You guys should watch the video linked to in the for sale ad... 4 wide SM finish at CMS...extra gewd stuff!

Just go the custom piston route ;)

Damn! That was awesome. Like watching the Blue Angels.

K series pistons are already short as fuck for car pistons.

the piston length doesnt have to change. Just push the wrist pin up into the oil rings.

4 piston racing makes a longer rod setup for the k24. Cost? That I don't know.

Got some awesome intake manifold testing to post up when I have time.

Long story short, we tested 4 manifolds, two headers, and managed to pull 17whp more out of the car. It's linked on the FB page right now, but I'll try to get it on MT.net shortly.

Nice comparison David. I wonder how much the throttle body accounted for the differences. It would have been great if that variable remained constant. The 74mm to 90mm shows nothing is gained when going larger anyway.

Thanks for sharing!

At this power level, I wouldn't expect the TB to be worth more than 1-2whp given that the base is already more than large enough. F/I past 300whp and I think we would see more delta.

I'll have some data on that soon enough. I swapped my 62mm for 74mm. It will be the only thing I will have changed before the re-tune. I don't think it will make more than 3hp difference but you never know.

Andrew had a 74mm that fit my manifold up for sale. It looked really cool. I could not help myself. If it makes HP I will be thrilled.

I know this is an old post I'm replying to and you've already got your solution, but this is probably a decent solution depending on the K-series heater hose setup. Would it potentially be helpful?

From GoKart's thread on m.net
https://www.miataturbo.net/attachmen...ine=1427213101

https://www.miataturbo.net/attachmen...ine=1427213101

Link to pictures with heater core and hose modifications:
MX-5 Miata Forum - View Single Post - GoKart's LS2 NB Build Thread

https://www.miataturbo.net/attachmen...ine=1427213101

https://www.miataturbo.net/attachmen...ine=1427213101

https://www.miataturbo.net/attachmen...ine=1427213101

https://www.miataturbo.net/attachmen...ine=1427213101

<p>To all the Californians out there...&nbsp;</p><p>&nbsp;</p><p>Is it possible to get a 1991 k24 swapped miata BAR approved for legal street driving? It seems like I would have to use all of the honda sensors and emissions equipment and ECU. I'd probably have to swap the complete harness and achieve full OBD2 functionality. The electrical/wiring side will be a headache...</p><p>https://www.bar.ca.gov/Industry/Engi...uidelines.html</p><p>Do you think this swap driven legally in CA is possible?</p>

Not an expert on BAR regulations by any means but a couple things come to mind immediately:
-The fuel system on the NA is a return style instead of returnless. Pretty sure a BAR legal swap will require a retrofit of a returnless style fuel system. The NB is returnless so that would probably be a better choice.
-I believe you need BAR legal exhaust/intake manifold if they're not OEM correct? That will be a challenge. Andy Hollis had a setup that worked with OEM parts on both sides (in an NB) but it would be a pretty significant compromise.

I would read some of the swap stuff on K20A.org because they have a lot of experience with BAR legal swaps into older chassis.

Or just move out of California. :party:

One thing to consider is that the engine must be newer than the vehicle. So you could (probably) get one legally into a 1990, or maybe 1991.

isn't the header usually the biggest problem?
When they say all emissions equipment, they really mean ALL OF IT. like, down to the very last detail. And it cant' be modified in any way.

This. Going through the BAR process is not a joke. The best chance the Miata community has at a BAR approved swap are NBs using the LFX. You can purchase CARB approved LFX crate engines straight from GM IIRC.

Well kind of.
There are something's that simply will not work. In those instances, the referee can make exceptions. The best thing to do is go and talk to your referee before you begin the build. Bring him some detail on the areas you know will be a problem. See what he says. If he is a complete hard ass you'll be screwed. But most of those guys are car guys and if they see you are doing everything possible by the book, and this one thing just won't work without mods... They'll give it to you.

^ this of course is for individuals doing swaps. Not for company's going for full CARB cert.

Yup. ALL OF IT always means ALL THE CATS as well.
One of the major sticking points for the BAR approved 5.0 swaps here in :eggplant:.

I mean. California.

K swap aint going to happen with carb. exhaust would need to route through the front wheel.