Author Topic: Mid- Engine Modified Sports  (Read 788498 times)

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Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1830 on: September 06, 2021, 10:14:03 PM »
The saga continues. My friend Wayne Luddington came over at 9 AM this morning to help me load my car on the trailer. Wayne is an old drag racer and flathead engine builder who is riding up with me and has volunteered to help. We were ready to roll the car out of my shop and on to my tilt trailer. I put the transaxle in neutral and we both pushed the car backwards toward the open door, just as I have many times before. This time the car wouldn't budge! Arrrggghhhh. We checked the gear- neutral- and tried again- still stuck. What's going on? This never happened before. We put a jack under the rear and raised the rear tires off the ground; the left tire would turn by hand but not the right. Hmmm. We pulled off the RR wheel and now the hub would turn. Something was wrong, maybe the brake pads were jammed against the rotor by a stuck caliper piston. We pulled the caliper off and pushed the pistons (there are 4 pistons in this Porsche caliper) back with a c-clamp and things looked normal so we re-installed the caliper and re-torqued the wheel studs. Same thing!

It was clear that something was causing drag when the wheel studs were tightened when we put a stack of washers on each wheel stud and torqued then. This eliminated anything from the wheel & tire. We could see that the pads were well clear of the rotor so that wasn't where the problem was. I had noticed that there was what looked like a shiny spot on the inside edge of the inside pad guide but when everything was bolted up, it wasn't possible to see visually. When the lug nuts were loosened, it sounded like there was a light scraping noise when the rotor was turned slowly by hand. To check for interference I put a strip of blue painter's tale across the both faces of the rotor and turned it. Voila! The tape in the inside had a 1/8" piece torn out. That little edge was hitting the inside face of the rotor when the wheel studs were tightened. We unbolted the caliper again and I ground off the offending piece and the problem was finally solved. The big question is why this happened this morning-nothing has changed that I can think of. ???:?

My wife told be "Race cars and airplanes break just sitting there". My wife is a wise woman.
Regards, Neil  Tucson, AZ

Offline WOODY@DDLLC

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Re: Mid- Engine Modified Sports
« Reply #1831 on: September 07, 2021, 09:37:38 AM »
Neil, Kilroy made Murphy do it!  :evil:
All models are wrong, but some are useful! G.E. Box (1967) www.designdreams.biz

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1832 on: September 13, 2021, 01:46:49 PM »
It's Monday morning and I'm back home in Tucson. We left Wendover yesterday morning and arrived home late last night after an 800 mile drive hauling the car on a trailer. We lost 3 hours getting our trailed fender re-welded in Boulder City, Nevada. The vibration had cracked a weld but Sparc Welding worked us into their schedule and we were back on the road.

On Friday afternoon I was in the Short Course staging line ready to run, 4 cars back when the course was closed due to high wind. My crew, Wayne Luddington and Chuck Huber towed me back to our pit and we secured things by taking the canopies off of the Easy-Ups, etc. and left for a quick bite to eat at the Salt Flats Cafe.
 
It had rained a little overnight so we had to dry off the car and get things ready. A throttle sticking problem was discovered but quickly fixed by Wayne and Chuck so they towed me over to the Short Course staging line and we waited, gradually moving up. I suited up, got into the driver's seat and fired up the engine to warm it up. Once at the starting line I pulled on my helmet, tightened my belts, and started the engine once again. The starter stooped down to see me through the windshield, gave the "visor down" motion with his hand and indicated that I could go when I was ready.

I shifted into 1st gear, let out the clutch and felt it bite hard and the car moved off down the course. Since this was only a shakedown pass for a "new car", I had planned to take it very easy at first. Also, since it was going to be only a test session, I had enter the car in the 150 Club class rather than run in B/GMS so I had to keep my speed under 159.999 mph or be disqualified. I shifted into 2nd at only about 5k rpm and still had hard acceleration so I just shifted into 5th gear and let the tach needle climb up to about 4800 rpm. I had marked my tach at 5633 rpm which should have been 150 mph so I thought I was going around 130-140 mph and I held it at that speed through the Quarter. Once through the timing lights I let off the throttle slowly and let the speed drop, eventually shifting into 4th and then 3rd, applying brakes very lightly and then I saw a turn-off and drove over to the return road. Since to chase truck was not going to arrive for a while, I drove back down the return road to get air flowing through the radiator to cool the engine. (since I was in the 150 Club it was legal to drive my car as well as be towed) The coolant temperature was 180F so things looked normal so I drove a half mile back towards the starting line on the return road and stopped.

Wayne and Chuck arrived, they hooked up the tow rope and we headed back to our pit. On the way back we stopped at the timing tower to get our timing slip. A fellow ran out, handed it to Chuck, exclaiming "A perfect run!". We looked at the numbers, 157.45852 mph- much faster that I had planned or thought I was going. Somehow I must have used some wrong data to generate my RPM vs Speed spreadsheet. After getting back to our pit we had a look under the rear bodywork- no oil or water leaks, the coolant level was normal and everything looked fine and capable of making another run.

A serious look at the weather prediction for that afternoon showed increasing winds and rain showers which discouraged us from trying another run; also, if I ran 3 mph faster I'd be disqualified so we decided to pack up and call it a day.

We had done what we had planned on doing.  :-D

Regards, Neil  Tucson, AZ

Offline PorkPie

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Re: Mid- Engine Modified Sports
« Reply #1833 on: September 13, 2021, 01:58:06 PM »
Neil,

now you be on cloud 69..... :cheers:

after all that years finally seeing a proper time slip....

did you picked your C license for this 157 runs?......you can get them at the 150 club from the USFRA....

if not....ask them....sure you got this time slips framed...

now I wait for more from you and your racer...

stay crazy
Pork Pie

Photoartist & Historian & 200 MPH Club Member (I/GL 202.8 mph in the orig. Bockscar #1000)

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1834 on: September 13, 2021, 02:16:37 PM »
Thank you for your kind words, Thomas. Yes, I am still smiling. Prost!  :cheers:

The car felt stable but wandered a bit at high speed, maybe it was just me getting used to the car and the salt surface but I may put a tiny bit more toe-in on the front. The engine had much more power than I was using, I was essentially just cruising through the lights trying not to exceed 159.999 mph. I didn't know about the license so I'll check on it. Thank you for mentioning that.

True to form, all the kids who saw my car called it "The Batmobile". I may have to change its name.

Were you there with Stainless this year? If so I'm disappointed that I did not meet you and get to say "Hello".
Regards, Neil  Tucson, AZ

Offline PorkPie

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Re: Mid- Engine Modified Sports
« Reply #1835 on: September 13, 2021, 02:38:57 PM »
Neil,

nope, I was again back home in Germany as the borders for us tourist from overseas are still closed.....now four years without the salt in the nose.....tough


by the way....if I had been at the salt for the WoS.....you could be sure you have seen me....latest when you was on the starting line at the 150 track for your run.....

to frame you and the racer.....


...and Batmobile.....why not.....
« Last Edit: September 13, 2021, 02:40:53 PM by PorkPie »
Pork Pie

Photoartist & Historian & 200 MPH Club Member (I/GL 202.8 mph in the orig. Bockscar #1000)

Offline jacksoni

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Re: Mid- Engine Modified Sports
« Reply #1836 on: September 13, 2021, 02:39:21 PM »
Neil- I am not sure I have accurate gear or tire numbers for your car as it sits. However, I have seen significant tire growth in high pressure M/T Bonneville tires. That growth could well account for the difference between calculated and actual speeds. Nice job. Now go for that real B/GMS time.  :cheers:
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
 G/GMS-182.144 2019

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1837 on: September 13, 2021, 02:57:54 PM »
Neil- I am not sure I have accurate gear or tire numbers for your car as it sits. However, I have seen significant tire growth in high pressure M/T Bonneville tires. That growth could well account for the difference between calculated and actual speeds. Nice job. Now go for that real B/GMS time.  :cheers:

I think it is just a bonehead error on my part, I need to find out where I went wrong with this simple calculation.

My friend John Horsman, who died last year, was Chief Engineer and eventually Managing Director of John Weyer Automotive Engineering who won Le Mans 3 times advised me that they assumed  4% tire growth at 200 mph in their calculations. I'm running Hoosier road racing tires which should be similar to a Le Mans sports racing tire.
Regards, Neil  Tucson, AZ

Offline jacksoni

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Re: Mid- Engine Modified Sports
« Reply #1838 on: September 13, 2021, 03:05:59 PM »
My above mentioned Bonneville specific tires grew more than that though your number may be in ball park. How much body to tire clearance do you have? Any rub marks? Anyway, nice going.
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
 G/GMS-182.144 2019

Offline gray63

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Re: Mid- Engine Modified Sports
« Reply #1839 on: September 13, 2021, 04:27:49 PM »
Congratulations Neil.
It has been a long road and the quest continues.
Dave Gray

Offline floydjer

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Re: Mid- Engine Modified Sports
« Reply #1840 on: September 13, 2021, 05:28:44 PM »
Well done Neil. :clap
I`d never advocate drugs,alcohol,violence or insanity to anyone...But they work for me.

Offline 4-barrel Mike

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Re: Mid- Engine Modified Sports
« Reply #1841 on: September 13, 2021, 06:36:37 PM »
Excellently done! 

Mike
Mike Kelly - PROUD owner of the V4F that powered the #1931 VGC to a 82.803 mph record in 2008!

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1842 on: September 13, 2021, 06:57:56 PM »
My above mentioned Bonneville specific tires grew more than that though your number may be in ball park. How much body to tire clearance do you have? Any rub marks? Anyway, nice going.

I have a minimum of about 1" clearance between my rear tires and the fiberglass body. No rubbing is evident, Jack.
Regards, Neil  Tucson, AZ

Offline manta22

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Re: Mid- Engine Modified Sports
« Reply #1843 on: September 13, 2021, 09:16:46 PM »
The salt surface was unusually hard and smooth this year. This was only a test run to evaluate the car's performance , not an all-out high speed run. I feel sure that the car will do its calculated 209 mph at 7200 rpm. Maybe next year? When you're 82 years old you keep your fingers crossed!


https://www.youtube.com/watch?v=mZnZ3qRed3k


https://www.youtube.com/watch?v=ysVSfpmNr0E


https://www.youtube.com/watch?v=3nrSbi_DaGM


https://www.youtube.com/watch?v=7H3FZ4gV7qk


https://www.youtube.com/watch?v=bW1PV_TcSxM


https://www.youtube.com/watch?v=Hr5zG5r35C8
Regards, Neil  Tucson, AZ

Offline sabat

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Re: Mid- Engine Modified Sports
« Reply #1844 on: September 13, 2021, 09:59:13 PM »
Congrats! Beautiful pics and video. Sounds fantastic. Cheers, Dean