Civic EG

I have a d15 in my hatch right now, and it's the CX with 70 HP. Someone has another d15 head that they are selling for $60, they say it's a complete head.

So shouldn't I be able to just pop it on my block? The HP for the head the engine came on was rated at 102, so shouldn't I see at least a 30 HP increase?

dont know if you can cuz i heard that the pistons for the 8valve only has relefs for two valves not 4

I am pretty sure the CX Block (d15b8) Comes with 4 Valve reliefs per piston, So you can put any 88-99 D Series Head onto it if you wanted to. Be it a D16z6 or D16y8 Vtec head, a D15b7 non vtec, or even the D15z1 Vtec-E Head.

platnuim86 wrote:dont know if you can cuz i heard that the pistons for the 8valve only has relefs for two valves not 4

not true. they have reliefs for 4 valves

well i was wrong

teal_dx wrote:

platnuim86 wrote:dont know if you can cuz i heard that the pistons for the 8valve only has relefs for two valves not 4

not true. they have reliefs for 4 valves

This comes up in every minime thread.

Is there anything I'll need to switch them over? It's D15B7 head, the engine is rated at 102 HP and 98 lbs of torque, so what kind of gains should I see?

I'm not looking to race, but it's going to be a little while longer than I expected until I'll be able to get the b20vtec and $60 for a little more fun is good for me.

Will I need a new ECU?

Get the SI tranny. Those tall CX gears suck a lot of the fun out of the engine

you will need a p06 ecu from a dx. Also the dx injectors are larger too I believe, so you would run lean if you used the cx injectors. Also doesn't the cx have a 1 wire o2 sensor? you would need the 4 wire from the DX and have to wire that in.

I suppose you could just keep the current ECU and see how it runs since this is going to be short term, but I bet it will be pretty disappointing since that ecu has fuel curves for an 8v head and you'll have a 16v head. You'll probably be really lean if you try that.

Plus by the time you ad in a new IM & head gasket, you've got minimum $100 into this. You shouldn't re use the head bolts because they stretch, but since this is short term, I'd do it.

But to do everything the right way, you'll be spending $200-300. Totally not worth it IMO, just live with the weak D15b8 for a little while longer and then save for your swap faster

teal_dx wrote:you will need a p06 ecu from a dx. Also the dx injectors are larger too I believe, so you would run lean if you used the cx injectors. Also doesn't the cx have a 1 wire o2 sensor? you would need the 4 wire from the DX and have to wire that in.

I suppose you could just keep the current ECU and see how it runs since this is going to be short term, but I bet it will be pretty disappointing since that ecu has fuel curves for an 8v head and you'll have a 16v head. You'll probably be really lean if you try that.

Plus by the time you ad in a new IM & head gasket, you've got minimum $100 into this. You shouldn't re use the head bolts because they stretch, but since this is short term, I'd do it.

But to do everything the right way, you'll be spending $200-300. Totally not worth it IMO, just live with the weak D15b8 for a little while longer and then save for your swap faster

I believe that's what I'm going to do. I was told that my car had a D15B7 engine when I bought it, so I thought this whole time I had 102 HP and 98 lbs of torque....so now I can't wait until I get the swap and gain 90 HP and 55 lbs of torque on top of much better gears