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Discussion Starter #1
Hey guys, love the sight. I drive a 93 mx6 Ls. Im looking for a boost in Hp just like the rest of you. I heard of the Jspec engine you can swap with the 2.5 V6 in the car already. The Jspec gives 200hp at the flywheel as opposed to the 164 in the American version. I would like to know who has the Jspec in their cars now and what modifications did they have to make to get it to run(ie. new motor mounts?...) Also, anyone tell me why the Japan motor gets so much more hp then the American, is it a higher compression ratio or new cam? Let me know.
 

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While I don't have the KLZE (that's the designation of the J-spec motor), here are some answers for you:

The engine drops in as a direct replacement for the KL03; it's got the same mounting points etc. No mounting mods are needed.

The KLZE was mounted in several different JDM (and other markets) vehicles and was fitted with intake manifolds that varied slightly from one another in the area of the throttle body - some came off at a weird angle making adapting the OEM intake system tough. Most places selling the KLZE have that worked out now and know which engine to get.

The KLZE uses higher compression (10:1 versus 9.2:1 for the KL03), different heads with larger ports, a much different intake manifold and, IIRC, different camshafts than the KL03. It doesn't make alot more peak torque than the KL03 but it does make much more torque over 6000RPM.

Because the intake is so vastly different than the KL03 intake, the VRIS points are different. From looking at some KLZE PROM code, the ZE points are:

0-4062: both closed
4062-4781: #1 open, #2 closed
4781-6812: both open
6812-fuel cut: both off

The KL03, by contrast, is:
0-3250: both closed
3250-4250: #1 open, #2 closed
4250-6250: both open
6250-fuel cut: both off

By using a KL03 computer with a KLZE engine, the VRIS points will not be correct, causing less-than-ideal output from the engine. A KLZE computer cannot be used with the KL03 VAF because they are calibrated differently. The best solution is to get the KL03 computer's VRIS points revised if you go to the KLZE.
 
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[Because the intake is so vastly different than the KL03 intake, the VRIS points are different. From looking at some KLZE PROM code, the ZE points are:

0-4062: both closed
4062-4781: #1 open, #2 closed
4781-6812: both open
6812-fuel cut: both off

The KL03, by contrast, is:
0-3250: both closed
3250-4250: #1 open, #2 closed
4250-6250: both open
6250-fuel cut: both off

Mike,

the klze ecu dyno plots i have seen at corksport.com on there project MX-3 show the same VRIS points as the stock unit. Tehrefore, the chip will not make a difernce in performance.
 

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MX-6 BOY said:
the klze ecu dyno plots i have seen at corksport.com on there project MX-3 show the same VRIS points as the stock unit. Tehrefore, the chip will not make a difernce in performance.
Well, those plots look like they are all done with a single PCM. In the install section, they said they "...also installed Mazdaspeed motor mounts and a KL_ZE tuned processor" so those ZE dyno plots are all with the "ZE tuned" PCM.

I'd like to see them "retune" the PCM back to KL08 specs and run the test again. The KLZE they used had a slightly different intake on it than others I've seen. The VRIS points, two of them at least, on that chart look like about 3850RPM and 4650 RPM, not far off what I said (4061 and 4781.) It might be that the slight manifold variations require slight differences in VRIS points.

As well, a couple of the stock KL08 points are not all that much different than the KLZE points: 3900, 4700... The KL03s points are quite different from both of these.

In the end, I've seen the actual KLZE PROM code and know the points to be alot different than what the KL03 PCM does. To really conclude one way or the other, I'd like to see a KLZE dyno'd with a KL03 computer and then right away again with a KL03 with modified VRIS points.
 
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Discussion Starter #5
Confused

Isn't is possible to get a KLZE PROM to replace the one in the KL03? Would you please explain the PROM and VRIS points to me. Is the prom just the chip that needs new commands burned into it? I am very impressed with response I got back from Mike. I like reading the messages you give back to other peoples questions. You actually give information as opposed to saying what you think looks good or sounds good.
 

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Re: Confused

Mx6Man said:
Isn't is possible to get a KLZE PROM to replace the one in the KL03? Would you please explain the PROM and VRIS points to me. Is the prom just the chip that needs new commands burned into it? I am very impressed with response I got back from Mike. I like reading the messages you give back to other peoples questions. You actually give information as opposed to saying what you think looks good or sounds good.
The PROM is memory in the PCM that contains the program the PCM's microcontroller runs and it also contains calibration data the program uses to calculate things like spark timing, fuel delivery, VRIS operation etc. All told, something just over half of the PROM (about 17K bytes) are devoted to calibration data, the rest to the program with unused bits here and there.

The KLZE and KL03 PROMs are remarkably similar to each other, with the biggest differences in occuring in the VRIS points & strategy, the main spark timing table and the VAF linearization table. To visualise the spark timing tables for instance, go to my web site and look under the PCME page. Near the bottom I show graphically the two spark timing tables. They are quite different.

"VRIS points" refers to the RPM at which the PCM switches the VRIS plates to a new configuration. In the KL03 for instance (assuming more than 2.75V of throttle), the PCM sets both VRIS plates to the closed position from 500 to 3250 RPM. When the RPM hits the 3250 "point", the PCM opens the #1 VRIS plate. Similarly, at the 4250 point, it opens the #2 plate and at 6250, it shuts them both again.

The "points" at which the plates are switched is programmed into the PROM and are determined from the design characteristics of the intake manifold. That is, in certain RPM ranges, the intake pulses from each of the cylinders resonates with the natural frequency of the volume inside the manifold. At this point, there's a small (but noticeable) "supercharging" effect as pressure pulses, enhanced by constructive interference due to the resonance, pushes air into a given runner. The strategy of VRIS is to try to make the manifold have several of these resonance ranges, thus maximizing torque, by varying the effective lengths (and thus volume) of the runners and plenum. This is primarily the function of the VRIS #2 plates. The VRIS #1 plate opens or closes the passage through the small "loop" on the passenger side of the intake (near cylinder #1) that connects the two plenums (cylinders 1, 3 and 5 share one plenum, 2, 4 and 6 share the other). By doing this, the pulses from cylinders 1, 3 and 5 can help cylinders 2, 4 and 6 and vise versa...but only in certain RPM ranges. In the case of the KL03, it's in the 3250 to 6250 range. Outside this range, not only is there no benefit but it might be detrimental to have the plenums connected; it may lessen output due to destructive interference.

Just by looking at the two types of manifold (KL03 and KLZE), it's clear they are physically quite different, with different internal volumes, runner sizes, shapes etc. As a result, the KLZE manifold has different resonance points than the KL03 manifold.

If the VRIS points are wrong, the torque curve will have drop-outs in it as the engine passes out of a resonance range and the plates don't change properly. For example, way back when when I was first playing with the VRIS points on my PGT, I lowered them a few hundred RPM. Compare

http://home.golden.net/~trinity/dyno/run3.jpg

with

http://home.golden.net/~trinity/dyno/Run5.gif

in which the points were returned to near-normal. Look at the torque curve for run3 at 2900 and 3750...look at the sudden drops in torque. In run5, things are much smoother. Even though the dip at the 4250 isn't tiny, clearly the engine has a much easier time pulling itself back up again, compared to run3.

This is why I say that, to get the most from a KLZE conversion, the PCM must be re-programmed with at the very least, the KLZE VRIS points, if not the KLZE spark as well.

A KLZE PROM cannot be used directly in the KL03 for several reasons. Primarily, the VAF used on KLZE cars was different than that on the KL03 so the PCM wouldn't be getting the correct airflow data. As well, the KLZE PCM doesn't have a baro sensor so the fuel calculations might be incorrect and it also doesn't have any EGR actuation hardware. One can, however, given the tools and knowledge, copy the VRIS activation points & strategy from the ZE to the 03 PROM (ensuring you get the addresses right :)
 

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hmmm, my brain just got another wrinkle or two!
 
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