Yet another launching question...

[REGALTURBO]

Here`s my deal....With simple mods, I used to be able to launch my car on the street with 4-5 pounds boost...no problem. It would hook on the 275/60 BFG`s all the time after a small burnout and 14 psi of air in them. Since then, I`ve done a rebuild consisting of this..TE-44, Jay Jackson ported TB, Champion intake, Champion heads, Ross pistons, 214/214 comp cam, 009 injectors, Art Carr 9in, TH 3" downpipe, 3" exhaust, intercooler &1/2 and some more.
Basically with same air pressure in the tires and air bags set @ 15psi on right and 5psi on left, + or - a few pounds to test, I can`t even launch this car on any boost. This car isn`t hooking at all when it used to hook like a basterd. I did all this work to better my ETs yet it seems like it may drop due to my traction problem. I have yet to test this at the track but on the street is where I made it all work before. I do notice that the motor flashes much higher due to the converter and in conjunction with that it spools up much quicker also.
Anyone with any experience street racing who can give me some tips on launching this car right?

 

[UNGN]

Drag radials are very sensitive to tire and track prep. Make sure they are very clean and you are running on a clean track.

I've never run that low of air pressure, but I have found on 7"rims if you go below 16 psi the tire can cup in center. On a wider rim you can go down to 13 psi. I try to run around 18 psi, a little more a little less. I have found that air pressure isn't as critical as tire cleanliness. Drag radials can hook at 24 psi or 14 psi, but will never hook if they aren't clean. Driving though one small patch of dirt on the return road can kill them for the night.

The tires may need a monster burnout to clean off the closed pores...not something you can do on the street.

I would also take all the air out of the driver side bag. Every psi you put in the driver side effectively takes a psi of the passenger side.
The idea is to preload the passenger side tire so that it's equal to the driver side at launch. Power braking on the track scale showed that 150 lbs was transferred off the passenger side tire at launch boost in my car. Because of the offset gas tank, if you run a full tank of gas and no spare, there is another 150 pounds you have to compensate for. Inorder for my car to get the 150lb preload I had to put 20 psi in the passenger bag.

 

[Chuck Leeper]

Mo powr??

Sounds to me that you have a problem that ALOT of folks would like to have.. The engine is now making considerably more power. Your post indicates you have the same suspension and tires and are expecting the car to behave like it did w/ less power.
IMO, you have work to do on the suspension, now that the power is up.
1. Higher stall allows the engine to get further up in the power band.
2. The tires, if the same ones, are most likely tired. Exposure to ozone and burnouts all contribute to loss of traction.
Burnouts cook the oils out of the rubber, making it less sticky.
Ozone makes the tire harder.
I suggest you do a search on suspension setups, get the suspension right, get a set of tires that will live at the higher HP/torque levels, and tune, tune, tune.....

HTH,

 

[REGALTURBO]

Thanks for the reply guys..you`ve left some interesting information. I do realize that with the increase in power, I will definitely have to tune my suspension to this new setup. I just didn`t think I`d have so much trouble. I figured with the tune I have that I would be able to put in the basic suspension upgrades and that would have been good enough...guess I thought wrong.Compared to many other cars running a similar setup as myself, figured low to mid elevens should be obtainable since it ran low 12s before all the upgrades. And again all the other cars comparable to mine just have the basic suspension upgrades....air bags, boxed control arms, etc.. Although the BFGs are only about 1 year old with about 6 passes on them, they still seem fairly good.
Of course...I am seeking some advice from someone with experience in drag racing as well as street racing. But if I must figure out this sweet spot where my car will respond well to my setup...be it the hard way (through trial and error), then it may be so. I am ok with that since I will have a better understanding as to what happens with my changes. Noone ever said these cars were easy to tune. Its just that when you see a guy run high 10s with moderate upgrades and BFGs...they make it look easy. But noone really knows what they did to get there. Thanks...

 

[Chris Cornett]

Sound like its time for some ET drags. Drag radials work great, but why play around. Put some slicks on it and leave the line with some real boost. Only problem is when you start hookin real good, thats when driveline parts start breakin.