Being a JDM car can I ask if the cruise works beyond 112kph (71mph). Mine didn't and was therefore pretty useless.Originally Posted by kzukNA1
I've "solved" the issue by replacing the airbag wheel with a lovely Momo Tuner but am interested if JDM cars can in fact cruise at more than 112kph.
Cheers
Mark
Platinum Member
Hi, Mark.
On JDM NSX with non-DBW system, the cruise computer will limit the set speed at about 71mph.
In Japan, even on the A-road, the speed limit is 31 or 37mph, on the Motorway, it's about 62mph and in the residential area, you just have to drive dead slow to avoid any accidents. Therefore, the IC inside the cruise computer is programmed with speed limit of 71mph.
You can keep accelerating over 71mph by pressing and holding the 'RESUME' switch but once you have released it, it will eventually drop down to 71mph.
There is no screw on the case of cruise computer so you'll need to carefully twist the metal frame to open the case and replace the IC with reprogrammed one if you want to overcome the speed limit. Or, you may try to divide the speed signal ONLY for the cruise computer or just simply replace it with non-JDM one but I haven't tried these two latter methods by myself.
On the DBW model, the cruise control is carried out within the ECU so it is not that simple to overcome this speed limit on JDM.
Regards,
Kaz
How about with a signal splitter like for the speedos, or is it like with a new chip?
Platinum Member
The nice blue car has been collected by the owner now.
About 150 photos were taken to support all the services carried out and they were copied on to the CD and handed to the owner.
Another happy NSX and owner.
Kaz
Platinum Member
Hi, all.
Based on the result of my Health check service, this time, I was asked to work on the suspension area, ABS, A/C cleaning and so on.
1. Bonnet release
Well, I started to work on this NSX but every time when I tried to open the bonnet, it was stuck in the original position and I couldn’t open it. I had to hold the opener upwards and pull the bonnet to open it. As I didn’t like to return the car in this status, I decided to remove the entire lock mechanism, soaked it in the cleaner and re-greased it. Now, it opens freely.
2. Bilstein damper with OEM early Coupe Spring
We spent long hours discussing about the chassis setup and for the damper/spring, we decided to go for the Bilstein damper with OEM spring.
For this combination, I always use new bushes and mounting rubber so placed the order to Japan.
I only drove the car to/from the alignment place but I already found it was a good combination to meet his demand and budget.
Platinum Member
3. Stabi link, stabi bush, tierod/rack end
While replacing the damper/spring kit, we also replaced the old and tired stabi links and stabi bushes. Removing the locking nut on the stabi link is always the challenge as quite often, the hex hole is rusted and too weak to hold the big torque on loosening the self locking nut. In fact, for one of the link, I had to cut the shaft to release it from the stabilizer.
Quite often, I found small movement on the passenger side tierod/rack end but on this NSX, both sides were rattling. So, new parts were installed before going to the alignment place.
4. Alignment
Back to my favourite 2Hr alignment session. From time to time, I found seized alignment bolt even on NSX but this one was really tough. After fighting against some of the nuts and bolts, the final alignment result came out beautifully. Although it is a very old frame, no severe damage to the chassis and thus, perfect alignment to my own setup.
5. ABS
ABS has been neglected for a long time so when I used my SST to drain the old fluid, some of the debris from the ABS were trapped inside the one way valve of the SST and when I lifted it, almost all of the ABS fluid was released on the floor… After flushing the system several times, I managed to push the debris out of the one way valve so my SST function was recovered.
Unfortunately, I found that one of the four solenoid was already dead no matter how we flush/activate it. I could disassemble the unit and try to refurbish it but instead, it would be best to convert it to the latest ABS system so that will be on the future menu.
Platinum Member
6. A/C Evaporator cleaning
Unfortunately, when NSX was designed, there was no plan to fit cabin air filter like the modern production cars. Because of this, you’ll be surprise to see or may be, I should say, you don’t want to know how dirty the air could be inside the cabin. This is one of the reasons why the fan on the cabin air temperature sensor starts to make some noise after several years.
You may find lots of dirt around the air inlet of the blower motor unit. Once you have managed to remove it, you can see the evaporator.
This one looks very dirty but in fact, not too bad. In Japan, the summer is very hot and humid so the A/C is continuously being used and thus, lots of moisture is always at the evaporator resulting in black dirt or even sometimes some mould on the surface of evaporator.
First, blow out as much dirt as possible. Then, wash it with water followed by the cleaner. Wait for a while and then rinse it with plenty of water.
Don’t be tempted to clean the surface fin of the evaporator as they are so fragile that you will do more damage than cleaning it. Just use reasonably high pressure to apply the cleaner and rinsing water. Once you are done, spray some medical alchohol or similar product to disinfect any germ.
Platinum Member
As I don’t like dirt to get inside again, I normally make simple cabin air filter attached to the intake. This is good enough until I make something out of FRP and commercially available cabin air filter.
7. Cabin air temperature sensor
The cabin air quality was so bad that I found so many dust and debris on the temperature sensor. It was also making quite annoying noise so although it was not requested from the owner, I decided to clean it. This is what I found and I’m glad I cleaned it….
Thanks Kaz,
That confirms what I thought and mine behaved in the same way i.e. would accelerate beyond 71mph but return to it as soon as you let off the button. Mine is a DBW car so would be tricky to fix. I guess an entire UK/Euro ECU might do it but there'd probably be other little issues arising from the swap.
To be honest I never use cruise in the UK (my Merc and Audi have it) as our roads are just too crowded. It would come in useful for the odd Euro jaunt though.
Cheers
Mark
Greetings all,
Great day out today for Supercar Sunday at Gaydon, llovely to see so many of these beatiful cars.
Noticed a number of JDM models and wanted to answer the questions within this thread regarding the Cruise Control on JDM cars.
If you have a JDM car you probably have an electronic Speed Devider installed which reprofiles the pulse stream from the wheel sensor in order to adjust the KPH signal generated by the car into MPH for the Dash, speedo etc,
As the cruise ECU utilises the same pulse strem to determine its "set" speed all you have to do is patch this into the output of the speeddivider that goes onto the dash. This way when the car is doing 70,80 or whatever cruising speed you want the cruise thinks its doing 50,60 etc which is under the JDM 71 Mph limit and allows the cruise to operate perfectly.
Kaz mentione dthis briefly and I am just posting this to validate his preposal as like most of his suggestions ( from reading here ) this works perfectly after I modified my Car in just this way many years ago.
Best Regards
//Max
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