.::|Active Autowerkes Stage "TrippinBimmer" 330i ZHP Supercharged Street/Show Car|::.

MarcusLSB said:

Meth is only good for 15rwhp?

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I realize this is just a general comment, but it's a good point for me to elaborate on.

To continue on from the other thread I started yesterday:

Octane
Pump 93 = 93 Octane
E85 = 102 Octane
Methonol = 119 Octane

Auto Ignition Temp (C)
Pump 93 = 280
E85 = 365
Methonol = 470

If E85 is like pump fuel on cocaine, then Meth is speedballing.

Meth is in most cases a better fuel for FI than E85, but it isn't as easy to buy or as cheap.

Meth can be worth a LOT of power when you replace/augment the fueling of an engine consuming pump fuel with meth. The HPF kit is a good example of this, where at a certain RPM/boost threshold, the meth system activates and takes over a large percent of the fuel requirements of the engine. As RPM increases, the flow rate of the meth stays somewhat constant, (It actually decreases slightly as manifold pressure increases) and the ECU adds more pump fuel to meet the fueling demand of the engine. This is why the HPF kits have such a nice torque increase in the midrange on meth, because a major part of the engine's fuel demand is being met by Meth injection, which allows a more timing and has the side effect of lower IATs. Meth is a good thing.

Aftermarket meth kits are disigned primarily to aid in reducing IATs, not to be part of the supply of an engines primary fuel demands. So the gains you can expect to see from adding one of these kits is a lot less than if the meth system is integrated into the primary fueling of the engine as HPF have ingeneously done.

Most engine tuners hate tuning an engine to depend on aftermarket meth injection, as it is not as reliable a fueling solution as "normal" fuel systems, and the effects of even minor failures can be devastating.

So the bottom line is that you can see 100+hp gains from meth injection, but it's usually as part of the primary fueling of an engine.

I don't think +15rwhp with a basic meth kit is unreasonable, but it's certainly not the limit of what is possible with quality components, installation, and tuning.

I hate to say it, but that BOV is the wrong part for a "draw through" MAF setup. If the sequence was Compressor - BOV - MAF - Engine, then there's be no problem. But as Zak said, you'll now have an engine that thinks a lot more air is being pushed into it than really is the case, and this is going to cause some really rich running at part throttle and upper RPMs.

If you have cats, it will likely kill them fast as well.

Turbos don't suffer as much when configured like this, because mass flow is controlled my manifold pressure/vacuum. With a SC, mass flow is directly proportional to engine speed...which means at 5000 RPM @ light throttle the compressor will be running pushing a ton of air through the BOV.

Ever wonder why the S65 supercharger kits have 2-3 BOVs? It's because of the mass flow that needs to be bypassed at part throttle. They are also tuned completely differently than this kit.

Sorry to deliver the bad news like this....

TrippinBimmer said:

Edit: Verify the Injector Cyl 6 injectors does not fire

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Check the connector with a DMM....with the igntion switched on, you should have 12.Xv (battery voltage) from one of the pins.

Also, measure the resistance of the injector across it's 2 terminal pins and compare that to other injectors. (You'll have to unplug the harness completely I think to get to injector #6)

It could be the injector

It could be the connector

It could be the wiring harness

It could be the ECU (Worst case)

Just to be sure, I recommend replacing everything and upgrading to Cosworth ECU, Mil-spec wiring harness, and Bosch Motorsport injectors. :yikes:

Other important specs that are hard to find:

Injector Dynamic Response Curve

Injector spray cone pattern (Spray pattern: It usually has 1 or 2 "cones")

Injector spray cone angle (Angle or width of spray cone)

Injector spray cone bend angle (Angle of spray cone when compared to the injector body centerline)

Average droplet size measured in microns (Changes with fuel pressure, so it's usually a 2D chart)


Against popular perception, fuel injectors when installed in modern fuel systems don't deliver linear amounts of fuel. Even when they are held wide open, (100% IDC) there is deviation in flow, droplet size, and cone shape from millisecond to millisecond. Better fuel injectors show less deviation from ms to ms.