89 Corvette Mostmint #39

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Feb 06, 2020 2:15 pm

GMJohnny wrote:That 13.90 is impressive. I didn't think it would be that fast. My stock C5 turned 13.65.
What gears does the Vette have that keep it at 95 MPH in the quarter?

GM


Rear gear in my plain Jane automatic is 2.56. Even with the cage mine should end up 500 lbs lighter than stock no to mention reduced exhaust backpressure so with any luck we'll be in the low 13's!
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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Re: 89 Corvette Mostmint #39

Postby Basement Paul » Thu Feb 06, 2020 8:11 pm

You'll be the fastest in a straight line, not by a little, in the champ car races. And at least as good in the turns.

-BP

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Feb 06, 2020 8:15 pm

I was looking for pics of C4 roll cages - so I thought about the original Corvette Challenge series cars and came across this:

https://www.barrett-jackson.com/Events/ ... R-10-19423
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Thu Feb 06, 2020 10:54 pm

More looking found tube weight info

1.75" x 120" wall DOM weighs 2.089 pounds/foot of tube length. The 1.75" x .095" wall DOM weighs 1.679 pounds/foot (19.6% lighter and about the same amount cheaper). The other choice for this weight is 1.5" x .120" wall DOM, which weighs more at 1.769 pounds/foot.

From this site: https://www.vorshlag.com/forums/forum/v ... one?t=8341

Also: rear glass came in at 46 lbs
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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Re: 89 Corvette Mostmint #39

Postby Basement Paul » Fri Feb 07, 2020 6:40 am

How about chrome-moly? It's a little more money, but certainly less weight.

I like the stripe on the hood of that Challenge car. Big stripe into a bowtie. Vintage 90's stuff.

-BP

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Re: 89 Corvette Mostmint #39

Postby Fred32v » Fri Feb 07, 2020 11:05 am

That is quite a build.
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GMC Canyon Crew Cab Short Box 4x4 V6!

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Fri Feb 07, 2020 1:07 pm

Fred32v wrote:That is quite a build.


There is a ton of great info in that thread, I will be reading it again to get specifics
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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C4 Cage Research and Design Proposal

Postby MostMint » Sat Feb 15, 2020 12:37 pm

I will start another thread for this but for now I'm posting it here so I can edit it at any time as thoughts come to me

Post #1:

Overview:
Based on ChampCar rules and interest of safety, Mostmint Racing proposes a roll cage design for a C4 Corvette.

Contents:
Problem Statement
General Design Proposal
Main Hoop Proposal
Halo Hoop and Front Legs Proposal
Door Bars Proposal
Seat Configuration Proposal
Remaining Details Proposal
Reference Material
Timeline/Status

Post #2:

Problem Statement


The Vette cage is not going to fit the typical cage configuration described in ChampCar rules, and typical cage designs (approved by various sanctioning bodies) do not provide adequate structural integrity

1. The floor comes up directly behind the rear seat, meaning the main hoop cannot practically be full length
2. With a shorter main hoop, the door bars cannot be attached to the main hoop
3. With a flat seat slider (about 1”) and an aluminum seat my helmet clears the roof by less than 3/4”
4. My helmet is above the highest point attainable for the main hoop in the rear
5. The design of the car has the passenger compartment getting more narrow as it gets closer to the roof, which means my helmet is very close to the targa top frame on the left side of the helmet – putting the halo hoop will be in the same or closer proximity
6. The factory chassis uses a premium grade material in the rollover protection between and connecting the B pillars
7. The high point in the interior is directly behind the top of the windshield and the entire roof line slopes down from there
8. Typical designs attach door bars to the floor behind the driver seat which does not provide adequate side impact protection. Pre-fab kits attempt to fit the traditional main hoop on the flat floor surface behind the driver

<pic 1> picture of the Vette silhouette *
<pic 2> picture of the Vette blueprint structure *

General Design Proposal

1. The halo hoop is going to be above the main hoop
2. The factory rollover protection will not be cut to put the main hoop above the driver's head. It is considered an extension of the main hoop, and the main hoop will be within 1/4” of the rollover protection on the roofline. Top of drive helmet to be 7/8” below the top of the factory rollover protection
3. The halo hoop and top portion of the front legs are going to be outside of the original designed structure of the car
4. Where the door bars typically connect to the main hoop, they will instead attach to flat plates secured to subframe of the car
5. There will be one additional bar between the front center of the halo hoop and the center of the rear main hoop

Post #3:

Main Hoop Proposal

Plan A:

Put the hoop under the factory rollover protection – keep it within 1/4” along the top and attach the sides with gusset plates.
Cut through the fiberglass to get to the subframe and weld mounting plate to that

<pic 3> Vorshlag main hoop to roof bar

Plan B:

Put the hoop directly in front of the rollover protection
Cut through the floor in the subframe area just before the floor goes up behind the driver and put mounting plate there
Note: Based on our measurements this will not provide adequate clearance to the helmet, and if we do put it here the driver seat angle will have to change quite a bit so we are NOT going this route.


Post #4:

Halo Hoop and Front Legs Proposal

Eliminate the targa top mounting brace for helmet clearance on the left, and possibly for main hoop clearance
Mount the fiberglass top to the cage
Install an extra bar along the roofline in the center of the car from the halo hoop to the main hoop

Plan A:

Front legs of the cage will run outside the A pillar up to the halo hoop. Halo hoop will also be mounted out
Attach front legs to A pillar with gusset plates
Front legs to mount to subframe at top of rocker panel/kick plate area. Will have to cut through the fiberglass to reach the subframe
The halo hoop will be located above the rear main hoop and the bars will have a small bend to come down and attach to the main hoop

<pic 4> Vorshlag front leg pic *
<pic 5> possible example of XP Motorsport C5 with bars going up and center bar *

Plan B:

We can move the seat over enough to the right to get adequate clearance and the halo hoop will run in the same location as the targa top frame. Note: With a 7" Kirkey style seat there is not enough room to move the seat to the right without hitting the tunnel or extensive modifications to make the seat smaller so we are NOT going this route

Note: could be alternatives here depending on the final decision of the main hoop.

Post #5:


Door Bars Proposal

Plan A

Typical installations I have seen attach these bars behind the driver seat on the angled floor plane, instead of the main hoop. The issue here is that the floor is thin metal and may crush in a side impact.

Our proposal is to cut open the floor in this area and attach to the subframe, which is much sturdier and should do a better job support the door bars in event of a side impact.

<pic 6> inadequate side door guard design *
<pic 7> pic of where the plates/side bars will attach to subframe (still need to cut floor and take this pic)

Plan B

If we can get adequate leg room we can put the seat further forward, use typical rear hoop and just attach to the rear hoop

Post #6:


Seat Configuration Proposal

My tallest drivers are 39” tall with helmet in the seated position
We have large height variations we need to accommodate 5' 4” to 6' 3” so we will be using an adjustable seat
Current plan is to use an aluminum Kirkey 17” or similar and have drivers use inserts for adequate height, length, side support or comfort
We will fabricate adequate brackets to hold the seat in place and connect to the sliders

Current adapter slider configuration is just under 1.25” tall and fits on stock moorings. We plan to use stock mounting locations.


Post #7:


Remaining Details Proposal

1) The fifth belt mount will need to be fabricated as it appears the location where it would attach is fiberglass
2) The floor is fiberglass below from under the pedals to the front edge of the seat. I would think metal would provide better/extra protection

Post #8:


Reference Material

Sources of information

Robert Brown XP Motorsports – recommended by Jay Mauney ChampCar Technical Director
Mark McMahan rollcageguy.com – the guy for race car cages in NE Ohio
Vorshlag Motorsports – amazing detail writeup on a NASA legal Corvette build
Lots of time measuring and looking at the car


Timeline/Status
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Some roll cage pics

Postby MostMint » Sat Feb 15, 2020 12:44 pm

From a Vette racing in ChampCar:
0502.JPG

0511.JPG

0510.JPG

0513.JPG


From a Vette that ran SCCA ITE - Nonnemaker
33 Vette 8.jpg

33 Vette 4.jpg


From Vorshlag Vette built to run NASA
V04.jpg

V07.jpg

V with driver no door.jpg


"blueprint-ish" diagrams
84Vettesteelframe.gif

C4structure.jpg
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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Fred32v
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Re: 89 Corvette Mostmint #39 (Parts Car)

Postby Fred32v » Fri Mar 13, 2020 8:53 pm

32V and the jimmy spent Friday the 13th with the MintOne.

Completed the Saturn parts car stripping and push it out to pasture.

He found an exact match to the Corvette Race car and had to have it.

one.jpg
Fun loading up, does not run.

two.jpg
Twins.

three.jpg
Out with the old, in with the new.


The beat goes on!
Fred32v
GMC Canyon Crew Cab Short Box 4x4 V6!

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Wed Apr 15, 2020 8:55 pm

Progress has been slow on this car due to countless other car projects - scrapping teal #2, acquiring Vette #2 and getting it running and into storage, and prepping the green Saturn.

However I did cut open the floor to identify places to mount the cage, made cardboard templates, took pics and completed my proposal. I also acquired the metal and had Kurt cut the pieces from flat stock

The proposal was submitted to ChampCar last week and it was approved today.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Wed Sep 02, 2020 8:31 am

Work resumed on the car this past weekend.

The first issue to address was the fact that it would barely run. After I spent a bunch of time vibrating the car by cutting out fiberglass and metal, to provide access to solid frame to mount the main hoop and the door bars, the car decided it would not run.

I quickly traced the problem to lack of fuel pressure. Change of fuel filter and fuel pump did not fix the problem. Somehow I learned that the thing would run if the fuel sending unit was not bolted down, which I assumed was due to pinching the in tank fuel screen. This was in May and I set it down as I was having serious race car project burnout.

This past weekend I went back to work. I started by changing to a new fuel tank screen, reconfiguring it's location, evolved to blowing out the lines again, cleaning the tank inside, fresh fuel, replacing power relay, checking the fuse, confirming power and ground at the connection to the sending unit, to the plug for the fuel pump. Three different pumps and none could get over 20 PSI. After a while of cranking, I upgraded my testing equipment, using my fuel pressure gauge and creating a switched wire to get +12v to the G port on the ALDL diagnostic terminal inside the car. There were several phone consultations with people.

Eventually I came to the conclusion that there might be a bad ground - like enough to power things but not good enough to let the amps through. I read the ground wire for the pump connected inside the car near the rear interior light. All my lights are long gone but figured I could find it. Sure enough I had disconnected a ground wire from the B pillar to avoid cutting it as I was working on the floor. I am still quite confused as to how it worked at all.

Next goal is to get the roll cage mounts fabricated and welded into the car, followed by install of the main hoop and permanent mount of the racing seat.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Fri Sep 04, 2020 4:39 pm

A tale of two gauges.

The electrical gauge was way off and eventually quit giving me a pressure reading so I went to mechanical and Obtained a replacement sending unit for the electrical.

So today I started it cold and got a reading on the mechanical. 30 minutes later the electrical was installed and I took a reading with it.

3361FDD9-98A1-4612-B06A-FBF1395C1C04.jpeg
F8FDE3EA-2EF0-42DD-830D-FE790B2CB76D.jpeg


Which one is right? Ugh
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Wed Dec 09, 2020 8:08 pm

DE5F16B4-3B2C-4DDE-96EC-B2D6D635B3E0.jpeg


DC211B7E-9C5A-4364-A456-AB6C9D654768.jpeg


Lots of progress since last update. Biggest is roll cage which is at least 2/3 done. Still need door bars, dash bar, should belt bars. Also going to have one bar inside front to back at center of the targa top.
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]

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MostMint
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Re: 89 Corvette Mostmint #39

Postby MostMint » Sun Dec 13, 2020 9:22 am

• Roll cage:

o Roll cage about 2/3 done: Base plates are fabricated and welded in. Main hoop, main hoop cross brace, front legs running from near A pillar base up to main hoop, halo hoop, back supports for main hoop are fabricated and welded in
o Fabricated the car to fit the cage also about 2/3 done: Removed rear hatch, fabricated new attaching hardware to allow install with main hoop in place. Temporarily removed fiberglass panel covering the B pillars and top of factory main hoop – trim this panel to accommodate roll cage bars. Cut access holes in the main hoop to allow proper weld of roll cage bars, and subsequently welded them back into place
o Other details: Painted the bars in the sections that will be hard to access once installed. Much time spent cleaning metal to prep for welding, and cleaning up metal from cutting and grinding. Remove trim from targa top and A pillar
o To do: Door bars, dash bar, seat belt bar, extra top bar need fabricated and installed. Fabricate method to attach targa top to the roll cage since stock brackets removed to fit roll cage. Fabricate covers to close up the holes in the fiberglass where roll cage is now attached to the frame

• Electrical – addressing minor issues

o Replace low coolant sensor, though light seems to be coming on intermittently
o Fix fuel gauge sending unit
o Troubleshoot factory engine temp gauge. It was jumping around. Root cause has to be ground in the wire, since the sending unit was removed in 2019
o Move aftermarket temp gauge sending unit into intake manifold directly next to factory ECTS for ECU – keep wires from hot exhaust, better read on coolant temp that ECU is reading. Engine fan kicks on automatically at 218
o Removed 8 non essential fuses from the fuse box, eliminate wires associated with those circuits – most were just pigtails left over from prior wiring cleanup

• Other

o Install factory power steering cooler
o Measure for and obtain engine and transmission oil coolers
o Obtain a stack of spare body panels and misc from an 86 Corvette
[quote="Basement Paul"]Is that a mint rocketship on the hood?? :shock:
-BP[/quote]


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