Quote:
Originally Posted by ttrainxl
I have a stock ‘95 Civic Ex with the D16z6 and a 5 speed transmission. I’ve been getting anywhere between 39-44 mpg, depending on the temperature outside. I just bought a D15z1 long block from the junkyard. (For the non Honda guys, this is from the Civic Vx.)
My plan is to put the D15z1 head on the D16z6 block. I don’t want to swap the entire engine in for now. Swapping the head will bump compression up to 10.7:1 with a thicker head gasket. I’d like to make about 100-110 hp with this setup, rather than the miserable 90hp stock D15z1 engine provides. I don’t have the P07 ECU yet and I’m wondering if a chipped P28 with P07 fuel maps would give me more tuning ability. I know almost nothing about tuning but I’m curious if a chipped P28 and possibly Hondata will open up a little more power and fuel economy that a stock P07 ECU would give me. It seems that if you can tune an engine for more power, you should be able to tune for more fuel efficiency as well.
Anyone have thoughts on this? I’m aware of the five wire O2 sensor issue and I’m aware that my engine will be running in Vtec at 70mph and that I need to swap a transmission, or preferably (after looking at D series transmission gear ratios), keep my transmission and swap in a lower final drive. Right now I’m only asking about the ECU options.
Any help is much appreciated. Thanks.
|
Hondata allows you to change the VTEC crossover point, write your own fuel and spark tables, and adjust fuel enrichment (among many, many other things).
What Hondata doesn't do is factory lean burn. You can't (to my knowledge) chip any of the factory lean burn ECUs. The VX/HX ECU have separate tables that are used during lean burn operation, and trying to tune a P28 to do something similar has some compromises you might find unacceptable, particularly during warmup. Additionally, if you intend to run P07-style fuel maps, you'll also need the P07 spark tables, and I am not sure if anyone has them. That said, I had a lot of fun playing with my Hondata setup (see my K24 swapped Insight thread for details).
What might actually work best, is using a P07 ECU as-is, and having the injectors modified for ~7-10% more fuel flow. The spark tables will be a bit off due to the higher compression, but not by much, and you can probably drive around as-is by running 89 rather than 87 and pulling 1-3 degrees of ignition timing at the distributor (which is approximately what you'd want for the extra compression anyway).
Alternately, you could do an OBDII conversion and run an HX (P2M?) ECU, again pulling just a bit of ignition advance, and with higher octane fuel to take care of knock.