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 Post Posted: Thu Oct 09, 2008 1:39 pm 
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Location: Montgomery, Alabama
The bottom bar needs to be 3 to 4 degrees down at your power level.
No need to move it after that. Just adjust with shocks. If the shocks wont fix it get better ones. Your chasing your tail moving the 4 link all over the place.

Bottom bar 3 to 4 degrees down, and an intersect point about 50% of the wheel base of the car and call it a day.

I haven't touched the bolts on mine in 5 years other than maintenance.

I did get rid of the Koni's and put a set of Afco's on. Best thing I ever did.


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 Post Posted: Thu Oct 09, 2008 8:58 pm 
 
ok scott, just found out tonight that I only have 1" of shock travel below bump stop.  I'm thinking this is not enough, altough on the front struts Lamb said I needed 7/8 to 1 1/4" of travel.  These are koni's as well with 110# shocks.  I guess I will get some 125's but I read on koni website about how to trick lighter springs with a formula for compressing spring a calculated amount.  What do you thick about trying that first before spending $.

Thanks


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 Post Posted: Thu Oct 09, 2008 9:34 pm 
 
also any comments on the graphs, I don't really know what all the steps and s's mean?


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 Post Posted: Thu Oct 09, 2008 10:39 pm 
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I chased my tail for almost a year and probably wasted about $1500 chasing a handling problem on my Camaro!  Finally realized, from info that Scott posted, that the 95lb springs on the rear were bottoming the shocks out at about the 330 timers.  Replaced them with an $87 pair of Competition Engineering 125lb springs and you wouldn't know it was the same car!!  BTW, that's with a little over 1200lbs on the rear tires.

At static height (race ready with you in it) you should have at least half the shock travel available.  A small tie wrap on the shock shaft will tell you exactly where it goes during a run.  Mine had O rings on’em so I was able to check mine with those.

As for the Ss on the graph, any blip or upturn in that graph in a short period of time is tire spin!  You can plot the RPM rise and time across the drive shaft RPM graph at intervals to see exactly what it happening, ie, RPM rise per half second, etc.  In a perfect world that graph should be smooth from start to finish.  When you get there, please let me know how you did it!  O:)

There are two places you will likely not be able to stop tire spin.  A) On the starting line and B) at the gear change.  At other places during the run it will depend on several factors with shocks, tires and track condition being at the top of the list and since every car will be different, there is a learning curve to see what the car wants.  The time slip will tell you what it’s saying, ie, check the incrementals after you make changes to see where it picks up or slows down and look at the MPH to see what makes it faster as well.  Keep in mind though that if it’s spinning then it will MPH faster and if it’s not then it won’t.  Look at the graphs to see where evidence of tire spin is also.

Yeah, I’m logging 18 channels and at times I think I’ve got too much info!  Sort of “information overload” if you will! ;-)

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 Post Posted: Fri Oct 10, 2008 5:24 am 
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Location: Montgomery, Alabama
Yea you do need a little more bump travel. I don't think it's hindering you because your Koni shocks have a 2" tall snubber that acts like additional bump control. I would get another 1/2" of shock shaft showing with driver on board.
Be aware if you change the ride height of the car your bar angle will change.

If you do buy new springs get 130's.


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 Post Posted: Fri Oct 10, 2008 9:12 am 
 
This is what koni tech guy said.  After I told him I had 1" of shock travel, and how much was suggested.

"If you cut the bumpstop and raise the car up about a half inch, it should help out and may be enough."

So question, I don't have adjustable shock mounts, therefore to change rideheight, I will need move rearend side of bars up one hole??


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 Post Posted: Fri Oct 10, 2008 6:17 pm 
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How high are the spring platforms. (The big threaded nut)


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 Post Posted: Sun Oct 12, 2008 10:25 pm 
 
sorry scott, I will lok tomorrow afternoon, what exactly do you mean by the big treaded nut?  Do you mean the top of the shock?  How high in reference to what?  Maybe I will take a pic.  

I installed 130# this weekend, gained another inch of travel.  I will test next weekend and see if that's enough, if not I can cut bump stop down.

thanks


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 Post Posted: Sun Oct 19, 2008 10:17 pm 
 
ok made one pass this weekend before riped tranny gear out.  new 130's and set rear tire weight even.  nuetralized anti-roll.  still driving left while front end is in air.  the bars did not touch.  i evidently had them to high.  i lowered them for next pass, but didn't matter.

also my ziptie on shock still buried into bumpstop?

the rim/body seperation seems to be about 1-2"

thanks for your thoughts


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 Post Posted: Tue Oct 21, 2008 4:59 pm 
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Casey when you are setting up the rear weights on the car use opposite corners on the front to help get the car back level again, ie, if you have to jack the right rear to balance it with the left rear, then part of that adjustment should be made on the left front.  If weight needs to go the other way, the do the opposite.  If you screw the spring platform up on the left front it will increase the weight on the right rear and it may take some off the left rear and right front at the same time.  It may take you a while to get it level with the weights right but just keep plugging at it taking notes as to what changes do what on the scales.

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Necessity is the plea for every infringement of human freedom. It is the argument of tyrants; it is the creed of slaves.

William Pitt, British Prime-Minister (1759-1806)


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 Post Posted: Thu Oct 30, 2008 10:53 am 
 
I started moving the springs weights around and the body height started being noticeably higher on one side, so I called bob mandell of bob's profab in tn who i bought my TD from and he said to put some rear steer in it by shortening both left bars 1/4 turn and as long as front weights were within 75/100# of each other and rear were within 50# of each other then it will not drive car.  So I tried this and seemed to work alot better on two qualifying passes on sat but on sunday eliminations it was driving right slightly (but not the same amount it was driving left before) so I believe I will lenghten it back 1/8 turn and this should be good.

It was really riding on wheelies hard and as I said the are only 48" so I will get some 60" this winter and it should help because it had a small hump in drive shaft graph.

thanks for you help

just arrived in mail: bickel chassis book.


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 Post Posted: Fri Oct 31, 2008 8:59 pm 
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Let us know what you think of the he bickel book.

Greg


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 Post Posted: Wed Nov 05, 2008 4:14 pm 
 
IMO its not worth the $90 (with shipping).  The first 3 chapters were describing drag racing and how to stage and how to drag race, well if were buying a chassis tuning book...we know how to dragrace.  the middle chapters might be good for someone building a car, talks about how to mount shocks and structs and stagger.  The last three chapters described what I was looking for in how to set up fourlinks, shocks, strut setting.  Really though I wish it had more indepth descriptions about what different IC's do and what different shock setting do, seemed to be very general.  

I did learn some stuff from book, but maybe $45 worth!  

It did confuse me and maybe you guys can help...it said long and low ICs hit the tire harder.  Now I had a 62" and 5"  then went to 62" and 7" and it really crushes the tires and rides the wheelies hard, going back to the way it was so doesnt' ride bars so hard (something I learned from book) also probably cupping tire with this setup too, will look at tracks (also tip from book)

???


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