The Car Thread

Ratty · Post by **Ratty** » Tue Dec 15, 2015 12:46 am

I had a dune buggy and loved the 40 Ford. I also loved the PT Cruiser when it first came out. Then I realized how small it was.

Captain Goddammit · Post by **Captain Goddammit** » Tue Dec 15, 2015 5:51 am

Hate to say it but I kinda like the PT cruiser. And they feel roomy when you drive them.
I mean, it won't tow a backhoe and carry a full unit of plywood, but it's got room for people.

Disclaimer: This opinion courtesy of a guy who uses a Mazda Miata for a daily driver.

sadie · Post by **sadie** » Tue Dec 15, 2015 6:39 am

I LOVED my PT Cruiser. On many occasions I got two people, two big dogs, and
enough camping gear for an army packed into it. It wouldn't win any races but
served me well for 14 years....and then died a horrible death in a monster hail
storm...it was a sad day...

Elliot · Post by **Elliot** » Tue Dec 15, 2015 8:59 am

And I loved my Miata, a white 1992.
Being six feet tall, I hit my head on the top. It needed a Gurney bubble! But difficult to do that on a soft-top. Instead I removed the seat track and bolted the seat directly to the floor. That solved it.

Captain Goddammit · Post by **Captain Goddammit** » Tue Dec 15, 2015 9:40 am

They did sell the PT Cruiser with an optional turbo. I drove a borrowed one, with turbo and wood grain sides, all over SoCal a few years ago and it didn't feel sluggish at all.

Elliot · Post by **Elliot** » Tue Dec 15, 2015 11:22 am

.
Alas, my Miata was a bit sluggish sometimes. Not sure why. I always
made sure there was nothing heavy in the trunk.

^Rhino! · Post by **^Rhino!** » Tue Dec 15, 2015 3:09 pm

I hesitate with embarassment when I want to remember the hills of East Tennessee and tooling down the road in a '67 VW Squareback. Air cooled engine, too...., but man would that car take the tight hairpin turns on the old roads......and it would carry four people and equipment for a weekend on the Appalachian Trail easily.

Except we normally went below Norris Dam to fish for trout all night long, o up onto Watts Bar Lake for a striped bass run.....ah, the good old days......

Skuzzy61 · Post by **Skuzzy61** » Fri Dec 18, 2015 2:08 pm

Well, the IRS system for the Cobra is coming together. Finished welding up the cage for the pumpkin. Got the upper control arms fabricated as well. The lowers are trickier as I need to incorporate a toe adjustment.

The frame is on target for being a roller by the end of the month. WOOT!

Captain Goddammit · Post by **Captain Goddammit** » Fri Dec 18, 2015 3:54 pm

You should get a trailer hitch welded in while you're at it, otherwise I don't see how you'll get all your Burning Man gear into that thing!

Skuzzy61 · Post by **Skuzzy61** » Fri Dec 18, 2015 4:46 pm

LOL!

Actually, I am trying to convince the Wife unit we need a box truck I can use to haul the Cobra around with and we can use it to also attend BM with modifications, of course.

Captain Goddammit · Post by **Captain Goddammit** » Fri Dec 18, 2015 6:17 pm

Truck campers mounted on a really stout truck (I use a Dodge dually with a Cummins) work great at Burning Man, you have all the comforts plus huge towing ability.
You'll need that... for the MV you're going to build...

ygmir · Post by **ygmir** » Fri Dec 18, 2015 6:28 pm

Captain Goddammit wrote:Truck campers mounted on a really stout truck Fire Truck(I use a Dodge dually with a Cummins) work great at Burning Man, you have all the comforts plus huge towing ability.
You'll need that... for the MV you're going to build...

there , fixed it for you.

Elliot · Post by **Elliot** » Fri Dec 18, 2015 10:59 pm

Skuzzy61 wrote:Well, the IRS system for the Cobra is coming together. Finished welding up the cage for the pumpkin. Got the upper control arms fabricated as well. The lowers are trickier as I need to incorporate a toe adjustment.
...

Designing your own suspensions.... I think I like you. How do your camber profiles look?

Captain Goddammit wrote:You should get a trailer hitch welded in while you're at it, otherwise I don't see how you'll get all your Burning Man gear into that thing!

See photo of Miata above.

Skuzzy61 · Post by **Skuzzy61** » Sun Dec 20, 2015 6:42 am

So far the camber angles look good. At static it is neutral. The center of gravity and roll centers combine to transition the outside wheel negative while holding the inside wheel near neutral. Should corner like its on rails.

Much, much better than the straight axle.

We could not dial much anti-squat into it though. Moving the top spring/shock mount inboard a little bit helped reduce squat a bit. Going with the heavier springs for that adjustment required a little more beef to the lower control arms.

Trade offs.

Cut the bearing/hub retainer yesterday and got the jig built to make the upright/spindle. Got the upper controls arms completed and powder coated.

Ratty · Post by **Ratty** » Sun Dec 20, 2015 9:04 am

This post is like the DaVinci Files. I DID understand 'powder coat' though. Like Gomez Adams, speak french to me, I love it.

Captain Goddammit · Post by **Captain Goddammit** » Sun Dec 20, 2015 10:01 am

What wheels are you gonna run?

I've needled you about it a few times already, but I'm warning you: As a car guy/builder of stuff, you ARE now screwed, you ARE going to build a Mutant Vehicle. When I first went to Burning Man, everything about it blew me away but the motorized custom creations really caught my attention.
Things have shifted a bit, it seems like there were more real custom creations before. There always have been and still are the low-effort decorated golf cart rigs, but now it seems there are more big bus based rigs. Not as many clean-sheet, from-scratch creations. There was a hot tub that had fully articulating, electronically-controlled hub motors that moved in any direction, or could spin in place (and I mean spin!), big walking machines, an awesome steampunk machine based loosely on an old railroad hand-pump car, and any number of others.

I've always been a car guy and had grown tired of car shows that are always dominated by the guy with the deepest pockets, and the same '55-'57 Chevys, '32 Fords, As or Ts, Camaros, Chevelles, Mustangs, Corvettes and Cobras even... no offense, I love Corvettes and Cobras and have a '55 Chevy and a Trans Am (close enough to a Camaro) myself.

For BRC, you can build ANYTHING you can think of (and transport out there). And it's a harsh, dust-stormy desert; finishing things like jewelry isn't in this world. It's gonna get dirty, drinks will be spilled on it, and you'll generally have a ball. It doesn't need to be street legal, it can have flame throwers and it only has to go 5mph on flat level ground so all sorts of things are possible that can't happen on street cars. The part that sucks is that most MVs are good for NOTHING else, but I can pretty honestly say I actually drive my Land Yacht MV more than my '55 Chevy. And I worry about it a lot less and have more fun on it!

You're building your own IRS for a Cobra... you're a fabricator, it sounds like a good one too. And you're a Burner.
You might as well start thinking about what you're gonna build. You're screwed... I'm telling you now... mark my words and all that shit...

Elliot · Post by **Elliot** » Sun Dec 20, 2015 11:00 am

.
Sounds good. (I would have become nervous if camber went substantially positive on suspension extension.)

And you probably don't have enough suspension range to affect track width significantly.

I have built only two cars from scratch, and both had solid axles. But I enjoy reading and thinking. And I was an auto journalist on the side, so I have seen cars catch air elegantly and then... "become ungraceful" on landing.

On one of my roadsters I toyed with anti-squat. The layout was a pair of quarter-elliptics below and a big 3-point (V-shaped) upper link. The springs stayed put, but I could re-position the upper -- a lot. Learned a lot too, from that. Most fun was max anti-squat. (Some drag racers called that "planting the tires".) I sat close to the rear axle, so when I accelerated... the car tossed me not only forward but also upward. Nifty sensation. Home-designed and -built amusement park ride.

Of course, these two cars were intended only for casual driving on public roads. And they did that perfectly well.
(Caution; anecdote approaching.)
I have the honor of the personal friendship of a true automotive expert -- and perfectionist. He may also have a touch of Aspberger Syndrome -- he speaks... bluntly. No kid gloves on his tongue, ever.
We went for a spin in my first roadster, taking turns driving, and brainstorming along the way. His verdict was that the car functioned much better than it looked. I'm still proud of such gushing praise. And that was 35 years ago.

Only problem was the enormous unsprung weight of the rear axle. Both cars scored Massive Fail when hitting a bump in a curve.
At one point I installed 300 pounds of lead to compensate. I seem to remember it helped, but it slowed the acceleration like... 300 pound of lead. That was the first car, which I eventually sold.

On the second car I lopped off the rear third of the frame and was pondering the Mazda Miata when I kind'a outgrew the concept of the car itself and parted it out.

Ah... the goddam captain is here. Actually, there is something else you can do with a Playa MV. Parades. Christmas parades, 4th of July parades, Cucumber Sandwich Festival Parades. Mine are only pedal-powered vehicles, but people love anything unusual.

Skuzzy61 · Post by **Skuzzy61** » Mon Dec 21, 2015 4:50 am

Captain, I did start sketching an idea, but quickly put it away. I have three projects underway now, and really do not have the time or money to start another one. While the third project is a "ground up" design of my own, it really is not going to be suitable for the playa.

IF I was going to do an MV, I think I would look at using a very different power train. Something interesting.

I attached an image of the wheels I will be using with the Cobra.

Elliot, I have lot of things working for me with the Cobra suspension. Very low center of gravity and a light car. The weight distribution looks like it is going to be 45/55. I cannot move the engine any further forward without hood clearance issues. As it is I need to use the hood scoop area for clearance of the EFI manifold. I'll draw fresh air from the front opening, instead of the hood scoop.

Anyway, the body roll is minimal and travel is short (+/- 2.5 inches). Short wheel base cars present other challenges though. The Cobra's nasty tendency to swap ends, when the rear breaks loose in a turn should be tamed a bit with the IRS. No more multi-link/panhard bar trying to twist the straight axle in opposite directions, binding up the entire suspension. Of course, it is all theory until I get on the track. The computer says I should be good to go. That is sort of like hearing the phrase, "Hey guys! WATCH THIS!"

The bigger challenge is getting the cockpit gauges in front of me and not off to the side.

Captain Goddammit · Post by **Captain Goddammit** » Mon Dec 21, 2015 7:33 am

You'll be able to hear when to shift!

Ratty · Post by **Ratty** » Mon Dec 21, 2015 7:41 am

Skuzzy, The length of time it takes to build is the gestation period. Firing it up for a spin down the street is birth so what is 'this'?

Elliot · Post by **Elliot** » Mon Dec 21, 2015 8:37 am

The short wheel base occurred to me earlier, but in a different context -- Ackerman. The shorter the wheelbase, the more the spindle arms need to be splayed out, and there may not be room in the wheels. ...Unless you can fit the rack behind the spindles. (Some cars have the rack on the firewall, which is actually a great idea if the proportions of the car are suitable.) Where is your rack?

(I'm enjoying this refreshing of dusty knowledge. Somewhere here I have a terrific book on chassis design by Mike Costin (of CosWorth). Folks like Costin and Colin Chapman had this all pretty well figured out by 1960, methinks.)

Skuzzy61 · Post by **Skuzzy61** » Mon Dec 21, 2015 8:47 am

Captain Goddammit wrote:You'll be able to hear when to shift!

It depends on how good those noise cancelling headsets are. I need to be able to hear the pit crew when I am lapping. The only race I am participating in is the "Big Bend Open Race". I'll be registering for the "Grand Touring (GT)" class which posts a tech speed of 140MPH.
The "pit" crew is the co-pilot and a couple of strategically placed spotters as the race is all about the time you make the run. Headsets and helmets are mandatory for me. Assuming they all work well, I will need to depend on the tach for shifting, or at least keep it under the redline.

I will not be ready for the 2016 race, but the 2017 race is a no-brainer.

Ratty wrote:Skuzzy, The length of time it takes to build is the gestation period. Firing it up for a spin down the street is birth so what is 'this'?

Definitely in the "gestation" period. The frame is bare, right now, as I have it in a jig so the brackets for the suspension can be accurately placed.

Elliot wrote:The short wheel base occurred to me earlier, but in a different context -- Ackerman. The shorter the wheelbase, the more the spindle arms need to be splayed out, and there may not be room in the wheels. ...Unless you can fit the rack behind the spindles. (Some cars have the rack on the firewall, which is actually a great idea if the proportions of the car are suitable.) Where is your rack?

(I'm enjoying this refreshing of dusty knowledge. Somewhere here I have a terrific book on chassis design by Mike Costin (of CosWorth). Folks like Costin and Colin Chapman had this all pretty well figured out by 1960, methinks.)

Had no choice on rack placement. It is just in front of the spindles. In that small area, I have to contend with an oil cooler, radiator, steering rack, and fan. I tried my best to get that thing at 90 degrees to the spindle arms so there would be no angular displacement as the wheels move up and down. As it is, I have 1.5 degrees of arc. Not a lot, but with that short wheelbase it is enough to be a little unsettling.

I am still playing around with the front suspension. We make make some new lower control arms to remedy the deflection issue. I'll look hard at it when we complete the rear suspension.

Elliot · Post by **Elliot** » Mon Dec 21, 2015 3:03 pm

Hmmm.... I may have lost my train of thought somewhere around Chattanooga. Are you talking about bump steer? My rusty brain hadn't even thought of that yet.
I was wondering about tire scrub in tight corners, if you cannot get close to ideal Ackerman geometry. I wasted a lot of rubber off my first roadster before I mustered the courage to bend the spindle arms with heat. ...And figured out to fabricate a fixture to bend them to. Narrow tires, heavy engine and power steering -- I didn't feel anything, but one day a friend who was right behind me said a left black streaks on a tight street corner.

Skuzzy61 · Post by **Skuzzy61** » Tue Dec 22, 2015 4:19 am

Elliot wrote:Hmmm.... I may have lost my train of thought somewhere around Chattanooga. Are you talking about bump steer? My rusty brain hadn't even thought of that yet.
I was wondering about tire scrub in tight corners, if you cannot get close to ideal Ackerman geometry. I wasted a lot of rubber off my first roadster before I mustered the courage to bend the spindle arms with heat. ...And figured out to fabricate a fixture to bend them to. Narrow tires, heavy engine and power steering -- I didn't feel anything, but one day a friend who was right behind me said a left black streaks on a tight street corner.

I misunderstood you first. I WIN! WOOOT!

Bump steer: There are two ways to get bump steer. If the pivot point of the tie rod end is not in the same X (left) and Y (right) plane (looking from the front of the car). The second way is to have the tie rod not located in the same Z (front/back) plane as the spindle mounting point. The second one is my problem. The mounting of the rack is ahead of the spindle mount point. It creates an arc which is not parallel to the arc of the wheel travel. Thus bump steer.

And no, I cannot implement a perfect "Ackerman" geometry. Like many, I compromised in favor of high speed handling, and will make do with the scrubbing at low speed. In other words, I depend on a bit of body roll to reduce the scrubbing.

Cobras are tough to get the suspension bits right. So little space to work in and still cram so much into it.

Elliot · Post by **Elliot** » Tue Dec 22, 2015 9:05 am

Even so, you are in great shape. In "my field" of street-driven hot rods, I have seen some grotesque geometries -- cars that would "change lanes from running over a pebble" (if they had any suspension travel worth mentioning).
Carry on!

Ratty · Post by **Ratty** » Tue Dec 22, 2015 9:08 am

File this under, 'learn something everyday'. We had to climb under the 81 Mercedes and wire the muffler up just to get it to the muffler shop. They rehung it with 2 mazda rubber donuts. $24 dollars and 15 minutes later we're good for another 200,000 miles. So easy.

Skuzzy61 · Post by **Skuzzy61** » Tue Dec 22, 2015 10:06 am

Actually, I had an epiphany (clean up on aisle 12,....STAT!).

If I cut 2 inches off the frame horns I can move the rack directly in line with the spindle tie rod mounting points. It means I will need to fabricate a different mount for the radiator, or get another custom one made which is 3 inches shorter. Hmmm,...would need another set of core tubes and make it a bit wider.

That might just work. I'll need to run the thermal equations to make sure there is sufficient dissipation of engine heat, but I think I can make that work. Off to order some metal and more cutting and grinding wheels!

Skuzzy61 · Post by **Skuzzy61** » Tue Dec 22, 2015 12:42 pm

WOOHOO!

Just got a Christmas present! New Wilwood rotors and calipers for the Cobra! SWEET! 12.19" of cross drilled/vented goodness clamped by six piston calpies up front and four piston calpies in the rear!!! Now to get rid of the Baer stuff!

WEEEEEE! The Wife unit is sooo cool! I think I'll keep her! I mean, 20+ years together is just a long test drive,...right?

One day, I'll have to get serious about it.......NAH! lol!

Elliot · Post by **Elliot** » Sat Dec 26, 2015 11:43 am

As a simplified explanation of your thermal equations.... When facing a choice between a wider radiator or a thicker one, go with wider. The most efficient radiator has only one row. Each additional row behind the first receives air that is warmer than the incoming air, so can remove less heat from the water.

On my second roadster I built a long pointy nose for the look. That left a rather small cross section for the radiator. So I commissioned a 5-row radiator.
It didn't work worth a hoot, and that was with only a mild Chevy 283.
I bet the 5th row did nothing but add weight to the car.

More rows also add restriction to air flow, making even the front row less efficient.

Carry on.

Captain Goddammit · Post by **Captain Goddammit** » Sat Dec 26, 2015 5:32 pm

To simplify even further, when building a hot rod, the old hot rodding adage "too much is not enough, and when in doubt double it" is well applied to radiators and fans. Especially with old flatheads, Caddy 472 - 500s, or anything that makes a lot of power.
In the diesel truck world, cranking up power level is easy, it's ALL about how much power you can cool.

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