Well that certainly gives it some perspective!
Well that certainly gives it some perspective!
Oh yeah... when driving a car like a Europa on the street, you need to assume nobody sees you and is out to kill you. Like being on a motorcycle, only with less safety. Seriously - I would either drive with the headlights on or wire in LED DRLs. And also consider adding a 3rd brake like into the body above the rear window.
Otherwise - great progress!!
AngryCorvair, thank you for pointing me to this thread.
Maschinenbau, awesome project, great story. It reads as a good book, a thriller. It has twists and turns, more than one climax, and most likely a happy end :-). And as a bonus, it’s full of useful practical information.
In regards to your brake system:
With your rotor diameters and brake pad shapes and dimensions I would change the Effective Rotor Radius FRONT to 3.7” and REAR to 4.5”.
You deducted 0.5” from both front and rear radii to get ERR. With a friction material height of (roughly) 1.75” in the front and a little less than that in the rear, I would deduct more, did so and ended up deducting 0.85” and 0.80” respectively.
Enter the new values in BrakePower.com and your MC dimensions front and rear are getting closer together. When working with a tandem MC, your goal is to get both values as close to being equal as possible in order to reflect reality.
Now choose the right brake pad CoF and you have a set up reflecting your tandem MC. See https://brakepower.com/share/180e7f5a0e8 But let’s keep in mind that with all the assumed values (car weight with driver front and rear, CG-Height, CoF of tires, etc., for now the calculator results can’t be accurate and are of course only for entertainment ;-).
About your brake pads: For auto-X and public roads you’re not concerned with sky high operating temps, so street pads should work fine. And like you, I use RockAuto (and yes, McMaster!) to get more info. In this case info on friction codes (more on that here: https://brakepower.com/brake-pad-friction-coefficient.htm).
Your front pads will have EE friction code (µ = 0.25 – 0.35), as long as you buy street pads from the auto parts store or RockAuto.
Your rear pads (2006 Avalon) are available as EE, FF, GG and even GH. For your car I think a µ of 0.4 would be good, so let’s go for now with FF (µ = 0.35 – 0.45). You can always upgrade; these pads are all under $30 a set at RockAuto.
Getting the MC bores to reflect the size you have (0.875”) is just a matter of pedal pressure. In your case, 30 lbs will do, but it would be way too “touchy” for most race car drivers, considering “the standard” is 75 lbs for max. deceleration (when all four brakes begin to lock up). But depending on the driver’s personal preference any value is a good one, of course.
If 30 lbs is too light, a change in pedal ratio (1:3 requires 40 lbs and 1:2 requires 55 lbs) or booster delete (modify pedal ratio towards 1:6 or 1:7 and get in the 60 to 75 lbs range) are options.
Thanks for posting your journey. Amazing how fast you work, considering you have a fulltime day job on the side!
In reply to AvR :
It's good to have another brake guy around!
In reply to AvR :
Wow, really insightful stuff here! Thank you so much for such a thoughtful response. I think the light pedal will be great so it better matches the accelerator e-pedal effort (I find this helpful for the quick inputs for auto-x), so I will probably stick with ratio of 1:4. Can always adjust it with extra holes. Glad you are enjoying the project!
Your front pads will have EE friction code (µ = 0.25 – 0.35), as long as you buy street pads from the auto parts store or RockAuto.
What I meant to say was: Your front pads will likely have an EE friction code (µ = 0.25 – 0.35), as long as they are from the auto parts store or RockAuto.
Here’s why: The back plate of Europa front brake pads (FMSI#: D44) is an old model from long before friction codes were mandated by the DOT to be printed on street pads. And as long as there are no new cars brought to market that require D44 pads (don’t keep your breath ;-), the ones made until then will not be coded.
But knowing (thanks to RockAuto) that D44 street pads are either organic or semi metallic and cheap, they will most likely fall in the 0.25 – 0.35 friction range (EE).
In case higher friction D44 street pads are needed, Hawk Performance has the HB118-HPS and HB118-PC that are still considered street pads. Hawk is just one of the many motorsport brake pad brands that carry the D44 in street compounds (and many race compounds too).
Sorry for carrying on this long about small details.
I like the small details being discussed here. I'll bet OP appreciates them, too.
Do carry on.
Indeed, I very much appreciate all the technical details! As an engineer I nerd out over stuff like this.
More brake progress. Booster/MC bracket:
This is the bellcrank mechanism. Not only does it position the booster just above the steering rack, it's also for dialing in the correct pedal ratio. It hangs down from a window in the top of the frame "T" section. It's built very similar to the suspension rockers. 1/2" bolt through some oilite embedded flange bearings. The bellcrank is 1:2.5 ratio, while the pedal is 1:1.6, for a total pedal ratio of 1:4. The 2nd set of holes correspond to another set on the pdeal, which together changes it to a 1:3 ratio in case I want a firmer pedal. I had to weld washers so the booster shackle fit snugly. The brackets were trimmed down from angle section.
I also added tension stiffeners inside the frame cavity, since the booster bracket will want to pull on the front face of the frame.
All hardware for this will be Grade 8 with nylocks when finally assembled. I might go ahead and make a mount for the clutch MC and a pushrod for it. The original clutch was a cable, pulled by the tab on the right side of the pedal assembly. A common mod is to drill a hole through the frame T for a pushrod, similar to what I did with the brakes. Since the clutch MC doesn't have a booster, it will fit under the steering rack. I am planning for the car to retain the automatic initially, so the clutch will be a dead pedal until the manual swap.
Just wonderful to see how you solve one problem after another!
In one weekend the chassis went from this:
To this. Epoxy primer.
And finally, to this. Rust-Oleum gloss black. I really enjoy painting. Looking forward to one of my other favorite parts: brake lines.
Mmmmm flaring hardlines....... enjoy that
I really like this part. Just so satisfying.
The fronts use a -3AN braided hose, so I used a bulkhead AN connector, tube sleeves, and tube nuts to connect the hard line. Everything else is standard 3/16 galv steel hard line and inverted flare nuts.
The first of many lines has been run through the inside of the "backbone".
I went ahead and sourced a clutch MC for the inevitable manual swap, so I'm going to run a clutch line while I'm at it. It will need a custom stand-off bracket and pushrod, of course.
Brake engineer approves of your hard lines. Nice work!
Are you sure the front port on that master cylinder is for the front brakes? Many times they are opposite.
gumby said:Are you sure the front port on that master cylinder is for the front brakes? Many times they are opposite.
Good catch. If it's from a FWD passenger car, chances are the donor was diagonal-split and the circuits are equal volume.
AngryCorvair (Forum Supporter) said:
If it's from a FWD passenger car, chances are the donor was diagonal-split and the circuits are equal volume.
TIL
That's great news because I was just winging it
More great fab work.
IMEO - Best part is your engineering / reengineering it and not just buying stuff...
And appreciate the time it takes to document what your doing.
I'll have to remember it when I come to Atlanta next time, but I have a new LUK 3VZ flywheel I bought to modify for my 1uz manual swap, but ended up buying a pre-machined one for $200 instead. I believe the 3VZ one was around $40 when I bought it, but my current plan is to weld it to an LS crank for a table. If you trade me another flywheel or flexplate I'll give you the 3VZ flywheel since it's junk to me. I think there's some ways to get the Tacoma flywheel to work with a 2GR by only shimming the starter. I also have a spare Toyota master cylinder that's worthless to me but it looks like you've already got one.
GM > MG said:More great fab work.
IMEO - Best part is your engineering / reengineering it and not just buying stuff...
And appreciate the time it takes to document what your doing.
Much agreed
I think I wrote this already but I am predicting this wins in October
I appreciate the vote of confidence, but I have doubts it'll be racing by this Fall. Still a long road ahead, and I'm trying to keep a pace that lets me enjoy the process.
I went ahead and added the clutch master cylinder and pedal linkage, so the manual swap will be easier in the future. This was tricky because I had to angle the line of action away from the brake booster. The MC is for 97-03 Camry/Solara V6, same vehicle that my E153 trans came from. The push-tube is 1/2" with a M10 nut welded to one side and a 3/8-24 on the other. The MC mounting bracket is just a scrap piece of exhaust tubing, some leftover Lotus frame material, and a off-cut of 1" square tube sliced in half.
Had to add more weld-nuts after painting, oops. The frame is already dirty from being stored outside under my deck (don't forget I'm building this car outdoors).
The push tube connects to the same lever used for the original clutch cable. Instead of pulling a cable, now the pedal pushes the push-tube to pressurize the MC. The Toyota E-throttle pedal will hang down above this connection just like the original Lotus pedal.
In reply to maschinenbau :
This is why you never paint the chassis... .
In reply to nocones :
At least he didn't powder coat it.
Painting with Rustoleum has the benefit of touching up with a rattle can!
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