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Lets talking launching with boosted cars

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Old 06-30-2012, 11:10 PM
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Default Lets talking launching with boosted cars

I have been testing for a few dozen passes and still am at a stand still on what is best for my setup. So lets talk about launching your boosted car!!!

- How much boost you leaving on
- RPM leaving at
- trans brake?
- footbrake?
- 60ft times
- What boost controller you using


I will go first. My best 60ft is a 1.39 leaving off the footbrake @ 4psi. I have a eboost2, and left at 3800RPM.



THIS PASS WAS A 1.43 LAUNCHING OFF THE BRAKE @ 4500 AND 5PSI.

Old 06-30-2012, 11:27 PM
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That things rolls out once it hits about the 20ft mark!!
Old 06-30-2012, 11:36 PM
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Originally Posted by speedfreak2685
That things rolls out once it hits about the 20ft mark!!
It feels just like it looks
Old 07-01-2012, 12:27 AM
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Damn that thing is nasty!
Old 07-01-2012, 03:03 AM
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You're only getting 4lbs on the T-Brake? What convertor is in the car? Stock brakes?
Old 07-01-2012, 03:38 AM
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Originally Posted by TheLS1Lover
You're only getting 4lbs on the T-Brake? What convertor is in the car? Stock brakes?
No i can get it up higher on the brake. Ive just never gone any higher. I wasnt trying to stand on the brake forever. How high should i be able to get it? I have a PTC converter(specific for my build)
Old 07-01-2012, 08:47 AM
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two step at 4800-5500 depending on conditions, pull a little timing again depending on conditions. dump clutch. usually leaves between 0 vacuum and 2-3 psi. cuts consistent 1.50-1.53. really want to get in the mid 1.4's

[youtube]8cimFeH_m1k[/youtube]
Old 07-01-2012, 10:39 AM
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Originally Posted by BlackWS666
No i can get it up higher on the brake. Ive just never gone any higher. I wasnt trying to stand on the brake forever. How high should i be able to get it? I have a PTC converter(specific for my build)
Try this.

Try building that same 4psi at 3500-3600rpm.

If you're able to build it at that rpm you should get more of a run at the converter allowing it to really flash and lock up hard. 9/10 this is worth a good bit in the 60' with more return in the 330' as the car is up on the tire accelerating harder earlier into the run. Also a drag radial likes to be smacked hard initially and then using power management and shock compression to keep it planted down track.

If you can hook that, try building 6-7psi at that rpm and do the same.

When you do this tighten the front extension 1-2 clicks at a time each time you add psi to the launch rpm. It should go faster. If you can't build it at that low of a rpm try building your launch boost at the lowest rpm you can. I know this seems counter intuitive but it works at least in all the cars I've tried it with and on my personal turbo and nitrous cars.

If it will hold that you can try ramping the boost in quicker and using more compression setting in the shock to hold the tire to the track.

I think I remember you saying you had a good ways to go on your rear compression setting before it topped out on clicks going tighter. It already looks like you have a good working rear suspension set-up as you are getting separation which is what you want to an extent as long as you have the compression setting in the shock to hold that separation where it stops when the car launches. If you don't have enough compression setting to hold the shock in that position it's in when the tire separates the tire will bounce up and down uncontrollably. I don't think you will have this problem though running the afco shocks like I do.

Last edited by Fbodyjunkie06; 07-01-2012 at 10:44 AM.
Old 07-01-2012, 01:27 PM
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Originally Posted by Fbodyjunkie06
Try this.

Try building that same 4psi at 3500-3600rpm.

If you're able to build it at that rpm you should get more of a run at the converter allowing it to really flash and lock up hard. 9/10 this is worth a good bit in the 60' with more return in the 330' as the car is up on the tire accelerating harder earlier into the run. Also a drag radial likes to be smacked hard initially and then using power management and shock compression to keep it planted down track.

If you can hook that, try building 6-7psi at that rpm and do the same.

When you do this tighten the front extension 1-2 clicks at a time each time you add psi to the launch rpm. It should go faster. If you can't build it at that low of a rpm try building your launch boost at the lowest rpm you can. I know this seems counter intuitive but it works at least in all the cars I've tried it with and on my personal turbo and nitrous cars.

If it will hold that you can try ramping the boost in quicker and using more compression setting in the shock to hold the tire to the track.

I think I remember you saying you had a good ways to go on your rear compression setting before it topped out on clicks going tighter. It already looks like you have a good working rear suspension set-up as you are getting separation which is what you want to an extent as long as you have the compression setting in the shock to hold that separation where it stops when the car launches. If you don't have enough compression setting to hold the shock in that position it's in when the tire separates the tire will bounce up and down uncontrollably. I don't think you will have this problem though running the afco shocks like I do.
Damn good info man!!! Thank you. That makes sense as to why it has gone faster off the footbrake then off the transbrake. I bet it was because i was only able to hold it to 3400-3600 on the footbrake, but made 3-4 psi. That really makes sense. I will be sure to play with it next time i hit up the track.
Old 07-01-2012, 02:04 PM
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Do none of yall have a 2step? I leave around 4500 on the 2stwp leaving at 11-12psi. In half a second it goes to 23. 1.3 60'
Old 07-01-2012, 02:47 PM
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Originally Posted by FasTimeSS
Do none of yall have a 2step? I leave around 4500 on the 2stwp leaving at 11-12psi. In half a second it goes to 23. 1.3 60'
Im sure we all have a 2 step, If you watch that race you could have easily seen i have a 3 step. Can you give a little more info about your setup. Possibly a vid. And when you say 1.3, are you saying you go 1.300 60ft, or 1.399 cause there is a big difference.
Old 07-01-2012, 04:40 PM
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I leave on the 2 step and transbrake with 8 psi set at 3800 rpm. Converter flashes to 4800 when I let go of the button and all boost (22 psi) is ramped in by about 2 sec track prep permitting. Yields high 1.2-to mid 1.3 60' depending on how shallow I can get my stage. For you guys that aren't aware, the difference between a shallow and a deep stage can be a full tenth.
Old 07-01-2012, 05:11 PM
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Originally Posted by 98Z28CobraKiller
For you guys that aren't aware, the difference between a shallow and a deep stage can be a full tenth.
**** yeah, get the second bulb flickering and thats it
Old 07-01-2012, 06:31 PM
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Originally Posted by 98Z28CobraKiller
I leave on the 2 step and transbrake with 8 psi set at 3800 rpm. Converter flashes to 4800 when I let go of the button and all boost (22 psi) is ramped in by about 2 sec track prep permitting. Yields high 1.2-to mid 1.3 60' depending on how shallow I can get my stage. For you guys that aren't aware, the difference between a shallow and a deep stage can be a full tenth.
I think im gonna try lowering the 2nd 2 step to about 3800 instead of 4500 and see if i can get the boost up to 7-8 psi. I can get the boost up to around 2-3 on the footbrake at 3000rpm bouncing.

Think you could post a good 60ft vid of your car bro!?!
Old 07-02-2012, 03:02 PM
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thank goodness the dragster stayed quiet so you can hear what i'm doing.

footbrake in, single 2 step at 4200, 24# by top of first

your boost seems to come on real slow, t6 turbo or you got no timing in the thing off boost? turbo in the back? whats the set up?
Old 07-02-2012, 03:22 PM
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This is with the th350. I don't have any video with the glide but it's the same difference.

You can see the 1.30 on the board.
Old 07-02-2012, 05:51 PM
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Originally Posted by MIGHTYMOUSE
http://www.youtube.com/watch?v=vw5P4P415zg

thank goodness the dragster stayed quiet so you can hear what i'm doing.

footbrake in, single 2 step at 4200, 24# by top of first

your boost seems to come on real slow, t6 turbo or you got no timing in the thing off boost? turbo in the back? whats the set up?
Yes its a GT55-94 on a 370.
Old 07-03-2012, 12:56 AM
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OP: If you can get the car to leave on more initial boost(more shaft speed) it will make a big difference on how quickly the rest will come in. I've got a 88 on a 5.3l engine and it has been on the bumper leaving at 12 psi or so. If I am track-tion limited and have to leave on less boost initially the car will leave similar to yours.

Last edited by black98ws6ta; 07-03-2012 at 01:06 AM.
Old 07-03-2012, 07:04 AM
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wrap them pipes!
Old 07-03-2012, 08:26 AM
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i had a 4.8 with a gt45 and a pretty tight converter (foot brake 2800) and **** brakes
stock 82 fairmont brakes with drums out back lol...

i would leave at 2800 and on a 125 shot and it would scoot a 1.77 pretty regularly but still take off like a sunofabitch at about 80ft mark when it would get up to 20lbs

off nitrous it would cut a 2.0 60ft

the car needs a brake and a bigger converter, but i might go 80e before i do any of that with a looser converter.

ideally i would have liked to get a 4000 stall that drives nice and tight, and a brake and wire the two step into the brake for consistent leaving rpm

that seems to work great for 2 of my friends
f


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