Delimiting - How to?

[Digsy]

Right-ho. First off, sorry for the long post. I know this subject has been covered before on and off but I wanted to get all of the information I have learned from you guys together in one place so that a final verdict can be delivered.

 

Everything I know about delimiting has been gleaned from you guys, so you only have yourselves to blame is any of the information below is incorrect! I am also familiar with the technical data on Pete Bett's' website, which was very helpful in understanding how the speed sensor signals are used throughout the car's systems.

 

Here is what I know: There are two main ways to delimit a MKIV.

 

1) Use the speedo converter (speed signal DIVIDER) to fool the ECU into thinking the car is going at 5/8 of its true speed all the time. This is especially easy if you want the odometer to be converted to record miles instead of km since the ECU and the other speed-sensitive systems all take their speed signal from the odometer. Therefore if you divide the signal going to the odometer you also divide the signal to all of the other systems (its not quite as simple as that, but please read on).

 

Note that this method does not actually delimit the car as the limiting software in the ECU is still active. Since the car thinks it is going at only 5/8 of its true speed, the speed "seen" by the ECU never gets high enough to trip the limiter. Hey presto - an effectively delimited car.

 

I gather that most importers use this method because you get it "for free" with a speedo / odo conversion. With a little more perseverence and Pete Bett's diagrams you can also take the divided signal from the speedo converter and only wire it into the car systems that you really need to. This is especially useful if you want to fool the ECU and also raise the cruise control trip-out speed, but do not want systems like active aero and speed-sensitive PAS to respond atthe wrong speeds (as these both require NON-divided signals straight from the speed sensor). The odo can also be left to read in km if you want.

 

However, there appears to be another way...

 

2) Use a true speed signal limiter (speed signal "CLAMPER"). This is a second "black box" which operates differently to the signal divider used to change the speedo from reading in kmh. Its allows the speed signal from the sensor to pass through unaltered until it reaches a threshold which is just below where the ECU would normaly step in and limit the car's speed. After this point no matter how "fast" the input signal is, the output from the clamper unit will always stay just below the limit threshold. This unit is obviously only connected to the ECU.

 

This would seem to have the advantage of keeping the other car's systems unaffected and all working at the right speeds. Yes, you still need a separate speed divider to convert the speedo and yes you must still supply a converted signal to the cruise control ECU if you want to remove the trip-out limit on that.

 

There is also apparrently a third "cheapo" way to delimit the car AND convert the instruments in one go - put a signal divider straight onto the speed sensor. From what I hear this has so many bad side effects that it should not even be considered.

 

So assuming I've got all the above right, I now have a few questions:

 

a) I've heard that the Supra in fact has TWO engine speed sensors. Using method (1) means that the two signals will NEVER agree since one is always divided. Using method (2) they will only not agree above the limited speed. Does this cause any problems?

 

b) I would guess that the ECU needs to know the true vehicle speed for other reasons than just to limit its top speed. If it is constantly fed the wrong speed will this make the car run incorrectly? For example, if the car uses the engine RPM and roadspeed to work out which gear it is in, it will always get the wrong answer.

 

c) What about the auto box? Doesn't the kickdown need to know how fast you are REALLY going? I drove an NA auto that had been converted using method (1) and the operation of the kickdown seemed very strange indeed. When I buried my foot, the car just sat there screaming for about two seconds, then launched off towards the horizon. When I drove my in-law's Merc a few days later I noticed that the box dropped a cog before the revs started to wind up.

 

d) If anyone has direct experience of method (2), how much are the clamper boxes? I've been told £200 or so, fitted.

 

e) In short - WHICH METHOD IS BETTER???? I know one is free, but I want to know the warts-and-all effects, including the ones that might not be immediately obvious (like the affect of delimiting via the odometer on the PAS). ECU error codes? Cruise / kickdown problems. Etc, etc, etc...

 

I need to get a consensus before the end of the month when I go to JIC to look at my car.

 

Thanks in advance, and hopefully you will put me right if any of the information I have above is a little wide of the mark.

 

Cheers,

Darren

 

[Guest Ash]

 

 

The way to delimit the car and have everthing working correctly and reading miles, is to first buy a speedo convertor from Pete Betts.

 

Cut the wire that feeds the speed-signal into the speedo. Connect the loom side of this cut wire to the input of the speed-convertor box. The output of the speed convertor is connected to the speedo side of the cut wire.  

 

That gets the speedo reading miles.

 

To get the odo reading miles, you cut the speed-signal wire to the odo and connect the odo side of the cut wire to a new wire that runs from the odo speed-signal input to the output of the speed convertor, i.e. the same wire connected to your speedo.

 

That gets the odo reading miles.

 

NOTE: If you are handy with a small soldering iron, you can also change the legend to state MILES instead of KM's (details are on Pete's website, I think, or I have them if not).  

 

But there is a slight problem here as the odo actually re-broadcasts the speed signal to a host of other devices which will now also be receiving the divided signal.

 

So all you do is to cut the re-broadcast output wire at the odo. Then to the loom side of this cut wire you attach a length of wire that will reach and connect to the raw speed-signal wire that you use to feed the speedo-convertor.

 

To remove the speed limit, you need an HKS SLD (Speed Limit Defencer). There are 2 types depending on whether you car is manual or auto.

 

The first type, for the manual, simply clamps the speed signal. But the auto uses the signal for gearbox control, et al, so the SLD for the auto is a little more involved.

 

HTH

 

Yours,

J  

 

 

 

[Digsy]

Hi Ash,

 

Pete Betts seems (according to his website) to be an advocate of also using the converter (divider) to delimit the car.

 

Since I do not want to have my odo reading in miles it sounds like I need to just use the divider unit to convert the speedo and then get the HSK SLD to work its magic on the ECU and auto box. This sounds like method (2) to me.

 

Interestingly (and at risk of this going off-topic) I also hear that if you ONLY want the speedo to be converted to mph, and something else is handling the delimiting, the easiest way to do it is to buy a UK spec speedo head.

 

I need to get to the bottom of this. Which method does your car use?

Darren

[Guest Ash]

 

The actual speed-signal is the same on both the UK and J-spec car. The speedos read differently because the UK speedo has additional divider electronics built into the speedo head. Likewise with the odometer.

 

So by fitting a UK speedo it will automatically read correctly because, as I say, the speed signals are the same on each car. A speedo swap, in terms of ease of installation, I suppose is about the same as fitting a five-eigths divider to your existing speedo. It's a matter of personal preference I guess.

 

Pete has fed the divided signal to the ECU on cars before now but I, personally, do not recommend it.

 

For instance, the HKS SLD's for the manual and auto are *very* different. So there must be a good reason why this is so.

 

Looking at the way the two are connected, the auto SLD connects to various wires both on the engine ECU and the auto box ECU. So it would appear that simply clamping or dividing the frequency of the signal (as per the manual SLD) is not the way to go about things.  

 

On my car I did the same as I described in my previous post: Pete's divider on the speedo and odo (with the wiring mod for the odo re-broadcast signal) and the HKS SLD on the ECU.  

 

Yours,

J  

[Digsy]

Hi again Ash,

 

Thanks for the continued replies. This is actually just what I wanted to hear. I don't like the sound of using the speed divider to delimit the car one little bit either.

 

So this begs the question, how difficult is the HKS SLD to fit? If I'm thinking in terms of time, would it be worth asking JIC to fit one or is it so easy I could do it myself? Where does it fit, etc, etc?

 

If its easy to do I'm thinking of not having the car delimited at all, but living with it for a while and then (probably) delimiting it myself.

 

Oh yeah - dumb question: How fast can a LIMITED car go? Is it 120mph?

 

Regards,

Darren

[Guest Ash]

 

 

Complexity depends upon whether it's an auto or a manual and how comfortable you feel using a small soldering iron and some basic hand tools. The manual SLD has 4 wires to connect and the auto about 15.

 

The units connect to the ECUs situated in the passenger footwell which are easy to get to. I cannot advise you about recommending anyone to fit the unit as I do all the work on my car myself.

 

With the exception of Chris Wilson, the only few times I ever had contact with tuners always turned out rotten. So you see, I'm definitely not the person to ask for recos.

 

The limiter calls it a day at about 120 mph.

 

If I were you I'd check exactly what the company do first. People have said that JIC have the car fully converted for you, i.e. speedo and odo reading miles, etc. But find out what it is they do and get back to me if you need further info.

 

Yours,

J  

[Digsy]

Hi (again) Ash!

 

I'm fairly comfortable with a soldering iron. I didn't really want to rip the dash off my car to get to the ECUs but if they are easy to get to then it sounds fine. Hopefully the correct wires are easy to identify?

 

I'll check it out with JIC, but I am almost certain they just wire up the ECU to the speedo divider. I don't want my odo converted anyway. I'll ring them this week to find out and let you know what they say.

 

I would like to read up a bit more on the HKS SLD. Where can I do that? Do they have a website?

 

Cheers,

Darren

 

[Paul Booth]

Quote: from Ash on 7:56 am on July 17, 2001[br]

 

If I were you I'd check exactly what the company do first. People have said that JIC have the car fully converted for you, i.e. speedo and odo reading miles, etc. But find out what it is they do and get back to me if you need further info.

 

Yours,

J  

 

I'd like to hear what JIC do also as mine was converted there. I haven't bothered tracing the wiring as i assumed a speedo conversion would have no other effect.

 

I know the line is cut into at the point it feeds the speedo and odo as I noticed the mod when I've  been working on the ICE (removing the facia).

 

I have to 'go in' sometime soon to renew the ICE mounting bolts (1 short when I opened it up for the first time & Toyota have taken weeks to get a new set) and that would be a good time to check what I've got and what, if anything, needs fixing.

 

[Guest Ash]

 

 

The ECUs are under the carpet of the passenger footwell. Takes about 2 mins to get to them. HKS have a website, I think it's hksusa.com. Or something like that.

 

I don't know of any other basic info on the web about the SLD units. I suppose it's because they are quite basic in their operation, so there really isn't all that much to say about them. Perhaps one of the tuners on the other list might be able to give you more info.

 

Yours,

J  

[Branners]

Its a shame Pete Betts is so busy with work as it would be good to have his input here. He has 'examined' most of the major electronic components out there and so could tell us exactly what the differences are and the ideal way to convert a car.

 

If you really need to find out the major differences you might want to contact Pete direct, he can probably sell you all the required items to do the conversion.

 

But it does have to be said, I have not heard of anybody having any problems with the way JIC convert cars, the active spoiler, cruise, engine, gearbox all work correctly.

 

I can probably get Tim at JIC to let me know exactly what they do and then keep it for future reference.

 

JB

Shop!!

[Digsy]

Pete seemed sold on the "divider" method last time I corresponded with him, which is partly why I'm so surprised that there is such a consensus over using the HSK SLD this time around.

 

I have just talked to Steve at JIC. I sent them a letter with my deposit cheque outlining pretty much the same concerns as in my original post (but with no conclusions as to which way to go). He is going to pass it to the garage that does their conversion (anyone know who this is?) and then give some feedback to me.

 

Darren

 

[Digsy]

Ash, just planning for the future here...

 

If JIC say they will not delimit my car using the HKS box (or equivalent) and I opt to do it myself, could you photocopy or scan the fitting instructions and mail or e-mail them to me so that I can have a trial run without buying the part first?

 

Cheers,

Darren

 

[Guest Ash]

 

 

No problem, I've got instructions for the auto and the manual SLD depending on which car you buy.

 

Yours,

J

[Phil Wall]

I had a slight problem with my conversion from JIC

 

Speedo was fine but the ODO was reading way out.

 

Took it back, and had loan of a tiptronic gear box VVT MKIV for the day, while it was put right.

 

Problem solved.

 

Everything appears OK.

 

But you have me wondering now.

 

Is there something else not right that I am not aware off?

 

Are there any checks I can do?

 

Anyone any idea?

 

 

[Digsy]

Cheers Ash! Did I ever tell you what a top bloke you were?

 

Mine will be a pre-VVTI auto. I'll be in touch when I find out more from JIC.

 

All the best,

Darren

 

[francesca]

My odo reading is out too (also from JIC) I spoke to the guys that do the conversion & they gave me instructions how to sort it - I haven't yet, wrote down what to do & it is a case of re-connecting one of the wires I believe. Was very cold & snow-y at the time, not much inclined to sit on the drive fiddling with wiring! They offered to fix it for me if I opted to drive it down. Speedo is fine.

[matt]

Err...... when did it snow last?? :wink:

 

 

 

 

 

[francesca]

February - ish! I've been busy!

[Paul Booth]

Quote: from francesca on 5:12 pm on July 17, 2001[br]My odo reading is out too (also from JIC) I spoke to the guys that do the conversion & they gave me instructions how to sort it - I haven't yet, wrote down what to do & it is a case of re-connecting one of the wires I believe. Was very cold & snow-y at the time, not much inclined to sit on the drive fiddling with wiring! They offered to fix it for me if I opted to drive it down. Speedo is fine.

 

Share! Come on Francesca, get that keyboard going and enter the info.

[Phil Wall]

Yes pass on the info when you have cleared the snow

[francesca]

need to locate said piece of paper..!! Failing that will ring again & pass on info. No snow tonight, p**ing down with rain though! So3's DO grip in the wet (one small twitch coming off roundabout)

[Doughie]

 

My neighbour's got a snowplough actually.

He sats you can borrow it Fran to clear those 6 foot drifts you've still got over there.

 

And i can send you a woolly hat too, free of charge, no problem.

[Doughie]

My neighbour's got a snowplough actually.

He says you can borrow it Fran to clear those 6 foot drifts you've still got over there.

 

And i can send you a woolly hat too, free of charge, no problem.

[francesca]

That's very kind, I can get at the car to clear the penguin poo off too...

Need a hat with those earflaps & a long tassel

[Paul Booth]

What are the characteristics of a car hitting the limitation barrier?

 

While mine is supposed to be de-limited, getting it passed a displayed 120 is near impossible; well, it struggles beyond.

 

If I know what to look for, and we get the specs for a good conversion, I can do the work to ensure mine is done correctly.