Project Elvira – Intro and Update

[phantomjock]

Been "messing around" some

Figgure its time for an update. With the flares mounted and building the light boxes - I started sand/fill/sand/fill/etc/etc, you all know the drill. Was doing it in the garage and made an absolute disaster of that area, so moved nose and tail outside.
There I worked first with Chopped Strand to do the build up and then fairing compound.


Then lifted the birdcage off the chassis & roll cage to get that out to work:


Built a low body dolly to set the body on - makes the neighbors think there is progress on this effort:


The wheels on the dolly are "playful"


With a cover on it - It even looks near normal.

Hmmm, I may need to forgo the induction cowl for visibility. What do ya think?


With the body off, I can get the garage cleaned up and get back to the mechanicals this week. Hope to report some more progress soon. I've been told by She Who Must Be Obeyed; "Do that bodywork outside - or take it to the shop!" I'll now be at the mercy of the weather.

Cheers - Jim

 

[JPhil]

Hmmm, I may need to forgo the induction cowl for visibility. What do ya think?

No, I think it's fine. It's very visible.

 

[denpo]

Well, this entire build is bonker in an awesome way, but the cowl.... I'm in no way a racer, but wouldn't it be impeding your driving skills?

 

[phantomjock]

Well, this entire build is bonker in an awesome way, but the cowl.... I'm in no way a racer, but wouldn't it be impeding your driving skills?

yeah - I'm thinkin' it would be like: "Juggling Chainsaws with a Blindfold on!"
I may take off the blindfold - while on the track. Can't get old by being stoopid!
Cheers - Jim

 

[Red77]

I like the bicycle wheel placement for the neighbors. ;-)

 

[phantomjock]

So its been 4 years since I've posted on this thread. FOUR YEARS! I looked through all 500 of my threads - and this was over halfway back! I have been goofing off.

Well, She who Must be Obeyed; declared, I had to get some work done on the 'vette before I get to race the SR this season. I've done some and will share what and where I am on it.

WHEELS AND TIRES:
I was using an old set of 17" wheels for all the build. Don't like the huge backspace and wanted to swap out for something else. Cost a big factor, but was looking real close at some custom mini-lite style in a large diameter. In 12 inch width, they were under 500 each.

Also looked real close at the Wide-5 wheels. Liked the approach but only available in 15" - good choice in widths and backspace though.

For tires I kept looking at the used Race Tires and was about to go with 15 inch Formula A tires, 10" front and 12 rears. Damnit. The Wide 5s were not available until late summer. CRAP.

Did the look at Aero/Basset/Bart/etc for Circle track rims and found that Speedway had a special going on their 15x10s for $50 each. DEAL.

But What tires?

Back to JB the used tire king, and I scored a set of 100% Perelli P-zeros in 265/60/15, under 100 each.


(lettering on my set is Yellow - DH model)
All excited we got them loaded on the rims and came home to mount.

More to follow...

I'm such a tease.

Cheers - Jim

 

[mfain]

Jim,

Glad to see you back on it. Now, let's see some progress!!

Pappy

 

[phantomjock]

Pappy asked for more - in Vegas and Phoenix he gets a "dry heat." Not so here in the Panhandle. So, I'm at it but slow. Some of this work was done a few days, well maybe a week ago, but need to get the backlog of corresponding done.

IT WAS A BIG DAY! The tires and wheels finally came in and got mounted. The old rims (bent and pretty messed up) were off to the scrapyard. Now, with the wheels and tires mounted up I was able to put the car (now looking very much like an oversized Go-Kart) finally on the ground. Off the jack-stands where it has resided for the past several years.

While at it, I borrowed my buddy's racing scales to take some measurements, and preliminarily scale the chassis. I weighed the setup - READY FOR THIS? 1879#. No body (birdcage etc.), no interior, no fluids, no driver, radiator etc - but under 1900! Awesome. Front/rear split was 45% front, 55% rear. Maybe went a bit over in moving the engine so far aft? Ahh well. [Add a bigger splitter maybe.]

I really wanted/needed to measure the rake. I had become very concerned that having raised the diff 2 inches, I might have a reverse rake problem, you know - "nose-high." That put me on the quest for drop spindle options. I'll cut to the chase, I opted to go with C7 front uprights over the options. When compared to the C3 spindle, the C7 builds in quite a bit of "drop." But that comes with its own challenges on 15 inch wheels - more on that later (not just mounting brakes.) Rake was good as a Go-Kart. 1 inch nose down, and more available by bumping rear ride height on the springs - maybe.


Then we loaded up the body. Had to get the scales back so missed a more complete weight check - bummer. Now the bad news. I misread the diameter of te wheel tire combo, and at nearly 2 inches larger than the 17s. So when we mounted the body, it was sitting on the tires. ARGHHH! Ain’t hot-rodding fun?!! That will make it very difficult to move. We some 2x4s placed on the chassis made it marginally "pushable." Just needed to get it out of the garage and outside. Eventually it would go onto the trailer, so I could swap it with the SR to get it race ready for this season - or what's left of it.


and the front too:



This would require some heavy thinking, cutting and maybe some fiberglass. Put the final resolution on hold for a few days. One option is build a set of molds like the Greenwood slab-side extended-box rear quarters. I do have the mold I made for the flares in the attic so that is one option. Another, Just cut-and-run, but then I'll have to dodge the coppers. One objective is make it street legal - which is pretty easy here in FL.

I'll work on something else for a bit. More will follow - honest. Maybe tomorrow.

Cheers - Jim

 

[mfain]

looking good! Kind-of looks like a Cheetah in that last photo.

Pappy

 

[rtj]

I went to the used tire site (I think). Did you have to contact them for a list of available tires? Not much listed, maybe I had wrong site. If this is the right site, I may ping them.

https://www.jbracingtires.net/

 

[69427]

I went to the used tire site (I think). Did you have to contact them for a list of available tires? Not much listed, maybe I had wrong site. If this is the right site, I may ping them.

https://www.jbracingtires.net/

That's the guy I bought my 15 inch track tires from. Friendly guy, great service and prices.

 

[rtj]

Okay, Thanks!

 

[phantomjock]

John is a phone guy. He has "people" that will answer email, and may keep the site "warm" but he is the guy.:thumbs:

Today's post in a bit
Cheers - Jim

 

[phantomjock]

Pappy -

yeah I like the Cheetah. Always liked but understad they had some real bad oversteer habits. I copied some of my gullwing mod from it too.

Here is a summary on a topic that is important to my build. Seems like a good place to insert here, just now.

DROP SPINDLES

There have been some questions regarding this in years past, and seems like a number of options are now coming available. One idea that I decided to implement - after a number of posts elsewhere here is using the C7 spindle. It adds a lot of drop over a typical C3 spindle. The bearing is mounted higher in the upright relative to the bearing, and the lower a-arm mounts below the hub, not "inside" like on a C3. I called Tim Savitske to get some ball joint taper details and when we started talking about using C5/6/7 for front end he was very discouraging about the trip down the rabbit-hole. I told him I was mad or insane and it didn't matter. He let me go asking to see how it turns out. BTW he does have a lot of other options, but I was already committed.

Here are some interesting notes from an outfit that makes a variety of drop spindles for other model Chevys (A body etc), maybe you'll find it interesting:

How do I know how much spindle height I need? UMI has a number of solutions to the A-body spindle height problem. Most of them utilize the factory GM spindle and a combination of ball joint heights. We are happy to discuss tall spindle applications as well. Please call the tech line at 814-376-6000 or email [email protected].

½” taller upper and standard height lower – when combined with a 1 or 2 inch lowering spring, this cost effective option helps your daily driver perform better when cornering at everyday speeds. If your car squeals the front tires on exit ramps, this mod is for you.

0.9” taller upper and standard height lower – this option is for the corner carver looking to add almost an inch of spindle height at a very nice price point. A 0.9” tall ball joint setup helps control camber on fast corners without breaking the bank. No modifications are needed to the lower a-arm which makes the UMI upper a very attractive and easy to install item.

0.9” taller upper and ½” taller lower – with a total of 1.4 inches additional spindle height, the 0.9/0.5 package is intended for auto-x and track use. The camber curve is quite aggressive and really helps plant the tire properly during suspension travel. A 1.4 car can use a very mild static alignment and have great grip in the turns. The 0.9/0.5 package is awesome for Pro Tour style cars destined for long trips combined with track duty. A true high performance suspension for sure.

Not associated, just passing along. I bet they might be helpful given the range of options on their web site (but no C3 directly.)

Using a combination of a drop spindle, and tall ball joints, a lot of options open up.

Enjoy. I'll be adding some details on the front uprights early morning.

Cheers - Jim

 

[phantomjock]

So, here we go. I've had my first cup of coffee, and hope I'm ready to type.

FRONT SUSPENSION

The upper a-arms are the SPC adjustables. I've added Howe Tall Ball Joints to work camber gain. Can't say I need to yet, but building it in -- you know -- while I'm at it.

I pressed out the "standard" C7 upper ball joints, and had "slugs" machined for the upper ball joint mount:


If anybody needs some of these, now that the code is run and a fixture made for the cnc you can get a better deal. Just ask and I'll get you the details.

For the bottom of the upright, I drilled/reamed the lowers to meet a 10 degree tapered 6141 ball joint. The ones I chose are rebuildable circle track gear from Coleman Racing.


One of the things Ron Sutton advises is to have a means of adjusting the roll center. These are not the easiest way, but do-able. On the lower control arm, I removed the original lower ball joint and welded in the Coleman Racing "barrels." There is some "slight interference with the transverse spring outer on mount lower arms. This was resolved using a slightly smaller washer.

The Vette Brake lowers needed a mod for the Dual Coil Over adjust shocks as well as drill out the ball joint for the replacements. Kinda' like this:


The real challenges are yet to be faced, brakes and steering on the front. Some fun on the horizon -- I'm pretty sure. You can see I did a bit of a tease in the upright image - the brake bracket. More on that later.

Cheers - Jim

:yahoo:EVERYBODY have a GREAT 4th of July! :yahoo:

 

[phantomjock]

Y'all get a double dose today as I do some catch-up.


STEERING/BUMP STEER & ROLL CENTER

Steering is important - even though so far we have yet to fire the engine. And, the transmission needs some finish work too - so it is more or less a "push-car." With the winch dead, it took us almost 2 hours to get it on the trailer! Wheels go one way, then the other. Push chock the car, straighten the wheels, push, chock. Repeat until complete. Though of using the trailer as an oversized shovel! Grunt, groan and 2 aspirin later the job was done. Then a trip to HF to buy a new winch. (Yet to install - not needed just yet)

Now I can get back on to the build.

Having shoved the engine back 13 inches gave me a lot of space not only for the radiator duct/airbox, but also a chance to think about mounting the rack and pinion in a front steer/upper mount. The front steer was going to present its own problems down low with the transverse spring and the lower a-arms. Building a new K-Member could be a solution - but ohh what a job. So up top it must be. Now what challenges exist there?

I've done a bit of roll center calcs off and on during this build. There is a lot to sort out including Bump Steer, Ackerman, Scrub Radius, etc. You can learn a lot over at Pro-Touring and Lateral-G from Ron Sutton. But at some point I just gotta "cut metal." Well, maybe do some modeling first, but gotta' get going.

I've used a variety of programs and graphics to sort out the "planned" RC and instant centers on the front end. So, with the front raised to reach max droop, I made a quick measurement using a few metal rods. Nothing like trying to get the truth over modeling assumptions:
In this pic you can see the rack is sitting on the chassis arms, and the rods are aligned with the steering arm (tie rod) and the UCA and LCA, and even spot the approximate RC - when at full droop. I wanted to check full droop to ensure the upper mount of the tie rods wouldn't hit the chassis arms. At full compression, I would certainly clear the chassis.

With this information I was then quite surprised. The Grand Am rack is almost perfect width. Some judicious cut and grind on a couple of chassis tabs, and cut the rubber mount on the rack a bit -- and it FIT! At last, a break. (Maybe...)



Now to just work out bump steer and...OOPS! The steering arm on the C7 would put the balljoint right into the tire! ARGHH. (And that is with only 2 inches back space!)

This is the approach I planned, but need to wait on some solid rod ends (back-ordered) to complete. I'd use those to make an offset for the steering joint. Basically look a bit like this:


Most likely adding an offset spacer to get things where they need to be.

These "RACK EXTENDERS" are used a lot in drift cars, so there are so available. Think I'll do some modeling. Back to the drawing board (CAD)!

Ahh, what the hell. I had a sizeable plate of aluminum, so cut out a piece to fabricate a set of Tie-Rod-Extenders. No fancy CAD here, just some TLAR - That Looks About Right. Pappy gets it I'm sure. And more that a few on the board have experienced it too. A run to Fastenal for some sizeable nuts and bolts, and - voilla! I have made the extensions!



Quite nice, even if saying so myself! :thumbs:

BUT... This little bastard has been killing me!



I need a U-Joint:

I've been all over this board, other vette sites, the inter-web and the 39 pages of Karsten's pdf and post. I cannot find the right U-Joint for the rack! I'm connecting to a DD - so that end is GTG-and plenty of options available. Karsten used a 17mm end on his - but that may have been at the 'vette column end - not the rack. It is NOT 17mm, and NOT 3/4" either.

I have had little luck in sourcing a joint. ANY IDEAS?

Meanwhile - everyone have a safe and Happy 4th of July. :bestwishes:

Cheers - Jim

 

[mfain]

Jim,

Woodward has a pretty good selection of u-joints, if you can figure out what size it is. Your tie rod extenders look like they will work, but you will need to calculate (or measure) what that change in geometry does to your Ackermann. A way to adjust Ackermann (if you need to) is to move the rack forward or aft. Where are you trying to get your RC? I use .75-1.0 inch above ground with full compression (splitter on the ground), and I just let the RC be what it is at ride height - you don't corner at ride height so I shoot for the proper dynamic relationship. Fortunately, I don't have a lot of roll center migration with travel, so all is well.

Looking good!

Pappy

 

[mfain]

Jim,

FWIW, I built longer control arms for my Focus track car, which required longer tie rods. I cut the end off the tie rod, had it threaded (14mm, in this case) and got another set of tie rods, cut the outboard ends off, and had them threaded. I then made a threaded sleeve that I screwed the ends of the tie rods into to get the length I needed. I further pinned each end of the sleeve with a roll pin just to make sure nothing moved. This allowed me to keep the Ackermann as it was. Here are a couple of photos.

 

[mfain]

Pappy asked for more - in Vegas and Phoenix he gets a "dry heat." Not so here in the Panhandle. So, I'm at it but slow.........Cheers - Jim

Here's how you handle the dry heat - a 3.7 ton dedicated garage air conditioner...and note the Coors sign. There is an appropriately-sized beer refrigerator in the corner.

 

[BBShark]

Are you using a Grand Am rack in a front steer setup?

I used a steering coupler shaft from a late C4 with my Grand Am rack. They are both the same (rack shaft size)

 

[phantomjock]

Yes - Grand Am in a front steer mated to the C7 uprights.
Thanks for the head's up for a C4 linka. Gives me more to check out.

I'm off to search... Pappy - thanks for the link, but no joy at Woodward.

Others?

Cheers - Jim

 

[phantomjock]

Pappy - I "think" I can make "some" Ackerman adjustments with the tierod extensions. It should effectively be the same as shifting the rack fore/aft. "Fingers crossed!



BBShark - thanks for the tip-- found a piece on eBay - cheap enough - we'll soon know if that is the ticket!


Cheers - Jim

 

[BBShark]

Yes - Grand Am in a front steer mated to the C7 uprights.

Cheers - Jim

Won't it work backwards (turn left and the car turns right)?

 

[mfain]

Yes - Grand Am in a front steer mated to the C7 uprights.

Cheers - Jim

Won't it work backwards (turn left and the car turns right)?

If the Grand Am was a rear steer car, I am afraid you are correct.

Pappy

 

[phantomjock]

Hmmm. Its early this morning - but what the heck, I'll check after breakfast and see if i'm on the quest for a "different" part. I did trial on the setup and was pleased to see both moved correctly. But, I may have missed a key detail. Will know soon enough. I may have some components that will be excess to requirement!

 

[phantomjock]

Added a piece of bar stock to check steering - and both wheels turn! Yep - Just as suspected - opposite of desired. :bomb:
Rather than toss a wrench across the garage - or :banghead:

I went for a walk and sorted out a list of alternatives. (Yes my NEPA training has paid off). Too early for a whiskey.

1. Do Nothing -- No cost but have to learn to steer opposite of where I want to go
2. Fabricate a Bellcrank that with a linkage and rods beneath the rack, effectively "flip" the steering -- easy build - complicated install
3. Flip to Right Hand Drive -- Very interesting, some complications but I have years of RHD experience -- creates a novel look too
4. Rebuild the Rack and "flip the internals" -- may be do-able, may not


5. Buy another Rack for Front Steer -- another OOPS, and bits to sell off
6. Return to "Original Setup" Flip the uprights side-to-side, but complications as per before
7. Make a Gear Drive Box to effectively switch CCW to CW and vice versa --I have some gears too

Well I have made a choice. Some waiting involved, but it will be Alternative #7, Gear Box. This is a trick (again) used by circle track guys, to mod front/rear steer.

Part should be in next week sometime. Simple enough to mount anywhere in the column. "I'd rather be lucky than good!" Just moving sideways--not backwards (just yet...)

When parts arrive later this week, including; new U-Joint,gear box, I'll get that all installed.

Cheers - Jim

 

[BBShark]

Learning to drive it that way would be interesting. I saw a guy that had geared handlebars (so it steered backwards) on a bicycle in Austin once. He would bet people $20 they couldn't ride it across a line about 20ft away. I was hilarious, I saw about 10 people try. No one did it.

I looked at changing to front steer. The appeal of the CTO rack is you can dial in bump steer so well. Couldnt find any CTO front steer racks. But I did consider taking a C4 rack, remove the tie rods and connect a plate that was connected to both ends. Then connect the longer tie rods to that plate (similar to the Grand Am rack plates. I think that is doable as the C4 rack is only about 24 inches long.

 

[phantomjock]

I once did some work on the sailboat steering quadrant. It went over a couple of days, and when we hooked it all up, we went to leave the anchorage. But, the quad was, yep - backwards.

I tried and tried to "get my head around it", then just faced aft and took verbal steering directions. Don't think I'd really try in a car!

I was looking at some rebuilt C4s with just the idea you mentioned. The short 24" makes mounting options better. The I found the other alternative -- and it will be here Monday/Tuesday, and I'll be back at it. BTW the "drop" in that device will help clear the dash roll bar--good thing I have a small wheel.

Cheers - Jim

 

[mfain]

I once did some work on the sailboat steering quadrant. It went over a couple of days, and when we hooked it all up, we went to leave the anchorage. But, the quad was, yep - backwards.

I tried and tried to "get my head around it", then just faced aft and took verbal steering directions. Don't think I'd really try in a car!

Cheers - Jim

We lost an F-15 at Spangdahlem AB when they hooked up the hydraulic lines to the horizontal stabilizer backwards. The pilot, a friend of mine, almost figured it out on takeoff when the flight controls were backwards - push forward on the stick to go up..., but he finally lost it and crashed off the end of the runway. After that, they changed the fittings on the stab actuator so you could not hook them up backwards.

 

[69427]

Are you using a Grand Am rack in a front steer setup?

I used a steering coupler shaft from a late C4 with my Grand Am rack. They are both the same (rack shaft size)

You caught the details I missed.

OP: I'm just curious Is the front steer that big of a plus (given the lack of bushing deflection in your setup). Given that the engine is that far back (making rack packaging easier), does it make sense to go to rear steer mode for even better weight distribution?