Street rail bump steer help

[jdcool4]

I have a street legal sand rail with alot of bump, throttle and brake steer. From what ive read and learned on here its because the suspension is unloaded and needs to be lowered untill the tie rods are straight inline with the gear box.
It is stiff enough to bounce the front tires off the ground on rougher roads.A few options ive considered are.

Through rod either the upper or lower tube
Through rod both tubes and run coil overs with the proper spring rate
Remove leafs from one or both tubes to achive height and spring rate
Cut and turn/ adjuster but it wont help spring rate
Cut the beam off and run short a arms

Its a ball joint front end it that is welded stright to the frame. The shock towers where also cut off the beam and new ones made onto the frame. Any suggestions?

[Aerindel]

What kind of air pressure are you running in your front tires? You only need about 12 psi...could help with the bounce without giving up clearance.
_________________
Homemade woods/street, bug out rail. IRS, Balljoint front end. 1967 1600cc DP, Weber 32/36 progressive, tri-mil quiet pack. Rear only cutting brakes.

http://www.thesamba.com/vw/forum/viewtopic.php?t=630046

[jdcool4]

28 psi or so i didnt think about runing less pressure. Clearence really isnt a issue it dont go off road. I wont have a chance to drive it again till spring .

[cbeck]

My bj front also lifts tires often, not sure height is your problem, plenty of people run adjusters for more lift without bump steer. Joints and ends tight? Pittman arm on right side up? 4 wheel alignment? Rear alignment out can cause funny handling. Some pics might help.

[Aerindel]

Pics would help...but I would drop your air pressure. 28 is way too much pressure for a rail front end. It's a vehicle that probably weighs 1000lbs max with 70-80% of that on the back wheels. Your running enough pressure for a vehicle with 500lbs of load per tire on one that probably only has about 60-70lbw of load, no wonder your tires are bouncing.
_________________
Homemade woods/street, bug out rail. IRS, Balljoint front end. 1967 1600cc DP, Weber 32/36 progressive, tri-mil quiet pack. Rear only cutting brakes.

http://www.thesamba.com/vw/forum/viewtopic.php?t=630046

[jdcool4]

Sorry i cant get any better photos its burried in the garage right now. I took a few that i could. The outdoor one was from this summer showing how high the front is now.

[jdcool4]

Forgot to mention the ball joints where super tight when new. Almost undriveable. But they seem to be alot smoother. It has never had a alignment only checked front toe 1/8 toe in

[dustymojave]

In that pic it looks to have a lot of toe-out and positive camber.

The ride height is not a problem for steering. If it were, all of us offroaders would never have used the VW front suspension. But the VW beam front suspension has DOMINATED offroading worldwide for the last 60 years.

Potential problems include the weakness in your beam due to having cut away all connection between the outer ends of the beam tubes, leaving it very flexy. Taking out the bearings and welding in end plates would help. The cutting torch followed by a welding torch may very well have, in fact, should be expected to have, melted down your trailing arm inner bushings and outer bearings. Thi scan only be fixed by replacing the bushings and bearings.

THEN you can start to fiddle with front spring rate and ride height.

Since your car is built with not only a short wheelbase, but the vast majority of the mass around the rear axle. On top of that, the gas tank is mounted way high and the Ecotec engine which makes plenty of power is also substantially heavier and longer than the VW air cooled engine. This moves the CG even further back. All this is great to a drag racer concerned with planting the maximum traction on the rear tires. Not good to a road racer or slalom racer who wants the car to turn when the steering wheel is rotated. Moving weight forward in the car will help.

On top of all of this, that poor VW swingaxle trans was designed for mild driving with 40 horsepower and skinny little bias ply tires. I don't think you should expect it to tolerate the Ecotec or spirited driving for long.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet.

[Aerindel]

Yep. With a big heavy water cooled engine behind your rear axles and a swing axle suspension I think its going to be hard to get good handling. Reducing spring rate and proper tire inflation should help...but its kind of a problematic set up.

Also, move some weight up front. Battery, fuel tank, spare tire, etc should help.
_________________
Homemade woods/street, bug out rail. IRS, Balljoint front end. 1967 1600cc DP, Weber 32/36 progressive, tri-mil quiet pack. Rear only cutting brakes.

http://www.thesamba.com/vw/forum/viewtopic.php?t=630046

[jdcool4]

The frame is very short 83inches center of hub to center of hub. I really don't have room for the fuel tank any where else. It is also very low 44inchs tall overall, The seats mount to straps that are welded directly to the rear torsion and drop below it 6inches or so.

The throttle steer was made worse with the Ecotec swap but the bump steer brake steer is still just as bad as with the vw engine.

I also plan to take the leather cover off and make a fiberglass one which will look better and add weight to the front.

The problem I notice most is if you jump on the front you can watch the toe change radically.

the trailing arms moved smoothly at the time I changed the ball joints. I can add spacers to the ends of the torsion tubes if that will be helpful.

When I hit the brakes it trys to dart left when I am on the throttle it darts to the right.

[Gary Massin-Ball]

Here's a cheap way to get rid of any bump steer on a rail!

_________________
Warrior sand rail:
2276cc 82x94
Engle FK-41 with 1.25:1 street style rockers
40x35.5 stock cast single port heads
Single 40mm Kadron w/32vent
Equalizer 5lb pulley
Stock lifters
Stock aluminum pushrods
26mm aluminum oil pump full flow
*Poor mans rack and pinion up front*
-------------------------------------------
The Ugly Bug is on the road!

[VWCOOL]

Don't confuse bump-steer with a complete lack of build finesse and alignment in the front (and/or rear) end

[dustymojave]

Yeah, that's a CHEAP bump steer ...fix? The reason VW never used that setup on Bugs, Transporters, Ghias, Things or other products is because it's WEAK!

Bump steer? The 1st bump and it will steer all over the place. Ford used a similar arrangement on twin I-beam trucks, but with forged steel bar 1-1/4" thick. Offroaders have been fixing that 1 weak point in that suspension design ever since 1970.

A setup like that used for Super Beetles would be FAR better.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet.

[Gary Massin-Ball]

You know I have hundred of miles on these tie rods with next to zero toe and zero breakage and one drive straight into a sand wall at 30mph with minimal damage was able to drive it back to camp once I re inflated one of my tires.

dustymojave It "almost" sounds like you have tried this set up!

Gary
_________________
Warrior sand rail:
2276cc 82x94
Engle FK-41 with 1.25:1 street style rockers
40x35.5 stock cast single port heads
Single 40mm Kadron w/32vent
Equalizer 5lb pulley
Stock lifters
Stock aluminum pushrods
26mm aluminum oil pump full flow
*Poor mans rack and pinion up front*
-------------------------------------------
The Ugly Bug is on the road!

[Gary Massin-Ball]

Nobody has mentioned that jdcool4 O/P is running a "street Legal" rail on the road with no front shock.............

Running without front shock will definitely make the wheels bounce uncontrollably as well!

Tried it on the rail in the dunes and any bumps would cause the wheels to bounce multiple times.

Before I went to air shocks and aluminum beam on the front I did remove the bottom torsion leaves and re-indexed (cut and welded) the top adjuster to return the height and worked well to soften the front up.

In this picture of my old set up I had to cut and turn the adjuster to compensate for taking a set of springs out.

Gary
_________________
Warrior sand rail:
2276cc 82x94
Engle FK-41 with 1.25:1 street style rockers
40x35.5 stock cast single port heads
Single 40mm Kadron w/32vent
Equalizer 5lb pulley
Stock lifters
Stock aluminum pushrods
26mm aluminum oil pump full flow
*Poor mans rack and pinion up front*
-------------------------------------------
The Ugly Bug is on the road!

[dustymojave]

Nope. Not tried it myself. But I HAVE seen it tried by someone else back in the 70s with bad results.

I'm glad you've had good results on yours.

How much do those tie rod clearance hoops drag with them nearly as low at ride height as the bottoms of the rims? Are they as low as they look in that pic?

I consider it good to think outside the box. I'm very much a "path less traveled" sort pf person myself. So I applaud that aspect of that setup. But I would not try what I've already seen fail when I understand the failure.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet.

[Gary Massin-Ball]

Oh The hoops....Those are not as low as they look and are my jounce stops. I'm in the sand mostly so I added the hoops so I could get maximum tie rod travel with the suspension at it's highest. They also double as suspension stop when they do touch the ground. I do nor have any other down travel stops on the car and use straps to limit the upward travel so the tie rods do not hit the steering shaft under jounce.

I'm a little afraid to remove the of frame top rail between the top hoop as I have done on the bottom. I did hit that sand wall at 30 MPH and was pleasantly surprised I did not collapse the lower Hoops!

_________________
Warrior sand rail:
2276cc 82x94
Engle FK-41 with 1.25:1 street style rockers
40x35.5 stock cast single port heads
Single 40mm Kadron w/32vent
Equalizer 5lb pulley
Stock lifters
Stock aluminum pushrods
26mm aluminum oil pump full flow
*Poor mans rack and pinion up front*
-------------------------------------------
The Ugly Bug is on the road!

[dustymojave]

The OP says in his 1st post that his car has shock towers fabricated of tubing. So I take that to indicate that even though no shocks are shown in the pics, it is apparently his intention to use shocks.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet.

[jdcool4]

I do have shocks for it i took them off when breaking in the ball joints. I throught maybe the extra movement would help because they were tight like a over adjusted gear box. Now it steers better i do need to get them back on. But would that help with the throtttle and brake steer. I just assumed that because when i bounce the front end the toe changes badly that it was a bump steer issue.