with a pattern to make it as smooth as possible.

 

[Aeroking]

Re: Whats for Launch?

i look at from a racing standpoint. For the street you want a converter that stalls right where the turbo spools. However for racing, you want your launch rpm to be at peak torque. Most well built engines have a broad torque curve, which gives you some room when selecting a converter rpm.

Exhaust pressure is what spools the turbo. Bigger turbos require more pressure. Smaller motors at lower rpms develop insufficient pressure to spool a larger turbo. The easiest way to fix this is with a high stall converter, but its not the best. You want to leave the line at max torque. So you need an anti-lag deivce. Some people use a shot of nitrous oxide to increase exhaust pressure for a quicker spool. The 2step, or any other soft rev limiter works good. It cuts the ignition at a certain rpm, and generates exhaust pulses which spool the turbo quicker, and its adjustable.

Look at all the outlaw turbo cars at the track. They are on the cusp of not making boost at the line. They want to launch at peak torque low rpm, but still make boost. you'll see they shoot flames from the headers from an anti-lag.

On the street its different, you want to be able to brake torque the truck and build boost. And most dont run any device to help spool the turbo, so they run a high stall converter, which pulls the rpms out of the peak torque curve. :2cents:

My turbo started to make boost at 3400rpm. I have a 3600 converter. With my 2step on, i had it set at 3000rpms, and i can hold 10psi on the line no problem. For the money, it is the best mod for consistent racing.

Drivers love simplicity, racers love adjustability.

 

[TYTILIDIE]

Re: Whats for Launch?

So what are your times? What do you mean when you say big cam? a 67gtq is quite a large turbo, should make for 10second truck?

I can cut 1.7 60's in my stock Ty all day long on radial tires, and im launching at 5-6psi at roughly 2800-3000 on a stock TC.

10's? I don't think so, not at this altitude. You figure, I am in a Ty at 6000'. Not likely to happen. Bruce went what, 10.7 at sea level in a LIGHT Sy with the 67dbb. I don't think I'll see 10's anytime soon.

Now back to the subject and comparisons, I too used to cut 1.7's regularly. I ran 1.69 two times. I have no real explanation for why I can't do that with my current set up but my wife's Ty does the same thing. She has a 20g with 9/11 converter. Her truck spools super fast and can easily cut a 1.7 60'.

I personally think we will get my Ty's 60' down to a solid 1.6. As of now, I am only running 15 psi and launching at 10. You don't even feel the engine get in to the power band until 10psi. Im sure that sounds weird but, lets say I am driving along at 40mph. If I give it xx amount of throttle and it rolls in to 5-8psi, it doesn't feel very impressive. In fact, it feels like a normal car. I don't believe its converter related because it behaved the same way with the stock converter. Floor it and when it gets in to 10+ psi, its a very different story, you cover ground so fast you don't even have time to look at your gauges.

I am sure most of my negatives at this point are due to lack of tuning, I really haven't gotten a good thorough tune down yet. I have it good enough to go out and play but so far that's about it. I suspect we will get it to a better point soon.

The converter topic, seems to me that some things are just the way they are. Obviously the custom cam route can make a huge difference but for most of us who just slap things together the high stall works so why not do it? You aren't really losing anything, except gas mileage I guess.

 

[BMFB]

Re: Whats for Launch?

This is a side thought...but for anti lag if you were to say, ground out the coolant temp sensor wouldn't that make the truck think that it was -50C and pull a bunch of timing, so much so that you could effectivly run it as an anti lag on the line if it was hooked up to a switch? Pulling a bunch of timing would dump alot of fuel into the exhaust and help spool the turbo, as well as taking all the power away fromthe motor while still allowing it to spin at a higher rpm on the line, thus also helping to spool the turbo. just a thought, I;ve never really looked into it.