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Discussion Starter #1 (Edited)
****UPDATE AND FIXED***So after a few outings I can say the cars heading in the right direction. Moved ladder bar crossmember up 3" and now have the bars running significantly uphill which causes massive seperation which I control with shock settings. Changed to a longer stroke shock and 85lb 14" springs also On a small 150hp tune it consistently turned in 1.29 60' times. Theres more work to do there but it is definitely on the right track! Thank you all for your help and ideas! 1.1x hopefully right around the corner! , may have to get the fronts revalved tighter... ONCE AGAIN, THANK YOU ALL FOR YOUR IDEAS AND ADVICE

Hello! I'm sure this has been discussed at length here and other places but cant quite find what I'm looking for. I'm thinking I just need some basic ideas. First things first...
67 Camaro 3225 race weight
427 sbc turbo 400 3.90 gears
325 50r15 et street- 28" tire
Strange double adjustables rear with 130# springs
Stock front with shitty 90-10s
When it hooks runs 10.0 on motor mid 1.40 60ft

Problem is it WILL NOT leave consistently. Since I built it. Last year end of year i thought i was getting a handle on things, played with shocks, air pressure, burnout length, things were coming along. Ended up with a second-third gear burnout, 16 psi in tires compression full tight and extension 1 click from full loose. Even turned on the bottle and got 60 down to 1.30s with a 9.2 pass .Then like a dumbass i changed things. Lowered the car, cut a coil out of the front, lowered the rear 1" by moving front up 1 hole and shock brackets the same distance thereby keeping ladder bar angle the same. Last nite car refused to hook, slow motion video shows pushing rear into pavement then 5 feet later seems to unload and spin the tires. Tightened up extension to about midway with no change, then to 2 clicks from full tight with no change. Tires really wrinkling and pushing into pavement on the hit, then seems to spring off the ground. Raised pressure to 17.5 with no change.

My question. I want to start over with all adjustments. My lower bar is about 1/2" lower in front then rear, but I'm not sure the brackets are on the "normal" spot. So how would I measure to get a baseline bar angle? Never had this much problem with leaf springs and slicks. Trying to get in the 8s and it ain't gonna happen like this. Hell, even point me in the direction of a good book that can help me.

Thanks guys for any help!
 

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Ladder bar needs about a 2 degree down angle when compared to the rocker panel or fame. Park your car on a level surface where you can step back and see the bottom bar of the ladder bar. sight it and compare to the bottom of the rocker panel. the front needs to be running down in comparison to the bottom of the rocker panel. What kind of shocks do you have on the corners? what type of floater do you have on the on the rear springs where the rear is attached at the spring. Get your self a set of real race slicks to get a base line.
 

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Discussion Starter #4
Slicks would help I'm sure, but I really want to get radials to work for me. Double adjustable strange shocks in the rear and it's a true ladder bar/coilover setup. They are angled down but theres gotta be a measurement there that I'm missing.
 

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I would look at the front and see what it's doing if you can. Sometimes when you cut off a coil it really changes the weight transfer... How much travel, is the front end moving upwards at the hit ? too fast and too slow front movement can be a problem. How is the car balanced ? I would not hesitate to put weight in the rear bumper area.
From what I've seen, track prep for radials is pretty specialized.... If you are trying to run on a local bracket race type prep with those tires, and have power to run 8's, that's asking for a lot imo.
 

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Think excessive pinion angle can cause this from a buddies car I worked on. I checked it and it was at -7* so changed it to -3 and definitely helped the situation.
 

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Too Strong, For Too Long.
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When you cut the spring it raises the spring rate on the spring. When it's sitting at ride height now, it's not sitting there with the spring compressed storing energy as it was before you cut it. So now you have a fast reacting high bar setting (pickup point) on the rear and a slow reacting spring on the front. That's why it compresses the tire and has the bounce. You need a spring on the front that compresses to ride height, storing energy. Which will make the front fast reacting to match the back.

Then you optimize it with with rear ride height and shock adjustments front and rear for the radial. Compressing a radial will never work. If you wanna speed up the front with ballast, you don't put the ballast in the bumper, you put it as high as you can over the back tires.
 

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This is a 23 sbc Brodix Track 1 427. High bar fast reacting pick up point with 10 x 28 bias tires. 1.27 60ft. It'll go double O's rt on a 370 or 400 Pro Tree with a 1.69 low 5.00- 4.88 gear 2sp trans dipping in the 5's 1/8 mile N/A 3250 pds.

You want it fast reacting (high bar pickup point) for a radial, you have the right idea there.

60ft and around the 1-2 shift is where all the big gains in performance are N/A or nitrous.


 

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Discussion Starter #9
I'll get a set of coilovers and double adjustable shocks for the fronts. I figured that anyways. But what would you say should be the starting point for the ladder bar angle. I'm not talking degrees down angle, but difference in height from axle centerline and front eyelet centerline with a 33" bar axle center to front eyelet center?
 

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Too Strong, For Too Long.
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I'll get a set of coilovers and double adjustable shocks for the fronts. I figured that anyways. But what would you say should be the starting point for the ladder bar angle. I'm not talking degrees down angle, but difference in height from axle centerline and front eyelet centerline with a 33" bar axle center to front eyelet center?
There is no starting point, depends on how you want it to work. Listen, if you have the bar nearly level, that's a fast reacting high bar, high pickup point.. If you move the pick up down a hole, it'll be slower reacting.

It's not like a pro stocker with multiple interchangeable plates with multiple hole configurations of holes for minutiae adjustment. It's a Ladder bar with 2 possible pickup points.

For minutiae bar angle changes you're gonna have to compromise on ride height through the spanners on the rear coil overs to raise and lower the pickup point. Think about it.
 

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Discussion Starter #11
So if I was to say the front eyelet is 7.5" high and the axle centerline is 14" and the distance between the 2 is 33" is that a good place to start with drag radials and my car specs? I feel there has to be some kind of math equation that tells me where it should start at. I realize my front needs work and I'll take care of that, the front seems to rise alright in the videos I have, but even if it didnt I couldn't adjust it anyhow. I have 5 adjustment holes 1.5" spacing in between. I could drop it down to 6" height...?

Thanks again guys for sharing your knowledge.
 

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For any given ride height, you have the option of two holes realistically speaking, because you don't want the bar uphill or pointed at the ground." You have two holes to choose from". The higher the pickup point the faster reacting separation, less squat. The lower the pickup, the opposite.

For fine tuning bar angle, you're gonna have to compromise on ride height (looks).

Again, There's no starting point. No equation except roll up your sleeves.

Put some Santhuf springs on and 2way dampers to manage the energy.

Good luck
 

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Discussion Starter #14
Hi guys so an update. after installing front strange double adjustable coilover with 325 lb 10" springs I'm still dealing with the same bs. The video above is shocks all around 3 clicks from full tight except rear compression which is full tight. Left at 75% throttle and stabbing it after release of trans brake. This video it hooked up. If I leave at full throttle it spins. Tried it softer extension in front and rear with no help. 1.5 60ft times it doesnt leave particularly hard cause of the tight nitrous converter. Looks like maybe the front is still rising too quick and maybe a couple more pounds air in tires? At 16lbs now. Ran out of time last night or I would have tried it. Thanks for any help guys. Nobody I talk to knows much about radials and just want me to go back to slicks which I'm getting frustrated enough to do...

Thoughts???
 

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looking at the only video u posted it looks like the Front comes up to fast and when the front shock tops out the rear tires brake loose. i would try slowing the front down or tie it down a little bit at a time and see how that helps. By looking at the rear when it launches it looks like it squats or is trying to. A better side view and slow motion would be much better help. to me it dont look like u are hitting the rear tire very hard at all. the other thing i was thinking is u may have to stiff of a rear spring in the car. i have tried to use a 130# 12in spring and it was way to stiff for my 68 camaro so i ended up with a 97# 12 in spring and now the car and suspension moves more freely. have u hit it with alot more power to see how it woks? if u are on a so so track u need to have it softer in the rear. the other thing i have seen with all Quick radial cars is that they all set low. not sure how low yours sets or how much lower it can go but it may help also. my car is 9in from the ground with a 315 tucked in the rear and it will probably set 3in lower once i get the 275s under it.
 

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Discussion Starter #16
Thanks for the feedback. Car sits about as low as it can. The rear isn't separating much cause the shocks are pretty tight. When they were 2 clicks from full loose on rebound it seemed to quickly smash the tire into the pavement but only 2" or so. And yes, I'm 99% positive the shocks aren't topping out. Guess I'll try a setting in between? I've hit it with 125 hp and 250 hp with soft settings and just spun. Maybe it would better handle it with these stiffer settings? But man, I cant even get it to leave right on motor! This should be easier than this, i feel I'm missing something...
 

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Your car is the same weight as mine, I have a 3rd Gen F Body. I am pretty sure my front coil overs are 225lbs or so, and the rears are around 125lbs. I normally run 10.00, but with N2O have been 8.80, all on a 29x10.5 slick at 20psi (bias ply slicks), no changes except for putting sissy bars on! My front struts have no adjustment, the rear coil overs so and are set at mid way, I never touch them. The ladder bar runs 2 to 3 degrees downwards rear to front, again, never touched them since I put them in, pinion angle is -2*.

Why such a stiff front spring? I also run a SBC, Dart block, aluminum heads/intake.
 

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Discussion Starter #18
Your car is the same weight as mine, I have a 3rd Gen F Body. I am pretty sure my front coil overs are 225lbs or so, and the rears are around 125lbs. I normally run 10.00, but with N2O have been 8.80, all on a 29x10.5 slick at 20psi (bias ply slicks), no changes except for putting sissy bars on! My front struts have no adjustment, the rear coil overs so and are set at mid way, I never touch them. The ladder bar runs 2 to 3 degrees downwards rear to front, again, never touched them since I put them in, pinion angle is -2*.

Why such a stiff front spring? I also run a SBC, Dart block, aluminum heads/intake.
Strange recommended a 275lb but we decided to go with a 325 since its driven quite a bit on the street. I also had a 3rd gen back in the day and I believe the geometry is different. my coils are closer inboard than struts therefore requiring a stiffer spring. My coils sink down quite a bit with weight on it. Anyways your car sounds exactly like mine but I run radials. Have you ever tried radials and had success? And off subject but how much n20 did that take to get to 8.80? Thanks for the reply man, I appreciate it
 

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Never tried a radial. I would leave the line with a .063N jet in the plate, then switch to a set of .030N in the direct port. EFI combo, ECM took care of the fuel side. I would run an 8.90 Index Class on a street car day, wasn't always easy to get down the track. On really bad days I would turn the second stage on 2.5 seconds out but leave the first kit on also. Would still go 8.90 at 156 or so. I always deep staged and left at 3000, trans brake bothers my back! :)
 

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Discussion Starter #20
Never tried a radial. I would leave the line with a .063N jet in the plate, then switch to a set of .030N in the direct port. EFI combo, ECM took care of the fuel side. I would run an 8.90 Index Class on a street car day, wasn't always easy to get down the track. On really bad days I would turn the second stage on 2.5 seconds out but leave the first kit on also. Would still go 8.90 at 156 or so. I always deep staged and left at 3000, trans brake bothers my back!
If you were to leave higher than 3000 would it still stick? Maybe I'm asking too much of my car trying to leave at 3800...
 
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