Hi,
I'm currently planning a budget B20V build. I'm from overseas so performance parts are hard to find (and very expensive). I have set a power goal and planned a very simple build. I want to do this right so the engine will be carefully built and I have a good machine shop to work with. The main question is if I'll be able to reach my power goal of 170whp with only these parts:
- Ported B16 head, valve job and stock B16A2/3 cams. Milled 0.0255 in. (I have detailed pics of the port work if anyone wants to take a look).
- Stock B20Z block (PHK pistons) with ARP rod bolts.
- Cometic .051 headgasket to compensate for the milled head. About 10:1 compression.
- 3" Short Ram Intake with velocity stack.
- DC JDM 4-1 2.5" Header.
- 2.5" Exhaust, no cat, resonator and muffler.
- Chipped P30 ECU tuned on HTS.

The idea was to stay with the stock pistons so I can run 87 octane (it's either 87 or E100 around here) if I could reach my goal. I would like to avoid running a flex-fuel setup as ethanol availability is not ideal. I will think about running aftermarket pistons if my goal is not reachable with this setup.

 

yes. easily.
i would try to avoid lower octane fuel though.

 

I agree is not ideal, especially with the B20 sleeves. My stock B16A runs fine on 87. Around here it's actually E27, which should be higher octane, but isn't. I guess the ethanol content lowers the combustion chamber temps and helps a little to prevent detonation despite the low octane. High octane gas (which would be 95 only) is simply not worth it being double the price of 87 so I would rather run a flex-fuel system or just straight E100. Do you think that power goal is reasonable with a more conservative tune staying on 87?

 

Run the flex fuel setup. If you have access to good quality ethanol fuel then it is 100% worth it.

What country are you in? I'm taking a SWAG based on your fuel woes and guessing Brazil. If so, you guys have way worse gasoline than the US but much better (sugar cane based?) ethanol... much more efficient production/higher quality stock than our corn-based dumpster ethanol.

Watch out for the valve pockets on the PHK pistons. I've heard of issues with larger cams or head lowering (through milling or thinner gasket) due to 33mm vtec sized intake valves vs 31mm piston pockets. Something worth looking into. 10:1SCR isn't too terribly low as long as you stay with milder cams... likely no larger than a CTR/ITR variant. Bigger cams can still make power but will push the peak power up the range, something you want to avoid with a stock sleeve B20.

No hard facts, just food for thought.

 

Bullseye guess. Yeah, mainly sugar-cane based ethanol, 105 octane. Actually, the current octane rating is gradually changing to 88 E27 then 89 E27 minimum, no major difference. My only concern really is to be able to travel with the car, as not every station has ethanol available (some states support it more than others, and I'm in a "bad state" to run Ethanol). With that in mind, ideally I would run a (highly detuned if needed) map for 87 and another for an E51 blend (94 octane) and let the compensation tables do their job. From what I've been told the flex-fuel compensation tables do not work well with a wide range of ethanol content (say 0 to 100%), and it's an extreme range of ethanol content and octane ratings. I guess the ideal setup would be something with no more than 11.5:1 SCR, with the stock cams giving me trouble with a higher than normal DCR that will need to be tuned for.

In regards to the pistons, I would avoid that with the thicker head gasket, but I'll be essentially locked to the stock cams. I've found some Nippon Racing "Turbo Pistons" in 84 mm that the seller confirmed had wider valve reliefs for a VTEC head. Another option would be the Nippon Racing "GSR Flat Top" style that they make in 84 mm, which would bump the compression more and possibly have deeper valve reliefs. SCR would be either 10.56:1 or 11.37:1 with one or the other according to the specs they gave me and my questionable head cc measurement. My plan is to build a mild setup that is reliable, anything above 170whp would be a bonus, so no huge camshafts on the horizon, as I'm probably limited by the header too.

 

Id say the budget/reliable way to get to 170hp is to just stick with a B20 long block, or B16 long block. Either one can hit those numbers with cams, a good header, and good tuning. Higher compression pistons will help a lot.

Doing the whole hybrid VTEC setup is not worth it for that power goal imho.

 

I get where you're coming from. I got the B20Z block for a very good price, so it seemed more logical than spending money on cams and valvetrain for my B16 as it was planned for a rebuild anyway. The B20V has a lot more area under the curve and would give me 40hp more than my B16 with a simple setup. Not to mention it would take a better header and higher compression pistons to make that power on my B16, and parts are not easily available here. That power goal was just a number that I've found was reasonable given my simple setup. Definitely wouldn't be mad if it makes 10-20whp more.

 

Well a B20 VTEC, with stock B16 cams and stock pistons, shouldnt have trouble getting to 180-185 hp. That wouldnt even require a high end header or anything. Just use the stock B16 intake manifold too, it will outperform every other manifold on this kind of setup.

 

Good to know my goal is reasonable. I'll probably be knock limited on 88 octane, so it may be closer to 175, or do you thing it wouldn't?

I'll definitely run the stock B16A manifold. I was also thinking about boring the stock TB to 64mm. Not sure if going for a 70mm one is worth it with that setup, most definitely overkill.

 

You definitely don’t need a 70mm. 64mm will be just fine.

People almost universally go overkill on throttlebody size, especially on NA builds. You also run out of room to bore without running into the idle ports if sticking with a stock manifold.