Question on launch

[Buick Beginner]

Gentlemen,
I notice that I can't seem to hold more than 2 or 3 lbs of boost on the line, I've already got the Kirban soft shoes but I don't have the S-10 wheel cylinders yet, I guess they will help. Anyway I've read a number of articles that say the more boost you can hold the better. Now, with this in mind I've noticed the following: If I take it up to 2 lbs of boost and release the brake I can immediately feel the jerking forward and so I punch the gas WOT. About 1 second after the punch the rear tires go up in smoke. Now, if I build 2 lbs and then release the brake I can immediately feel the jerking forward and then EASE into the throttle mashing it to WOT over a period of 2 or 3 seconds the tires don't come loose. So, now with that in mind is the following information correct? If I can hold say 10 lbs on the line I will have a harder initial launch, (the car lunging forward), but then I will still have to EASE into WOT to keep the tires hooked to the pavement? Or is there something magical that happens by launching at 10 lbs where I can immediately floor it with no tire spin? My suspension is set up pretty good as you can see on my signature but I want to make sure my launches are the best they can be. Thanks - BB

 

[tim87tr]

I have the S10 wheel cyl but the stock suspension setup will not handle a 10 lb launch, I tried . It transfers to the rear too quick it seemed, bounced off the air bags, unloaded the 28x9 slicks, spun them over a bit, rehooked and still got a 1.75 60'.

I've only ran the car about 25 passes total, but I can tell you what works for me on launch, and I read it on board to know to try it. I have stock suspension except air bags. Build a few pound boost, mash the gas, then release the brake. With 235 BFG DRs it gave me a 1.71 best (4 lb launch) on four passes, and with 28x9 MT slicks it gives me consistent low 1.7s on a 2 to 3 lb launch.

The first time I raced the car, first time ever drag racing, I tried to "pedal" it taking off, and got a best of something like 2.0x. So you can see the difference Try out that mash gas, release brake technique on your 275 BFGs, and let us know how it worked. When I got that 1.71 on the 235 BFGs, I just spun the tires over to clean them off (minor smoke), no waterbox or burnout, and with 24 lb air.

 

[KEVINS]

Originally posted by Buick Beginner If I can hold say 10 lbs on the line I will have a harder initial launch, (the car lunging forward), but then I will still have to EASE into WOT to keep the tires hooked to the pavement?

It will be trial and error but YES this can generally work and is how I would go about doing it. Some of the fastest DR cars (1000hp) use this approach. They use a higher stall but dial in less horsepower through the engine timing so the high stall "kicks" the car out of the hole and gets the suspension working THEN dial in more power a few feet out to keep the suspension working and the weight transffered.

I would spend your $$ on the Jumper Valve for your brakes instead of the larger brake cyl's. The larger shoes/brake cyl seems to be a 50/50 shot at working. I still have factory size brakes and stock brake cyl's and I can hold 15+psi of boost..

hth's a bit..
ks

 

[Donald McMullin]

Just remember that with the larger rear wheel cylinders you will have problems with the rear locking up on a slick (wet) road. Just a warning.

With the jumper valve you only get added rear break pressure when jumper valve is activated, not during normal driving.

With my 275x60 DR's I was able to run a 1.65s 60-ft (w/stock turbo) by holding 8lbs by the 2nd light, on the 3rd light I mashed the gas and then released the foot brake. This was without any air bags.

Now I am running slicks and have had to go with one air bag in right side, but still only run max air in bag of 6 psig. Best of only 1.63s (w/TA34 turbo and unopenned motor) but still lots to learn.

Deep Enough
Donald McMullin

 

[bwallace]

Although I don't have any experience with drag radials, someone can correct me if I am wrong, but I would think you could build a little more than 2 to 3 lbs of boost, I can usually get a least 2 lbs on Dunlop radials. With your rear suspension setup and drag radials even with stock wheel cylinders you should get at least 5 or 6lbs of boost at the line. You might want to experiment with tire pressure and install line lock. I have airbags( haven't made a pass with them yet), snubber and MT streets and have launched as high as 7lbs with no spin at all. I know if I do a long burnout I will push the car through the lights with any boost higher than 7lbs.

 

[1QUIK6]

Who sells the jumper valve? I haven't been able to find a post on where to purchase one & What about the mighty vac? What's it used for & where can it be purchased? Thanks

 

[Buick Beginner]

Thanks

I appreciate the responses - BB

 

[charlloots]

get rid of the drag radials and get a pair of 28in slicks or et strets this should help your short times and your launch also.