Nostalgia 102" iron 392 hemi Topolino front end question

[Merryknees]

Hi guys
Just wondered what your opinions are as to whether I look at my front end spring rate/damping adjustment after last weekends interesting ride. Waiting to hear back from the coil over supplier as to what spring rate is on there, although I think we are running 220lb springs

https://www.facebook.com/photo.php?fbid=1287947327904812&set=a.1287947151238163.1073741944.100000686709090&type=3

The car is new out this year and has made 12 runs mostly in the 8's and straight. Yesterday however I did get out of the groove and leant on the suspension more than previous. As you can see it likes to cock a rear 

cheers

[dreracecar]

Lock the front end and make sure the left front spindle is 1/4" lower then the right front

[GlennLever]

Took some driving.

[Merryknees]

[dreracecar]

crank up on the left front spring to load the right rear more

[glofria]

Looks like the car drives to the left at launch with the front tires off the ground. Looks to me like a sure sign of a larger circumference tire on the right side than the left. Measure the roll out of each and match them within a 1/8th inch. (Sorry no metric system here.)

After watching the slo-mo video a couple of times, I have to ask is this a solid mounted rear end car or is it sprung with a latter bar/ 4-link in the rear?

[Merryknees]

It's a solid mount rear.
Running 33" slicks at 6 1/4psi
Gonna look at four corner weighing and see where we are with it.
Also planning to stiffen up the front end

[glofria]

I asked about the rear end mount because at launch it acted like a live axle car. Being that it is solid mounted, scaling the car won't have much affect unless you start altering the tire pressure.

Again I suggest, checking the roll-out (circumference) for evenest and start upping the tire pressure too. I watched the videos again and you got too much bite and not any slippage. Get the car going and let the tires catch up. I also looked at the stills on you facebook page and watched the in car video too. 3000 RPM on the tach is okay, but I'd bump it up to about 3500. Only if you raise the tire pressure though, otherwise you'll make the situation worse.

Equal roll out will make the car go straight.
More air pressure will alleviate the tire bounce (walking).

Just my humble suggestion.

[dreracecar]

I have 4 short wheelbase fuel altered running straight, you must load the left front to load the right rear slick to make the car go straight, that's more important then tire dia. If you don't load the right rear it will grow and turn the car, period

[Merryknees]

Thanks for the replies guys.
Just to add - previously I have launched the car from tick over [hunting 1500-2000rpm]and it has just gone straight down the groove everytime [10 runs on the car with this combo so far]
I launched with the brake and 3000rpm to see if we could improve the 60ft and pull the wheels up.
60ft went from previous best of 1.344 to 1.309 at Shakespeare County Raceway. The cars best 60ft was at Santa Pod of 1.298 launched from tick over.

I think that is it for this season. My plan is to uprate the front springs from 220lbs to 260lbs and try loading the front left 1/4" as advised by dreracecar. Also the dampers are set at softest so will add some resistance there too.
We will check circ of the tyes and play around with tyre pressures if need be after spring uprating.

Slomo of previous runs launching from 1500rpm
You can see some tyre bounce on this run also although I didn't see it as a problem whilst driving.

[dreracecar]

Solid mount rear end, locked/solid front end   105" wheelbase  blown fuel 417 Donovan
My chassis and set-up---"The shortest distance between two points is a straight line"

[Merryknees]

The Mr Boston Topolino! nice one 
I will take your advise and stiffen up the front end considerably. When I built the car I picked the Bad Habit car raced by Charlie Hill as the style I wanted hence the coil over front end.
Obviously I am just guessing as to what suspension movement Charlie had in the car but solid or as stiff as I can will be the way I go.
Thanks dreracecar.

[slingshot383]

If those shocks are adjustable, tighten up the extension in addition to add the aforementioned pre-load.

[Merryknees]

UPDATE-

Now getting ready for our first meeting in three weeks.
Some minor alterations have been made to the set up as advised by the replies above THANKS GUYS.
Previously the front spring rate was 220lb per spring, we now have 500lb per spring. Shocks setting was at softest spot so plan to tighten right up.
Today we have loaned a four corner set of scales to weigh/set up the car. With the front right tightened up more than the front left we have equal front weight of 444.2lbs and rear equal weight of 427.7lbs.

My question is should i add more weight to the left rear or left front to counter act what happened last season.
Your thoughts would be greatly appreciated



Ian

in reply to glofria the rear tyre circumference is spot on equal at the same pressures

[dreracecar]

Personally, I would replace the shocks with equal length tubing (to eliminate variables) scale car and register corner weights, lift front end and add 1/4" shim under the RIGHT front tire and record corner weights. Remove tubing struts and replace with shocks and adjust corner weight to match previous numbers. and that where you start from. from then on you can tighten left front spring till car leaves straight consistently. Make 3 passes before any adj to eliminate outside influences