[928uk] 3 speed gear change rpm

[Simon Watson]

+ 1 from me 😁
Well done Todd!  Enjoy!
Simon
Sent from my iPhone

> On 14 Jun 2024, at 23:07, Ben Hodges via 928uk <928uk at lists.928.org.uk> wrote:
> 
> Good work Todd
> 
> 
> 
>> On Fri, 14 Jun 2024 at 23:00, todd via 928uk <928uk at lists.928.org.uk> wrote:
>> 
>> Just to wrap this up (for anyone with similar issues)
>> 
>> I adjusted the bowen tensioning bolt (side of gearbox) and the gear change
>> raised to 4500. I increase pressure module one complete turn (clockwise)
>> and gear change raised to 5000rpm. Im happy there. At some point I will try
>> Smithy's suggestions below, but for now Im happy.
>> 
>> I must say, for a 45yr old car that has sat dormant for 16 or so years,
>> then rebuilt by a novice like me - it does accelerate pretty well. Its not
>> rocket, but it certainly respectable. And the thrashing its been getting
>> recently has only made it happier.
>> 
>> Thanks all
>> 
>> Todd.
>> (had to resend for various stupid reasons 😊 )
>> 
>> -----Original Message-----
>> From: todd at oxfordeye.co.uk <todd at oxfordeye.co.uk>
>> Sent: Saturday, June 8, 2024 11:19 PM
>> To: smiffypr at gmail.com; 928uk at lists.928.org.uk
>> Cc: todd at oxfordeye.co.uk
>> Subject: RE: [928uk] 3 speed gear change rpm
>> 
>> Solid suggestion... I'll give it a go tomorrow
>> 
>> I have 100% confirmed the kickdown now works, that at least that 😊
>> 
>> Thanks 😊
>> 
>> -----Original Message-----
>> From: 928uk <928uk-bounces at lists.928.org.uk> On Behalf Of Paul R Smith
>> via 928uk
>> Sent: Saturday, June 8, 2024 11:15 PM
>> To: 928uk at lists.928.org.uk
>> Subject: Re: [928uk] 3 speed gear change rpm
>> 
>> Bear in mind that I know nothing about autos, so I am just talking theory.
>> If you want the box to think you have WoT, it will have no vacuum, so
>> disconnect the vacuum line to the box and block the engine side of the line.
>> You want the cable to tell the box that the throttle pedal is on the
>> floor, so cable tie the lever to imitate that.
>> You want the kickdown solenoid powered, so run 12v to that.
>> 
>> If it still won't go to higher revs, you then know that the problem is
>> inside the box.
>> 
>> Smiffy
>> 
>>> On 08/06/2024 23:05, todd via 928uk wrote:
>>> Just to update :
>>> 
>>> 
>>> 
>>> I adjusted the Bowden cable and lock nut(side of gearbox where Bowden
>>> connects) and it's definitely tight enough (I can even tighten it
>>> enough to stop throttle opening fully. I've wound it back a bit now).
>>> 
>>> 
>>> 
>>> But, the car changes at 4500rpm max throttle.
>>> 
>>> 
>>> 
>>> As I understand it, the gear change is based on pressure. On one side
>>> you have the vacuum of the engine and on the other you have the
>>> throttle position (communicated to gearbox via Bowden cable). Once
>>> vacuum pressure exceeded throttle pressure the gearbox changes gear.
>>> (Shout if that is
>>> incorrect)
>>> 
>>> 
>>> 
>>> So, my new question is : what else could be wrong? Low gear change
>>> tells me the vacuum pressure is too high for the throttle pressure
>>> (but I know the throttle is max). Is there an o-ring or something I
>>> need to change to increase throttle pressure? Or a way to reduce vacuum
>> pressure ?
>>> 
>>> 
>>> 
>>> Perhaps increasing pressure modulator?
>>> 
>>> 
>>> 
>>> Any help appreciated
>>> 
>>> 
>>> 
>>> Todd
>>> 
>>> 
>>> 
>> 
>> 
>>