Twin charged bp

[bhearts]

Im thinking I'll take that head off and go to town on porting those runners. I want a round head port to mate my intake to do that I won't have to bend my pipe to an oval on one side

[bhearts]

Something like a 1.75 inch runner

[Advancedynamix]

I hope that's a generic photo, because those aren't Miata cams. If the core is 250x2 then that's not too bad of a deal, but if those are 750 a set for regrinds then I'd say the price is quite steep.
Also, tit is my understanding hat a cam set worth buying for these engines will not run well with the standard LJetronic style injection. The VE will change so drastically that the stock management will barely run the car, so if they advertise a good idle, it's not much of an improvement.

[bhearts]

Could one get much for gains with adjustable cam gears

[bhearts]

Cams offer lift, duration, and overlap. Amiright? It's something I don't pay much attention

[ZephTheChef]

I still think you should put off cams til you run out of other ideas to make power. If it was just a race car that would be one thing, but this car is going to spend most of its life on the street. Aggressive cams are about the most pain in the butt thing you can do to a street car...along with maybe really high stall converters or loud exhaust that drives you crazy at cruise, or solid motor mounts, things of that nature. Perfectly acceptable mods for something you don't spend a lot of time in, but it gets old fast.

In other news, I received my top adapter plates today, but am headed out of town until Wednesday, so I will be back to work on my car then and will hopefully be able to put some of these questions about twincharging to the test pretty soon.

[bhearts]

With a supercharger based engine, is head porting and velocity of the highest concern? I know a radical port job will hurt low end torque, but that can be offset with a supercharger, and it's not like its the factory motor, it should always be more torque than the b3 could offer at said rpm

[ZephTheChef]

You know how I feel about head work. So I'll leave that to Charlie to answer, lol.

[SIBladerunner]

I generated 164.7 at the wheels on a stock transmission and a N/A B6D from a Capri. It's not that hard when you can spin up the rpms. Proper cams, crank, and flywheel will give you this. You say you have a knack for fab, well shave the flywheel, get the fastest cams and strongest springs for the valves, and shave weight off of the crank. Make it the lightest reciprecating mass you can and you'll generate some serious power. These little engines can really rev up. I had it float the valves at close to 13,000. You'll be amazed. I can't wait to make my next project

[bhearts]

That's quite the number.

[bhearts]

The m90 makes roughly 9lbs of boost on the 3800 with factory pulley size of 3.6 +/- so I need to figure out a way to make an underdrive pulley so I don't end up around (math time estimates) 3.8/1.6x9 lbs of boost with a similar to factory pulley ratio. I'd like to keep it under 15. I realize that les boost will be made if the engine becomes more efficient at breathing and farting. So I'd like to adapt a 5 inch or so pulley 6 rib, so I have room to spare I'm c case I suck at lining up pulleys, I'll use the factory 4 rib pulley at the crank. I doubt that I would be able to cut the center of the supercharger pulley off, and weld it to a larger 5 inch 6 rib outer part.

[ZephTheChef]

7-8lbs on a stock 3.8" pulley. Driven by a 6.8" crank pulley. So your drive ratio rounds to 1.8:1 for 8psi on a 3800. Do the math on your engine cfm demands and I can tell you what size pulley you need for x boost.

[eurotiva]

This thread needs more pics and videos.

[bhearts]

This thread needs more pics and videos.

Ill try that this weekend. I have a part that I need to make for a member on here, and I also need to finish up my collection of b3 upper intakes, but maybe I'll just multi task and build this supercharger b6 intake while I'm at it. I think I'll have to cut the mounting holes off the charger, so I have enough clearance between head and fire wall, but I see no issues with welding it into the plenum, as long as I can do so without warping the case. Anyone here with more aluminum welding experience than me want to chime in on welding techniques for cast supercharger housing welding?

[eurotiva]

It's Nice and thick. Should be fine, Just make sure to stay away from seals and gaskets