How much Boost of the line with a.....

[my1stgn]

Im looking at getting a line-lock to help with burn-outs (once I get slicks) and to hold me off the line during launch.....

What kind of boost should I shoot for with a line-lock holding the front brakes? Brake system is pretty much stock. Also this will be my first time at the track with alky. Also Im running a RJC plate between the doghouse. Any adverse affect with alky? Ill be running street tires also. Thanks!

 

[Quiky One]

Dont use the linelock to launch. Use it to do a burnout then just use the footbrake to launch. With street tires 1 PSI will blow them away if not launched correctly...

 

[2QUIK6]

As mentioned above, the line-locks purpose is for the burnout to hold the front brakes while the rears are free to spin with no pressure...
With the line lock, you mash the brake pedal, push the linelock switch, then release the pedal while you keep the switch depressed which keeps full brake pressure on the fronts while the rears are free.
I guess you could wire it up so that it holds rear brake pressure but that would not buy you anything over just 2 footing it on the brake and gas pedal at the same time.

 

[my1stgn]

Well I know the line-lock is moslty for burnouts but Ive heard of others using it to launch the car also..... Ive been launchin @ 0-1psi so far, anything more and the tires break loose once the turbo spools up!

Also Im probly going to get slicks here in the near future. Any recommendations. Ill be starting from scratch so what rims should I use, and what tires should I run and at what PSI? I drive the car to the track with the regular tires/rims then swap in the slicks at the track. Also what size tires? Thanks!

 

[2QUIK6]

To be able to hold more boost, you can use 2 pairs of the "long" pads...buy 2 sets of rear brake shoes and use the 2 longest pads from each set ( a normal set has a short shoe and a long shoe per wheel) Use organic soft shoes from your local parts store...these will be high dusting shoes And install / replace the rear wheel cylinders with the S-10 cylinders..do a search on here to find the exact part#..again you can get them from your local parts store. and sand/roughen up the drum.

If you still need more pressure to hold boost, you can get a brake line diverter valve that works similar to the line lock but it bypasses the front brake lines and diverts all line pressure to the rear brakes. I use this setup and can hold 13-15# on the power master brakes.

 

[supercoupe5]

dont mean to seal your post and sorry if this does. since you use a line lock to do a burnout. what is the best way to launch would it be the two foot or would it be better to do a trans brake for the launch. dave

 

[my 1st gn]

dont mean to seal your post and sorry if this does. since you use a line lock to do a burnout. what is the best way to launch would it be the two foot or would it be better to do a trans brake for the launch. dave

well if you have a trans brake it would be best to use it.
but if not then get a line lock to keep from heating up the rear brakes when doing your burnout. An do the rear brake shoe upgrade an after you stage the car. Push the brakes as hard as you can while pulling on the steering wheel. An pray that the tires hold it might not be the best way but it works for me.

 

[RUQWKNF]

Two other things to mention.
When you do the longer brake pads and S10 wheel cylinders, don't forget to do a proper brake bleed, as well as adjusting the tension on the pads to drum. I always adjusted my pads so that the drums just barely slipped on without having to use force to push the drum on. The line lock with this combo will really help to hold more boost at the line when foot braking. The other comment about pulling on the steering wheel, will eventually cause your steering wheel to bend. Been there done that. But you are right, there's really not another good way to put more force to the brake pedal without pulling on the steering wheel.
After I bent my steering wheel, I started experimenting with and finally perfected E-brake launching. Now, this type of launching can and will eventually take it's toll on your brake parts and I do not really recommend it. It will take a lot of practice to perfect. Eventho it did allow me to launch with 14-15psi, I've heard and seen some horror stories about broken backing plates and brake shoes.
The best way to do it is with long rear shoes, properly adjusted, with a line lock used for burn outs only, and working on getting your launch tune perfected so that you don't have to leave with so much boost. There are a few threads that talk about what part number to use for the rear wheel cylinders. I have always had good luck asking for ones for an '86 S-10 with manual brakes.
HTH.

Patrick

 

[RUQWKNF]

Here's a couple of videos that best describe what I mean by tuning the car to leave hard on lower boost launches.

Video - Another pass with my bolt-on (stock un-opened engine) Grand National - TA49 turbo. - NOPI

Video - My bolt-on (stock un-opened engine) Grand National making a pass during our outing at Norwalk in 2005. Not too bad for a TA49 turbo. - NOPI

Props to the owner for some good runs.

Patrick

 

[my 1st gn]

tuning

Here's a couple of videos that best describe what I mean by tuning the car to leave hard on lower boost launches.

Video - Another pass with my bolt-on (stock un-opened engine) Grand National - TA49 turbo. - NOPI

Video - My bolt-on (stock un-opened engine) Grand National making a pass during our outing at Norwalk in 2005. Not too bad for a TA49 turbo. - NOPI

Props to the owner for some good runs.

Patrick

could you give some tuning tips on how to leave hard with low boost

thanks jay

 

[vader87]

Brake Bypass! What this does is bypass the proportion valve. Here is how it works. You mount a switch so that when it is activated the valve opens and allows all the pressure to bypass the Pro. valve. You do this when spooling at launch. As soon as I launch and flip the switch off, the valve closes and normal brakes return. You have twice the rear brake holding power.

GNX342@aol.com sells them. It is called:
Ron's Max-Boost Launch Kit

 

[RUQWKNF]

Exactly what vader just said with the Max Boost Launch kit. Then you throw in the a TT Pro chip that has the 1st gear tuning feature and you can really improve your spool up. This basically allows you to lean out the bottom end to help promote quicker spool. Throw in an RJC boost controller as well. There is one other item that can help that not too many people now a days mess with, and that would be cam timing. Having a few extra degrees of cam timing ground into a new cam will definitely help. A lot of this is really not needed with a dual ball bearing turbo, and I know I sound like a salesman trying to sell people on these new turbos. Trust me, I'm not trying too. But dbb dramatically helps with spool up. I'm sure others will chime in here with more secrets of the game. Unfortunately, I can't jeopardize my Clearance Level by revealing anymore at this time.

Patrick

 

[my 1st gn]

boost

Brake Bypass! What this does is bypass the proportion valve. Here is how it works. You mount a switch so that when it is activated the valve opens and allows all the pressure to bypass the Pro. valve. You do this when spooling at launch. As soon as I launch and flip the switch off, the valve closes and normal brakes return. You have twice the rear brake holding power.

GNX342@aol.com sells them. It is called:
Ron's Max-Boost Launch Kit

So do you still launch with high boost

thanks jay

 

[2QUIK6]

So do you still launch with high boost

thanks jay

Yes, that's the object of gaining the extra holding power on the rear brakes with this mod!

 

[Boost231]

damn so your telling me my 20psi E-brake Lauches might hurt my Backing Plates and Shoes humm maybe i need a Trans Brake

 

[my 1st gn]

60's

Yes, that's the object of gaining the extra holding power on the rear brakes with this mod!

ok maybe it's just me but I don't see the part about leaving hard on low boost

 

[SouthernCal GN]

ok maybe it's just me but I don't see the part about leaving hard on low boost

Here's the deal- street tires suck for racing; you launch at low boost so you don't blow them off, then 60' out you hit full song on the turbo, and it's white smoke city.....you need to get the power to the ground.

Take off the front sway bar, if you like.

Get some drag radials. Lower the pressure to about 15 psi. Get them hot & sticky, go to the line, and do your best. With the better tires, you can launch off the foot brake at 4-6lbs of boost......

 

[2turboRX7]

Launch technique

Here's one you may want to try.

1. Do your burnout using the line-lock.
2. Stage the car and press and hold in the line-lock button.
3. Now pump the brakes to direct all the pressure to the rear brakes. (no additional pressure will be allowed to go to the fronts since the line-lock is blocking the fluid flow)
3a. Once the pedal is hard, hold down the brake pedal, release the line-lock button and build boost.
4. GREEN LIGHT .... GO!! Lift your foot off the brake pedal.

This all needs to take place in just a couple seconds. You may need to practice this a little. Using this method, I was able to hold 18Psi of boost on the foot brake in my old Z.

 

[vader87]

Bottom line is you have to have the right tire and build boost at the line....period! I don't care how good a street tire is, it will not keep traction. When I first got my car, I took it to the track and the absolute best was a 13.2 because I had to come off the line so easy. I changed to a slick (no other updrades) and ran a 12.0. Left at 3lbs. (TE44 and 2800 stall). It doesn't matter how fast your car is but if keep running 2 second plus 60 fts, what is use? You must get your 60 fts. down in the 1.5-1.6 area. There are many ways to do this, its your choice. You have to build boost before you leave. Here is what happens when you do not build enough boost then the boost hits. I only built 1-2 lbs. of boost and at about the 30ft mark 20 lbs of boost kicked in. I should have ran a high 10 with that mph, but it took 2 seconds to back off the throttle and get the car moving again.

 

[SouthernCal GN]

My point exactly.