$900 isn't bad at all, but it doesn't *LOOK* like it would flow that well and it doesn't leave much room for the rest of the piping...though i've rarely seen a turbo'd car that had any room in the engine bay anyway.
Yes I'm running megasquirt. I'm not an expert on the GM PCM's so I hesitate to comment, Erik supplied a lot of info to another member who claimed to get it working by rescaling the map tables etc. Best to let Erik chime in.tubing is easy, 120 mig welder and parts from autozone will take care of that if you're desperate. Good to know it flows well, that takes care of alot of people's concern. You're running megasquirt, right efi-diy? that eliminates alot of forced induction problems, but there's still no work around for a stock ecm right?
I'm not sure that there is room to expand the air flow enough via the MAP tables. While we can enter any figure into the table that we desire, getting the actual performance from those entries is another issue. Just not enough air and fuel flow capability (our system is close to maxed out, as I gather from around a year of investigation).
For turbo use, a MAF would be a better way to go, I think. Measure actual air flow versus trying to scale MAP above atmospheric levels. Ignition could probably be handled by the Ford ECCV computer -- more tunable than the current GM offering -- especially for boost-level output.
Placement of the MAF (needs scaled linear air flow) is critical, and it probably needs to be in a straight-line section of intake tube, and then carefully calibrated via wide-band O2 sensor and dyno data, with appropriate tables drawn for the PCM.
Just a few thoughts I've had in regards to tuning the turbo 4.2. I REALLY wish it were easier, but alas, it is not. I'd do a STS remote in a heartbeat if it were, but the cost of the kit will at least double before you end up with a drivable (if ever) vehicle.
Well Megasquirt does not support drive by wire so the TB needs to be changed to a early LS1 type. You also lose VVT cam control ( at least right now). For a TB install if the tuning can be sorted out the best to stay with the GM PCM.There is a work around for the stock ECU, some guy tried it, reported he got it working, then screwed. No one knows where he went.
You need to upgrade the MAP sensor and scale tables pretty much. If I recall correctly in order to use Megasquirt you had to change around some engine components?
Either way if you want it to work, it will in the long run. But don't expect to go crazy cranking up the boost on a stock block