And one way to make them work in reverse is to take the slapper-bars front mid-spring "clamps" and set the top of them right on the top main leaf's so that when you go into a hard brake, they pull down on them and keep the rearend from reverse wrapping the springs up. But doing this will probably make them way noisy running down the road.
pdq67
Homemade slappers! Thats just what we run under the racecar, and forward clamped superstock springs, and a set of pusher bars to relive some strain from our front spring hangers, lets the axle move free'er.
1963 Plymouth S/FX, 3215lbs, straight axle, best time 7.99 @ 170mph
572" mopar wedge, 8-71 @ 28% over on alky, glide, dana 60, 31.25X12 slicks.
Interesting topic,since i run -57 chev and Cal-Tracks,monoleaf's from Durant and Rancho 9000 shock's.
Car has 3.73 gears,th350 and 3300-3600 stall.
With old engine(350 making 442hp "free breather",420 on torgue,best ran was 12.02/105mph.Best 60ft was 1.77
Since tha car weighs 3750,and i don't have transbrake,i think this was ok and car had traction bars.
Now i have 350 with blower making 630hp at 10psi,560 on torq,best ran was 10,97/126mph.Best 60ft 1.68 with Calverts.Cal,s were at bottom hole on this one,and 3/4 turn preload.Shocks were at 7(9 is max).
Later my converter failed on me,so i had to new one.
I tried to put the bars at top hole,same preload,car responded 1.74-1.77 60ft times(same as the 442hp engine).Best time was 10.91/125mph.
Car launches more violently,it jumps out of the line,but it doesen't carry wheels,it just hops and comes down.
It might spin tires,when it does this,i think.
I was sure it would be faster with bar's on top hole since it seemed more powerful on the line.
Would set of double adjustable shock's like QA1 help to control this tire spin?If i could slower the shock rebound out back,would it help?
Kind of slowing weight transfer at the start.
4:11 gears or more would help,of course,but i like to drive on highways also.
So,can anyone give me ideas how to make this on work?Or am i banging already as fast as this thing will go?
i look at the calverts ,, i just think a good set of traction bars , with the pinion angle right , with a set of sliders on the rear of the spring ,, would be alot less complicated , be less chance of something breaking , and perform the same function ,,, but i could be terribly wrong ,,,, its what i'm going to try on my next one though ,,,
i had a tubbed car with tractions bars ::: hangs in head in shame ::: ,,, but the car hooked on a track that wasn't known for traction and the ladder bar cars were spinning ,, so i say ,, traction bars can work ,,
I have problem that i haven't been able to fix yet.
Really violen't wheel hop on street tires.
It seem's to happen right when i tires are spinning really fast and i'm not moving very fast.Like doing Pro-style burn out on street.
If i squeeze power out little by little,problem is not so bad.
If i break the car loose big time just to burn tires,rear starts to hop.With or without brake.
I've tried to adjust preload from 1/4 turn to 1 1/2 turns,no big influence here.
Rear shocks are Rancho 9000 with 9 settings,these are at nro9 and 8 right now.No help...
Tire pressure is 44psi right now,i have 295-50-15 tires and car is weighs 3700.I've tried 30psi but it still hops.
Rear spring is from Durant,and it's mono-type solid piece.Front eye has rubber bushing and rear eye has solid steel bushing.
Funny thing is that on strip with street radials on M/T et streets this problem doesen't seem to happen.Or the tires just absorb this problem and i don't feel it.
stuubi57 wrote:Attention to all you who know about Calverts!!!!
I have problem that i haven't been able to fix yet.
Really violen't wheel hop on street tires.
It seem's to happen right when i tires are spinning really fast and i'm not moving very fast.Like doing Pro-style burn out on street.
If i squeeze power out little by little,problem is not so bad.
If i break the car loose big time just to burn tires,rear starts to hop.With or without brake.
I've tried to adjust preload from 1/4 turn to 1 1/2 turns,no big influence here.
Rear shocks are Rancho 9000 with 9 settings,these are at nro9 and 8 right now.No help...
Tire pressure is 44psi right now,i have 295-50-15 tires and car is weighs 3700.I've tried 30psi but it still hops.
Rear spring is from Durant,and it's mono-type solid piece.Front eye has rubber bushing and rear eye has solid steel bushing.
Funny thing is that on strip with street radials on M/T et streets this problem doesen't seem to happen.Or the tires just absorb this problem and i don't feel it.
Please throw any ideas you have.
thanks.
30lbs seem too much for 295 tires...I use 17-20 in my Toyos 295/50/15 in my 71 Z28. Good grip at street bad grip at strip
Check the pinnion angle and poligraphite bushings instead of rubber is highly recomended.
Have you tried lower shock settings?
'71 Z28 street strip car
Pump gas All motor SBC 427
3308 lbs-29x10.5 Hoosiers
NEW BEST ET
1.38 60' / 4.05 330' / 6.32@111.25mph
Not with these current settings i haven't tried different shock settings.I've always thought that harder the shock,better it will stop movemen't.
But it's worth trying.
Pinion angle was 1 deg with 4degree wedges.I've made 6deg wedges so it was at 3deg right now.I'll double check this.
Bushing's were my main concerne,but they came with this kind of bushing from Calvert so i didn't replace them.
stuubi57 wrote:Not with these current settings i haven't tried different shock settings.I've always thought that harder the shock,better it will stop movemen't.
That's correct, but what happens if the rear want squat ( check if the axle centerline is above the front leaf eye, inducing squat) and the shocks don't?
The shocks will fight against the weight transfer, throwing the transfered weight back to the front , unloading the axle.
On the dragstrip you probably isn't seeing the wheel hop because the increased grip transfers more weight to the rear suspension "loading" more the shocks to a point they compress more rapidly and not "lock" the rear suspension.
I believe the stagered settings on the rear shocks can help a little (more compression load on the passenger side), but a anti roll bar is the final answer.
My $.02
'71 Z28 street strip car
Pump gas All motor SBC 427
3308 lbs-29x10.5 Hoosiers
NEW BEST ET
1.38 60' / 4.05 330' / 6.32@111.25mph
My kids have a pretty fast Nova drag car-- It has the Caltrack bars= I called over to talk with the people at Caltrack-- They gave us a few pointers, and the car picked up a tenth of a second the first time back to the track= We only use a 28 by 10 inch MT slick, and this car car run 9.00 s with those little tires. I am very impressed, Of coarse, the best engine I have ever had in the car helps alot== My question to caltracks wasabout the body leaning over on the starting line== They said it was not hurting our times, and that many fast cars had a lot of bodylean over too= We still have the original monoleaf springs , but I am considering the split monoleafs that they offer
Few updates:
At local airport 1/8 mile race i tried few things i hears from BrazilianZ28 and Travis from Cal Tracks.
I loosened rear shocks from right 9 and left 8 to nro 3 on both sides.And moved bars from top hole to bottom hole.Car felt a whole lot better and was "on traction" lot more distance than on previous settings.
I also had removed rubber bumbs up front to give the car more front end travel,i had 4" and Cal Tracs said i should try 5".
On next i losened preload to 1/4 left and 3/4 right,car showed improvement on 60ft and top end.
At this time i had run 7.3xx at 100mph and 1.80 60ft.Best i have ever driven is 7.0sec on 1/8mile,10.91 on full distance and 1.68 60ft.With M/T et street tires.I'm running on M/T street radials 275-60-15 now.10-14psi.
And then it was time to start Eliminator.. I had 1st run solo,so i figured that i have few chances left.
I tried something that i haven't ever tried before:I gave the bars "negative" preload.On right side i adjusted the bar so that the pivot lightly touches spring and left side i left 0.07" air gap.
Car responded with 1.72 60ft and 7.19 and 102mph.All my runs so far were made with 2nd gear and going thru the traps at 7200rpm.
On second run i tried to hit the car more on start(i leave by footbrake),and shift 3rd gear and drive the car on torgue thru the traps.
60ft was 1.70,7.10/102mph(11.08 on 1/4).I still coulnd't hit the car as much as i wanted,so i'm lookin forward on the next race which is 1 week from now.
That Airport has way more traction than this one.Car was spinning tires really easy and i had to baby pedal it of the line.
When i compared these 2 last run on time slip i saw that improwement was made on 60ft and that was the reason why i had better et on last run.
Comparison showed that on 60ft i gained 0.02sec.On 330ft i had gained 0.088sec and this was diff on top end also.So the car didn't seem to like or dislike that did i drive thru the traps on 2nd or 3rd gear.
Am i wrong?
Anyway i really supprised on these street radials and how good they work even on tracks that have poor traction.
Thats nice to know your car is faster and wheel hop is over!
The clearance in the bars aren't a good idea IMO...they should be preloaded ( a bit more on the passenger side)...check the pinnion angle again if you preload the bars.
'71 Z28 street strip car
Pump gas All motor SBC 427
3308 lbs-29x10.5 Hoosiers
NEW BEST ET
1.38 60' / 4.05 330' / 6.32@111.25mph
I'm not 100% sure about the wheel hop beeing gone.
But i did see huge impromen't when i loosenend rear shock's to 3 and 3 from 8 and 9.Way more less wheelhop occured when i did drive it hard on street tires.
I read somewhere this negative preload thing with Cal Tracks,so i gave it a try.If recall it right it was at this forum.Well any way,i'm going to try normal preload once i get to next race.
I loosened shocks to nro1 on left and nro 2 on right,and put some weight on driver seat (driver weight)and adjusted bars to 1/8turn left and 1/4 turn on right, and managed to get 1.62 60ft times,10,96/125mph.This was almost my personal best.On 60ft this was my personal best at 0.6sec.
But what really wonders me that i've managed to get 10,91/and 126mph on 1.68 60ft times,7.01 660ft, so running 1,62on 60ft and 6.99 on 660ft, should have been faster than 10.96?Something like 10.83?
Even more weirder thing is that 660ft and 1/4 times were almost same?So were speeds at same points.
Were there a problem with 60ft beams?Were they not at correct position?
But overall,car feels better with your help BrazZ28,and has showed improvements at track.Thank you!
I have some slow motion video my camera,and i'll try to get them on YouTube,and i'll post a link here.
Sadlly,it almost winter time here,season is allmost over so i don't have any chance to try anything more trick's at this point.
Pete
But i'll absorb any ideas there is,so keep them coming!
Front end has about 4 1/2" travel right now.And body is full steel so replacing front bumber to fiberglass one might help a little bit and get those front wheel's up
I'll post high speed version as soon as i have a chance,on that one you can see interesting things...
