Ok so short story shorter, I kinda raced a 2nd Gen MX-5, lost tragically, and in the process I bounced of the limiter as I shifted from 1st to 2nd gear. It seems that the limiter is at 8k RPM. My Copen is a UK 659cc btw also the red line starts at 8K which happens to be where the limiter also lives. The reason I bring all of this up is because, I was wondering where the limiter would actually kick in, because looking at pictures of JDM Copen's, their red line is at 8.5K and I'm assuming their limiter is at Red line too? Anyway, how come JDM Copen's have 500 more RPM's to play with? Is it just an ecu thing? Why would they do that? And would it be possible/safe to install a jdm Copen ecu into a UK copen and get 500 more RPM?
I know thel Dsport ECU raises the rev limit but won't work on the UK copens. In my opinion unless you have installed a bigger turbo increasing the rev limit is a waste of time, the standard turbo starts running out of puff about 6.5K and power starts to drop off. I'd suggest shifting about 7k or earlier to keep in the max touque band.
You can't fit a Japanese ECU without changing the whole electrics I believe, somebody in Germany actually did that. As Jez said, you don't really want to go to the redline, it's a loss of power and acceleration. If you look at the graph below, you can see that both power and torque peak then begin to fall off way before the rev limit (this graph isn't great but I can't remember where I've seen better) so you want to switch before the power drops and keep the rev's between 3500-6500 as much as possible.
Interesting I read somewhere (I think it was a YouTube comment) saying that the ecu reduces boost after a set RPM to prevent the engine from making anymore than 63hp because of the kei regulations or something like that?
I've read the same, the graph certainly looks as if it's restricted from reaching it's peak there although I don't think that's a genuine rolling road graph. There's a couple on the site somewhere but I'd just paused Thor Ragnarok to get a drink so I couldn't be bothered finding them
The ECU actually retards the timing above 4ish K revs to keep under the limit. That's why the power flattens out as you see on the dyno chart above. When I had the Unichip installed most of the gains where from fixing the timing, I believe the Dsport does that as well but the main problem is the tiny turbo when it comes to more power.
What kind of power gains did you get when installing the Unichip? I'm curious to see how much the engine was restricted. Also, how come euro Copen's have 67hp and jdm Copen has 63? Is it the fuel we use in the uk?
Uk cars have a different ECU, so a slightly different map and aren't restricted as much by it, if at all. His thread is here Unichip on Aussie Copen and he got about 11bhp from the chip, that's at the wheels which is less horsepower than official figures, those are usually given from the engine flywheel and are higher because you lose power transferring through the transmission ect. The red is the stock hp (kw are 1.34hp) and torque on his pic here:-
you need this one.. DX SPORTS TURBINE KIT：COPEN but only for racing tracks..illegal on offical streets
It's legal to fit a bigger turbo in the UK, you can do practically anything as long as it still passes the emissions test for the MOT. And declare it to your insurance which is the painful part!
I've come across that turbo before, would get one but insurance would leave me broke for the rest of my life if I did
In reply to the first comment I hit limiter on the first day I owned the copen. 8k for Aus Delivered copens it seems too. Thought on this topic: The Jb-Jl engine which was pretty much the engine before the jb-det would rev out to 9.5k limiter a good friend that has one has informed me. From the jb-jl engines I have heard (only 2) of they have either bent rods or of blown a hole in the block. It is my guess that after the jb-jl daihatsu decided it maybe a good idea to reduce the limiter back to 8k so as not to do as much engine damage. I haven't taken turbo off a copen as yet or even looked into it but to increase the power output wouldn't it be an idea to make an adapter use a bigger or better turbo and up the boost more. Even if you have to run a piggy back ecu rather than increase the rev limit. I think it would be safer. I'm no expert so if I'm wrong someone please steer me in the right direction.
According to this website: JB-JL vs JB-DET Daihatsu engine comparison | Kei Throttle The JB-DET has slightly stronger con rods. still doesn't really answer why jdm Copens red line at 8.5k compared to the 8k redline in UK Copens.
Aaron, have you by any chance watched Initial D? Your music choice in the youtube videos gives me a strong suspicion Congrats on passing the test
I know this is an old post but I thought it would be helpful to those that still own these great fun cars... The Ultimate Copen was a up market more modified Copen released in Japan. White faced dials, Momo Steering wheel, extra inside add ones as well as outside mods. It also had a 8500 red line. I have fitted the dials from that model but only the rev counter & fuel/temp ones as the speedo is limited to 140kms and only good in Japan. When the D-Sport ECU is fitted it moves the Rev Limiter to 8500 as it also increases boost and adjusts fuel etc. Correct you can not fit one on the European Copens. But, for Countries that can not fit the D-Sport ECU and those that can not afford it then a another much cheaper option is to fit a manual or electronic boost controller. I fitted a manual one as it was cheaper and much easier to tune. It made a massive difference and it pulls really well in all gears. Easy to tune in as the Copens have a fuel cut which makes it so easy without a boost gauge. Just screw the controller a few clicks at a time & test drive. You will know straight away if you have over done it as it just dies when you accelerate. Then just screw it back, one click at a time until it doesnt die and then lock to that position. Job done! One Copen with heaps of extra power for less than $50, for me anyway. You will also notice after driving it for a while the ECU will adjust itself and I found it accelerated even better. With my other mods, like intercooler, intercooler piping, air cleaner, down pipe, exaust & blow off valve its a huge improvement.
