I ran an 8.74 at 155.3mph w/ 1.24 sixty foot on my second pass which is a new personal best! DA was around 2,500 feet.

Unfortunately I had to abort the first run becuase of a massive wheelie where it pulled to the right, I tried to soften the landing by hitting the throttle on the way down, but that just caused a second wheelie, so I gave up, and it hit the pan on the track a couple times.. .

For the second pass which was my new record, I increased the slick pressure from 9.75 to 10.25, and tightened the front shocks from 2 clicks (from full soft) up to 4 clicks. I also lowered the wheelie bars down and made sure they were level. On that fast pass it still wheelied hard, but the bars kept it down some and although it kind of pulled left, I stayed in it and rode it out.

On the third pass I tightened the front shocks one more click to 5, and it ran a 1.23 sixty foot with another wheelie, wandering around for the first 50 feet... ET was down to 8.85 and mph dropped to 153.5 but that may have been from waiting too long to shift out of first as I was preoccupied with the wheelie.

After lunch for the first round of eliminations, it wheelied hard and shot to the left, so I aborted (causing further oil pan damage) and lost the race. They did spray the track real well this time, and my slick pressure was down to 10.125psi from the previous 10.25 which probably didn't help.

Perhaps the lowered wheelie bars are now steering the car around???



I am going to make a taller adjustable snubber to limit the front end travel, and take off the pan to repair it before i go back out...

What thing would you guys suggest I try next time to ensure it goes straight and does not shoot the moon???

Cheers,

Arnie

Your cooking now! congrats on a very fast new best Arnie. I think you are right to assume the wheelie bars are now steering the car.
I wouldn't raise the wheelie bars, just move the side the car steered towards. lower that side about 3/8 to 1/2 inch to help even out traction.
When you build your travel limiter, figure a way to put a soft stop in the system. I use an eye bolt with two shock absorber rubbers from the top of a front shock on my car. It takes to shock out of hitting the travel limit and keeps the rear tires planted.

Yeah adjust the wheelie bars so it drives straight
as Greg said .... also get the air pressure up...
keep going up till you spin then back it down...
most likely it'll pick up MPH and ET with more air

Thanks for the input Guys!

Greg, do you have any pictures of your travel limiters??

I will try the left bar down 3/8 and see if it goes straighter...

Cheers,

Arnie

I would also keep tightening up the front shocks. On a car with that much power you dont want all that weight transfer all at once. Tightening the front shocks will allow it to slow the extention and carry the tires out further but less high and makes for a less violent launch.

Looking for pics of my limiters. This is the best I could find. I drilled a hole in the upper A arm, run the eye bolt through it, slid two rubber shock bumpers on the eye bolt, then the big washer that goes on the top of the shock held in place by a nyloc nut. The nyloc nut lets me use the long threads to set the limit.

Hey Arnie, congrats on the new best, they always feel good .
Jim.

Yes, the wheelie bars can steer the car.
Sometimes a little off from equal height (while pulling up on the wheel) is needed.

My Dart responds well to limiting front end travel to control weight transfer and wheel stand. It is amazing that 1/16 to 1/8" change at the upper rubber bumper can make a noticable difference. I made large dia flat "washers" to put under the rubber bumper for fine adjustment. 0.080", 0.125", 0.187", 0.250"
But my car hates stiffening the front shocks as it causes wheelspin. Likely because my front end is too heavy.

When I was making adjustments to reduce excessive wheel stands, I would just shift to 2nd rather than lift the throttle. Another racer told me you can keep the throttle wide open and just ride the brake pedal. But that seems kind of tricky to me.

Congrats on the new best ET. I love it.

This picture was taken with the engine out, so the suspension is raised just touching the rubber bumper. But you can see the two "washers", one is 0.080" the other is 0.125".

Thanks Jim, I am using a very similiar rubber snubber, and a spacer that actually looks larger than your washers...

How much total travel do you have before the front tires actually lift of the ground???

I did not realize that 1/8 inch makes such a difference, so that is good to know when I decrease the travel.

Any comments on the balance of ET and mph along with 60 foot?

My 1/8 mile incremental was 5.61 at 125.45 mph.

Cheers,

Arnie

When measured at the front fender wheel opening (top center), from sitting at rest until the front tire comes off the ground is about 4". I can't find my notes right now, it could be 3.75". Sitting at rest, the fender opening is about 25-26" from the ground.

My front fender wheel center height is currently at 25.5" although I have ran it as high as 26". I will measure travel when I get the car out of the trailer.

My oilpan is already too low, so I don't want to lower the front end to help reduce the wheelie.

Any other ideas/comments??

Cheers,\

Arnie

Nothing to add,Arnie,but that is haulin the mail!!

Congrats on the new best ! When I had a stock style front suspension on the car it really responded to limiting front travel but I was making less power then you are now. IIRC your car has ladder bars I would consider trying a ladder bar adjustment to reduce the hit on the chassis.

Thanks Edge, but it is already in the bottom of the three holes, and has a 2-3 degree downwards angle to the front. Middle hole is basically level, but I believe that increases the hit?

I am sure that more travel limiting should help!

Arnie

Can you lower the rear of the car to obtain a lower instant center?

I did not use the snubbers in the picture. I welded a 1/2" nut in place of the hole and made a jack bolt for a limiter.

The snubbers on the lower control arms work. You can take a lot of preload out of the torsion bar. This way you don't have so much stored energy.

Leon

Thanks for the reply Leon,

I can't lower the rear much as my 10.5W-31's completely fill the mini tubbed wheel wells... I will look and see if 1/2 inch is possible.

How much total front end travel do you suggest? I am modifying my upper control arm snubbers for more adjustment, but was concerned that if there is too little travel, the front shocks would not get enough stroke for the valving to work???

So you are saying to put a lower control arm snubber that is tall enough to be preloaded at static ride hight, and then possibly back off the torsion bar a little bit?? Or leave a small amount of clearance and use a harder rubber for the snubber??

I appreciate the ideas.

Arnie

Ok,

Scaled the car and after leveling everything and adjusting the torsion bars to equalize as much as posible, we ended up adding 1 flat of preload to the RR ladderbar. This gave us the following corner weights:

LF= 854 RF=740

LR= 596 RR= 589

Total wieght with 190# driver = 2,779#'s

total front = 1,594 or 57%

Total rear = 1,185 or 43%

41.2% of left side weight on LR, and 44.3% of right side weight on RR

I am going to tighten the frt shocks to 7 from soft on ext, and 8 on compression.

Rear shocks at 8 on EXT and 6 on Comp.

Built some cable travel limiters set at 4" travel right now as I had 4 1/4" before, so I want to sneak up on it, and since the frt shocks will be tighter, should help.


Wheelie bars Left side 3/8" higher than right.

Going racing tommorow so we shall see...

Cheers,

Arnie

Best of luck tomorow. Weights look good, I had no idea the car was so "light". It is almost 120lbs lighter than mine but my front to rear bias is almost the opposite of yours I am 46/54 usually hooks in the mud

Thanks Al!!!

The notchback seems to be lighter in the rear than the Fast back???

Can you post your corner weights?

My Aluminum Block helps... My battery is in the RR and my 4 gallon fuel cell is RF. Very small radiator due to the Methanol injection.

Cheers,

Arnie

Just looked at your corner weights... in most cases
the right rear will be about 20# to 35# heavier to
drive the car straight... some car can get away
with less... I prefer to set the preload to get it
to drive out straight but if you have to add alot
of preload it will give you the opposite effect
on the top end when you let off so in that case the
wheelie bars can help so you dont need to add so much
preload
EDIT
If its still pulling the big wheel stand... tighten
the front shock and limit the travel... plus up the
rear air pressure so it will just spin a little so
you get up on the tire

Went to an 1/8th mile airport track this weekend to test on Saturday and race on Sunday...

Saturday i started with stiffer EXT and Compression on the front, and cable limiters set at 4" travel from 25 1/4" static, to 29 1/4 " at lift off. This static was lowered from my usual 25 3/4 to 26" height in order to reduce wheelies.

Only got two passes and the first at 10 1/4 psi spun, and the second was better with 9 3/4 psi and the Car sort of lightly hazed the tires and ran an 5.59 at 125 mph w/ 1.25 sixty foot. Absolutely no wheelie, but it felt stiff going downtrack as airport strip was not exactly smooth.

For Sunday I thought i would loosen the shocks down to 3 clicks EXT due to lack of traction, but what i failed to factor was that they did much better track prep for the race day and traction was much better off the line. Result was a instant wheelie and carried it out to the sixty foot mark, with a best ever 1.22 sixty foot, but as it came down, I lost a bit of traction as the suspension unloaded and i went left/right a few times and had to abort the run...

Next pass I tightened the shocks up to 5 on ext and 1 more on compression to 7 and in the left lane it picked up the tires immediately, but less violently, and carried them out about 50 feet and set down with a lot of "wobble" or Bump steer from the front tires toeing in and out through the travel, but kept straight enough to finish the run. That one gave a 1.25 sixty foot, and did not feel dead hooked.

On to eliminations so i left it alone and in the left lane it seemed to work OK, but felt like a bit of spin? It also drifted left about 1 foot in the first 100 feet, so perhaps i need to reduce the 1 flat of preload down to 1/2 flat, but the right rear weight is already 7 #'s lighter than the left, so not sure???

They had 4 Alky funny cars for Exhibition and they made 3 passes each which helped the track further out.

Got to the semi finals and they put me in the right lane where it hooked like a bear, and i went a 1.21 (new best ever) 60 foot, but once again came down from the big wheelie and unloaded the suspension a bit and had to get out of it...


OK, for next time if i am at a good track with traction, i will tighten extension 1 more click as well as 1 more click compression in order to slow the wheelie on the way up and down, but what can be done about the bump steer???

I was thinking to reduce the travel a little more maybe to 3 3/4" and perhaps replace the lower snubbers with poly (harder) snubbers to reduce bottoming out as far...

Any other ideas??

Thanks,

Arnie

Sounds like progress with the 1.21 and 1.22 sixty foot times. But I will have to think about the rest. Are you using the wheelie bars to avoid the worst (too high) wheel stand? I have found that when balancing the weight transfer with front shock damping and travel, it can get touchie with wheel spin. Since I have the longer wheel base and worse weight disribution, my car is real sensitive to front end adjustment. So, for me, I use the front travel and extension damping for 80-90 percent solution and the wheelie bars for the "safety" margin if I get too much weight transfer (rather than risk wheel spin).

Front shock compression damping is a good thing when coming down from a wheel stand.

To clarify, my car always touches the wheelie bars. But if it pushes too hard on them, then I reduce weight transfer with the front end adjustments. IMO, a consistant 1.24 with a smoother landing and not upsetting the chassis is much better than the 1.21 and ultimate sixty foot time.

Thanks for the comments Jim,

I did lower the wheelie bars from where I used to run them, and with the left side 3/8" higher they don't seem to be the problem, in the right lane with the faster 60's, I definitely rode the bars hard, so the answer is more ext and probably more comp for the landing.

The question is should I also further reduce the travel down to 3 3/4"??

Also I would like to learn how to reduce the bump steer, as the landing seems to upset the car and cause issues on the harder /higher launches.

Thanks.

Arnie

Thanks Mr P Body,

I have the CE Sprung Wheelie bars...

I am going to tighten limiters and then one click each on EXT and Comp then try again. It was real close in the left lane, but too much traction in the right for my settings.

I don't have the Chassis book. Any where else i can learn how to eliminate bumpsteer?

Thanks,

Arnie