Differences 99-00 to 01+

[CARBmiata]

Sorry, I am new to the miata community and looking to buy an NB. Hoping to supercharge it, keeping it CARB. But why are the 99-00 separate from the 01+ NB on this forum? What changed? Thanks.

[CARBmiata]

Did some homework. Variable valve timing is the culprit of the kit change?

[Wayne-n-Fla]

The VVT and higher compression

[Tom @ Fast Forward]

Only difference in the kit is the harness for the PC-Pros. They have different connectors on the ECU.

[Kyp J]

Only difference in the kit is the harness for the PC-Pros. They have different connectors on the ECU.

This brings up a question I have had in my mind and don't remember if I ever asked it before. (There are some disadvantages in being old after all.)

In the MSM 04s and 05s, I have heard they went back to a 99 "style" head. IOW no VVT. Did they go with a completely different 01+ ECU or go back to the 99 ECU. I am not sure if any thing else significant changed from 00 to 01. I probably knew at one time but I forgot.

[Tom @ Fast Forward]

Engine wise, I believe the VVT and 10:1 compression pistons were the only changes of interest.

Interesting question about the ECU? No idea but my guess would be that they used the 01-05 ECU and dropped the software for the VVT. Easy to tell. Find a MSM and count the rows in the connectors. The 99-00 had two rows of pins and the 01-05 has three rows of pins.

[Kyp J]

Engine wise, I believe the VVT and 10:1 compression pistons were the only changes of interest.

Interesting question about the ECU? No idea but my guess would be that they used the 01-05 ECU and dropped the software for the VVT. Easy to tell. Find a MSM and count the rows in the connectors. The 99-00 had two rows of pins and the 01-05 has three rows of pins.

OK Next one I see at Wallmart with the top down I will jump under the dash and start unplugging things. I may be delayed visiting by the end of May. Maybe 3-5 years.

[Tom @ Fast Forward]

What worries me is that I can visualize you actually doing that. :tank:

[ThomS]

Ok under the dash of the 02 there are three rows of wires in a rainbow of colors going to the ECU.
In the 05 MSM there are three rows of wires in a rainbow of colors going tothe ECU.
Both cars the plugs that go to the ECU look excatly the same.
Now I only looked at that section of the car and touched the ECU wires again so Kyp J won't go to jail and be late for your party Tom.
:sweatdrop: :sweatdrop: :sweatdrop: :sweatdrop:

[Tom @ Fast Forward]

Thanks. That answers the main question. They must have used the 01-05 ECU and simply deleted the code for the VVT. That would make more sense than to use the 99/00 ECU.

[Scuba Steve]

OK Next one I see at Wallmart with the top down I will jump under the dash and start unplugging things. I may be delayed visiting by the end of May. Maybe 3-5 years.

THat might be best case. Worst case, you might wake up dead :nono:

[Kyp J]

Thanks. That answers the main question. They must have used the 01-05 ECU and simply deleted the code for the VVT. That would make more sense than to use the 99/00 ECU.

Thinking (or something similar that I do in place of it) more about it, I was trying to imagine how they handle the fuel issue in boost. I guess they must have at least a boost detecting switch to tell the ECU to use a modified process similar to whatever they do when they go open loop in hard acceleration on a normally aspirated car. I tried looking in the MSM sub heading on Mnet and got lost in the chaff. Apparently there is a lot of upgrading of turbos in that group making the use of after market ECUs necessary.

Quote:
"What worries me is that I can visualize you actually doing that. :tank:"


Actually, I learned early not to touch anybodies stuff without explicit permission. I didn't like the "constructive criticism" I got when I dumped the change to see how it worked on the city bus I was getting on when I was about 12 years old. I had to walk about 5 miles to my grandma's house.

[Tom @ Fast Forward]

Actually there is a "boost" sensor but I'm not sure, on the newer models 99-05, what exactly it does. I thought it would set the ECU to Open Loop but it appears not. The Long and Short term fuel trim continue to work at atmospheric pressure and the ECU still tries to control to stoich. A Stock Miata can't actually reach atmospheric pressure so the switch surely wasn't designed for higher (boost) values? The only thing I have seen, so far, that actually sends it off to the Open Loop lookup tables is the TPS at WOT.

PS. We all owe a debt of gratitude to ThomS for keeping Kyp out of jail/morgue so he can come and visit on Memorial Day Weekend. ;) Some of those 'Good 'ol Boys' in Texas carry and don't like people messin' with their babys. That includes their girlfriends but starts with their trucks and Miatas. ;)

[Kyp J]

I was a bit worried about moving to "tough guy" Texas with a Miata since I had been told after I got it that they were "girlie" cars (only not that nicely) but I figured I was old enough that it didn't matter. (I did get a few suspicious waves from strangers at first that kind of worried me.)

After being here awhile I see more Miatas than I thought existed and they are mostly driven by non girls. There are a lot of them at the autocrosses as well.

Girlfriends are part of the "stuff" of other people I don't touch, even with their permission.