thread: Gearbox choice

  1. #1

    Mar 2011
    england
    39

    Gearbox choice

    Hi,

    Just spotted another topic for the V6 where there were a lot of talk about the gear ratios of various gearbox options. Sadly I've already got a gearbox and it's in the chassis with the engine, clutch etc.

    The box I've got is a rev2 turbo LSD box, I've never run it but it turns smoothly by hand and didn't look too bad, aside from lots of road dirt.

    The engine is a gen4 Caldina st215 3sgte, it's got the heavier of the Fidanza flywheels and a 'stage 2' single plate clutch.

    So how are the gear ratios going to be with this setup?
    There is lots of talk about the gen4 only revving to lower rpms with the auto ecu (I have the auto ecu for now) but much conflicting 'information' floating around with some people getting the full 7250rpm and other only getting 6700rpm. Some talk of needing to make sure the speed input to the ecu is connected to access the fuller rev range and others saying they have this but still get less.

    Sadly for the moment this is all just research as the car isn't yet running (would you believe fuel hoses holding up first start) but what sort of gearing is it likely to have? Is the turbo box a good pairing with the gen4 or should I expect to need further mods in the future to better match the engine? Are there better boxes out there or even 6 speed options?

    thanks for the reading :D

  2. #2
    Woodsport Paul Woods's Avatar
    Mar 2005
    Durham, UK birthplace of the 1.5,v6 and v8 Mr2
    14,617
    I would always advise using the turbo box on a 3s-gte of any variant, it's the one with the correct ratios for it and the strength to cope with the turbo power delivery (ie not linear like the V6 engines), your ratios will be fine.

    There are no 6 speed options for the 3s-gte yet, the EB60 kit for the V6 i am developing doesn't line up with 3s-gte block holes, you might find the EA61 from the Auris does bolt up (i haven't tried yet) but it is stupidly long geared and not suitable for the 3s-gte in my opinion.

    If you find the current gearbox too short, there are Gt4 internals you can use to make the final drive longer.

    TB Quote of the month:"I split my ear open whilst masturbating" - Jasper Full story Here

  3. #3

    Mar 2011
    england
    39
    Thanks Paul.

    Good to know I've started with the right box. Will stick with it for now and see how it drives before jumping into final drive changes, good to know there is room for maneuver should it feel too short later on.

  4. #4
    Woodsport Paul Woods's Avatar
    Mar 2005
    Durham, UK birthplace of the 1.5,v6 and v8 Mr2
    14,617
    Yes a lot of people have ended up changing to the 3.9 E153 final drive for roughly 8% gain and can give up to 18% longer gearing with the 3.6 variant i'm led to believe.

    TB Quote of the month:"I split my ear open whilst masturbating" - Jasper Full story Here

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