Well considered opinion
I'm with David Vizard on this one:
I've read a great deal of his published material - even had dinner with him. It is my opinion that as far as automotive high performance engineering writers go, he's on the genius side.
Would someone please show definitive proof behind statements that the hemi runs rich, richness produces excess Hyrocrbon emissions; how could it pass the the stringent US emmision control requirements if it ran rich?The factory would be penalized, emission testing stations throughout the US and Canada would be failing the cars and the dealer problems section of this forum would become full of problem posts relating to richness.
a basic explanation of mixture http://www.autoshop101.com/forms/h55.pdf
My statements about the SRT8 airbox giving an 8hp increase (now quoted out of context) are correct, but the whole SRT8 computer has been remapped over the 300c to include the changes caused by the SRT8 airbox as well as the other SRT8 engine mods over the 300c. It's not as if they took the SRT8 and added the air box only, they also reprogrammed the computer.
As far as CAI's producing more HP on the 300c - maybe but maybe not. It could all be in the ear of the beholder.
As an explanation I will include some basics so that some reading these posts who may have a basic understanding of fuel systems may pick up some more information. This is only trying to take into account a varied level forum member knowledge.
All Otto(4)-cycle engines - including the 300c - are essentially pumps with design-based limits for the amount of air they can pump - exceeding the design requirement for the early portion of the air intake only brings you bang up against the brick wall of the engines other inherent airflow limitations - the plenum, runners, ports, valves and their shrouding in the cylinder head. Once the air feed is cold enough and fed in adequate velocity and quantity for the engine’s needs, then other parts of the engine must be addressed to obtain more power from the intake side.
Early on with carburetted cars cold air intakes would just about guarantee HP increases from the fact that the no longer drew air from the heated under hood area, but took higher density air from the front of the car, gains were also realized from the increased air velocity gained by using a long feed tube of optimum diameter. Not to large or too small
An opinion based on the premise that the IAT (Intake air temperature) sensor is going to become significantly cooler and air denser with CIA than with the standard air intake and and adjust the mixture to produce more power, implies the standard 300c has an inadequately designed “warm air intake” not supplying sufficient cold air for both highest vacuum and Wide open throttle airflow engine conditions. This premise might apply were the 300c air intake was not engineered from the factory to provide an aquequate volume of air at a sufficiently low temperature..
Manufacturer’s engineers have been gradually incorporating more CIA principles into the design of the air feed system, if the factory system takes cold air of adequate in volume and air velocity for the engines max vacuum airflow and WOT airflow requirement then only improvement that CIA can be effective is in conjunction with other modification
MAF sensor (Mass Air Flow - the type not used on the 300c) fuel injection can within the limits of components such as injector size adapt automatically to changes in air flow and exhaust - the 300c does not have this type of system it has a speed density system
Speed density systems have a factory programmed fixed map* of the engines’s fuel requirements in the controlling computer. At the current state of fuel injection technology “map” is accurately tailored to the engine’s fuel requirements for all reasonable conditions.
Because a Speed Density system has no sensors that directly measure engine airflow, all the fuel mapping points to give the correct mixture must be preprogrammed. Chrysler do that at the factory. Airflow is calculated (not directly measured) by measuring engine speed rpm and manifold vacuum - which increases with engine load - using a MAP (manifold absolute pressure) sensor. The computer then calculates airflow requirements by referring to a programmed table in the computer’s memory, so any significant change to the engine that alters its Volumetric Efficiency requires reprogramming the computer - not yet possible in the 300c
The Speed Density computer also takes info from an oxygen sensor mounted in the exhaust. The computer looks at the air/fuel ratio from the O2 sensor to compensate for small variations that occur engine to engine. It corrects the fuel delivery for any small discrepancies in the stored computer data
There is a situation I alluded to in one of my previous posts that can be the key to CIA and improved HP on the 300c:
quote from my previous post on the subject: “With SPEED DENSITY injection there are limited situations where extra airflow can be beneficial to RWHP but the require other mods and can never be really accurately calibrated due to the fixed profile factory SPEED DENSITY inj. software the 300c cannot be messed with”.
A parallel increase in exhaust flow (header and free-flowing exhaust) will allow the computer to keep the fuel mixture approximately balanced and correct within the limits of the fixed computer map providing the fuel delivery
With a well designed non-factory air intake and non-factory free-flow header and/or exhaust installed; some may see a benefit because the mixture is kept within a still balanced position within the FI computer’s fixed fuel map keeping the fuel air mixture approximately correct. Without access to the computer software in speed density to fine tune it this is at best good guesswork or lucky synergy - admittedly sometimes educated guesswork.
An oxygen sensor in the exhaust also tries to keep the mixture correct compensating for small variations from stock engine to stock engine. In tandem the overall the mixture has a possibility of remaining in mixture balance - we hope by educated guesswork.
The problem is that Chrysler is not releasing the code for the FI software, or the way to access it for fine tuning it to new mixture requirements when changes are made.
Some have already fitted CIA, and the sound of the CIA may be influencing judgement. I have taken these quotes directly from their forum posts; it's their language not mine, they have no reason to lie.
• We are talking maybe 15hp for CAI. If gains claimed were 50hp, my answer may be different, but for the nominal gains of a CAI? Personally, I could care less about 10 or 15 extra hp. The car is more responsive, pulls harder, get's a little better mpg, and it sounds AWESOME!
Are these the results from my own "butt dyno"? YES!! And that's all that matters! Best $260 I've spent on the car so far.
The only thing I can do with a dyno sheet is post them on my dash and stare at them while driving - or post them on the net for bench racing....
You can wait all you want for a dyno sheet proving it makes 10hp on a particular vehicle, but your own butt dyno will tell you a whole lot more than a real dyno sheet proving 10hp
• I don't care about all the people who said that this intake doesn't make the car faster. From my butt dyno, this car is faster with my Borla and Volant. Borla + Volant = AWESOME COMBO!!!
• More air will equal more horsepower. As many of you know we do alot of work with GM's Camaro/Firebird. The 1993 version didn't have a MAF. I had a very heavily modied '93 that responded well to induction and exhaust mods.
This was before programming became available
• This is an AWESOME mod. It really comes to life and loand and 30%+ throttle and it just RIPS at WOT with the Borla's.
• more half-truths appear to be surfacing...adding a hi flow intake DOES add power to our car..all this talk about mass air flow vs speed density is bunk..u add MORE airflow, ure going to get MORE power..ESPECIALLY since the factory ECU has been proven to run TOO RICH for optimum HP which is common for a stock car for various reasons.
(My own comment: this is incorrect as the 300c would not pass the stringent emission control standards if it ran measurably rich - particularly those in California)
• The sound is great. It's not any louder until you hit 2500 rpm, then it just rips... It feals quicker, but not sure if that's the case.
• thing is, sometimes when sounds and sensations are different, it gives the impression of better performance...not actual results.
• Just got it installed and wow what a sound. I'm not sure if it is faster or not but with the WOT sound, sure feels fast
• Everybody send me a check for $350 and I'll send you a tape of me making vroom vroom noises.
Dyno results, directly from respected independent testing outfits performed on the same day with the same atmospheric conditions: 1st stock and then with the modification fitted is the only way for me to even consider putting money down. Then I would consider the possibility that my speed density injected car I will almost certainly be running with an incorrect mixture for at least part of the time every time I run my car. Then I would look at what significant non-cosmetic advantages: material quality, general design quality, and other consequences of fitment.. Then I would look at any DCX warranty considerations. Then value/bang for the buck and the reputation of, and warranty offered by the CIA manufacturer. Do we have any such independently produced HP/Torque graphs for your (or any) CIA on the 300c?
Some may have already been seduced by the siren song of increased horsepower promises. They have bought CIA already. The only real defence when challenged is a before and after independent dyno result graph with superimposed before and after HP and torque curves, this will show any gain or losses - and yes there could be losses as well.. .
I do not see this forum as an I win you loose situation. rather that by refining our understanding we may arrive at a better picture of what is really going on behind the assumption that any of these products are giving value for money. Otherwise the mods may be just cosmetic, and we may just be sheep
* not a reference to the MAP sensor (manifold absolute pressure) which responds to changes in manifold pressure measuring engine load by the amount of vacuum present.
Man I feel like a nap now