Sirfallsalot243

There is a reason why apexi had to upgrade the vafc.

do you know what tuning resolution means?
if you have only 8 rpm points to set your manifold pressure voltage on the vafc1, what happens?
Let's say you pick 1000, 3000, 4000, 5000, 6000, 6500, 7000, 8000 rpm as your tuning points, what happens in between those points?
According to apex, there vafc1 assumes that the manifold pressure voltage will be linear in between 2 rpm points.

What does this mean?:

Let's pick a random numbers for setting for the MAP voltage change on the vafc1.

5000 rpm - 4
6000 rpm - 8
So at 5500 rpm ( a point you did not set and cannot set on the vafc1) the setting is assumed to be - 6.

is -6 the best setting for you? what if it isn't? what if your torque dips at 5500 rpm and the af ratio reads 12:1 still?

You can't do anything about it.

You are stuck with the setting because you can't enter more than 8 rpm tuning points.

This continues up the ladder...a standalone has the best tuning resolution.

The only reason people think VAFC2 is MAINLY for K Series motors is because it allows you to adjust the intake cam degree of the I-VTEC system. It contains many upgrades that were beneficial for B and H series.

AF, if you saw a GSR head make 10hp more than a B16 head on the same motor, than that GSR head was NOT stock. I can guarentee that stock for stock, the b16 makes more power. While I dont have a dyno slip to post, nor am i going to go to the trouble to get one to prove you wrong- i have seen it in person, and i know it to be true.

The B16 head is essentially the SAME as a B18C5 ITR head. The only differences are the actual internals. The bare head is almost identical. Ever heard of a B16 head on a B18C1 block? Its called a poor mans type R, because the B16 head has smaller combustion chambers yeilding higher compression.

AcuraFanatic

You lose 0.5 compression B16A vs. B18C1, but whatever floats your boat dude. I can't argue results.

Sirfallsalot243

Upon researching, youre right, the GSR head does give a higher compression ratio- but I still maintain that the B16 makes slightly more power.

Heres a good read on LSVTEC:
http://www.superhonda.com/forum/show...threadid=55995

RicoD

lots of info... h: i didnt really bother reading... :hs:

how ever that comment is somewhat odd... its like saying the B18C GSR is the same as the B18C Type R... only difference is the internalsh:

AcuraFanatic

He said the B18C5 and B16A head is very similar, which it is.

RicoD

just like the B18C GSR is the same casting as the B18C Type R yet different internals... that part just... gah nevermind :run:

Sirfallsalot243

No where did I say that. I stated that the B16 and B18C5 are almost identical heads, aside from the upgraded type r valvetrain. The only point where i was incorrect was where I stated that the B16 gives a higher CR, which it doesnt. The difference in power from the B18C1 to the B16 (however minimal it may be, which is still open for debate) is due to the better flow of the B16 head.

92b18hatch

so gsr would be the way to go with a head. what rods should i go with? oem rods from the b18b cant handle 8,000?

dubcac

A few points:

1. The head casting is identical. This is why ITR heads are stamped PR3. Everyone knows this. Have you ever seen the flowbench numbers of a B16 head vs GSR head? I have. They flow very similarly, but the GSR flows better at higher valve lift. I know all about the poor man's ITR, but the people that did that weren't ditching their GSR head...they were people that had a GSR short block, and no head to go with it. Obviously they're going to go for the cheaper B16 head. Also, if you find a cheap first gen b16 head, you're going to need to replace the internals anyways...those valvesprings are terrible. If you want to see a dyno chart of an LSVTEC build with a B16 head vs GSR head, I'll gladly post that for you.

http://www.importreview.com/reviews/...sB16Ahead.html

Identical bottom ends, the B16 head was ported by portflow, had springs/retainers, ITR manifold, and a CTR intake cam/ITR exhaust cam. GSR head was stock, with ITR cams. The GSR head made 7whp and 4wtq over the B16 head, which utilized a higher flowing manifold, more aggressive intake cam, and a port job. If you want to maintain that the B16 head is better, that's fine...but you're wrong. I bet that guarantee isn't looking so hot on your part right now is it. I would trust one of the best engine builders and tuners on the entire west coast over some douches at SHO any day of the week. Do you even know why the ITR uses the PR4/B16 head? The GSR got the new technology honda developed, but they used the PR4 head on the ITR because they were overstocked of head castings at the factory, and they wanted to get rid of them. So take that for what you want. You can't dispute or debate numbers like that, I don't care what you've seen. I have never ever seen a b16 head make more power than a GSR on the same motor...on a B16, GSR, LSVTEC or CRVTEC.

2. In your first post, you said that he should use OEM VTEC internals in the block, instead of going forged. That makes your LSVTEC build completely pointless. Swapping in VTEC internals into an LS block means that you'll have the VTEC stroke, which is no different than the original VTEC motor...meaning you're not getting the added displacement and torque. If you want to rev an LS bottom end to 8k, all you need is ARP rod bolts. Higher than that, go aftermarket. I've even seen stock LS motors hold 8k and boost, but it's a hit or miss situation.

3. VAFC's suck, whether its the first or second gen...it's not a tuning solution.



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AcuraFanatic

Rods, rod bolts and head studs are weak points in both the B18B, B20B and B20Z as far as RPM limitations are concerned.