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sr2

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Posts posted by sr2

  1. 13 hours ago, zep said:

    Interesting stuff - thanks! I'm going to go with the 35.1mm pistons. Can adjust MC to suit if necessary.

    Hi, sounds like a great project – a few words of advice from a boring old fart if I may.

    Dropping from 38mm x2 floating to 35.1mm  x4  fixed will reduce the clamping figure on your front callipers.

    Swept volume being πR squared (remember your old mate Pascal). Your standard configuration (π x 38/2 squared x2 x2 –i.e. floating) is 4,536 square mm. For the Willwoods we have (π x 35.1 /2 squared x4 – i.e. fixed) giving a figure of 3,870 square mm. This equates to a loss of front wheel clamping of around 14.7 %.

    How this reduction in front calliper clamping equates to the effect it will have on your cars braking is also dependent on pad composition & area, suspension design, and a myriad of other factors; braking systems have a bad habit of getting f***ing complicated quick!

    Over decades of playing with brakes on standard cars, modified street cars and all out race cars I’ve learnt one basic rule; unless you can quantify the pre and post braking performance of any modification you make you will always be floundering in the dark (if not farting against thunder!).

    Step one is easy and a shit load of fun. Set your car up with the right tyre pressures, the average load (gas, passengers, firearms, blow up sex dolls, accumulated junk,…. etc.) and find an empty carpark to do some very, very hard stops to zero from 60K. Have a mate spot for wheel lockups (front, rear, left right?) and get a feel for how she pulls and how controllable it feels. Next hit the open road and see what happens with at least 3 consecutive hard stops from 120K to 50; (look for brake fade, directional stability, wheel lockup and most importantly look in your rear vision mirror!).

    The next thing to try is even more fun – repeat the above in the wet!

    If you can achieve these simple before and after tests you’ll be streets ahead of the average car nut who tries to modify their brakes.

    Sorry for the long reply (i.e. rant) feel free to contact me if there’s anything else I can contribute.  

    • Like 3
  2. The main 2 reasons manufacturers introduce sliding calipers was ease of manufacture (i.e. Price) and that floating calipers show less tendency to convert rotor runout ( both lateral and thickness variation) into pedal pulsing; the reason being is that a sliding design uses mechanical movement to compensate for runout whereas a fixed design will use fluid movement. That said a fixed multi piston design will allow for more consistent pressure control over far larger pad area and will also  enable more pressure to be applied to the pads leading edge with the use of varying piston diameters; there is also better heat dissipation with increased pad/piston contact. 

    The science behind  the relationship between piston size and clamping force (with both fixed and floating calipers and all hydraulics) is based around Pascals Law. The result is that for a fixed caliper to have the same clamping force as a floating caliper it will need  X2 pistons of the same size for each single piston in the floating caliper.

    • Like 2
    • Thanks 1
  3. 23 minutes ago, markw said:

    I don't believe that the areas were designed to flex (the flex is likely due to the cost effectiveness of spot welding). However, the flex would have been present during testing. You are correct that the stress would be transferred elsewhere, and strengthening the shell likely pushes the car into untested, unknown territory. The same risk would exist with the installation The value of seam welding cars of a similar category to mine is supported by its continued use by premium restomod companies like Retropower, who state that seam welding of window and door apertures greatly improves rigidty of the cars they do, and Alfaholics. Granted, these shops likely understand the additional strengthening required to mitigate any shift in stress.

    Bit confused with your comment. All steel structures flex, they don't have to be "designed to flex"? (Enjoying the discussion by the way).

  4. Having run a T5's behind a Small block Chev and a Holbay Cosworth in the past I've found them to be very clunky, old tech, agricultural boxes; (and yes they do break!).

    I'd be looking at a W50 or W58 Toyota; sweet shifting, great value for money and with no integral bell housing they lend themselves to g/box swapping.

    Making an adaptor plate isn't rocket science (it doesn't need to be CNC billet alloy) and hydraulic clutch release bearings solve a multitude of issues, your biggest challenge would be finding a suitable flywheel. 

    I'm sure the "Oldschool Brains Trust" will provide great advice. (Love the idea by the way).

     

    • Like 2
  5. On 12/10/2022 at 18:18, Early jap nuter said:

    I’ve done it before and wouldn’t recommend.Seem welding on a road car doesn’t really make stuff all difference without a cage. Just ads more weight and makes it a real bitch to fix if you bend anything major.

    +1 re adding a cage. Just a reminder that if you do so you're trading crush zones for structural integrity,  6 point harnesses are a must! :thumbright:

    • Like 1
  6. From an engineer’s point of view I’d argue that seam welding a monocoque shell unnecessarily strengthens small areas of a structure that is designed to flex when under load. The result adds both stress raisers and excessive localised flexing increasing the chance of structural failure.

    Short answer is sorry no, don’t  seam weld. 

     

    • Like 3
  7. Pulled the grill out of the nose cone to figure out how to get a big enough radiator in there.

     

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    There’s a reasonable amount of extra height available if  I start cutting out sheet metal but at only 400mm wide it’s going to hard to find something to fit.

     

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    Thought I’d change the lower grill brace mount to keep it out of the way.

     

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    Bent up a piece of flat……

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    And welded it in place.

     

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    Made the call that because I’ll be building up a 2nd bigger and more highly tuned motor I really need to make sure I have adequate cooling capacity. After failing abysmally to find anything that would fit I’ve made the call to have something custom made.

     

     

    • Like 4
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