I have a full chassis car strut frt and 4 link rear 1000 hp at the tires 1.80 glide 33x16x15 tire 4.10 rear gear current set up is 52 out 6 high car seems lazy in the 60 ft 1.25 going to rescale it this week as its launching left with the new power and suggestions on changing the IC to improve the 60 ft? thanks

just suggesting. Have a friend with very similar set up. 2500 lb. car 116 wheelbase. same tire and HP with 4.30 gear. Car was lazy and didn't hit the tire hard enough. We raised the bottom bar up 1 hole which changed to 46" and removed any reload on right rear and reset anti sway. Worked for him and reaction times improved a ton, it picked up the nose on launch. 2 cents

Really need to see scale

Raising top bar up will push instant center forward and up on the car. Think about pushing your lead hand further out on a gun or shovel. This will make the head of the shovel feel lighter (motor). It is now easier for the car to lift the front end and put weight on the rear tires without working as hard. Catch 22 here though is that the top bar up a hole actually doesn’t hit the tire as hard. Lowering the top bar down a hole will hit the tire harder.

I am also using the top bar as a reference because it is my opinion that the bottom bar should be set to “level” with the ground in most cars and then IC adjusted with the top bar. Others may disagree

Any idea of current scaled numbers? Can you show us a video of car launching? Which struts do you have?

Forget about 4 link for a second, may want to look at other issues. Is it spinning? Pulling big wheelies? Pulling left or right?

Even if it was doing those things it may not be the chassis set up but the tires.

If the car is lazy off the line it may not have anything to do with chassis. That could be motor or converter.

Unless you scale the chassis with 4 link wizard, you`re only guessing.

If the car drives right - shorten the right upper bar (positive pre-load)
If the car drives left - lengthen the right upper bar (negative pre-load)

Pre-load is last resorts. If it's going left tighten the extension on the driver front side strut in conjunction with staggering the rear damper clicker adjustments by running extension a couple clicks looser and the compression the same tighter on the passenger (right) rear damper.


More power, I always treat it like I would a tight track - lower tire pressure - loosen rebound - tighten compression.

Here is how I do it. OLD SCHOOL!

little update I will be rescaling the car this week it has been 10 yrs since the car has been finished. I have my notes to compare and will update later this week.

1/8 or 1/4 mile. 4.10 is a not much gear with 1.80 and 33" tall tire. Mine is 2440lb chassis car 1100ish hp and I run 4.86 gear. Switched to a 4.30 and car slowed down .10 or maybe a little more to the 1/8 and slowed 2 mph.

quote:

Originally posted by inferno camaro:
1/8 or 1/4 mile. 4.10 is a not much gear with 1.80 and 33" tall tire. Mine is 2440lb chassis car 1100ish hp and I run 4.86 gear. Switched to a 4.30 and car slowed down .10 or maybe a little more to the 1/8 and slowed 2 mph.

1/4 mile I had my 4.56 gear in it las weekend it runs out of gear up top I dont have a 4.30 to try

What rpm did the engine make peak power at, what rpm are you shifting at and what rpm are you turning at the stripe?

Gotcha. I figured it would be breathing hard if 1/4 mile and 4.56. What kind of mph, 165ish?

quote:

Originally posted by camaro77:

quote:

Originally posted by inferno camaro:
1/8 or 1/4 mile. 4.10 is a not much gear with 1.80 and 33" tall tire. Mine is 2440lb chassis car 1100ish hp and I run 4.86 gear. Switched to a 4.30 and car slowed down .10 or maybe a little more to the 1/8 and slowed 2 mph.

1/4 mile I had my 4.56 gear in it las weekend it runs out of gear up top I dont have a 4.30 to try

quote:

Originally posted by inferno camaro:
Gotcha. I figured it would be breathing hard if 1/4 mile and 4.56. What kind of mph, 165ish?

quote:

Originally posted by camaro77:

quote:

Originally posted by inferno camaro:
1/8 or 1/4 mile. 4.10 is a not much gear with 1.80 and 33" tall tire. Mine is 2440lb chassis car 1100ish hp and I run 4.86 gear. Switched to a 4.30 and car slowed down .10 or maybe a little more to the 1/8 and slowed 2 mph.

1/4 mile I had my 4.56 gear in it las weekend it runs out of gear up top I dont have a 4.30 to try

with the 4.56 gear 161 with the 4.10 gear 169

you did not gain 8 mph from this gear change

quote:

Originally posted by 1320racer:
you did not gain 8 mph from this gear change

converter also

and maybe much better air too

quote:

Originally posted by 1320racer:
What rpm did the engine make peak power at, what rpm are you shifting at and what rpm are you turning at the stripe?

launch at 4400
shift at 7400
dyno sheet is showing peak @ 7400
with the 4.57 gear it was 8000 at strip

with the 4.10 gear its at 7100-7200 at strip

current weights before adjusting anything

LF 639 RF 528
LR 735 RR 656

this is with driver

total 2558

you've got work to do

quote:

Originally posted by camaro77:

quote:

Originally posted by 1320racer:
What rpm did the engine make peak power at, what rpm are you shifting at and what rpm are you turning at the stripe?

launch at 4400
shift at 7400
dyno sheet is showing peak @ 7400
with the 4.57 gear it was 8000 at strip

with the 4.10 gear its at 7100-7200 at strip

First off if it is not spinning, unloading rear tires and it is going straight I would not expect much if any improvement by moving four link around. Is it spinning or anything like that? What does video show?

If your peak power is @ 7400 RPM then you need to try shifting about 200 RPM Higher than that. Often it will pick up ET by not dropping out of main power band as much at the shift.

Which brings us to what may be the biggest problem- Converter. Assuming that you are not spinning etc at the hit the converter is probably where I would start and HUGHES is who I would call. If you have a good dyno sheet and know what car weighs, gear ratio and all of that information they are very good at getting it right on the money.

Now with all converter companies if you do not know what the power and torque is, weight etc it is garbage in garbage out and everyone will have a hard time getting it right.

As for scaling the car I like to get car working good then scale the car and have that as the baseline. More or less let car tell me what it needs. Get it launching nice and pretty and straight first. If I scale the car first I am really just looking for anything out of line.