Now you're talking! Eliminate (or minimize) the valve pockets and make the motor interference. Gonna be tricky getting to 13.5:1 but it will be NA glory on E85!

With the 2mm O/S exhaust valves and valve lift we're running, it'll be way interference. ;)

wrong thread.....

After reading this thread, I've come to this conclusion. The ultimate price comparative street engine would be a VVT engine with minor headwork (slight P&P with+1mm OS valves), a RB header and cat back exhaust, a square top IM and an after market ECU with tuning. :idea:
Am I correct? Or did I forget something.

Been done quite a few times, most recently with a rather dumb setup, in my opinion.

Street?
No, for street you want boost.

For track this is a pretty solid idea though.

N/A whp on a Dynojet? Define "quite a few".
GT3 Miata guys of which there are what.. 4-5, ever. Maybe a 2-3 barely legal EP motors. A few Japanese tuners with 2.1L builds. I'd venture to guess that there have been less than 25 or so genuine 200whp N/A BP engines in Miatas, ever. In street cars, maybe 2-3.

So yes, it's been done but not a bunch. We'll do it with a wet sump. Like I posted earlier, just because.

Still guessing at WHY?
 

Okay, there are sooo many ways to add power, not all of them smart and not all of them cheap. I still don't want to know WHY?! "Because cnc" just doesn't do it for me. Why'd you get drunk last night? Because cnc. Why is the sky blue? Because cnc. Nope, don't get it.

And then I thought, "okay, if I have a complete program to cnc-machine the ultimate BP head, then perhaps it would be very easy to break down the individual processes and replicate them on a stock BP head as needed." Possible? If so, this would be how to make cheap OEM heads fast....or fast OEM heads cheap.

While a cnc head would be a noble quest, machining the same dimensions on a stock head would be Miata heaven.

Reproducibility at a lower unit cost.

Someone can now buy the fruits of all the R&D we accumulated over the last 6 years of messing with BP heads. The head the customer buys is precisely our best performing head.

The "because CNC" is a riff on an internet meme that you're probably too old to understand. I'm old too, I just spend too much time on the interweb :loser:

I grew up after the Macarena, so it's all lost on me anyway. I'll be right back up to speed once my 8, 5 and 3 year olds get into middle school. :facepalm:

Until then, if you can easily reproduce that work on my OEM BP4W, let me know and I'll be right over. I want to bear some fruits, man!!! :idea:

Send your head core in and we'll CNC it. That's what this is, CNC machined heads that one purchases from us.

For a built engine, same deal. Tells us what your budget, usage and power goals are. We'll put together and custom engine package. Complete engines from us are not cheap however. For most owners looking for big power, it's more cost effective to just buy the CNC head and assemble their own bottom end.

I dont think you understand. The 949 cnc heads are OEM head castings that are CNC ported. They're not designing custom heads from the ground up and CNC machining them from a billet. That would be mega dollars unless its an american v8, and I mean, it would have VVT on both cams and a direct injection option.

YES, that is EXACTLY what I thought. All--or or most of--my respect for Emilio went out the window when I thought he was cnc-machining a BP head from billet. Holy CRAP batman! However, Emilio is not one to shy away from a challenge, so I just sat back and watched from the grandstands. :)

PHEW! My faith in humanity has been restored. :)

There are Race heads available for I4 blocks with 91mm bore spacing. But it have not been mated to a BP block (pick up a head gasket from a Volvo V40 if you want to see if it's close to possible).

But casting a new head is a little different than using CNC in a smart way to make reasonably similarly high performing heads out of the Mazda castings.

I'm happy to see the dyno comparison of the RB and Maxim and seeing that they have shown pretty similar dyno plots I wonder if there isn't another aspect to this namely throttle response. The Maxim has a 2" collector OD and the RB has a 2.375" OD and generally they are paired with exhaust that have the same OD. I have driven my 1996 NA8 in in a few configurations Stock, Stock header without a cat back, ported stock exhaust with just the resonator and ported stock header and cat with 2.25" mazdaspeed catback. I noticed that without the cat the throttle response was the slowest and the next slowest I thought was the 2.25" mazdaspeed catback and the 2" stock versions of the exhaust had what felt like the quickest response. I primarily street/autocross my car and that might make throttle response more critical to me and from what I have experienced I still think that for autocross the Maxim will result in lower times. I'll go ahead and put my flame suit on and see what you think.

There's been a couple of the Japanese tuners recently doing it. Again, not with setups that necessarily make sense to me, but the peak number is there.

I'm betting that you'll do a bit better. :)

I think you will send Maxim Works your money regardless of the data.

The only dyno I've seen was for the 2.1L Maruha. Stroker with 85.5 pistons. Chikara's was on a Dynapack, which in my experience, reads 8-11% higher than a Dynojet. The original one was that Garage Hundred One 2.1L with a sequential trans. That one was said to have made 210whp or so IIRC. GT3 motors were in the 240whp range but that's dry sump, 14:1 compression, 50m ITB's, no one home below 5000rpm, 3-6hr service life and about $25K to build.

Ours will not be a stroker so we're already at a disadvantage to the Japanese 2.1Ls, in theory. I have a few ideas though that should give us good midrange torque while still pulling to 9k on top.

Anyway, it's a fun project and we'll learn a lot from it. We're experimenting with cams and intake manifolds primarily. So far, I'm of the opinion that very little gains are to be found beyond the OTS racing Beat header. What we have seen is the BP's sensitivity to cam overlap period more than lift. This comes from the low rod ratio and shallow valve angle I think. It's cylinder filling at low lift is pretty good but ho-hum at high lift compared to a steep port angle motor like a K20. Lots of overlap means EGR, low vacuum at low rpm and not so awesome idle qualities. We want to figure out where the boundaries for daily driveability and big power lie. If we come up with a worthwhile cam design, it will go into production and be an option with our CNC head.

We have also observed how sensitive the BP is to intake piping and manifold design. This, more than anything else is where the power is in this engine. The square top flows well up to about 175whp N/A or well past that F/I. Eventually it runs out of CFM even though the lengths and diameters are almost perfect. Better internal shaping and flow than the USDM VICS (NB1) and VTCS (NB2) but still along way from awesome. All the Honda manifold hybrids are simply too short. ITB's always work but are not practical for street use and far more difficult to tune. I believe there is much to be gained with a proprietary single throttle body manifold (STB) design. I'm not sure we'll be successful but if we are, we'll find a way to produce the resulting manifold.

And you should probably be sending it to murahahaha instead if you want a sexy as fuck looking $1500 off the shelf header that probably doesnt make any more power than a racing beat.

Anybody that reads MT.net and buys a Maxim Works header is an idiot. The dyno doesn't lie, especially Emilio's.

85.5s need a 5mm stroker crank to break the 2050cc barrier. Maruha's crank is an 89mm crank, which measures out to ~2044cc. Kind of silly and a little disingenuous on their part to call it a 2.1L, IMO.