boosted.CRX

Hey guys, didn't get much help over in the Hybrid forum and had a question and wanted some opinions.

I'm going to be swapping in a JDM D15B obd2 (three stage vtec) into my EF and wanted to know if I will be better off going with an obd1 D15B instead because I don't know what it's gonna be like (or if at all possible) to tune boost on this thing being as it's got the complex vtec system. Am I gonna need three different maps?? I didn't come up with much info on this motor and am starting to think maybe a regular old Z6/single vtec D15B might be better.

Although almost VX-like milage and Z6 power all in one does seem appealing, but is it worth it?

boosted.CRX

Nobody's tuned a 3-stage D15B?

HiProfile

Nobody really bothers with them. You'll need some way to activate the 3rd stage, either RPM switch or an ems like ectune. Most ems's have secondary maps, however you could get by with keeping the 1/2 stages on the first map, and vtec only on the vtec map. You have the ability to get close to the VX, however good luck finding an aftermarket EMS that will offer you lean-burn mode like the VX. You'll only be able to run it a point leaner with current EMS & wideband offerings. People with z6's still can get >35mpg if they drive slow.

The other problem is the oil system. The 96+ motors like to spin bearings. People claim that porting & shimming the oil pump helps, but they still don't have cross-drilled cranks.

boosted.CRX

That was exactly the answer I was looking for. Thanks for the insight. Definatly sounds like the obd1 variant is a much better choice. I wasn't aware that the newer D15B's shared the same oiling issues that the Y8's do.