jaycorolla

iTrader: (1)

Ok here is the questions I'm trying to find some answers for.. done lots of searching around but have not found difinetive answers on what can be done with this motor.

here is what I have heard or read about that can/could be done to the d15z1 setup.. mind you this is not going to be built to make power but more milage and efficiency . Yes this is going to increase hp but not for racing.... I am not new to the Honda game.. I have searched around for a long time for this info but cannot find what I need.. so please let's
Keep the Non-tec remarks to a postivie manner. I know there are others out there with d15z1 motors that are looking for some oem type style upgrades and different ideas.

so here we go :

1. That you can take a d16z6 head and basically swap out the d15z1 roller rockers and cam caps.. basically the whole setup into the d16z6 head.. including cam... point of this is for bigger valves intake and exhaust but still have d15z1 lean burn and egr setup going with the cam way of working in 12v style under 3k rpm...

2.. taking d16z6 pistons and swappng into the d15z1 block, raising compresion from stock 9:1 to around 10.5:1 depending on head gasket used.. while using the d16z6 head.. my question is would the car still be able to run with stock ecu with no problems in lean burn while still using regualr gas.. 87oct. Or 89 depending on station? ( since it uses a wide band o2 sensor) or do I have to use 91-93 Oct to retain ecu usage or go get a tunable one for this?
3. question is would it be better to use the d16y5 intake manifold which is like a d16y8 but with an egr valve and slightly smaller* throttle body (I think*) since this will allow more air flow compared to the tiny one on the d15z1 stock motor.
4. Finally what exhaust piping size should I use for best results for these type of modifications and/ or using the motor in stock form but increasing exhust piping to bigger than 1.6in diameter? (I was thinking at least 2in but probably 2.25in piping after cat.)

p.s. anyone know of a good exhaust muffler brand and resonators to go with make this new exhaust piping that is not open pipe loud at full throttle but isn' dead silent either... a deep quite note while driving... not that droning ebay sound..

thank you for the help.

Relic1

a little slow on the response but hopefully it helps you are someone else with the same ideas.

the D15Z1 and it's ECU are designed to work together to get mpg that only hybrids are even close to.
1. the Z1 head is what allows the higher AFR's to be run by having the walls thinner to allow more cooling effect closer to the combustion chamber. Removing this means no lean-burn mode which reduces the mileage quite a bit. (ie from high 40s combined driving to high 30s)

2. the shape of the dome and head is designed to work with the intake charge swirl pattern to enhance and work with the higher AFR charge.

the engine is going to have issues when the ECU starts into the lean-burn mode. Not 100% sure about drivability at this point, but I'm guessing lower power and noticable higher EGTs and head temp.

a tune-able ECU can get you around the lean-burn mode issues, if you create your own open loop mode induced lean-burn mode section of the maps. But without the ability of monitoring the head temps at the chamber you risk too high AFR for your setup and melt down situations quickly.

3. the Z1's intake manifold is designed to work with the odd flow rates of the head design and optimize the cruising RPM's efficiency

4. exhaust changes may change the mpg slightly, an intake (ie CAI) can help also.
which to use, the WS2 is the one everyone likes.