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MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster
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Author:  Mnot [ December 1, 2019, 3:02 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

So you think simply adding a friction material will help? Interesting and certainly easy to test. thanks

Author:  Miatav8,MstrASE,A&P,F [ December 1, 2019, 4:42 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

If you meant a dead pedal for your clutch foot, A couple strips of 1/8 steel or aluminum with 4 sheet metal screws is all you need. The heel portion can stick out as needed to fully support while the toe support is minimal but since it screws on, you can always change it later if it is too much, too little, wrong spot, etc. You can add a flange if you don't like the knife edge against your shoe or give it teeth to grip your sole.

Attachments:
mnot dead pedal.JPG
mnot dead pedal.JPG [ 49.46 KiB | Viewed 1544 times ]

Author:  Mnot [ December 5, 2019, 7:47 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

No, not a dead pedal for my left foot but a heel rest for might right foot while on throttle. It feels like I have to keep my foot hovering to maintain throttle, otherwise it wants to slip forward into the pedal assembly. I hope that makes sense.

Author:  rx7locost [ December 5, 2019, 8:23 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

If the pedals are nominally at the same level to each other, a simple 1" square tube across the floor, that your heels can rest against and pivot on might help. Similarly, my passengers liked a piece of wood, lying on the passenger floor that they rest their heels against to prevent muscle strain from holding their feet in free space.

Author:  hfmaxi [ December 5, 2019, 8:59 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

I forgot to save the picture but saw interesting way of doing this that I am planning on using for my build. It was for a bolt in pedal box: just a piece of thickish AL sheet bent at 90deg with slotted holes to mount with the pedal assembly.

Author:  Lonnie-S [ December 6, 2019, 9:51 am ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

You want a heel rest. I've seen some cool ones. One was even adjustable. Maybe check on Pinterist too. That may be where I saw it. Here's one from the UK that goes all the way across. You may want to take the idea and just make a smaller one.

Heel rest ==> https://www.motamec.com/motamec-univers ... plate.html

Cheers,

Author:  Miatav8,MstrASE,A&P,F [ December 6, 2019, 7:03 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

I'd use a block of wood such as a 1x3 that fits snug between the rails and is notched to clear the pedals to test out the best position for something more permanent.

Author:  Mnot [ December 11, 2019, 9:52 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

I wonder if seat angle doesn't affect this. According to UltraShield, the seat manufacturer, the Rally seat isn't intended to have much angle that is why a "bucket" is built into the seat. When I installed the seat I took this into consideration but it feels like I am sitting flat/level on the floor. After final welding, I intend to use sparco adjustable mounts to allow more angle in the driver's seat and provide more thigh support. I am also considering a derivative of MiataV8's suggestion and that is to use some wide grip tape at the base of the pedals to provide grip for my heel.

Author:  Mnot [ December 11, 2019, 9:53 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

On a side note, I am noticing that cold tires (55* ambient) don't provide much grip. I am running 20lbs of pressure in my BFG's. What are you guys running?

Author:  Miatav8,MstrASE,A&P,F [ December 12, 2019, 7:26 am ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

I just noticed your vsusp specs posted in August. Lower the car 1/2 inch as shown and see if it exhibits any issue from the high rc and short swingarm jacking and one wheel bump camber loss. It appears camber gain is at the top of your list anyway as the rc is already high and the swing short. How much can we get away with for the sake of camber gain in roll? gavin

Four, 205-50-16s are a lot of rubber for a 1600lb car to heat up on the street. Thrown some sandbags in for some ground-hugging curb weight! It will lower itself! :lol:

Author:  Mnot [ December 13, 2019, 8:27 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

I have to admit, I don't really know how to answer your question. I realize I have A TON of negative camber gain in bump due to the short upper arms and long lowers. But I don't know how much is too much and how to predict how much roll I will experience. I have some friends in various racing series that I plan to solicit over the holidays to drive the car and provide real world feedback as to what it is doing and how best to compensate/correct it.

Author:  Miatav8,MstrASE,A&P,F [ December 14, 2019, 8:14 am ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

That sounds like a great idea. Let us know what they think. It could be you are not able to generate enough cornering loads to cause jacking with your current hard compound tires and low curb weight. Your numbers were not as aggressive after I added the tire compression below.

My goals:
* an rc below 3 inches to reduce jacking.
* an rc that doesn’t move in Y and X to maintain consistent steering effort /leverage when cornering as the roll angle changes.
* a swing arm at least 90 inches to reduce jacking and aid rc stability.
* adjusted zero neg camber for even tire wear/heating and best traction
* 0.75 deg or less neg camber in one wheel bump for traction under hard braking.
* 1.75 deg or less pos cam in 3 deg roll on the outside wheel, for cornering traction.
Here are your specs from back in August. I switched them to inches from metric and eliminate the neg cam to make it easier to compare. I added rc X and Y and camber left and right to the chart. I selected all labels. I also noticed you have no sidewall compression so I added 0.5” which is typical when inflated to the correct pressure for the load and improved the numbers substantially except for a raised rc. You can enter actual spec measuring loaded wheel from hub center to ground.
gavin
Your specs but zeroed neg cam (adj uca):
1”bump =0.958 deg neg cam
3 deg roll = 1.493 pos cam
Rc height Y = 4.016”, almost flat
Rc lateral movement within 5 deg roll = 0.70”
Virtual swing arm = 64.537”
gavin
Lowered to level lca and moved the ucap around:
1”bump =0.739 deg neg cam (0.219 deg improvement)
3 deg roll = 1.872 pos cam (0.379 deg worse)
Rc height Y = 2.362”, (closer to flat 1.654” lower)
Rc lateral movement within 5 deg roll = 0.32” (42% improvement)
Virtual swing arm = 90.534” (25.997” longer)

Author:  Mnot [ January 26, 2020, 9:25 am ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

Well, I wasn't able to have the guys come over to drive and evaluate the car over the holidays. I have been struggling with the brakes for months! Once bled, they feel good and firm. After a short drive (5-7 miles) of using/testing the brakes, they get soft. Then, when I bleed them, they have a lot of air in the system. The air is only in the front circuit, so I have been remaking each brake line and then retesting. Last night I remade the main feed to the tee and omitted the residual pressure valve to see if it is either the valve, or the flares going to it. If this doesn't work I don't know what else to do. The calipers are new/reman units, and there are no fluid leaks anywhere.

Author:  davew [ January 26, 2020, 9:51 am ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

About the only thing left, is the master cylinder. If the M/C has not been rebuilt, check for rust, or oxide in the cylinder bore. Or it could be sucking air from around the shaft seal. Pull the dust boot and look for signs of weeping. If driving that short of time, if it was a caliper you would see the air in just that side. Davew

Author:  Mnot [ January 26, 2020, 1:42 pm ]
Post subject:  Re: MNot's Bimmer M42 > Getrag > T-bird IRS Haynes Roadster

Thanks Dave, that is the only thing I haven't tried. I just spent the last 2 hours swapping the front calipers with junkyard spares. No bueno :(

The M/C is a new unit from OBP that came with the pedal assembly. I will pull the boot and check for weeping as you suggested.

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