I'm digging that manifold. Really looking forward to it's completed state and some power figures.....and price.

First post over here, though I've lurked awhile :). My suggestion here is that you should not have to up your pulley size to hit an easy 220rwhp. It is an already known quantity, with a 126/65 pulley ratio, air/air IC and good tuning you should hit 220-230rwhp. That is running a JR header and stock exhaust. If you are running one of the bar/plate ICs then I know the answer. It is the IC that is giving you the bottleneck. I ran into this issue many times and eventually did back to back dynos while at BRP to prove the problem. With near identical core sizes (8x16x2.5 if I remember correctly), the bar/plate cost nearly 20rwhp compared to the tube/fin (Track Dog Racing). I think it is an airflow issue. Putting on the TDR IC is like uncorking the SOB LOL. Another possibility is a clogged CAT. Simple way to test that though it loud as heck.

As far as tuning goes, I found that the best combination of power and reliability occurs with a relatively flat 12:1 a/f ratio across all rpm and running the timing around 20 deg. You can probably run the timing up to 23-24 deg without ping on the dyno, but I would suggest backing it down to 20 to be on the safe side on the street and track.

Finally, I don't think there is huge gain you would see with a 2.5" exhaust. Removal of the cat will probably be the largest gain. The problem, I think, is the JR header is the bottleneck. This is a problem with the Hotsides. The Gibb header was very promising but it didn't work out unfortunately.

Bill

This Gibb header?........

Yep that is the one. Are they back in production?

Not likely.
I bought the header brand new last year from Bill at miataroadster. The header was unused and ceramic coated in and out. It performs and sounds great! I was talking with Gary@trackdog. We're gonna see if an MP62 blower will fit over it, just to verify.

Looks identical to the Gibb header, note that the top of the header primaries are all on the same plane (unlike the Racing Beat) so I think it will very likely fit under an MP62 Hotside. That sort of header is worth a lot of power at higher boost levels.

Bill

Welcome to the forum Bill ;)

I saw a 510 just the other day. It didn't look like much but I'll see if I can take some pics.

Why does your sig say you're stock?

Thanks Rafa! I know I have said this years ago, but one of these days I am going to get a 510 again. Really miss that car.

My Miata is currently back to normally aspirated. I removed the Hotside because the times got a bit rough and I needed the money. However, it looks like that situation is only going to be temporary. More on that later :)...

Bill

Good to hear from you. I'll see if I can take some pics of the local one.

I didn't clarify what I meant. It's not likely that anyone is producing them and it is a Gibb Header.

I made 250/200 in Sept 2007 at a Ft Lauderdale shop with mild tuning. Engine was built. I don't remember the pulley sizes, but I was hitting 12 psi-ish with a TDR IC setup. Injectors were RC 550s and a Hydra ECU.

The key is long primaries=POWER!

Funny how you need the extra horsies. I have a Brand NEW Gibb/Boig header that will guarantee you 12-17 horse (dyno proven) increase just from the bolt on. Problem is when I bought this header it was listed as a 1.6 header when it is actually a 1.8. PM me for pics and price. This header IS NOT for the faint of heart. You might get leaks until the primaries heat up and expand. Slip on primaires that are 1 5/8". All balls stuff. Here is a pic:
Attachment 205860

You are in an excellent place because you are only supposed to run this header if you generate 200+hp.

There is a guy with a 1.6 Tec2 Autorotor making 225 with a boig. I know you can do more. see it here: http://forum.miata.net/vb/attachment...chmentid=38527