Power expectations from a ported cammed BP4W
 

Hey guys, I haven't really been able to find expected HP numbers for my upcoming build.

Here's the specs;
BP-05 with a BP4W head, the head itself has had a very basic portwork, I believe it to have a slightly mild increase over stock, either way I got it for $100 and it will be way better than the BP-05 for now.
It's will getting a port match and polish on exhaust side.

Cams, I have about 275* with about 8.5-9mm lift in mind, don't really want to go digging away the lifter bosses, I'm getting a billet ground up. I'm still very undecided on duration though but I will be having adjustable cam gears.
Will have upgraded valve springs and retainers and shim under bucket lifters

Pistons I'm still yet to decide, I was thinking 9.1 for the moment as I will be bolting up the T28 I have sitting here for ages now, just need the cash first, but either way I will be beating around NA for a few months or so.

ECU is DIYPNP
intake and 4-2-1 headers

I'm looking at roughly about 150HP, does this sound about right?

What fuel?

If you aren't running E85, you are going to want 8.5:1 for FI.

Your T28 could get you to 250+ without any headwork or cams.

Edit: I see, you want to know how much power you will be making n/a before you put the turbo on. Gotcha. The Miata N/A Power Bible as told by Emillio

Is there differences between your 93 octane and 98 that I get here in Australia? I'd like to run E85 majority of the time but id also like the flexibility of 98.

Yeah I know the headwork is unnecessary for my 220hp power goal but i've gotten everything (for quite cheap) minus the cams.

But thanks for that link, I'll read into it :)

Also in Australia, everybody that is hitting 250hp is doing fine on 9.1 on 98. I'd love to go 11.2 but I don't want to be restricted to purely E85

I'm also going 9.1 because I'm just planning on reusing the stock pistons with a re-ring and hone, and some forged rods just for peace in mind that I won't bend something incase I do ever see 250-280hp.

How does a 8.5 cr motor perform NA anyways? I have this big fear of sacrificing response for power levels way beyond what I would ever need/want.

like crap

Haha yeah I figured. Seems like I'll be able to hit 150hp with just bolts ons and a tune. Whereas other information I've gotten said I'd only hit 135hp. I'm not sure what to believe now :/

LOL you realize that dyno variations can be up to 15+hp. If you really think all these "predictions" are within 1hp of the actual results you should see you're dreaming.

What the guys suggested are solid mods though, and should result in a nice little n/a track car you can rely on.

Yep fully aware, there's a mx5 specialist in Sydney and their dyno is is quite optimistic so to speak. Either way if I can get 150hp NA I'd be happy. It would be quite a fun street and track beater until I slap the turbo on

It's just nice to know how much power I can expect, I'm getting all excited to get the motor done and drop it in with the 6 speed :)

For 150 whp: get a 99-00 head with P&P work, +1mm valves and MSM intake camshaft, a VVT bottom end, tuned ECU with AFM delete, I/H/E.

That stuff above should do the trick.

Remember to account for the temperature as you are in 30degC average day temp. I would want to run e85 on any hi powered car over there.
You'll need some serious cooling power!
I'm lucky that I live in NZ and an average day is 13degC people here run huge power with very little worry about to much heat