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12get wrote: When the engines are imported to europe, the guy who imports them already removes the speed limiter in the ecu.

Wonder how he does that? Usually you just cut the wire going to the speedo. No signal, no limiter. Anyway. Adding NOS would probably improve your top end.

it's possible. probinator chipped ECUs have the speed limiter removed through actual software changes. i highly doubt an importer would do this to every ECU he has coming through though...

Not only do I agree but in doing so it could become an issue of liability. Speed limiters are a safety feature are they not?

Danny, 150 will kill you just as dead as 250.

Liability, I think is a non-issue, insurance covers stupidity all the time. They can sell you a gun, but you have to shoot yourself...

No the ECUs are definitely not chipped, maybe the Pin is disconnected inside, would be the easiest way. Unfortunately I do not have further informations regarding this. If I do remove the ECU next time, I could have a look inside.

As I wrote before, I use topspeed as an indicator of overall performance. And there I do not see any improvements to my K8. Getting 5 kmph more from a KLZE swap than a K8 cannot be correct. Checking topspeed on downhill brought only a plus of 5 kmph.
Acceleration and torque have improved. However, if I compare acceleration from 120 to open end with the MX-5 (140HP) of a friend, he can absolutely keep up with me. I nearly cannot get away from him. Although his car is equipped with a full body kit including rear spoiler, mine has only a decent front spoiler lip.
The KF transmission is the longest available, longer than the MX-6, you can have a look there http://www.mx-3-tom.de/tutorials_k_trannies.html" onclick="window.open(this.href);return false;
So of course I also was wondering if it could be too long, but if so, the more power I should have from the KLZE should make it at least possible to get it in 4th gear to the rev limiter, but even in 4th gear I stuck at 7200rpm.
And the fact that I know from another MX-3 with KLZE and KF transmission that performs much better, hits the rev limiter in 4th, without any further modifications, definitely tells me, that my KLEZ lacks power.
The question now is why? What could be causing the poor performance, where is the fault?




About top speed and it's risks:
Of course I do not run top speed all the time, that is not my goal and the traffic would not allow this, too. I check this only besides the rush hours, when streets are nearly empty. And if we get solve the problem of power lack and I can reach higher speeds, I would use this only sometimes. Normally I drive around 120-140kmph.

It is also a bit different if you live in Germany, you are used to the speeds and it's not so special about this.
I could say that I have grown up on the backseat of my farther's car while the speedometer needle hit the 200km/h needle. Driving even faster like 250 is not so unusual in Germany.
You, in the US, have other things in life that are usual. If I would claim, that my father has a gun in his cupboard, someone would immediately call the police. In your country, someone would ask why only one?
So let's get back to topic and end the discussion about risk of speeds.


Thanks for reading all the stuff.

12get wrote:The KF transmission is the longest available, longer than the MX-6, you can have a look there http://www.mx-3-tom.de/tutorials_k_trannies.html" onclick="window.open(this.href);return false;

That site agrees with me, the 323 KF is actually the shortest geared and the MX-6 is longest, if you have a Xedos 6 KF trans, it might be a little longer than the 323KF but look at the final drive, both KF have 4.390 which means short gears. The final drive makes the biggest difference.

The lowest final drive will make the longest gears. I think you may have performance problems with the engine but the gearbox will not help top speed. Get a dyno for the best idea on how much power you have.

http://www.youtube.com/watch?v=pDCHjC5gh94" onclick="window.open(this.href);return false;

See this guy on you tube, pretty sure he has a MX-6 gearbox, at 6000 rpms he is already over 200kmph.

Using top speed as an overall performance indicative is inaccurate. Top speed will only show you the engine's high end torque, relative to the car's aerodynamics.

12get wrote: The question now is why? What could be causing the poor performance, where is the fault?

No. The question is why you haven't taken your car to the dyno yet. The fact that your engine is not reaching its top RPM in 5th gear is clearly telling you (being that you know of another car, with the same setup, that does), that your engine is lacking high RPM Performance. Once you know that, you need to know WHY that's happening, instead of speculating about the possible causes.
The possible causes are many, from a dirty air filter, to poor compression, wrong ignition timing, ect, and, without any hard data to base our opinions on, we're just shooting blind. Get us a nice dyno chart, and we may be able to help you.

A tune up is a good idea anyway....

Having the Xedos 6 KF transmission.
Well, I have to correct a bit. The other MX-3 I mentioned, that is running KLZE and same transmission and hits 240kmph is heavily tuned, Megasquirt and so on, didn't know that.
So because I do not have same setup I cannot expect same performance, of course he will perform better.

Next step I will try, is increasing fuel pressure, got this advice from one guy in our german forum, this did solve his performance problems.
If it still is not getting much better, I will take it to a dyno, before I try anything else.

And then I will see if I am having the problems because of the transmission or if I have less HP than I expect to have.


Thanks so far.

Btw.: air filter, compression, ignition timing, of course all has been checked.

Ah, I can not swap in my own engine, but one who does, it has been several times, I would definitely say that he knows how to do it. The other thing is, I also asked him if this may be because there is a governor, but he believes that no effective transfer speed of limiter.The different problems may cause you.

I would say until you get a dyno, you aren't going to know what's going wrong (preferably a dyno with a wideband 02). I was having similar issues in my race car klze/4.39 tranny/probinator ecu and after the dyno I found out the fuel pump wasn't keeping up (I couldn't go above 120mph/200kph). The car just wouldn't go any more above that speed! I also installed an adjustable fuel pressure regulator with a gauge so I could monitor the PSI.

With my Daily Driver that has a klze/4.11 626 tranny/kl36 ecu (with limiters removed) I was at 140mph/225kph @ 6500 rpm and then around 7300 @ 150mph/240kph, I didn't try to go much faster after that (I went to what I think was about 155mph) and let off. I've only been that fast once in my mx-3... Although there was a period in my life I was hitting 140mph regularly...

The OEM speed limiter is set at 120mph/200kph on alot of kl31/kl36 ECUs...

Thanks, that's nice to hear.
I will get an adjustable fuel pressure regulator to the end of this month for some testing days.
If it still does not feel better I will take the car to a dyno.
But as this is already the fourth case I heard of, where the fuel pressure regulator did solve the problem, I am fairly confident, that this will solve my problem, or in other words: I hope so.

I hit 240 in mine with my Mx-3 trans

Nd4SpdSe wrote:I hit 240 in mine with my Mx-3 trans

I don't know exwctly how much I hit, but once I'm sure it was way more than 240. Actually, it wouldn't surprise me if it was close to 300.

Yeah...you wouldn't believe how hot the engine got...

In what, an MX-3?

I call bulls---.

0.795 5th
4.388 FD
205/55/15
7500 RPM

top possible speed = 278 KPH. We run out of power much before that point.

Bigger tires you say?

We still run out of power before that point.

Different trans?

We STILL don't have power for 300 kph. No matter what gears you cram 130 HP through, it still doesn't make more than 130HP. Conservation of energy!

I'm giving you benefit of the doubt on the 300 BHP N/A K8 stuff, but you can't push this one.

And I'm pretty sure the engine wasn't that hot. That's a massive airflow at those speeds. Dyno cars probably get the hottest, unless you're dumb, bouncing off the limiter in 1st down the highway, or in neutral...