So after like eight months of sitting outside and creating a patch of dead grass underneath it, we got the engine together and installed it. I'll post a photo before continuing...
So, 2003 engine with 43k miles. Didn't touch the internals so no chance of anything going wrong this time
I did have the head resurfaced though and I also removed casting imperfections from the ports.
I'm using AE111 throttle bodies and SQ Engineering velocity stacks as well as Garage Star water pump and alternator pulley.
So after Punknoodle mentioned Sam from SQ Engineering, I immediately contacted him and we began discussing possibilities for a Miata coil bracket. After months of conversation and design changes we finally narrowed it down to one, low cost, simple to manufacture solution. Because he uses a water jet to cut the aluminum I had to avoid making it into a 3D shape, besides the countersunk holes he will drill out by hand.
We also decided to use 1NZ coils instead of the 1ZZ coils. The 1NZ coils are the same overall height but the rubber seal part that presses on top of the valve cover is actually higher than the 1ZZ coils. This gives the section that actually fits inside the head a greater length which is perfect for the Miata application. The 1ZZ coils have been the miata standard for COPs with everyone buying the ugly flat plate with studs on it to mount them (or worse.) Anything thicker than a flat plate and the 1ZZ coils couldn't reach the spark plugs. Now there will be a bracket that looks great and exclusively uses the nicer, lower profile, 1NZ coils.
Sam shipped the bracket with their last shipment of parts to Battle Garage in California (their distributor) and they're going to ship it to me when they receive it. I will then Install it and post some photos on the Miata forums and hope to create some interest for the product. In return, I paid nothing for the bracket.
I've been driving it without the bracket and it seems to be fine so far. The coils pop up a little bit but stop after a certain point, still reaching the plugs. I'm also using UNI sock filters (not shown in photo.) I wanted to use the ITG JC40-100 filter but I don't have enough space with the throttle pointing parallel to the ground as opposed to the ones that point up. My other option is to use the ITG sausage filter since it doesn't stick out as much as the JC40. It's also more flexible. I really want to get it soon too since using sock filters totally defeats the purpose of having a properly contoured velocity stack.
Now to the tuning part. ITBs naturally produce less vacuum than plenum manifolds and lose practically all of it as soon as you start opening them. So you're getting almost atmospheric pressure through almost the entire sweep of the throttle which makes tuning with speed density practically impossible. The solution is using Alpha N. AN uses throttle position to calculate load instead of manifold pressure. After switching to AN the car ran great except during low loads such as starting from a stop or during cruising. In this area, small changes in TPS signal due to electrical noise cause large changes in fuel load which results in an unsteady AFR and just overall poor drivability compared to SD. So the solution to this problem is using a blend of AN and SD. SD at low rpm/low load where vacuum is high and stable. and then merging to AN tuning in the high RPM/high load area where vacuum is practically gone and the signal is unstable. This requires doing allot of data logging in order to plot points and draw a trend line where the two tables would switch. Not to mention I still haven't quite wrapped my head around how the two tables would work together (the second table is a multiplier table.) So for now I will be sticking to AN.
Another thing, I still need to get a VVTuner so that I could actually control VVT. Currently the intake cam is retarded 26 degrees (default.) so it really doesn't have "a little bit 'o pep" until you get past like 5000 rpms.
His 4AGE adapter plates look great. Did you speak to him about making one for your engine?
We have SolidCam which is the program that produces the CNC code from the solid works file and its supposedly "virtually plug and play" but we all know what that means. And CNC machine parts are expensive.
