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Ken...how did the testing come out? Any updates?

Reducing any restriction in front of the supercharger (high VE or not) will absolutely increase the mass-air flow rate. Try thinking about it this way; consider the extreme case wherein you completely block off the inlet and ask what your mass-air flow rate will be. Basically zero, of course...

If you get a chance, ask them if they know what the drag coefficient is. The original GT40 had Cd = 0.43, from what I've read. Reportedly, they were targeting < 0.4 on the new GT. Oh, and see if they can tell you the frontal area, too. Thanks!

Here's another comparo of a turbo vs Eaton (Roots) on an '03 Cobra crate engine measured at as close as they (MM&FF) could get them to the same "nominal" boost pressure (~11 psi, or so). Obviously a Roots is less efficient than a twin-screw, but you get the idea. Here's a plot showing boost...

Hey SLF - to make a comparison, just look at the least-squared fit lines to the data points at any particular boost pressure for the two different cases. For example, at 17 psi the Whipple car makes (on avg) a peak rwHP/TQ of ~600/560 whereas the turbo cars make ~710/685! Or you could look at...

You'll have to bear with me on the formulas, et al. I'm an engineer. And I honestly mean no offense, but I thought the point was clear? It’s what I wrote right above the link? Best bang for the buck is to just spin the blower a little faster. (How much does a cam change, head porting, LT...

Due to its higher thermal and mechanical efficiency, a turbo will make more brake power on a given amount boost than a P-D blower, hands down. Here's some data from your smaller 4.6L brother. 2.3L Whipple (Lysholm) blower data: Turbo data:

The purpose of cams or head porting, etc., is to increase power and torque of the motor via an improvement in the intrinsic volumetric efficiency of the engine, VEe. Normally, an increased volumetric efficiency means the engine will ingest more air (and proportionate amount of fuel), and hence...

Any chance you have before and after exhaust mod dynographs? And if possible, could I get a copy of the actual dyno RUNFILEs? Do you recall how much timing was in the tune and the AFR? What was the pulley size? Thanks!!!

Perhaps it is just the snout gasket leaking, but pics would be helpful.

Really? Ok...my bad. I thought it was 1:1. Scratch that one then! Thanks for the info.

There are a few more good reasons to run in 4th gear. 1) Power to accelerate a rotating mass (rear wheels, axles, gears, drive shaft, clutch, flywheel, etc) goes in direct proportion to angular acceleration, (i.e., P = Iαω). So the faster you accelerate, the higher the inertial losses in the...

Thanks SLF. I suppose I can calculate/estimate it if you can tell me the pulley ratio. I assume this was on a pullied car, yes? (That would suck for it to peg on a stock vehicle below the engine redline!)

Has anyone installed LTs on their car? If so, can you tell me what kinds of gains you saw and how much your boost dropped? Before/after dyno graphs would be awesome! Thanks!

Actually, if we’re talking about compression within the cylinder, more compression ≠ more air. Within the cylinder, more compression = higher thermal-conversion efficiency, (which does also increase power). Look at it this way. While the intake valves are open, a given mass of air goes into...

I would have thought it would be lower, too. Maybe someone here knows?

A formula for effective compression ratio comes about from the concept of mean-effective pressure, (which is optimistic in how power is scaled with comp ratio). The typical equation used is, CReff = CRstatic*(1 + Pb/Patm) where CRstatic is the static compression ratio, Pboost and Patm are the...

Yeah, that’s how I would do it. I was actually just doing that same thing from that 874 lb drag force number published in that article above. I went about it basically the same way, and your numbers seem pretty close mine. Here’s my engineering take on it. F = 0.5*ρ*Af*Cd*v² or Cd*Af =...

FWIW, your math sounds right to me. MPH = pi*Dtire*RPM/(1056*GRtot), where Dtire is the tire height in inches, and GRtot is the total gear ratio (= 0.77*3.36, in this case). I came up with 216 mph from the info you gave, which is close enough. That would have to be scarey going that fast...

Very good article! Does anyone here have reference #2 in that article, by any chance?