Superchager question

[AlaskaVX]

My butt dyno says +60 horses, and a 15.2 quarter mile time.

[mbeach]

A 50% gain makes for a very respectable bolt-on. I wonder what that conservative 5psi would make with some intercooling (or water/meth injection).

<--begins to reconsider supercharger options.


Oh, making that A/F mixture richer won't give you any more power -it will actually steal a bit. The purpose of tuning rich is to cool your cylinder temps and give your engine an increased margin of safety when on boost. I wouldn't venture near the double digit boost levels without some serious real-time A/F ratio feedback on hand.

EDIT: Just took a closer look at your dyno chart, noticed some interesting stuff.
-that funny wiggle at 4300 rpm, I assume that it was a shift. Cyrk's came on a few RPM later -tire size/gearing differences?
-Both plots are almost exactly identical in form, even though Johnny still has his variable intake plumbing and Cyrk does not -can someone tell me what this doodad is for again?
-Both of you started slightly rich, even considering the presence of the CAIs (known to cause lean conditions in many boosted vehicles). I wouldn't be overly concerned with a 10-12:1 A/F ratio at this point. My 362whp WRX touched 9:1 on high boost (= mad flamage on Sunoco Blue ).
-Cyrk? (it's hard to tell on the graph) should be concerned with the flat-spotting of the A/F ratio beginning at 4400 rpm. It stuck you at 12.5:1 even though you continued to accelerate. Notice the lower curve's ability to increase fueling to protect the motor. I think your injectors are maxing out early -but I don't think that the adjustable FPR is the way to go (That's how Honda boys do it).
-I assume that the VX has its fuel rails in series (right, then left) consider converting them to a parallel feed system (this will ensure equal fueling to both banks, preventing a lean cylinder when you begin tuning on the edge). This isn't as hard as it sounds, and its a common safety mod.
-Has anyone benchtested their injectors? Often better flow can be obtained by opening up the spray pattern. Check what's downstream of the spray path, you still want the mist, but without wetting the walls of the intake manifold.

After you can safely enrich the A/F ratio, and ensure equal fueling to all cylinders, then it's cool to advance the timing (how?!?) and crank up the boost.
I'll be interested to know how far the Isuzu motor can go before it starts making bad noises -hopefully some of Isuzu's bulletproof diesel tech has made it into these engines as well.

[MZ-N10]

at 4300 rpm is when our varible intake kicks in....i think

[Ldub]

MZ,
There is no more variable intake after s/c install...if thats what you were refering to.
Ldub

[MZ-N10]

MZ,
There is no more variable intake after s/c install...if thats what you were refering to.
Ldub

o didnt know tat

[Ldub]

mbeach,
This is just my understanding of "variable intake" after having mine apart...take it for what it's worth.
There is a set of "butterflys" in the intake that, when open, lengthen the intake runners thus increasing the velocity of the charge going into the cylinder.
I kinda miss that little spike in the powerband since s/c install...but not all that much.
Ldub

[WormGod]

Now lets just start shaving down some weight on these things and get that 1/4 mile eta down to a wee better time.

I havent heard much from FeatherFoot lately on his research. That would be another major aid.