Boost at the line

[TurboDiverArt]

4psi on the trans brake. 1.29 60'. MT 29.10.5 non W tires. Wolfe bar, upper and lowers, QA1's all the way around, no coil over stuff. :biggrin:

Car weight 3400+

Ted,

It's clear you did your homework regarding the setup. Additionally you put down just the right amount of boost that the track would hold. We all have seen the results of trying to launch with too much boost in competition. Most of the time it results in the other guy getting the win, even when he's the slower car but was able to put it to the track.

This year should be interesting for the Buick Community.

Art.

 

[MSDGN]

Those with slicks what pressure you running with?...I can't get my car to 60ft worth a crap...I have the MPH to run low 10's but can't 60ft...my car was lowered and the best 60 was 1.51...I have the following mods:

Front: no sway bar
3-way Comp Eng shocks(set at 80/20)

Rear: HRParts bar
3-way Comp Eng shocks(set at 50/50)
Metco billet lowers(poly bushings)
WolfeCraft Adj uppers(spherical bushings)
Stock springs
28x9 MT ET Drags(13 PSI)
Pinion angle at -1

...still couldn't 60ft so I put the car back at stock height...removed the drop spindles and rear lowering springs...took it out last weekend and 60fts are in the low/mid 1.6's...it hooks initially but then spins a little about 6-10 ft out...launching at around 6-8 PSI...have a PTC conv...sorry not trying to hijack this thread...just looking for advice...how can I get some traction...been 2 years of this...getting real old...have run out of ideas...

 

[Alky V6]

Have you tried the upper control arm relocating bars? I'm sure that's the wrong name for them. It changes the instant center. Plants the rear tires better.

 

[MSDGN]

Not sure I've heard of those for uppers...I've tried the lower CA relocation brackets when the car was lowered...didn't work out too well...I just thought by putting the car back at stock height...lowers/uppers in stock mounting locations that the car would hook...many...many guys with similar setups that are hooking very well...what about my tire pressure...I've tried it at 12 and 13 PSI...should I try it higher?...slicks also don't have tubes...maybe try them...some say the tire sidewall won't collapse as much with tubes...

 

[Alky V6]

The psi in your tires is more of a balancing act between traction out of the hole(lower pressure) and rolling resistance and handling on the top end(higher pressure). I run tubes in my slicks with 9.25 psi pressure. I prefer the sidewall to wrinkle good at the launch. The loss of tire radius at the launch gives me just a little lower final gearing to get me started and the contact patch is much greater for better traction. The air pressure for drag radials is different from what I understand.

 

[WINDMILL]

new 60 ft

went to the track sunday and got a 1.47 60ft leaving at 5 # boost. new time in the sig. this is a new motor too. and having problems making a pass too. think dusty told me whats wrong with it tho. thanks dusty bradford

 

[QUIP'6']

Alright, what gives? I have only been to the track w/ my GN once. Launched at 5 psi off the foot brake, Nitto 275/50 DRs, pass air bag (no other suspension mods), w/ front sway bar in place. Netted 2.0 60ft times with what felt like 0 tire spin! Where is all the low end power? Car has a
TA49, 009s, 3in DP, 2.5 in duals, stretch stock location intercooler. Likely with worn out valve springs. Anyone?

sounds to rich

 

[QUIP'6']

i noticed on this thread that there is a major variance in boost with different outcomes when the first guy asked what boost is best to leave at the line there is no magic number because of the different convertors i think the magic number is boost/rpm. take for instance me i have a 12 inch restall 2800. at 1 psi my rpm is 1500 netting a 2.0 60 ft and at 10 psi i am at 3000 netting a 1.6 60 ft.. well some one with a 10 inch or art carr 3500 will be 1 psi at 2800+- and 10 psi will be 3500 if they can hold the brakes. so this is where you cannot have a magic number for boost off the line.

 

[waddell87]

i noticed on this thread that there is a major variance in boost with different outcomes when the first guy asked what boost is best to leave at the line there is no magic number because of the different convertors i think the magic number is boost/rpm. take for instance me i have a 12 inch restall 2800. at 1 psi my rpm is 1500 netting a 2.0 60 ft and at 10 psi i am at 3000 netting a 1.6 60 ft.. well some one with a 10 inch or art carr 3500 will be 1 psi at 2800+- and 10 psi will be 3500 if they can hold the brakes. so this is where you cannot have a magic number for boost off the line.

Well put sir. I have a 3600 stall I have never seen it because of my brakes, I at the max hold 8 psi on a good(corr. Great day) and spool up or if waiting for the light and other guy taking too long, spool down--then launch. I found what helped me a little for what I can hold which is 2800max better if I red light...LOL) and 6-7 boost. I stage last and build boost on my own time. Very helpful. Thx:biggrin:

 

[YouLikeThat]

1.50 with a 15# launch. cargo springs, 1 airbag @22psi, lower control arms, boxed uppers,pinion snubber, front sway bar hooked up, M/T et drags at 12.5psi.

New set up HR bar, Stock springs, 2 air bags @ 3psi, no pinion snubber no front sway bar and and about 75lbs off the very front of the car (fiberglass bumper w/alum supports,alum radiator,remove front sway bar) NO TIME YET.

My Question is, what tire pressure is everyone running?
Thanks, Scott

 

[Alky V6]

1.50 with a 15# launch. cargo springs, 1 airbag @22psi, lower control arms, boxed uppers,pinion snubber, front sway bar hooked up, M/T et drags at 12.5psi.

New set up HR bar, Stock springs, 2 air bags @ 3psi, no pinion snubber no front sway bar and and about 75lbs off the very front of the car (fiberglass bumper w/alum supports,alum radiator,remove front sway bar) NO TIME YET.

My Question is, what tire pressure is everyone running?
Thanks, Scott

It really depends on the traction limitation you have with your setup. Run the most pressure you can get away with to lessen rolling resistance and provide better handling on the top end. When traction becomes marginal, lower the pressure to provide more of a contact patch at the launch. Lower pressures will also allow more of a wrinkle effect at the launch. This causes a change in the radius dimension from the center of the wheel to the ground which effectively lowers the overall gear ratio and gives you a little better launch. If the power at launch is high you could get too much wrinkle. With that, just raise the pressure a bit.

Most of the racers I know run between 8 and 10 psi, measured before the run. I run 9.25. I used to run 12, but traction was iffy and the sidewall wrinkle was light.

 

[imjoesnuffy]

Got the brake issue worked out on my car. I upgraded to the S-10 rear brakes over the winter, my powermaster went out. Turned out to be the electric motor. Replaced it and bled everything, the right way

Took it for a little spin tonight, can now launch at over 15 psi off the foot brake. Could probably do more, but will save it for the track.

 

[YouLikeThat]

It really depends on the traction limitation you have with your setup. Run the most pressure you can get away with to lessen rolling resistance and provide better handling on the top end. When traction becomes marginal, lower the pressure to provide more of a contact patch at the launch. Lower pressures will also allow more of a wrinkle effect at the launch. This causes a change in the radius dimension from the center of the wheel to the ground which effectively lowers the overall gear ratio and gives you a little better launch. If the power at launch is high you could get too much wrinkle. With that, just raise the pressure a bit.

Most of the racers I know run between 8 and 10 psi, measured before the run. I run 9.25. I used to run 12, but traction was iffy and the sidewall wrinkle was light.

Good info. Thanks!

 

[87GN.Rickie]

Got the brake issue worked out on my car. I upgraded to the S-10 rear brakes over the winter, my powermaster went out. Turned out to be the electric motor. Replaced it and bled everything, the right way

Took it for a little spin tonight, can now launch at over 15 psi off the foot brake. Could probably do more, but will save it for the track.

Glad to hear everything worked out for you man! Feels like a totally different car now huh?

 

[Turbo1dr]

I had 1.45 launching at 12psi of boost with a TE 70 P trim. M/T 28x10.5 slicks at 10psi. This was several years ago with a iron headed 3.8L engine.

 

[NJ Torque]

1.54 leaving off the footbrake at 0 PSI.

 

[bluehair]

i ran last night for first time, stock trans, converter, on 26 x 10.5 et streets, left at about 4-5# and was getting 1.80's....tire pressure at 18lbs.

 

[bad V6]

bluehair, what track you making passes at? Brandenburg? Beech Bend begins Saturday night races tomorrow night. Hopefully things work out to where I can be there.

 

[that guy]

.

 

[bluehair]

bluehair, what track you making passes at? Brandenburg? Beech Bend begins Saturday night races tomorrow night. Hopefully things work out to where I can be there.

ohio valley, but i might try to make BG tuesday night next week....