Hi everyone,i have a ek3 sedan with d15z4 non vtec engine and have just done few mods like cylinder head shaved by 0.030'',sport air intake system,oil catch tank,4-2-1 exhaust manifold outlet 2'',custom muffler but exhaust piping remain stock with an additional resonator,actually there are two resonators.

Well i think that the stock piping is 1.50'' or 1.75'' and i want to know if i must change the piping to 2'' as i have just removed the stock header and replaced with a 4-2-1 header.Thanks in advance.

to get the most out of it i would go to an aftermarket exhaust

if u took 30 off the head ur goin to need adj gear to correct the cam timing,u will see some improvement if u dial the cam back in, and i would def go ahead and go 2 on the full exhaust

Thank you very much.I was thinking about changing the cam gear to a adjustable gear.So i'll order one,and will also put a 2'' piping.

i will check in to it but im wandering if the D16A6 cam would be an upgrade for your engine, i know the single cam non vtec ZC is a little more aggressive. just some food for thought lol.
What was the reason for the head shave? what were u lookin for?

The previous owner had the head shaved because the engine was overheating due to lack of water in the radiator,he was careless of his car.

Here in my country we do not have enough parts for honda engines,it is very rare to find a ZC engine.So i'll order a adjustable cam gear from ebay,a good one.I'll also buy a stock intake manifold for d15b vtec year 99-00,the virs one,i hope there will be a good improvement.And later will look for a chipped ecu.

Even without all these stuffs,the car pulls great.I raced against a civic d15 vtec with few mods,and we reached together at the end of the 400m distance.

my engine

Looks clean! I like the green plug wires! lol i use the same header.

Shot was taken before the msd setup, Vision Gears, And Zex Kit

I like your engine.We have some on our roads here.but they are all stock.I'll ask another question about FPR of new topic.thank you very much for sharing your knowledge and ideas.