Author Topic: Bad Roadster to Good Roadster  (Read 13517 times)

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Offline Skip Pipes

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Bad Roadster to Good Roadster
« on: November 21, 2015, 05:33:02 PM »
You’ll probably think I’ve dramatizing this a little.

If I’ve left something out, Nathan Stewart will chime in or whisper Alzheimer’s.

You’ve seen the build diary and cheered the madness of a roadster.
http://www.landracing.com/forum/index.php/topic,6794.0.html

After 5 years of building it’s finally finished (relative term).  I was tired, enlisted Nathan Stewart to wire the car and tune the EFI, then I asked him to drive it (he had experience).
 
Here is how we started with the new car in 2014.
The car weights 3150 with driver
Weight distribution is 40% front / 60% rear
Were down to zero % cross weight
Toe-in 1/8 inch
Front tires 24 inch Goodyears
Rear tires 28 inch Goodyears
Torsen differential

In early May 2014 we rolled out to El Mirage for a test day. Braving the elements Nathan ran it up to 60 mph and noticed the car had a pull to the right. Satisfied with the system checks we put the wind to our back and made a 2nd gear run, which went well, however now the car now pulled to the left. Hmmm, changes to come!

We talked to the guru’s, all of them, the advice was consistent, and everyone had a differing opinion!
Change everything! Add weight, Swap the Torsen differential out for a spool, or open diff, go solid on the rear suspension, change the steering, raise the car, and take it to a computerized alignment shop!

A cafeteria of options, what to do?

I borrowed electronic scales, then promptly bought my own, squaring up the chassis (again) and balancing the cross weights.

Never got to run at the May El Mirage, we were fired up, strapped in, at the line, next car to run, when wind stopped the meet.

We ran June, got it up to 150 MPH, it was nervous as a pig in a bacon factory.
 
Guru’s back on the job, consensus was unanimous, change everything!   
Investigation revealed rear axle was bound up, no effective suspension action. The culprit, a self inflected problem, I tried to run 28” Goodyears on the rear (less costly to replace) than my 30” Mickey’s, which the car was designed for.
 
High dollar fix, new 30 Dunlops, a better choice for El Mirage. With compliance, decided to up the rear spring rate to a 700 lb/in.

2nd issue, every mail order Heim was junk, sloppy after 2 runs, replaced all with quality pieces.

Last, off to 4-wheel alignment shop.
 
Rained out for the July meet. Disappointed, we tested again, didn’t feel the car was stable enough to take to Bonneville.

For September race, 3 changes (I know) pulled the Torsen Posi for an open differential. Swapped the front Goodyears for grooved M&H’s, upped the rear springs to 900 lb/in. Tested again and the car felt better, but not great.

Gurus were clamoring for weight, and/or a solid rear suspension, who am I to argue, some have cars that run faster than mine.

So weight it was, added 250 lbs lead in front of the rear tires. Also physically added another 100 lbs steel plate directly under the drivers butt. He’s a health boy; this balanced the car L/R.

Again better, but not great. Were up to an unstable 150!!!

For October went solid on rear, got a spin tag. WTF?

For November added a spool to rear axle, rake to the chassis, added 200 lbs lead in rear. Car ran dead straight until it snap-spun. Made 2 more passes, right up to the nervous point, 150 mph, called it a year.
 
What did we learn this year? These cars take a lot of hard work to run, and I’m not as clever as I though.
The car does what it wants to do. But I have my theories on updates to make it handle.
 
2015

For 2015 I concentrated on the front end of the car, my ideas alone.  Cut the front apart, added conventional hot rod buggy spring, moved shocks to conventional hot rod position. Added additional 250 lbs over front spring. And, put the rear suspension back on with 1100 lb/in springs.

May 2015, rained out!

June 2015, new front end, handling not improved, sobering experience.

July, went solid on rear, built 120 lb new rear weight bar, back to alignment shop, handling not improved.

At this point…. I was apoplectic, highly irritable. I was determined to beat the gremlins off this car. A friend came over (he previously owned a fast roadster) and said, have you considered EVERYTHING in the front suspension? I hadn’t.

Being irritable, un-distracted and focused, I was determined to change everything, at once a last ditch move. So, I vented the cockpit cover, vented the engine side panels, and added 4 large vents in the rear deck lid.
 
Pulled the complete steering out of the car, from steering wheel to steering arms, everything in between. Added a new Corvair, hot rod drag link steering system, new steering shafts.  Ripped the front suspension apart, cut the mounts apart, built a custom, stiff, front spring from 2 springs. Repositioned the front shocks. Aligned the car myself.

September 2015, car ran straight on 1st pass @185 mph. 2nd pass @190 mph. Finally!

For October, needed to add acceleration, decided to go with a lower gear set. This required pulling the spool, adding a Detroit Locker. Drained the recent rear weight bar of lead shot, added molten lead (100 lbs additional).   

October, rained out, good I needed a rest.

November 2015 – ran 206 mph, qualified for the 200 mph lane at El Mirage.
Video (3.28 min, turn sound off if you don't like the music)
https://www.youtube.com/watch?v=S-cBfHoCM2A

Skip's Garage
Builder of the SUNBEAM ALPINE Police Interceptor

Offline Frankie7799

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Re: Bad Roadster to Good Roadster
« Reply #1 on: November 21, 2015, 05:50:46 PM »
Congrats Skip and Nathan! Glad to hear things went so well at this last meet. Was nice to meet you guys in June. See you next year!

Offline Elmo Rodge

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Re: Bad Roadster to Good Roadster
« Reply #2 on: November 21, 2015, 06:01:49 PM »
Good job Skip. Not bein' a quitter sure pays off, huh?  :cheers: Wayno

Offline Dynoroom

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Re: Bad Roadster to Good Roadster
« Reply #3 on: November 21, 2015, 06:49:46 PM »
Great Skip, Nothing to it!   :evil:

I'm glad to see things finally going your way.    :cheers:
Michael LeFevers
Kugel and LeFevers Pontiac Firebird

Without Data You're Just Another Guy With An Opinion!

Racing is just a series of "Problem Solving" events that allow you to spend money & make noise...

Offline wobblywalrus

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Re: Bad Roadster to Good Roadster
« Reply #4 on: November 21, 2015, 08:45:02 PM »
It sure was a lot of work.  The positive aspect is that you learned a lot more than if it would have worked nice from the start. 

Offline SPARKY

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Re: Bad Roadster to Good Roadster
« Reply #5 on: November 21, 2015, 08:53:54 PM »
congrats buddy-----think skinny to Drive!!!  gettin 'er done   :cheers:
Miss LIBERTY,  changing T.K.I.  to noise, dust, rust, BLUE HATS & hopefully not scrap!!

"Security is mostly a superstition. It does not exist in nature, nor do the children of men as a whole experience it. Avoiding danger is no safer in the long run than outright exposure. Life is either a daring adventure or nothing."   Helen Keller

We are going to explore the racing N words NITROUS & NITRO!

Offline Rex Schimmer

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Re: Bad Roadster to Good Roadster
« Reply #6 on: November 22, 2015, 01:47:50 AM »
So Skip, after beating this thing to a pulp what part of all of the things you did on the last mod had the biggest effect? I was a Jacks last Friday and heard that you went 206 and it seemed that there were a ton of reasons that your car "suddenly" became a straight arrow, but no one knew all of the things you actually did.  The general thought was that it was going to the new steering box, what do you think?

Rex

PS: A real BIG CONGRADULATIONS!!! on going 206, I can't think of anyone that has worked so hard with such a potent combination to break the 200 mph mark. May the records begin to fall!!
Rex

Not much matters and the rest doesn't matter at all.

Offline tauruck

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Re: Bad Roadster to Good Roadster
« Reply #7 on: November 22, 2015, 05:17:33 AM »
Way to go Skip.

Well done man. :cheers: :cheers: :cheers: :cheers: :cheers: :cheers: :cheers:

Offline Skip Pipes

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Re: Bad Roadster to Good Roadster
« Reply #8 on: November 22, 2015, 01:27:50 PM »
Rex

The magic bullet WAS the steering box, the biggest, final culprit. Could have reversed order of improvements, backed into the same results, I think.

Frankie - also good to me you

Elmo - Yep, we hung tough.

Mike - Haha, as you well know!

Wobbly - Yep, building another Roadster would be easy now!

Sparky - thinking skinny just to get healthy, watched myself in the video and said; who is that?

Tauruck - Thank you
Skip's Garage
Builder of the SUNBEAM ALPINE Police Interceptor

Offline Glen

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Re: Bad Roadster to Good Roadster
« Reply #9 on: November 22, 2015, 02:10:01 PM »
Skip,happy for you, now time for a rest and to make other refinements for next year, really enjoyed the build over the them past years. :cheers:
Glen
Crew on Turbinator II

South West, Utah

Offline John Burk

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Re: Bad Roadster to Good Roadster
« Reply #10 on: November 22, 2015, 02:21:13 PM »
Skip
Was it friction in the old steering causing the problem ?

Offline Skip Pipes

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Re: Bad Roadster to Good Roadster
« Reply #11 on: November 22, 2015, 02:35:48 PM »
Glen - yep, I need a rest. At least I don't have to cut the car apart this winter. Time to add HP and see whit it will do.

John - It was bump steer. The car only settles 1 inch at speed, but the steering input from the old system created a steering oscillation, to the steering arm, as the chassis settled.
Skip's Garage
Builder of the SUNBEAM ALPINE Police Interceptor

Offline RebekahsZ

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Re: Bad Roadster to Good Roadster
« Reply #12 on: November 30, 2015, 11:12:04 PM »
What style of steering did it have before you switched to the Corvair box (am I right to assume that the Corvair box had cross-steering)?

Offline Skip Pipes

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Re: Bad Roadster to Good Roadster
« Reply #13 on: December 01, 2015, 09:56:07 PM »
It had a Unisteer Cross Steer R&P, which is now removed. I originally was planning on a Vega cross steer, but I selected the Unisteer instead as it seemed like a good, precise alternative. The Corvair is a drag link system.
Skip's Garage
Builder of the SUNBEAM ALPINE Police Interceptor

Offline jdincau

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Re: Bad Roadster to Good Roadster
« Reply #14 on: July 17, 2016, 01:54:05 PM »
Skip's car ran 205 today, set a record and got Nathan Stewart into the dirty two club. Well done!
Unless it's crazy, ambitious and delusional, it's not worth our time!