MADJAK's NA8 - 200+HP N/A

[Ice88]

Take it, that its of a different design to the mx5 wheel, meaning you can use the stock one?

[madjak]

Take it, that its of a different design to the mx5 wheel, meaning you can use the stock one?

Sorry didn't notice your post. The wheel is entirely different so no.

Bit of an update:
So I've picked up some new shocks for the rear. They require some modifications to the lower control arm to fit the remote reservoir nozzle. I had to grind a little out from around the shock mount point. I figured I'd also get the blasted and powder coated whilst they were out. I've very glad I did cause they look awesome.



Into these I've installed the Energy Suspension urethane and then instead of the sleeve that came with the bushings, installed my custom bearings. When all mounted up to the car, and without a shock attached, the arms sag down under their own weight. With the stock rubber bushings and no sway bar or shock connected, I could stand and bounce on the hub and it would only just move a bit. Now the arms are free to move. It's nice to be able to tighten the suspension bolts with a big breaker whilst the car is on stands. Normally its a mission to get under the car to get them fully tight. Overall, I'm really happy with the bearings I've made and I think this solution is going to work great. The only question will be how long the plastic bushings last.

Here it is all mounted up. I better paint the rest of the under-guard so it matches the control arms. I can't run my new shocks until I get some lower rated springs, so here it is mounted up with the Cusco Zero 2s.



It's a good photo of my offset bracket to run the stock NA6 caliper on the 11.44" Honda wilwood rotors. I also made up some adjustable sway bar end links. Pretty easy and quick.

For the next event I'm running all weekend down at Collie, which is around 2 hours south of Perth. I take the whole family down there with the camper and stay in the middle of the race track. We can run a practice session on Friday, with a sprint on Sat and track run on Sun so I've mounted up the rear wing for the first time. We'll see if it works!

[NitroDann]

You're a legend, those bushes are a good idea. I wonder what else is available for MX5's outside of hard bushes and tubular arms with spherical bushings?

Dann

[madjak]

I think these are best, cheapest option around... They offer free motion and enough give for the alignment bolts. Also, the wearing part is only a few dollars per bush, not that I'm expecting a high wear rate. I would love to do sphericals but they still wear with time and really are just too expensive. Compared to the Urethane, the friction would be reduced 10 fold at least. Really they are so close to zero friction I can turn the sleeves with my pinky... except where the urethane bushings rub on the sides of the hubs.

Once I've tested them further I'll ask my local machine shop how much run of a five sets. It's been a lot of work to machine the 4140 on my hobby lathe plus I've had to make a few extra due to brain fade... I drilled the centers out to the wrong size. I still have 10 more to make so that I can do the fronts which is around 3-4 hours on the lathe. Its not really something I intend to do again!

[Zabinskii]

I think these are best, cheapest option around... They offer free motion and enough give for the alignment bolts. Also, the wearing part is only a few dollars per bush, not that I'm expecting a high wear rate. I would love to do sphericals but they still wear with time and really are just too expensive. Compared to the Urethane, the friction would be reduced 10 fold at least. Really they are so close to zero friction I can turn the sleeves with my pinky... except where the urethane bushings rub on the sides of the hubs.

Once I've tested them further I'll ask my local machine shop how much run of a five sets. It's been a lot of work to machine the 4140 on my hobby lathe plus I've had to make a few extra due to brain fade... I drilled the centers out to the wrong size. I still have 10 more to make so that I can do the fronts which is around 3-4 hours on the lathe. Its not really something I intend to do again!

shotgun a set ;)

[zossy1]

This is an awesome idea! Where did you get the bearings? What sizes?

One of 26 done.

4140 is fairly easy to machine, it will just take a while. I'll have to buy a few cans of wd40. Everything assembled will fit pretty snug and with the bearing running on the metal sleave giving a nice free rotation. I'll order 50 of the bearings now and start machining the sleaves. It will take a few weeks for the bearings to rock up from Germany.

[Apu]

Excellent! I'm due to replace the bushings in my car in the near future so...if you are going to do this, I'd be up for a set...but question is how different are they for NBs?

[Ice88]

I don't wish to clog your build thread up with sales posts, but I too am interested

Regarding the throttle, think I've worked out a solution will see tomorrow hopefully.

[madjak]

The sizes of the bearings ar 20mm ID 22mm OD x 30mm in length. They are Iglidur G bearings ordered from Germany.

I'm using pealed 20mm 4140 bar stock, cutting it match the Energy Suspension sleeve length and drilling out the center to match the bolts. On the adjustment joints, I'm putting a washer on each end to spread the load. These are 3.2mm 7/8" washers from Masters that I drill out the center.

I think I'll need 3-4 evebts to see how they wear. My concern would be if grit gets in between the bearing and sleeve and causes faster wear. These bearings are designed for wear resistance from dirt but it can't help.

[zossy1]

I'll be watching this closely. Would be an excellent candidate for CNC'ing a bunch of sleeves up, especially if a group buy could be arranged.

The sizes of the bearings ar 20mm ID 22mm OD x 30mm in length. They are Iglidur G bearings ordered from Germany.

I'm using pealed 20mm 4140 bar stock, cutting it match the Energy Suspension sleeve length and drilling out the center to match the bolts. On the adjustment joints, I'm putting a washer on each end to spread the load. These are 3.2mm 7/8" washers from Masters that I drill out the center.

I think I'll need 3-4 evebts to see how they wear. My concern would be if grit gets in between the bearing and sleeve and causes faster wear. These bearings are designed for wear resistance from dirt but it can't help.

[Dweezle]

Id love to buy a set too!!

Sent from my SM-N9005 using Tapatalk

[speed]

Me too!

[madjak]

So, I was thinking last night about my brakes. They are already working really well, however I think I'm getting lots of fluctuations in brake pressure. This is due to the very lumpy cams and me heel/toeing down through the gears under brakes. I could easily add a vaccum chamber to get a more consistent vaccum but then why add weight / complexity? Also after my last dyno tune I ran a couple of events with no check valve in the vacuum line to the booster and didn't really notice much difference, so I doubt I was getting much assistance from the booster anyway.

I think it's time to see if getting rid of my brake booster is good or not. There are heaps of posts querying booster deletes but no before / after results.

Here is my plan of attack:

1) install two brake pressure sensors in the brake lines and run a few events. I'm running the National Hillclimb champs in a little over a month so I wont change anything before then. I'll log the brake pressure (which I bet is all over the place) just to collect some data and verify. I'll be using the ebay specials - 1000psi 0-5v sensors I already have. I have MAP pressure logged already.

1.5) OPTIONAL : install a NB8B booster with 15/16 master. See if a newer booster and less pedal travel will give me better and more consistent feel.

2) Remove the brake booster and fit the existing master to the pedal... some custom fab will be required. I think a spacer plate that will bolt to the firewall with some studs to hold on the master, and a new pin. My pedal is already very firm so I'm happy with the existing travel, so first step will be just the booster delete. Later I can try a larger master, maybe the 15/16" sports or a 1" dual Wilwood.

3) If that doesn't feel right, I'll go modify a pedal box and run dual brake masters with in-car biasing. (Zozzy1 style)

Anything I'm missing?

[Magpie]

Here is my previous ramblings on the subjecthttp://mx5cartalk.com/forum/viewtopic.php?f=30&t=63464

You will need to at least adjust the pivot point for a start. Based on the data I have collected my ITB setup gave enough vacumn to make the booster still effective. A simple vacumn tank will not add that much weight.

Have a look at Zossy1's build, twin masters etc the whole box and dice track only brake setup.

Will follow this and learn!

[greenMachine]

Have you checked that your booster actually holds pressure (ie vacuum)?

If you want to go boosterless, just vent the booster to atmosphere.