How to get better 60'

[Roc87]

Got to go to the track last night, not really running for 1/4 mile times, but 60' times. Last time I went I got a 1.80 with stock LCA, rear anti-sway bar, and car still had the front anti-sway bar on. Couldn't hold more than 1# of boost because of heating the shoes during the burnout. Last night I only got a best of 1.83. This was with no bar on the front, an ATR bar on the rear, Tubular LCAs, same psi in the air bag on the right side. I got to leave with 4# of boost (All I could hold even with out the shoes getting hot because of a line lock). Should I just throw out the stock shoes and put in the soft shoes and try leaving at 10-15psi?? I have one soft rear shoe on each side and one stock replacement. When I have both soft shoes in, the car is "hard" to stop with out looking like I'm drunk as the rear locks up really easy. Thanks for any suggestions!

(Check out the web-site for a couple of pics from the burn out competition!! Gotta love 225/65/15s with a line lock. Pix are at the bottom of page)

 

[1of1035]

you could try the s-10 rear shoes and wheel cylinders with a proportioning valve. I have them in mine and have no problem with braking manners on the street. They also hold boost much better than the stock replacement shoes.

 

[murphster]

A higher stall convertor will help if you don't want to go the upgraded rear cylinder and shoes route. On my TType I have a high stall convertor, stock turbo, soft rear shoes, S-10 wheel cylinders, and the Hurst line lock (stock rear sway and no front sway).

I can hold as much boost as I like. Highest I've gone to just playing around is about 18psi, tires weren't even close to breaking. I could probably do it in snow. The high stall helps in that I put in just enough throttle to build boost, which happens before the convertor really kicks in... say 2500-3000 rpm or so. With a bigger turbo and a stock convertor it may be hard to build boost, regardless of brakes. You may be able to find a sweet spot where you build boost slowly and then just floor it and try to flash the convertor when you launch.

The only drawback of the brakes so far is that they bite hard when cold. After the first couple minutes they are ok, but half the time the rears lock up when I stop at the end of the driveway before I pull out. I usually avoid driving in the rain but its not really a problem most of the time, but probably wouldn't be good in a panic stop so I usually stay about 20 car lenths behind someone when its wet.

Also, with the bigger rear sway bar I would think you wouldn't have to run as much air in the right rear air bag since the ATR bar should help stiffen the chassis.

Of course, nice sticky tires will help too. What tires are you running? I'm assuming you are at least on DR's. Playing with the tire pressure can help too.

Your chip settings could come into play some if you are running too rich on the bottom it could slow the spool some and hurt your times some.

Lastly, you can look at the shock/spring combo. Some people get lucky with stock-like springs/shocks, some don't.

Those are the things off the top of my head. Each one could play a part in getting your times down. I'd work on getting the boost up to maybe 10 lbs or more and then you can figure out if you have traction problems and what needs to be addressed. Hope this helps.

 

[Roc87]

Thanks for the suggestions. I'm running a PTS Xtreme 9x11 3200 L/U converter and MT ET Drags 26x10x15 w/ 14 psi. Right now, the rear springs are aftermarket, not sure who made them, but they are variable rate, and I still have the "Nitro-Drop" shocks that were in it when I bought the car (It had a 2" drop on it, spindles/front, springs/rear) I was thinking about getting some QA1's at least for the front, but a $125 a piece, not sure I can justify it.

A couple months ago, I had replaced the wheel cylinders w/ stock replacements and the soft shoes from postons and came EXTREMELY close to rear-ending someone since the rears locked up, I would have, but the rear end swung out to the left. I pulled two of the four shoes later that night! (maybe a couple days before going to the track next time, I'll put all 4 in again, I was able to hold 15 then)

 

[murphster]

Also may make a difference what tires you run on the street. I run Nittos and haven't had a problem with locking them up, but I don't put myself in a situation where I have to panic stop either. Other less sticky tires may lock up easier with the soft brakes.

Seems like you should be able to build some good boost with that convertor, but brakes could be limiting you, not sure.

Are you spinning at all or do you think you just need more boost for a harder launch?

I would be expecting 1.6's with your tires, sway bar, and convertor. But launching at low boost I'm not sure.

With fairly stock-like setups like mine, most of the best 60 fts I've seen are from people launching at 10+ lbs boost. The more powerful cars I've seen lower 60ft's launching at 4-5lbs boost, but they are making a lot more power than me. My best is a 1.70 on my first and only time out with ET Streets (2 runs I think). The other times I went on my Nittos just to see what they could do and best was a 1.83. I was launching somewhere around 10lbs or so.

 

[1NASTY6]

building boost/ brakes

Fella's,

I have installed a manual brake system in my '87 GN, and as was the case with a Powermaster, and a power vacuum system, I still am having trouble holding at the line when fully staged.

I used to be able to build up some boost when running the PM system, but then started having trouble with that system, so converted to vacuum system, and now using manual system.

Car stops fine, but there seems to be a real "holding problem".

At one time, I could watch the boost gauge move up into the 6-8 lb. range, but now I can't seem to get the boost gauge to move at all while staging. (the gauge does work by the way)

So, if I have you totally confused now, here is my problem:

I can't hold at the line enough to get any boost built. If I try to "horse it", the car will just push thru the lights. However, even while "horsing it", I do not see the boost gauge even flutter a bit. I find it hard to believe that I'm not building any boost when I can't even hold the car from pushing thru the lights!

I've heard some talk of these "jumper valves"..... can anyone tell me if they think this would help my problem??

I run a PTE 51 Turbo, 42.5 lb injectors, front mount intercooler,
MT 28" slicks at 11 lbs., 16 position thumbwheel chip, and 110 octane. Oh yeah, I'm also running a Vigilante 9 1/2 in single disc lock up converter. Stall is supposed to be between 3200-3500.

Any ideas will be considered!!

Thank you in advance!!

Tim