The real jap car speed limit

[Jevansio]

I've just sold my speed delimiter and noticed for the first time it says it's a 200 kph speed jumper, this equates to 125 mph. Now I know it's common knowledge that the limit is 112 mph, but a lot of people say that theirs go past 112 mph and seem to cut at about 125 mph, is this just a coincidence that that's what is plastered on the side of the Blitz Speed Jumper or could the real limit be 125 ???

Jay

[MegatronUK]

125MPH is an error of around 11% on an actual speed of 112mph. A lot of speedos tend to over read around 10-15% at speeds over 100mph - its within the law. A speedo MUST NOT under-read, however.

Of course different tyre sizes to standard... will also play a part.

[Al-sw20]

I dont know what the limit is in mph/km/h but it seems to be 5500rpm in 5th and a tad before redline in 4th.

BTW who is silly enough to pay for a speed delimiter when you can get a 1 quid interconnect from a electronics store that will do the same thing?

[karammander]

yeah my car used to cut out at 5500 when it was fresh of the boat, a apexi rsm sorted that and 150 here you come.

cheers karam

[Stef Derner]

I dont know what the limit is in mph/km/h but it seems to be 5500rpm in 5th and a tad before redline in 4th.

BTW who is silly enough to pay for a speed delimiter when you can get a 1 quid interconnect from a electronics store that will do the same thing?

As the ECU counts pulses to see how fast you are going, how can a 1 quid interconnect stop this happening?

[Al-sw20]

Quite simple, its not a required wire for the ecu to operate.

You need a CMOS 4024 Bin Counter 7-Stage, should be cheap as at an electronics store.

The i/c connects in this fashion

Pin #1 -> Speed Input ( From Speedo ?)
Pins # 2 & #7 -> Ground
Pin #14 -> +5v
Pin #12 -> Speed output (to ECU)

[Chris \'aka rustboy\' Amm]

I dont know what the limit is in mph/km/h but it seems to be 5500rpm in 5th and a tad before redline in 4th.

BTW who is silly enough to pay for a speed delimiter when you can get a 1 quid interconnect from a electronics store that will do the same thing?

because people are lazy and not all are electronic nerds either mate

still nice tip for anyone wanting to ditch there limiter!

[Al-sw20]

Im no nerd; im a scottish kiwi.

Ive got the deep of pocket and the short of arm.

[BenF]

I've just sold my speed delimiter and noticed for the first time it says it's a 200 kph speed jumper, this equates to 125 mph. Now I know it's common knowledge that the limit is 112 mph, but a lot of people say that theirs go past 112 mph and seem to cut at about 125 mph, is this just a coincidence that that's what is plastered on the side of the Blitz Speed Jumper or could the real limit be 125 ???

Jay

On my Rev2 - the speed limit cuts in at 118mph according to a GPS - as found a couple of times at the Nurburgring

[BenF]

Quite simple, its not a required wire for the ecu to operate.

You need a CMOS 4024 Bin Counter 7-Stage, should be cheap as at an electronics store.

The i/c connects in this fashion

Pin #1 -> Speed Input ( From Speedo ?)
Pins # 2 & #7 -> Ground
Pin #14 -> +5v
Pin #12 -> Speed output (to ECU)

Al - nice one. Where would you connect it though? The Speed signal goes everywhere in the car - and you ideally want to PAS ECU to get the original signal so it doesn't lighten up the steering to 'shopping trolly light' if it gets the new speed signal.

Hmm, 4024 - nice idea, basically you're dividing the input signal by 2, rather than 0.65 - that will work, but won't be the most accurate speedo conversion. It will give you a healthy 30% over-read on your speedo

[Al-sw20]

You take the speed signal from the ecu. This has been done over here a few times by various owners.

[BenF]

You take the speed signal from the ecu. This has been done over here a few times by various owners.

Hmm, White / Purple wire going into the ECU?

I looked at fitting one there and it also changed the speed signal to the PAS ECU making the steering noticeably lighter

I think the PAS ECU takes a feed from the signal that goes to the dash unit - I'm fairly sure there's a speed in / Speed out pair of wires there.

[Al-sw20]

Yeah that sounds like the one, the purple wire with a white stripe. You just put the i/c on the speed input wire to the ecu

[BenF]

Yeah that sounds like the one, the purple wire with a white stripe. You just put the i/c on the speed input wire to the ecu

Heh - the speed signal loops through the ECU though doesn't it. You tried driving your '2 with the circuit in line and then removed and seeing the difference in steering weight?

[Al-sw20]

Havent done it on mine, but the source of the information tells me there is no change.