STILLEN Exhaust & Gen 3 Intake Dynos - 18hp Each!

shumby

yes they will

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Originally Posted by SAM@GTM
Engine detonation is not normal and it should never never happen, and whoever told that need to do something else for living .
Sam

Denny McLain

The question is why?
As mentioned, pulling both filters leaving the top open basically did nothing. For sure if the filters were an issue something would have happened. If there was an issue getting enough air into the box removing the top would make something happen also. Why I mentioned probably blew a hundred bucks on the high flow Cosworth filters.
If it ain't broke....don't fix it. So far, I can't find the broken part (intake wise) except the cars are way rich from the factory.

Did read in the March issue of "Modified Mag' pertaining to modifying the 370Z:

"Just for fun, they brought along their G37 POP Chargers, a bolt-on intake system for the dual HR engines. The intake kit is a direct bolt-on with only minor changes to one of the securing brackets. The necked-down intake also tricks the ECU into seeing less airflow and slightly lean out the OEM mixture to make some more power."

No argument leaning the stock 11.3-11.6 Fuel/air will produce gains. Tuning software and dyno tuning with a wideband 02 sensor will get one dead nuts on the money as to what the car likes to produce the most power.

ENT-Z

So if I am understanding what you are saying Denny, then perhaps these add on intakes are only helping because they are tricking the ECU into running leaning A/F mixture? So...perhaps a good dyno tune to adjust the A/F would be just as beneficial, maybe even moreso, than a CAI? Do you think a CAI + tune to adjust A/F would be even more beneficial?

I don't have any experience with working on these newer cars, but when I was building small block chevys I certainly didn't use the biggest 4 barrel I could get, in fact putting too big of a carb on would actually hurt horsepower.

wstar

I think that's the line of thought Denny is headed down, yes. If the stock intake is already cold air (sounds like it is - honestly I haven't looked to see if the stock boxes are really sealed off from the engine bay and sucking only air from the front ports (the ones that you would enlarge for running the Stillen Gen3 pipes)), and it flows sufficient CFM already to match bolt-on exhaust mods and a little ECU tuning, then intake mods aren't really going to help if you're going to tune the A/F mix in the ECU anyways.

Now, that being said, colder air is always a win, and perhaps the location of the Stillen G3 inlets (filters really) gets access to colder air than the stocks ports hidden back there on the sides of the radiator, especially on a real highway. There are some variables in play there with highway-speed wind coming in the throat of the car, air pressure under the car and near the front intake, and turbulence to deal with, etc.

However, given the impressive dyno results, I lean towards the idea that at least some of those gains on the dyno must be coming from leaning out the A/F mix like Denny's talking about. Hopefully soon we'll get some numbers to sort this out.

Denny McLain

My main experience also is with small block Chevy's, owned three modified import turbo cars but that's been a while and I'm sure a lot has changed. What I've learned from fuel injected small blocks (unlike carburetor cars) is you can have a garbage can for a throttle body and unless it's not getting enough air...so what? Same for intakes. Enough is enough.

This stuff really is a science and it takes a certain amount of air (cfm), at a certain fuel/air ratio, at a certain rpm to make X amount of power. A cooler charge will be denser containing more oxygen per liter of air. Other things like humidity and barometric air pressure also factor in. SAE uses 77 degrees air temp as it reference point.

A stock Chevy LT1 motor makes about the same amount of power as the 370Z and needs about 550cfm at higher rpm to make max power. In other words... No matter how much air you show the motor, it will not pull anymore than 550cfm as that's all it can use at its given power level.

No question there is a benefit from not drawing warm air from the engine compartment (why there is a difference in SAE and Standard hp scales) but any ram air effect is debatable. Some say nay while others say yay. My personal feeling based only upon mid 60's NHRA stock class rules is there is some beneficial effect. They made cars run one class higher if they had some type of scoop or ram air system.

Also did not physically remove the air box but basically stuck my hand down in it and noticed air was coming from somewhere below and in front of the radiator. Besides the filters being a bit on the small side, looks like a well designed system from the factory.

Can it be improved upon? Sure. How much.....dunno. There are effects from turblence, velocity and swirl that show up inside the heads but man, that air is moving tremendously faster. Dunno?

One dyno session to get a baseline really doesn't tell ya that much except what the car is making and wideband 02 readings. What I do know is the cars are very rich and my experience in dyno tuning is proper fuel/air settings are king. Screw the timing, I want somewhere around 13 to 1 fuel air depending upon what the car wants.

If the intake is a restriction, it would show up more after adding the higher flow cats that should increase power, increase the need for cfm of air. Got house guests, but I'll try and get the car on the dyno this week. Do the same trick: three runs for new baseline, pull the filters and lid. Check to see if power or fuel/air has changed.