Z32 TT clutch pedal vs NA ??

Discussion in 'Technical' started by koobaz, Jan 13, 2022.

  1. koobaz

    koobaz New Member

    Hi Guys

    Struggling to find a NA clutch pedal for my auto to man conversion.

    Is there a way to use a tt clutch pedal without mucking around with the booster and lines etc ? I already bought NA new master cylinder trying to avoid all the tt pedal hassles.

    Anyone have experience with this ?

  2. NI85

    NI85 Active Member

    From what I understand you need the NA pedal for the NA clutch master cylinder

    If you only have the TT clutch pedal and TT clutch master cylinder set up. The booster's vacuum line can be tee pieced in with the Brake booster line, for assisted clutch. If you don't have a heavy clutch plate, you could do without connecting vacuum line. Or just build up your left leg muscles :)
  3. rob260

    rob260 Administrator Staff Member

    OK so the NA pedal is designed to be used with no booster and the fulcrum/pivot point on the pedal is designed with this in mind.

    Likewise the fulcrum on the TT pedal is engineered around it being used in conjunction with a vacuum assisted booster.

    If you use an NA master cylinder and a TT pedal you'll have less mechanical advantage compared compared to an NA pedal, and accelerate wear on the celvis pin and the hole that it passes through.

    If you already have a TT pedal it may just be easier to use a TT master cylinder and booster?
    MickW likes this.
  4. koobaz

    koobaz New Member

    Thanks guys,

    I was hoping to wait and finally snag a NA clutch pedal to avoid having to install booster etc.
    As I already have an NA master cylinder which I guess I can sell and find a TT master.

    I should be able to find a TT pedal again.

  5. rob260

    rob260 Administrator Staff Member

    If you do that just be aware that you'll need a booster and vacuum tank as well
  6. koobaz

    koobaz New Member

    I know about the booster. Unsure about vacuum tank ? I thought you just T piece of any vacuum line along with fitting booster.. but I clearly dont know much
  7. rob260

    rob260 Administrator Staff Member

    The factory TT booster circuit includes two vacuum tanks - one under the driver side fender near the AIV assembly and one in the engine bay underneath the boost sensing solenoid.

    I presume these are to provide vacuum assistance when the check valve between the intake manifold and the booster is closed while the manifold is pressurised.

    You can probably install without - you may find that pedal feel is inconsistent though.
    MickW likes this.
  8. koobaz

    koobaz New Member

    Thanks Rob ! Much appreciated. Found a pedal with no vaccum tanks. Would not having vaccum tanks become an issue in the future ?

    Attached Files:

  9. rob260

    rob260 Administrator Staff Member

    I don't know I've never tried... I'd say at worst the pedal feel might be inconsistent. As long as the Throttle Bodies are closed when you put depress the pedal the assistance should be pretty well immediate.
  10. NI85

    NI85 Active Member

    No issue with my TT, that doesn't have a vacuum tank. I had planned to buy an aftermarket vacuum tank($100+) then figure where to mount it. However, sharing the brake booster's vacuum is sufficient ( a lot better than just check valve to intake), so I haven't bothered.
    What I don't know is if there was a tank, would it be as feather light as my N/A's clutch pedal.
    Picture attached shows my connection to the balance pipe. I would have picked up from the port on the intake itself, but connection angle was too sharp for hoses.

    Attached Files:

  11. rob260

    rob260 Administrator Staff Member

    So normally on a TT manual the brake booster vacuum line connects to the 3/8" barb on the back of the manifold next to the coil pack for #5.

    The vacuum line for the clutch master cylinder booster comes off the balance tube and runs from there to a tank under the boost sensing solenoid, then to another tank in the fender, then back to the booster.

    Each of the lines has it's own check valve the purpose of which is to stop the pedal being pressurised under boost.

    It's not uncommon to T the clutch booster and Brake Booster lines when doing a manual conversion if you are using a balance tube from an automaic car but in your case what you've done is no different (or better) to hosing the boosters separately from their respective vacuum sources as described above and running the vacuum supply for the clutch booster directly from the manifold or balance tube with an inline check valve. Potentially less good as you're splitting the supply line but you'd splitting hairs trying to quantify it.
    Last edited: Jan 18, 2022
  12. NI85

    NI85 Active Member

    Yes my TT is a conversion. Brake and clutch initially at their respective ports. Clutch only has check valve, no vacuum tank (Hence initially I was looking for one).
    I had joined the clutch vacuum to the Brake master cylinder line (After coming across an article mentioning it as an option). Yes I can't quantify the improvement (would need some sort of force/pressure meter). However with my experience, I think it's improvement enough to be worth mentioning :)
    For balance, the down side with joining the two if there is a leak, brakes would heavy when applied.
    Which is not fun: as experienced with my Z31 when it's booster failed. No accidentally exceeding speed limit on that L-plate test. (I got my P plates with no power brakes.)
    MickW likes this.
  13. koobaz

    koobaz New Member

    Thanks for the input the heavy brakes dont sound great if there was an issue. After giving it much thought I want to try and find a TT pedal now with vaccum tanks to do a proper conversion as I will most likely be removing the motor to do maintenance and checks. Still impossible to find any. The NA pedal does sound like its a lot less hassle...
  14. rob260

    rob260 Administrator Staff Member

    I don't mean to labour the point but for the sake of clarity for anybody else reading... you haven't actually made an improvement. Teeing into the brake line doesn't provide any additional assistance or rectify the missing booster tanks. That line is also closed under the same conditions that the clutch booster line is normally closed.
    MickW likes this.
  15. Dreilide

    Dreilide New Member

    Is there any difference in pedal feel? I had a TT ages ago, I think I remember the clutch being lighter and easier to work (which makes sense given the booster) but it was such a long time between that TT manual and an NA manual i can't really remember.

    I've thought about swapping in the boosted system if i ever found one cheap.
  16. koobaz

    koobaz New Member

    Hi Rob
    Tried doing my research to see if a LHD clutch pedal in a RHD would work and is the same shape (mounting points) etc but there doesnt seem to be any concrete evidence. Struggling to find any pedals for last few months

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