Tech Talk

Tested out late model for the first time this year last night, its a howe perimeter stock clip car originally but it just got a new port city tube clip. Running BBSS on stops. I have 51% front weight will fuel, had half full last night, 175's across front 375 rr 200 lr 1 3/8 hollow 3/8 wall stock type bar set nuetral, 4.5 frame height all the way around, 2900 lb car on hoosier 980s. Hope thats enough info. The right front is getting on the stop but the left front isnt. I was thinking about going to a smaller bar, seems like maybe its keep the left front from getting onto the stop. Also if I sit on the right front corner of the car it will get on the stop but when i go to the left front it takes two guys to get it on the stop, seems like something is holding it. Any other ideas or is the smaller bar on the right track? I have an 1 1/4 bar to try on it.

Also wanted to add some things I tried last night. Put a 150 in the left front and tried half a spring rubber in RR, the 150 helped and got the car turning better in, but the spring rubber made it free on accel. the softer lf did get the car down more but still not enough

I would start by looking for a bind in the Lf suspension. We run the same bar, stiffer springs and a little less nose percent and are getting on our LF stop. We had a similar problem after our first two races and finally found our upper a arm was hitting a coil on our spring when we were pushing the nose down. Corrected the problem and all is good.

Hope this helps or gets you in the right direction
22slm

If your going to run BBSS with a big RR spring setup you need to go all the way. 1 3/8" stock type bar will be in the 400-450 lb range not quite enough in my opinion, you need at least 1 1/2", 1 5/8"-1 3/4" is better. With a stock type bar you can shorten the arm length as much as you can, to get more rate.
RR spring, rule of thumb is 1/2 the rate of the bar to start with. The range between 250-400lb does not seem to work very well, so you need to be 400 min if your using big RR, 450-600lb range works well for many people. With a big RR spring you need to run the panhard bar really low, low as you can and then some.
Front springs 175 is okay, 150LF 175RF is okay, could go softer, softer will be better. When going softer check for coil bind, you don't want coil bind, coil bind is a whole nother game.
BBSS with a big RR has a very narrow range of working well, get it right, it works well, if your a little off, your at the back of the pack. I see a lot of guys struggle with it and end up going back to a more conventional setup, or a soft conventional setup which is much easier to work with and much more predictable.
Bump stops, there are several schools of thought, some guys bump stop only RF-LR, some bumpstop LF only and let the bar do the work for the RF, some will bump stop both fronts and the LR. You just have to play with things to see what will work for you.
Tire temps will tell you everything, which direction you need to go. Post some tire temps.

Ed

If I go softer on the left front, I think it may coil bind, its getting close now but I can see that it isnt with someone pushing the nose down to the stop. I can get tire temps later today. Ill also pull the left front shock and spring off and move the suspension by hand and see if it moves freely. Now the track I run doesnt have much hard braking, would that affect it also? 22slm, you said you run same bar with heavier springs, is this at a track that uses more brakes? Panhard bar is at 9 1/2 left (axle side) and 10 1/2 frame, I can go lower but ill have to flip it to the bottom side of the drive shaft because its close to rubbing where it is now.

To respond to your last question. We run at a flat 1/2 mile. I don't consider that track to be a hard braking place. Gental application and then we let the car roll the center. It is good to move suspension by hand without shock and spring, but like I said before, we had interference at full compression on our coil over spring. It moved free by hand, but not at compression. We had to tip the top of the shock inward and it made a world of difference for us. We also took the spindle off to make sure ball joints were free with no hard spots or binds.

When I first put the car together, the top of the strut made contract with the upper a arm but I needed more + camber anyways so the longer a arm cleared the strut. One thing that comes to mind was that I was worried the heim on the tie rod not having enough movement so Ill be checking that tonight

You might also try a different shock on the LF.

Check you're not getting a ball joint bind

Any luck getting your car down on the LF?

So for an update. Went to the track last and car handled nothing like it did 2 days ago. Pushed terribly and still not getting onto lf stop. Greased all fittings the night before, removed strut and checked suspension for binds. Did find the left outer tie rod heim binding on the bolt head so I used a bolt with a shoulder on it to give it more clearance. At the track I tried adding a shim to RF, went up 25 lb on lf spring and even tried a smaller bar but car was still tight. Before feature we swapped right side tires to get more rear stagger (2 3/4) and less front (3 down to 2 1/2) and also went down 25 lb on right front spring and took out 1 stacker to get front end lower. Car was just a little tight but the front end is coming down further now. Ill get some indicators on it this week so I can check shock travel.

Track scales showed I had 49% front weight, 58.69 left which is too much, and 56 cross. Maybe the front weight is part of the problem?