Printable View
Running a brake floater for the first time on a 4-Bar, ran it on a fast-boy set up for a mod a number of years back. We've noticed that the RR rotor is shinny and hot at the end of the night and the LR is warm at best and show's uneven wear on the rotor. I have the bar for the floater in the same hole as the upper LR Bar using the same rod length as the upper bar.
I was wondering if I missed something, or have we just wore out the rotor and pads on the left side?
You likely have a caliper issue. They should be resealed alot more frequent than most realize. Both the rear brakes see equal brake forces when both calipers are fixed. Their directly connected through the spool so therefore always spinning at the same speed
And if your gonna run the floater with the 175 rr you really are setting your driver up for disaster. Just because you hold the lr up and make the car so soft it rolls when you Even lean on it is not gonna make side bite. remember the seat belts
I suspect I found the "gremlin" in the car and it's the LR brake pads. Took them off last night an saw they are glazed over and dam near as smooth as and hard as glass. Must of been dragging and didn't realize it. Replace both rear rotors and brake pads and starting out anew.Quote:
Originally Posted by Jking24
Will set up two shocks for the RR, one with the soft spring for Hot Laps and one with either a 250 or 275
I'm curious as to what effect you think running the softer RR will do? Will it become tight and plow front end first into the wall, or will it become loose and make little circles?Quote:
Originally Posted by Jking24
Driver has been insistent he is loose in, and my my experience and notes + the books I have all indicate softening the RR Spring will tighten the car up on entry. I appreciate all the input you've given, I'm getting frustrated with finishing poorly and am looking to at least be able to run with the front pack on a Saturday Night local race.
Car will most likely be extremely loose off the gas going into corner, IE no side bite.Quote:
Originally Posted by 15D
Think of it this way, soften the RR spring is not as extreme or as soft as just removing the RR spring completely (extreme to show the idea). What do you think will happen to the RR traction with no spring there at all?
A. have tons of traction
B. none because there is tons of body roll but NO weight on the RR tire?
The softer rr spring will loosen entry. If it seems like it tightened entry then the car is way off balance and has many other issues. As to it's effects on exit from a purely spring and weight transfer perspective it tightens the car but in the real world that can greatly depend on travel and your shock package. Example if the car doesn't stick the rr on entry the weight won't transfer and the car won't travel the car will then be loose in and even looser off for several reasons. I personally think the floater is a bad idea it is only gonna make your loose car looser. They are a thing of the past before we had good shocks and dynamic tuning. You said you dropped the j bar on the pinion and softened the spring and the car got tighter on entry. The jbar did that not the spring. What kind of car is this and what springs are in it on the other corners. Also is this a crate steel block or open motor ? what kind of shocks etc...
and what size and type and racetrack are you racing
Thanks both of you for the detailed response. Hopefully I will answer your questions to get me on to the next stage:Quote:
Originally Posted by Jking24
1/4-3/8 track
LMJ Ohlin Shocks (first time we've run gas shocks, ran twin tubes before)
I figured the J-Bar was responsible for the noticeable improvement in handling
06' Mastersbilt Smackdown (less than 60 nights on this car, no cracking of the welds other then incident's on the track)
IMCA Motor, cast block, aluminum heads 450 or so horsepower
WRS 55 tires
LF 550
LR 175
RF 350 (cheating with bump stops to keep it from bottoming out, 2200 lbs on the smasher after 3 3/4' of travel)
RR 250
This was the set up of our best run, fairly competitive on a track that took rubber on the feature ahead of us.
75 lbs of bite, 53% left, 54% rear and nearly no crossweight
Unfortunately A has been our answer this yearQuote:
Originally Posted by billetbirdcage
Nothing their is to bad. The 350 is very high for how we ton today and most likely a big part of your loose in. What is your ride height c+c and what is the load at their. The left rear is on the light side for a conventional spring unless you have a very light driver, i tend to favor a 200 . Are these numbers with or without driver
Both the driver and I would make good anchors for a tug-of-war team, never ran into a sandwich we didn't like. The numbers are with driver in the car, though I tend to load the seat with extra weights I have rather then the driver.Quote:
Originally Posted by Jking24
Leaning towards removing the brake floater and stiffening springs on LR & RR to keep from making many changes so I have an idea of how each affected the car
Thanks
Any idea of what would be a good starting point for gas pressure in the front shocks? The competition that is beating us seems to be running "tie-down" rebound in their front shocks. Not sure what gas pressure should be for something like that, lower then the LR dummy shock I would think?Quote:
Originally Posted by Jking24
Shock PSI is really a question for your shock builder but I can't imagine it would be anywhere near what you run in your LR front shock. Depending on brand and valving you would likely be in in the 60-100 range on fronts.Quote:
Originally Posted by 15D
But "tie-down" has a lot more to do with low speed bleed than it does gas pressure.
Matt is correct. if i remember correctly i think we ran 50-55 in the fronts and the rr then 75 in the lr behind and 150+ in the dummy when i last messed with ohlins. Your rf spring load and rate are probably why it looks lounge they ruin more tie down. If your shocks are from a reputable guy and atleast from the least valved within the last 3-4 years their probably not your main problem
Cool, this makes sense. So, if I crank the rebound fully up on my Ohlins LMJ's on the front shocks with minimal compression in it, should the gas pressure be high enough to immediately extend, or should they slowly extend over a period of 10-15 minutes?Quote:
Originally Posted by Jking24
When I ran Twin Tubes with a lot of rebound in the front I would stand on the tire to get it to come down so I could scale it. I don't have to do this with the gas shocks.
No the gas will not usually push them out very fast. The best thing to do when scaling is to open all your rebounds up. When playing with traditional twin tubes vs newer mono/ canister stuff on the bench the canister stuff usually feels much different almost like its a less aggressive shock but this is not usually the case. It's just not a accurate way of checking a shock now days. Not really apples to apples persay. And i forgot to mention from the info you posted regarding your setup. My general assessment would be the car is probably loose in tight to the fuel and then loose off. When their is brown in the racetrack the driver can probably fix the center with the brake pedal . As soon add hee needs too steer the car in its probably no good. We used to have a guy around here that would say " my car is great until i run out of tear offs and then it's no good"