JayL

iTrader: (12)

My car is an 2001 and I want to put a 2000 engine it. At some point in time I will have to put the factory ecu and injectors back in it for emissions testing. They will check for codes as part of this and that's where my problems start. Is it possble to fool the factory ECU somehow so it won't throw a code? What should I do? My options seem to be: fool the ecu somehow, put my stock 01 head on the built bottom end, or get an 01 built and sell the built 2000 motor?

patsmx5

iTrader: (16)

Cheapest would be to fool the stock ECU. But would be a small step from impossible.

Best would be to build your 01 and sell the 00 motor if CEL lights and OBD codes have jurisdiction in your decision. Then you could just swap the Hydra and 750's for the stock ECU and stock injectors and go pass any test.

y8s

iTrader: (8)

I kinda want to post my dyno results...

I say use the built bottom end with the 01 head. swap over the MBSP and oil pan from the 2001 motor.

JayL

iTrader: (12)

Searching through all your old posts on here and .net is what really got me wanting to keep the vvt, but this 00 engine just fell in my lap and opened up many different options.

Here's another thought, if I built up an 01 head would that in any way effect how the stock ecu reacts (ie codes, etc) when I run that for emissions? Since it will be apart I don't think I could resist the temptation to make improvements.

y8s

iTrader: (8)

a mild build wont affect it. significant changes to the ports or duration of the cams might. a typical polish and valve job wont change a thing.

JayL

iTrader: (12)

What difference in power at the 300-400 level would we be talking between stock and a typical polish and valve job? From what others locally have told me it will be around 20 or so, but the biggest difference would be how it adds down low and helps with spool. I am having difficulty finding anyone that's even messed with an 01 head, much less combined it with a built bottom end.

y8s

iTrader: (8)

some day the spare 01 head and block in my shed will answer your question. From what I know, the later heads are pretty good as-is in terms of geometry. Really just smoothing things out, unshrouding, multi-angle valve job, etc. is going to gain, as you said, spool and a little bit of power everywhere.

I think I'd be happy with 20 hp and a few hundred RPM improvement in spool for just a little basic head work.

JayL

iTrader: (12)

That was painless. Guess I'm going to go with the 01 head and save myself the headache of trying to rig it up to pass emissions. Now to figure out the expensive question. Should I just get the 01 head built the way I want it done and split the other motor. Or just start from scratch and have a complete engine built. Why can't I ever be the guy who is happy keeping a car stock?

Joe Perez

iTrader: (8)

How much "building" do you have in mind for the '01 head? Apart from taking a few minutes to smooth out the runners and perhaps twirl the valves on their seats with some lapping compound, I can't really think of much more I'd do with it. Maybe send it out to extrude hone if you're really feeling exotic.

Seems like, all else being equal, you might as well just split the '00 engine, drop the '01 head onto it, and call it a day.

JayL

iTrader: (12)

I have absolutely zero experience with this so I really have no clue at the moment. I see the most I would want to do is listed on FMs website for their built head and the minimal is the stock head that's currently in my car. Whether I can get to my goal of 400 will determine which way I go. I'm very limited on what I feel comfortable doing myself. I can replace parts and follow instructions, but this part of the project is taking me into areas that I feel less than comfortable with.

patsmx5

iTrader: (16)

Don't "build" the 01 head, but rather modify it to perform better. A few brief thoughts:

You don't need bigger valves
Unshrouding the valves you have will make for large gains.
Stock undercut intake valves will flow better while reducing reciprocating mass, increase valve train stability, and negate the need for any other valve train upgrades.
New SS exhaust valves is something I would do. And extra wide exhaust seats to keep them cool.
New valve stem seals.
Blend the bowls into the throat and into the combustion chambers. (huge gains here too)
Buy a book to learn how to do all this on your own.

200 for the book and other things you'll need to do the headwork and 60 hours of your time. (30 learning, 30 working the head), and you will have the second best flowing head on a miata.

Or settle by paying FM 2K to "build" it and you will see moderate gains for much more cost.

JayL

iTrader: (12)

I'll be back in a few weeks after I get done doing some research on all of this. I value my time, so having FM do it is definitely still an option at this point, but very unlikely. Once I learn a bit more about what's involved it will be easier to decide. Any recommended reading material out there to get me started?

patsmx5

iTrader: (16)

How to Build, Modify, and Power Tune Cylinder Heads

4-Cylinder Engine Short Block High-Performance Manual

Those are a start. There are other books on porting that are more comprehensive, but that one is the only one I know of off the top of my head. Same applies to the second book. I don't agree with everything in it, and it leaves some things out, but overall it's pretty good. Definitely worth reading.