Odd handling

What shocks do you have in the car?

Do you have a front spoiler on the car?

The most likely cause of your odd handling at speed is chassis flex in the rear. That’s why it’s so scary; the rear wheels are steering the car.

140 mph is about the time front end lift begins to raise its ugly head with  a stock Pantera.  If that is going to be in your normal spirited driving routine, a spoiler should be on your purchase list.

I like this one from Dennis Q made of ABS plastic and much more forgiving than his fiberglass version. Nonetheless, damage happens and they only seem to last me 5 to 7 years. This was during installation and there is still some protective masking tape in place

your windshield trim is likely not an easily corrected problem. 🙁

The trim has a small J hook at the very bottom that indexes into the rubber gasket. Proper installation is to install gasket to glass, carefully and firmly install chrome trim and then install as a unit. Once the unit is installed the tension on the rubber gasket will usually prevent resetting loose trim such as yours. It may push down but getting it to actually latch the J hook is difficult

I would lubricate with a spray tube silicone can and then cross your fingers, attempting to reset - at the same time - from both outer ends of the problem area

Good luck

Larry

They look like stock shocks with no adjust ability and no front spoiler. I think some new shocks are in my near future. Any suggestions?? Are the J hooks visible in the pick?

As for the J hooks pretty sure you can answer that question better than us. If you can see the bottom of the trim then you should be seeing the J hook

Scott from SACC is very knowledgeable and sells good quality shocks.
Old shocks can get sticky and behave in a nonlinear way. Front end lift and old shocks can lead to instability at speed.

If one of the front shocks was not rebounding at the same rate as the other I see how that would make the car behave like that.

… but what could cause odd handling AND your windshield trim to pop out? Chassis flex! Jack up one rear wheel. If your deck lid doesn’t line up properly with one corner off the ground, that’s your problem.

I don't have that much Pantera specific experience and my project isn't on the road yet. Most of my experience is with race cars. I have read that P-cars do suffer from some chassis/body flex. Does a rust free car in good condition flex that much? Evaluating the chassis, I can see why there is chassis flex, especially with wide tires and lots of hp.

We found chassis flex caused unpredictable setups and compromised transitional behavior during cornering. I agree with David 100% about how diabolical unwanted rear steer is. We went to great lengths to eliminate rear wheel steer. Make sure your rears never go to toe out through their travel. If chassis flex causes that then that's a problem.

Good shocks are huge in chassis dynamics. If you are building a high speed car, don't overlook the spring/shock system and aerodynamics. I'm sure a flexible chassis doesn't help.

You will get lift at those speeds and you need to realize that a chin spoiler will help BUT what you are describing is also a cross wind scenario.

Put in double adjustable shocks and lower the car as much as you practically can in the front. The new springs and shocks will be stiffer then the stock ones ever were and will probably reduce the suspension travel up and down somewhat which will help reduce the bump steer you probably are experiencing as well?

IF you are still running the stock shocks most likely the 1" spacer doughnuts are still on them.

Removing them absolutely will help some. If you do. Measure the ground clearance that you do have now under the radiator support. That's as low as you dare to go and you might even want to consider mounting a skid plate there as well so you don't get "hooked" on something.

Then go back and check that you have sufficient toe in both front and rear. 3/16" to 1/4" total is a good number to aim for.

IF you intend to drive the car more at those speeds then you had better do a "bump steer" change check. It's possible that the pulling to one side or the other suddenly is "bump steer" caused by a sudden toe out in the suspension travel at one point.

That could work out since you will be removing the springs and shocks for new ones and you need to do that to check the bump steer changes. You HAVE to know that to understand what you are dealing with.

Also be aware that at that speed the aerodynamics could push the car down or up. When you get lift in the front it isn't smooth. It's sudden and it's a little like a speedboat's nose bouncing on the water AND the car can steer itself left or right like bump steer would. You don't want to be chasing the wrong solution.

You can only calm the car down so much, then you either have to live with it or decide that the car has a speed limit...or you do. It's not a simple solution there to anything.

The encouraging thing is that the basic design is quite capable of running over 170 or more with relatively simple "improvements" to the production settings. How high is up is difficult to say but I personally would be staying away from envisioning anything near 200mph. The car MIGHT be capable of it but I am not. That is professional racer territory and you just can't go out causally and expect to do it.

This is a good thread that covers quite a bit, all relevant to high speed stability. It boils down to chassis dynamics and aerodynamics.

Doug mentioned bump-steer and ride height, both important.

MJ mentioned the diff. It can change the car's off throttle, part throttle and full throttle handling characteristics. We would adjust our diff for desired results.

Unless you're not moving, chassis dynamics come into play. The higher the vehicle speed the more amplified the effects are.

Please dial in your car at a controlled place. Decent low-mid speed behavior doesn't necessarily equate to a good, safe high speed ride.

Mike, all good points.

When I read the initial posting, I couldn't help but wonder what kind of tires are on the car? If anyone is going to drive their Pantera on public roads at 140 mph, you better be damn sure everything is in perfect condition.

Moderate cross wind when going through some dips in the Nevada desert at extra-illegal speed!  I've heard it was 180 mph, 160, 170; suffice it to say it was north of 150 mph.  Be careful, and keep the shiny side up!

Tires and rear differential: You reminded me that the nature of the rear differential REQUIRES the circumference of both rear tires to BE WITHIN 1/4" DIFFERENCE! So you should EXPECT to match the tires like race teams do or suffer the consequences.

What does that mean? Well, you can "confuse" the traction lock unit and you do not want unpredictable transference of drive from one side to the other.

I'm saying what MJ said in a different way about the rear.

The more traction that you have in the rear, the more you need to consider race type chassis bracing. What you need to do to it, you are going to have to talk to someone who seriously races a Pantera.

The other thing with unbalanced rear tires is you WILL burn up the discs in the differential.

You have to remember the design parameters of this car are from 1968. It is not a GT40. It was never considered having over 500hp. The size of even the street treads now were never considered for a street car going that fast then.

Don't forget that race tires are almost always fresh for each race and depending on the longevity are changed several times during that race.

That WAS a pretty blue car. ANY of these items can be lethal.

Sometimes ridiculously stupid things happen at high speed. What I did was move the wipers to the '74 mounting position so that WHEN they suddenly popup at speed, at least it isn't right in my view point.  I NEVER expect that simply because I am concentrating on the road. It always startles me and that can cause an over reaction. It's just a stupid thing that happens at speed.

That blue car was wadded up, did the guy make it out alive?

@Donny Dotson posted:

That blue car was wadded up, did the guy make it out alive?

Yes! He was very fortunate!  I believe he suffered a broken collar bone and some broken ribs, maybe even a punctured lung. 

While my Pantera has a Grp 4 style front air dam and side skirts, I can do the standing mile to 170+ MPH with no stability problems.  When it comes to  doing 160+ on an open road for 90 miles (SSCC) things get a little twitchy. I believe that the road surface is a contributing factor.  Certainly not like a race track.

Most of us don't get to drive at high speeds frequently.  I found myself being tense at the beginning of a race and have to tell myself to take a deep breath  and relax. It makes a big difference.

I remember a quote from Bobby Unser saying that he wouldn't get on a track with amateur drivers. He said they were not over the condition of driving on Adrenalin yet and that made them very dangerous.

In my thirties, I used to race a 2-stroke kart. The 16 year olds that I competed with had the same adrenalin problem. This, coupled with Daddy funding/fixing the kart, was a dangerous combo.

@Rob Fridenberg posted:

In my thirties, I used to race a 2-stroke kart. The 16 year olds that I competed with had the same adrenalin problem. This, coupled with Daddy funding/fixing the kart, was a dangerous combo.

As I recall, many "Indy Car" drivers have extensive racing backgrounds in "carts"? I am pretty sure that the Unsers did.

I could never figure out the relationship of Carts to Indy's?

I personally stopped doing "open track" events because of the "suddenly unleashed" drivers on the track.

Many racers, including F1 get started in karts at a very young age. They say it it the purest form of racing - karts in your class are almost identical, there are minimal adjustments to be made - you learn about handling, passing and taking the most efficient line around a track.

My Yamaha 100cc 2-stroke had a multi-plate/oil bath centrifugal clutch that engaged at 10,000 rpm. Going around a track with your buttocks 1" off the ground with the motor screaming at 15,000 rpm will get your adrenalin going!!!

OK, I get the feeling some people think I'm a irresponsible maniac endangering innocent people on the public roads. Well, maybe a little bit but, when REALLY accede the posted limits I'm on deserted desert and mountain roads. Street racing is a very bad idea and usually ends badly. Here in So. Calif. on any given day the traffic on the 5 north and south you can be in the fast lane doing 80 MPH and the person behind you is riding your ass in a pile of crap that you can't believe is capable of that speed and you know more than likely they have bald tires and metal to metal brakes. I have decades of track time on circuits such as Laguna Seca, Circuit of the Americas, Willows Springs, Sears point just name the my favorites so, High speed is just another day at the office for me. After seeing that wadded up blue car and knowing that the dude didn't get jacked up to bad makes me feel a bit safer. I didn't think a Pantera would hold together that well. It can get extremely windy in these desert areas but, most of the time the conditions are beautiful and good for blasting. If it's legal it more than likely sucks!        

Not to rain on your parade Donny but in reviewing this thread there wasn't one post criticizing you as being a menace to society.

The worst Demons are the ones that you imagine are out there and coming for you but if I was a legal council I'd recommend that you don't post anywhere where and how you violated the law on public property.

State Fuzz in the past has come knocking on others doors for such public admissions. That certainly isn't what I want or would want to hear about in your case.

Squashed gila monsters? That's your problem. You're the one that has to scrape them off of the car.

No condemnation or criticism from me.  I was merely trying to say "be careful," and sharing pics of a friend's car after he encountered a cross-wind during a high-speed run through some "dips" in the desert.

As always, get out and DRIVE!  And, keep the shiny side up! 

I think somebody high jacked my computer, I would never ever say or do anything like that, honestly.

For interest , on speed limits, there is only one spot in Oz where there is absolutely no speed limit. Its in the Northern Territory. It goes from about 7 mile north of Alice Springs through to the Ali Curung Rail Overpass  175 Miles away.

Here is a shot of it.

I drove it two years ago in a 6.3l AMG ML ( Pantera was still in card board boxes )

Now you would think it would be really really good, and I admit to winding it up just a bit at first .

But here is the thing. Its mostly dead straight, there are suicidal kangaroos waiting to randomly leap out at you and there are absolutely no service stations in the middle of what is a 320 mile drive servo to servo  . None of this great for Panteras.

Not sure how much range you get at 140MPH but it likely is well less than 175 miles of no limit and then there is another 150  odd miles to do on top as well . At any elevated speed you rapidly work out you will not make the distance.

Slow down or run out of fuel.   

In the last 15 years there have been no speed related fatalities recorded on this 'no limit' road.

I always wanted to go down under and see all of those cool places and go fishing at all the famous hot spots. My most all time favorite movie series Mad Max, I always wanted to see the locations.  Do you live there? What is the normal speed limit on the freeways? What would the Man do if you get busted going really fast?

Normal limit is 110kmh. There are some remote roads posted at 120kmh. They run a demerit points system. A clean slate is 12 points. 19-29Kmh over is 3 points, 29-40Kmh over is 6 points, more than 40Kmh over is 7 points. Lose 12 points cumulative in any rolling 3 years is an automatic suspension for 3 months.

If you are being really stupid, careless , reckless or dangerous driving or more than 45Kph over the limit ,  they have the power to confiscate your car upon conviction for 28 days. If you are found to be reckless driving three times within a 5 year period  the police  can apply to have your vehicle crushed.

This always gets the press excited with pictures of some extreme modified rice burner before and after, and some sad looking idiot thinking about walking everywhere for the next six months.

In my experience if you are stupid in a vehicle you are more likely to be punished by the roads , environment and the wildlife than the police on remote roads . That will punish you allot more than the cops.

Wow! they don't mess around. You can burn a police station down in the US and you will probably get an award.

A couple of thoughts: on your loose windshield trim, it has an s-shaped projection on its bottom that presses into a molded slit in the rubber gasket. You need to add a bit of soapy water to lube the rubber when pushing the protrusion in. Using WD-40 may take a loooong time to dry.

I never understood people who pay extra to black out their windshield trim when simply leaving it out will show the black gasket underneath, with no expense or complication. Just take it off.

The Euro GTS & Gr-3 Panteras had 'wiper wings' that force the blades down onto the glass at high speeds. Hall Pantera used to sell these. They simply clip onto the wiper blade metal arms and are not expensive.

Hey Bosswench - great information.

I had those wiper wings on the wiper blades and pulled them off as I thought they were aftermarket.

Now where the heck did I throw them.......!!!!???

Australia has been near the top of my bucket list places to visit since high school.
They're not a big fan of "hooning" down there though.
https://www.thedrive.com/artic...-these-jdm-treasures

Oh, and there's this:

That's a little excessive I think on crushing your machine. I'm more afraid of the Box Jelly Fish than a sea snake. I deep sea fish religiously in So. Cal. all the time but, I don't really like to get i the water to much, I've been seeing many pods of Orca's lately,  they will jack you up!

Hey Donny - the best spot in the world for seeing Orcas is a place called Bremer Canyon in the WA south coast.  They are simply massive and pack hunt like wolves. A 7m great white shark was bitten in half down there two years back. Actually - more like thirds....!

https://www.youtube.com/watch?v=ZJ5hwZxi2xQ