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Discussion Starter #1
Hi guys,
I am from Slovenia and I am interested in speedo delimiter. I don't want mph conversion, since we use the km/h.

How have you fixed the issue?
 

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It's the ecu that enforces the speed limiter, so it's the proper way. Any other method simply tricks the ecu into thinking the car is going slower than it really is. Problem is modifying the speed signal on these cars can also affect hicas, power steering, attessa, etc, so it's best to do it properly and actually remove the limiter by changing/mapping the ecu.
 

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Discussion Starter #5
Hmm, friend that also has a GTT drove the car to 2 mappers, but they didn't know how to do it.
Maybe if I send it to some other more experienced tuner to just delimit the ECU...
 

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You can (on about 1/2 of them) modify the speedo safely, yes it will output a marginally different signal to the ECU, but it will NOT affect the way the car drives in any way.

Stuart 'knows' about all this but believes it is just plain wrong, (it isn't) but having run a car like this for years (and lots of other members) in practice rather than pure maths it IS 100% ok.
I did all of this research work on speedo conversion to MPH and de-limiting many years ago, after an 'aftermarket' MPH converter played up in the rain at 100MPH causing me to spin 3 times on a luckily very wide road.
I got the conversion working as I wanted it, safely on road & track at every speed, yes the ECU does get a slightly different signal, so do the other systems needing the speed-pulse, but the signal error in practice doesn't cause any issues, esp. not with HICAS, and cures many!

IF you want to try it for yourself I have made a few posts about it years ago as 'andy42uk' & andy42uk-2'
It is an option if your stuck, have a look and see if you understand it.
You'll need to remove the instrument cluster, split it down and remove the speedo 'head' then cut a pcb track labeled PESL wich I 'think' stands for 'programmed electronic speed limiter' after that you will then have to re-calibrate the actual speedometer needle reading using the calibration pads 1-10.
The odometer may read out afterwards - there are other pcb links you can join/remove to get this near correct if you find it an issue.
You will need common sense to do all of this, but it may well be the only practical way for you.
Good luck,
Andrew.
 

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You can (on about 1/2 of them) modify the speedo safely, yes it will output a marginally different signal to the ECU, but it will NOT affect the way the car drives in any way.

Stuart 'knows' about all this but believes it is just plain wrong, (it isn't) but having run a car like this for years (and lots of other members) in practice rather than pure maths it IS 100% ok.
I did all of this research work on speedo conversion to MPH and de-limiting many years ago, after an 'aftermarket' MPH converter played up in the rain at 100MPH causing me to spin 3 times on a luckily very wide road.
I got the conversion working as I wanted it, safely on road & track at every speed, yes the ECU does get a slightly different signal, so do the other systems needing the speed-pulse, but the signal error in practice doesn't cause any issues, esp. not with HICAS, and cures many!

IF you want to try it for yourself I have made a few posts about it years ago as 'andy42uk' & andy42uk-2'
It is an option if your stuck, have a look and see if you understand it.
You'll need to remove the instrument cluster, split it down and remove the speedo 'head' then cut a pcb track labeled PESL wich I 'think' stands for 'programmed electronic speed limiter' after that you will then have to re-calibrate the actual speedometer needle reading using the calibration pads 1-10.
The odometer may read out afterwards - there are other pcb links you can join/remove to get this near correct if you find it an issue.
You will need common sense to do all of this, but it may well be the only practical way for you.
Good luck,
Andrew.
Cutting PESL means the car only sees half the true speed. Basically, you'd need to be doing roughly 224mph before the speed limiter kicks in. But this also means the hicas ecu thinks you're only going half the speed too, so your power steering ends up way lighter than it should be. If you're doing 60mph, the car thinks you're doing 30mph, so supplies more assistance as it thinks you're going at low speed. It also affects when the hicas decides to alter the rear toe. It's simple maths, if you start halving some of the numbers, you can't expect the sums to still add up the same. When you remember that maths controls the car, it matters. However, if someone didn't have the hicas rack any more anyway, then that side of things won't matter any more since it'd no longer be able to change the rear toe. The power steering would still be too light though, unless the hicas is totally removed and you've got an s14 front rack instead.

That said, I've just looked at your profile and it says you've got an r34, so even this wouldn't work anyway. To remove the speed limiter properly without fooling signals that WILL affect how the hicas and power steering behaves, it's a mapped ecu you'd need. As said, there are ways to trick it, but the steering setup shouldn't be tricked when it's electronically controlled.
 

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I always assumed the Apexi RSM continued to show the car the correct speed until it got up to around the 180kmh mark, at which point is displayed a signal that didn't increase beyond 180/slightly lower. I.e. I thought the speed was only "wrong" at around 180 and above. Is this not how it works (I completely ASSUMED this is how it would work)?
 

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Not sure, never used one. But that sounds like it's a clamping delimiter in that case, does the same job as a 5 wire converter chip. That said, rumour has it that the hicas is still active at above those speeds. I've never datalogged the hicas at that speed to find out. But if it is, and it thinks you're doing 110mph instead of 140mph, then it may too cause problems. I've never tried to found out since I've never needed to, as my speed signal is unaltered anyway.
 

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I didn't see that this was for a R34, however I am not sure of the differences over and above the LCD odometer..
I believe there is a e2rom in there a Microwire 93C46, might be worth getting a e2rom reader (cheap on ebay for that device) downloading it's data and looking at with winhex.
Always save a good copy of the data as a backup!
It may well be that you can alter parameters in the hex to adjust the output, if you get a 'dump' from the I.c. I will happily have a look for you, this is part of my daily work.
There's always other ways of seeing and doing things.
Andrew.
 
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