I agree with you 100%, through careful conditioning of the vehicle you can cut down on the variabilty quite a bit. Some of the controlable things I have found are variance due to oil and coolent temp of powertrain, +- 3 hp. Heat bloom transients in the engine compartment +-6 hp(amazing isnt it?), electrical load due to fans +- 1 hp.

In my experiance there is also usualy a random variance of +-2-5 hp (depending on the car) for factors that are not easy to control or explane. This makes the testing quite imperfect. I also feel that SAE correction is imperfect, espcialy when heat is combined with extreme humidity.

In my opinion dynojets have better repeatabilty than load dynos (I suspect that the elertical resistance changes in the coils with heat on eddy current and oil properties like viscosity with temp change on hydralic loaded dynos. Dynojets run "shallower" into the high load cells on the maps and don't accurately represent what loads an engine really sees, one reason why they are not optimal for tuning.

I feel that dynojets are the most repeatable but the least accurate for this reason if you know what I mean.

So I think its important to try to be as accurate as posible but as you said, no results are going to be perfect. By being careful you can eliminate more than half of the variabilty which is significant.

Your results are pretty consistant, I am wondering why the output for the dynojet chart is so noisy with a smoothing factor of 3. Thats what I usualy uses to make it not look so jagged.

What I see is common, (especialy on the SR20 forum) is to do lame stuff like not use SAE correction, then test on a cold day then brag about the numbers while saying that corrected numbers are not real power. I have also seen dishonist shops maunaly screw with the correction and or smoothing numbers to show exagerated power numbers after their tuning or installation of their parts. A common method is to baseline with a high smoothing factor then dyno after tuning with a factor of one which produces higher numbers.

In my case, I did all the parts installs myself and then drove to a shop just to use their dyno, so the shop had no real interest in manipulating my figures.

Back on the subject of the article in question, to fork us off on a different path...

The most interesting tidbit I saw in your results was the gain from leaving the bumper off. A few weeks back in colder weather I did some IAT testing driving around Houston with the Stillen Gen3, which you can see here: http://www.the370z.com/intake-exhaus...eed-stock.html

Overall I was pretty impressed with it's ability to draw cold air, although it wasn't a perfect match for the air the car's exterior temp sensor was reading. Then again in that colder weather, there wasn't as much heat soak going on in the radiator area either.

I could be convinced that some ports like the Mine's ones might help us get fresh air into the Stillen intakes, and it might be worth it. I'd be a little worried about them rolling at slow speeds in heavy rain and wind though (or especially washing the car). I wonder if someone could fab plugs for the Mine's ports so they could be stopped up in heavy rain or when washing. Either that or perhaps someone else will have a new design idea along similar lines.

I just PM'ed Kyle at Stillen and the interesting thing he told me was that they found no difference when they tested with the bumper on and off.

Out of curiosity, we took the bumper off, saw a huge gain that repeated, then put the bumper back on and it went back to where it was before.

Technosquare's dyno has a huge fan the blows hard on the front of the car, not exactly road air flow but pretty darned close.

I was thinking one further, heat shields in back of the filters and vents in the front with a snap in cover or some sort of lovers for rain. I fabricated something like that for my Z32 Turbo but I don't have rain covers but I don't drive that car in the rain either.

The Stillen intake kills the JWT dual pop, thats for sure, if the bumper is off.

It will be interesting to see what happens when others experiment with this.

Another possible advantage of bumper openings direct into the filters of the Stillen Gen 3 intake is the fact more air volume might make it in, especially when you consider the ram air effect.

With regards to the water, perhaps the bumper inlets could be at the same height as the intake (like Mine's), but more inboard, not in front of the intakes. This would allow (given enough space behind the bumper) for a U shaped pipe with a drain at the bottom to connect from the inlet to the intake filter. That way water would only make it through the first half of the U, and not be able to move up (at least not a significant amount) the second half.

The ram air effect is highly overrated. Simply having a good, cool source of air that isnt full of heatsoak from the engine bay is fine.

Without testing it is hard to know what the airflow behind the plastic bumper looks like, meaning it might be harder for the intake to draw air from where it sits than if it had a more direct source, such as the U tube I suggested. It would be worth trying, for sure, the problem would be closing holes in the bumper if it didn't work too well.

But, based on the Technosquare testing we're discussing, it sounds like they repeatedly saw improvements with the bumper off, and a reduction in power when the bumper went back on, so one would think that the intake is having some difficulty drawing air behind the bumper. That is what I meant by ram air, not that it would be much denser (in Aerospace, the ram air effects are generally negligible until about Mach 0.6), but it would make it easier for the intake to breath.

I definitely don't disagree that, even with the Stillen long-tube kit, that it may have issues still getting the optimal cold air. But I think you have to draw a line somewhere, and that line is the safety threshold as far as hydro locking the motor in a rainy situation...

Yeah we're not yet closing in on Mach 0.6 :)

Ram Air is mostly bunk on cars, all it really means is a definite cold air source. As for the filter/hole placement, the Stillen Gen3 filters are near the center when installed. I actually think the Mine's holes, where they're at in the photos, wouldn't be directly over the filters anyways, they'd probably be hitting the pipe just behind each filter.

wstar, my point exactly, we don't go fast enough for ram air to matter.

Interesting point on the Mine's holes, as I had not imagined the Gen3 intakes would be closer to the center. Perhaps that is the solution already, meaning without water hitting the filter directly, and maybe being even a bit safer and moving the wholes down a little sop the air filter would reside above the openings, would mitigate any chance of water getting in.

Well considering the Mine's install instruction most likely amount to 'cut hole here and stick this in with glue', you can probably adjust the spacing to whatever's most optimal.

Does anyone know if Mine's sells those as a kit?

The second (bottom) product on this page is the one:

http://www.mines-wave.com/english/CA.../AIR_SCOOP.htm

A quick google search of 'mine's air scoop' shows there are a few sources shipping in the US, but looks like about $1K, which imho is ridiculous for the part. It's basically a pretty liner for two holes you cut in your bumper. I'm sure someone local could custom fabricate a clone far cheaper.

Ha! I looked through their website before posting, but not under "Carbon fiber". Thanks wstar. Crazy price.

With MightyPutty. :tup:

http://i618.photobucket.com/albums/t...ghtyputty2.jpg