Mini tub kits worth it?

Discussion in 'Suspension, Steering, Brake & Wheel Topics' started by vince72, Oct 22, 2020.

  1. badazz81z28

    badazz81z28 Veteran Member

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    I’m a fan of Global West too. Nice affordable parts with great quality.
     
  2. G72Zed

    G72Zed Veteran Member

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    Yep, saw the same thing more or less. One of the main reasons why I channeled them into the frame and reversed them to go through the floor and rear cross braces and into the spring mounts from the inside. That made a big difference, but very far from a "bolt on".

    Everything got fully welded up and reinforced, original 72 Z28, but it did not bother me one bit...glad I did it.
     
  3. G72Zed

    G72Zed Veteran Member

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    Ah that's cool, guess I still got a good memory LOL, great story of you and your Camaro Mr Lum, and thanks for the reply.

    The other thing that stood out was the simple OEM brake setup and how Mary Pozi was surprised how good it was. I remember you were using Vintage WW with a 17x9.5 with a 275/40's in front, was your back spacing 6" ? also, what was the rate of your leaf springs...must of been up there to match the 900# springs in front?
     
  4. JUNKYARD AUTOCROSSER

    JUNKYARD AUTOCROSSER Member

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    I did not like the stripes or the rear spoiler. I like the understated look because I think the body of 2nd gen is so beautiful and clean. I was able to order the car without the stripes but I had to accept the rear spoiler (Z28 requirement). Shortly after delivery of the car. I bought a standard deck lid, had it painted, and installed it on the car and I still have the original z28 deck lid with the spoiler. My son, who also autocrosses the car, may reinstall the spoiler when he gets the car. After winning the SCCA regional championship in 1988, Car Craft featured an article of the car in the May issue. I kept it of course, but I had no idea anyone else would remember. You must be an old guy like myself.

    A subframe connector would probably work better welded than bolted because the welded connection should be stronger. How much stronger, I dont know. Will it make a significant difference in the handling of the car, probably not. However I think the subframe connector by Detroit Speed is probably be the strongest because the stress points are uniformly distributed all along the full length of the subframe connector. It is welded the full length of the subframe connector to the body. I believe this design will make a difference in chassis stiffness. However the Detroit Speed subframe connector is not an option for me because I dont want to cut up the body. Take care and stay safe.
     
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  5. mid77z28

    mid77z28 Veteran Member

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    I'm 52.I was 20 at the time and still have the magazine.I'm into the autox and road racing camaros.Your car and the guldstrand 72 z28 test car I found the most interesting at the time.
     
  6. xten

    xten Veteran Member

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    Kid has a 10 sec Firebird along with an 8 sec 25.3 Camaro. As John mentioned above it was ripping the sheet metal at the front corner of the C pillar on the Firebird from launches with slicks. When we put his SFC's in, we ground the floor and connectors to bare metal at the entire mounting surfaces and used Lord Fusor 108B metal panel bonding adhesive, then welded the ends. We figured the constant contact would be better than fusion, plug, or stitch welding the length, and fire wasn't as much of a concern. Night and day difference in rigidity and droop when lifting.
     
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  7. badazz81z28

    badazz81z28 Veteran Member

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    For what you do with the car, I’m very surprised how much you hold back “cutting” the car. Fabrication done right doesn’t change the look of the car or really take anything away. You risk far worse damage and destruction of the car by racing it. I also have to remind my self I’m not going to live forever so do what you want to the car and not stress too much over the value or collector status for a car you’ll never sell.
     
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  8. G72Zed

    G72Zed Veteran Member

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    X2 with xten on this, that panel bonding is amazing stuff, and the fact of tying in to the most amount of flooring truly eliminates, or greatly reduces the cantilever effect, it pays back both in launch/reaction, easier to setup and helps in high speed hard corner braking, adding in the cowl Y braces just adds to this cantilever reduction or elimination as much as possible.

    Very good point badazz, I agree with you on that.
     
  9. JUNKYARD AUTOCROSSER

    JUNKYARD AUTOCROSSER Member

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    The backspacing on the 9-1/2" rims was 5-1/2" so it put the tire 1/4" closer to the top and leading edge of the wheel well. Very close fit given the lowered front end. BTW my Global West camaro came in 2nd place overall. The first place TCI car was not on Falken tires and should have been disqualified. Politics

    The brakes have been modified as follows: Changed the rear wheel cylinders to 15/16" from the stock 7/8". Installed finned aluminum drums from 3rd gen Camaro (lighter with better cooling). Installed Kelsey Hays proportioning valve to rear drum brakes. Installed aluminum master cylinder from 1979 WS6 Trans Am (lighter). Installed DTC-30 Hawk pads (aggressive), Installed RD4 brake shoes (aggresive) from Andy Porterfield. Stock rotors for 79 to 81 Camaro to fit spindles from 79-81 Camaro (lighter with larger bearings) . I have been able to get away with these simple mods because autoxing braking is much less demanding than Solo 1 braking. Braking is from 60 mph vs 100mph. Autoxing is maybe 60 sec. vs many high speed laps in Solo 1. I have run solo 1 and my brakes cannot handle it. I was able to do one timed lap at Willow Springs (big track), one warm up lap, followed by one timed lap, followed by one cool down lap. My brakes and cooling system was done after that. My car is light at less than 3300 lbs so that helps too. The rear drums only do maybe 30% of the braking so I find them adequate for autox. If you can lock your brakes on the last turn of an autox, why do you need 14" rotors with 4 piston calipers. My 11" rotor and aluminum drum brakes are much lighter also. Much time were spent in junkyards in the 70's, 80's , and 90's to obtain these parts, so I was able to build the car with less money. During that time period, junkyards were full of great parts. Not so much now. Also much experimentation and testing (trial and error) was done over many years to see what works and what doesnt work. I was young and energetic. Not so much now.

    My leaf springs came off of a 1981 WS6 Trans Am. The main leaf on the Trans Am is 5/16", my Z28 is 4/16", so the Trans Am spring is superior in lateral deflection stresses. Also Global West installed Cat 5 spherical bearings in the spring eyes which is amazing. Allows one wheel to articulate independent of the other wheel. Almost like independent suspension , but not quite of course. And the Cat 5 bearings has zero binding. My car is on the Global West site showing an installation video of the spherical bearings. The Trans Am has a 4 leaf set up while my Z28 is a 5 leaf set up. I have designed the leaf spring to reduce spring wrap and have better anti squat characteristics. I have read that my Z28 has a spring rate of 130 lbs/in. I would estimate that my modified leaf spring is between 150-160 lbs/in. Yes , my leaf spring is much lighter that the front coil that is rated at 900lbs/in. , but it seems to work. The original front coil on my Z28 was somewhere around 350 lbs/in, I have tried the Guldstrand autox spring 650 lbs/in and the Guldstrand race spring 900 lbs/in. The 900 lbs/in spring works the best. All of the coil springs have been cut to get the right ride height so the spring rates are probably higher. Take care and stay safe.
     
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  10. JUNKYARD AUTOCROSSER

    JUNKYARD AUTOCROSSER Member

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    While its true, I would never sell the car, my son might. Most of the mods I have made are bolt ons with the exception of the subframe connectors where I had to drill holes in my subframe to mount the connectors. I believe my car is restorable. I have kept all the original parts. actually I have no Idea what the car is worth. Dont even know if its worth the effort to restore it or leave it as a homebuilt pro touring car. Take care and stay safe
     
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