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Discussion Starter · #1 ·
i'm going to start by mentioning my goals here. atm i am rebuilding my d16y7. everything is looking good as far as the short block is concerned. aftermarket parts include aem cold air,skunk2 intake mani with injectors,complete head gasket kit,water pump,timming belt and i have both ECUs. now i recently bought a d16y8 cylinder head (with vtec of course).

i have had close family that works at honda dealers and they told me that honda has stated that it is normal for vtec motors to burn something like 1.5L of oil per 1000km. to me that seems extremely abnormal because my buddys corolla burns a similar amount and the car has been abused and whatnot. keep in mind i drive under 4000rpm 90% of the time, but the more horsepower (+20hp i beleive) the better. for the people who know about the design of each cylinder head, can you point me to the right direction because i don't want to start lapping the valves for the vtec head and not end up using it. my main concern is that i definatley want the extra power, but not if it will get in the way of the reliability because i don't want to run into problems and open up the head again.

of course that could just be nonesense but i guess for those of you running sohc with vtec, could i get your opinions on this?
 

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The info about oil consumption ist half true.
Dealer say for every engine 1L is normal, just to avoid warranty claims.

To me more than 0,5l shows that anything is wrong.
 

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well here ya go:

the y8 has vtec but it is wildly overrated on the sohc platforms. it was mostly designed to improve fuel economy and still have punch in the higher RPMs above crossover. the vtec head will have more aftermarket support but vtec itself limits the size of cam you can run and if youre looking to make a competitive or fast sohc then i say ditch vtec altogether.

that being said that doesnt mean you have to ditch the y8 head completely. the chamber design is phenomenal and improves burn. the quench pads on a y8 head (especially one thats been decked about .040") the right piston choice/design is tops in my opinion. more compression can be run on pump gas with a highly efficient chamber like the y8's. the head wont out flow a z6 but they7/y8 heads are fairly similar in flow numbers with the y8 beating out the y7 ever so slightly.

im a nonvtec fan all the way. id run a y8 head with y7 rockers and valves. stuff a nasty cam in there and get the best of both worlds. better quench and flow from the y8 but the ability to run a much hotter cam with the y7 guts and camshaft.

so what are your goals is the real question? daily driver? weekend warrior?
 

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Discussion Starter · #5 ·
well here ya go:

the y8 has vtec but it is wildly overrated on the sohc platforms. it was mostly designed to improve fuel economy and still have punch in the higher RPMs above crossover. the vtec head will have more aftermarket support but vtec itself limits the size of cam you can run and if youre looking to make a competitive or fast sohc then i say ditch vtec altogether.

that being said that doesnt mean you have to ditch the y8 head completely. the chamber design is phenomenal and improves burn. the quench pads on a y8 head (especially one thats been decked about .040") the right piston choice/design is tops in my opinion. more compression can be run on pump gas with a highly efficient chamber like the y8's. the head wont out flow a z6 but they7/y8 heads are fairly similar in flow numbers with the y8 beating out the y7 ever so slightly.

im a nonvtec fan all the way. id run a y8 head with y7 rockers and valves. stuff a nasty cam in there and get the best of both worlds. better quench and flow from the y8 but the ability to run a much hotter cam with the y7 guts and camshaft.

so what are your goals is the real question? daily driver? weekend warrior?
I would say it's more of a daily driver at this point. I just want it to have a little extra kick and my goal was to compete with b16s (so near 160hp at crank). If you're interested in looking my upgrades perhaps you could suggest me a suitable combination for the head.

Can i completely change around the springs between the y7/y8 head? To me it seems like vtec should have no effect on the springs right? What would be the best combination of the two with the vtec? I also have a skunk2 intake manifold and the y8 intake mani. I have y7 injectors/fuel rail and y8 injectors/fuel rail as well. Right now I'm thinking skunk2 with y8 injectors. I was told by my dad who worked at Honda and Mazda before that I shouldn't even change the valves from their respective seats due to compression issues because theyre not matched. I am planning on lapping them but can I really interchange them?
 

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lapping valves is a thing of the past. get proper valve work from a machine shop. 3 angle cuts are usually inexpensive and will seal perfectly without lapping.

the springs are different from the y7 and y8. the y7's are thinner gauge wire for the spring. you can run two sets of intake springs from the y8 or z6 (they are heavier quality as they handle the vtec crossover work). thats a good low budget option but id just stuff some isky, supertech or kms springs in. its cheap insurance.

y8 injectors are 240cc and y7's are 190cc...thats the only difference. use y8's if ya got em. fuel rails make zero difference. they just get fuel from point a to point b.

btw not to burst your bubble but 160hp n/a is no easy feat my friend. youll need lots of compression (12:1+), good fuel, good tuning, a high quality header, a very aggressive camshaft, substantial headwork, proper gearing and the like. and it probably wont be a great daily driver at that point. just a heads up.
 

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Discussion Starter · #7 · (Edited)
lapping valves is a thing of the past. get proper valve work from a machine shop. 3 angle cuts are usually inexpensive and will seal perfectly without lapping.

the springs are different from the y7 and y8. the y7's are thinner gauge wire for the spring. you can run two sets of intake springs from the y8 or z6 (they are heavier quality as they handle the vtec crossover work). thats a good low budget option but id just stuff some isky, supertech or kms springs in. its cheap insurance.

y8 injectors are 240cc and y7's are 190cc...thats the only difference. use y8's if ya got em. fuel rails make zero difference. they just get fuel from point a to point b.

btw not to burst your bubble but 160hp n/a is no easy feat my friend. youll need lots of compression (12:1+), good fuel, good tuning, a high quality header, a very aggressive camshaft, substantial headwork, proper gearing and the like. and it probably wont be a great daily driver at that point. just a heads up.
I appreciate the feedback but I think I maybe stated it the wrong way. Instead of 160chp I hope to compete with the 130-135whp that a b16 should make after losses to certain peripherals. I removed the ac and power steering belts and after research and a personal test, I can conclude that it gained approximately 7-10whp. I am hoping for somewhere near 130whp when all is done and here are my upgrades to justify why:

Y7 block (stock civic puts down 90-95whp)
y8 head and injectors (about 10.2:1 as opposed to the regular 9.6:1 compression so maybe 5hp+20hp from vtec)
Skunk2 pro s intake manifold+AEM cold air intake (8-10hp together)
Full exhaust: 4-2-1 header and 2.5" piping to 4" tip (8-10hp)
Ac+ps pumps are removed (10hp)
So somewhere between 131-140whp ( I subtracted 10hp due to likely personal errors made :p)

What do you think?
I tried to do estimates as best as I could but without Dino results I can't actually justify gains. For example I'm not sure that the skunk2 mani will actually give me 10hp since I doubt a cold air intake would make a difference at all (1 or 2 hp if I'm lucky).
 

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from my personal experience building a few sohc motors i feel like your estimates are off

youre unlikely to gain 25chp from the vtec head swap and a .6 jump in compresson over stock. the skunk IM may actually lose you power in some places...as will an AEM intake if its not 2.5"...most people choose the 3" for some reason. a full exhaust and header is likely to do 5-7hp or so most likely depending on the design. 2.5" diameter is a safe bet. ac+ps removed is more like 3-4hp.

so im guessing with a y8 head and subtle jump in compression, full i/h/e and an IM you might make 20 over stock and be in the 120-125whp range.

but i think youre forgetting the most important part of an n/a b-slaying build. a nasty camshaft. the stock camshaft will only run you to wherever it falls flat on its face...which is probably about 6000 rpms if that.
 

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Listen to Devin

146 whp 128 ftlbs for me on a Hub Dyno

Colt tri flow2 cam, non vtec in a y8 head, 12.5.1 Compression Lots of manifold porting, head porting. And lots more stuff. wont go into detail.

Your goals can happen but open the pockets a lot more and bump up the squishy. To make power. And a good bumpy stick.
 
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