Dyno after JR MAP & VPAC

[JRCivic]

Bill,

You got 40 HP just from moving your VTEC engagement point ?!?
This looks like a before JRSC/after JRSC dyno plot...


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'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[ArturboGSR98]

You must be powered by Jesus!! Good numbers.

art

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98 GSR Rev-Hard Turbo kit

[JRCivic]

Bill,

No explanation necessary for me... even though I did not follow your thinking about the difference between the graphs, I merely thought you were making a "funny"...

I do see your point now. You might consider a VPAC... and with this tool, you can smooth the graph across the 3K to 5K power band.

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'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[UberLude]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JRCivic:
Bill,

No explanation necessary for me... even though I did not follow your thinking about the difference between the graphs, I merely thought you were making a "funny"...

I do see your point now. You might consider a VPAC... and with this tool, you can smooth the graph across the 3K to 5K power band.

<HR></BLOCKQUOTE>

I see the spike, but here's my question. The point of VTEC is to allow the engine to breathe more freely at high RPM. With a FI system, allowing the intake and exhaust valves to overlap more can't actually help a boosted motor, can it? I mean, I'm not doubting the chart, but could it be something else? A fuel adjustment by the ECU, etc, that generates that spike? Or is my thinking flawed in regards to "aggressive" cam profiles and FI.

I know turbo and SC people who have both told me that more "aggressive" cams (i.e. more overlap and duration) is actually counterproductive to the FI. I suppose I've seen quite a bit of "get rid of the VTEC" vibe from Endyn too. Jim, dole out some truth to me here, willya?

Cheers,
Ben

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99 Prelude SH
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The world isn't run by weapons anymore, or energy, or money. It's run by little ones and zeros, little bits of data---it's all just electrons.

[lundgren]

When endyn talks about vtec being bad for FI, put it into perspective, we're talking about 15psi honda motors.

The benifit of having the intake valve open longer, is better at <11 psi, above 12psi I *think*, it just blows by.

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http://www.groupbuycenter.com/

[UberLude]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lundgren:
When endyn talks about vtec being bad for FI, put it into perspective, we're talking about 15psi honda motors.

The benifit of having the intake valve open longer, is better at <11 psi, above 12psi I *think*, it just blows by.

<HR></BLOCKQUOTE>

But... that would seem to indicate that higher pressure is a function of cam timing, which it isn't, cuz it's a function of blower speed. You know what I mean? Why would it blow by at 15psi, but not at 10psi? The charge is happening over the same time period...

I'm not sure if I said that clearly, but hopefully someone can read my mind as to the question.

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99 Prelude SH
--------------------
The world isn't run by weapons anymore, or energy, or money. It's run by little ones and zeros, little bits of data---it's all just electrons.

[JRCivic]

Ben,

It appears that the common belief is that there is little or no overlap on the low profile lobes of our camshafts, and there is a great deal of overlap when the VTEC lobes are engaged. The truth is that this is not the case. Even the high lift lobes allow very little overlap, and thus, create very little loss from blow-by. If you install larger lift cams with greater duration, then you do in fact risk boost losses due to overlap.


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'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[UberLude]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JRCivic:
Ben,

It appears that the common belief is that there is little or no overlap on the low profile lobes of our camshafts, and there is a great deal of overlap when the VTEC lobes are engaged. The truth is that this is not the case. Even the high lift lobes allow very little overlap, and thus, create very little loss from blow-by. If you install larger lift cams with greater duration, then you do in fact risk boost losses due to overlap.


<HR></BLOCKQUOTE>

So for my car, assuming 8-10psi of boost, would you want to modify the cams in any way?


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99 Prelude SH
--------------------
The world isn't run by weapons anymore, or energy, or money. It's run by little ones and zeros, little bits of data---it's all just electrons.

[zip]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by UberLude:
So for my car, assuming 8-10psi of boost, would you want to modify the cams in any way?

<HR></BLOCKQUOTE>

I forgot the members name on this board, something "hybrid", but he installed ITR or CTR cams in his GSR and reported significant gains. Not a lot of people on this board have tried experimenting with different cam profiles for the JRSC except him. He also went as far as upping the boost to 15psi.

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Mods

[UberLude]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JRCivic:
No... do not change your camshafts. So far there are NO proven Supercharger type cams for the B18C or H22A.

Zip is correct in stating that in SOME cases, there have been reports of small (3 to 6 hp) gains with the use of a ITR or CTR EXHAUST camshaft in the B16A/B18C applications. This requires a ton of dyno time to extract, but some may think that the gains are worth it.

<HR></BLOCKQUOTE>

Jim,

I wasn't necessarily limiting myself to production cams. I was thinking along the lines of a custom cam profile.

Further down the road, when I bore my H22 out to 90mm and do a crapload of headwork, I would think custom cams are virtually a given.

Mmmm. A 2.4L H22A w/10psi of boost. That sounds mighty tasty.

I wonder, does everyone here suffer from the same financial issue? Whether you are employed or not, and regardless of how much you make, you don't save a dime... *sigh*

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99 Prelude SH
--------------------
The world isn't run by weapons anymore, or energy, or money. It's run by little ones and zeros, little bits of data---it's all just electrons.