Chrysler 300C & SRT8 Forums banner

1 - 20 of 50 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter · #1 ·
I'm will be putting on a Volant air intake soon, and I was always under the impression that the computer would automatically re-adjust for the increased airflow through the intake. Then I happened to read a section in this artilce, and it states that it would have to be reprogrammed. Here's the link, and quote:
http://www.popularhotrodding.com/tech/0403phr_hemi/
"Unlike an LS6, which has a mass air system that allows the computer to adjust the fuel flow for any given airflow so that the mixture is always right (theoretically at least), the Hemi has a speed density system. This means that any increase in airflow into the engine goes unseen by the rest of the system. If a modification is done that increases mass airflow, such as a cold-air package, the computer has to be reprogrammed accordingly. Fortunately, two companies, Squier Inc and Street & Performance are working on this now and already have what is needed for transplants of the Hemi into other vehicles."

Is this the case? :confused:
 

·
Premium Member
Joined
·
4,071 Posts
300CmeFLY said:
I'm will be putting on a Volant air intake soon, and I was always under the impression that the computer would automatically re-adjust for the increased airflow through the intake. Then I happened to read a section in this artilce, and it states that it would have to be reprogrammed. Here's the link, and quote:
http://www.popularhotrodding.com/tech/0403phr_hemi/
"Unlike an LS6, which has a mass air system that allows the computer to adjust the fuel flow for any given airflow so that the mixture is always right (theoretically at least), the Hemi has a speed density system. This means that any increase in airflow into the engine goes unseen by the rest of the system. If a modification is done that increases mass airflow, such as a cold-air package, the computer has to be reprogrammed accordingly. Fortunately, two companies, Squier Inc and Street & Performance are working on this now and already have what is needed for transplants of the Hemi into other vehicles."

Is this the case? :confused:
Unfotunetly yes, this is true.

Aftermarket intakes are a waste of money if you ask me.....At least right now they are.
 

·
Registered
Joined
·
375 Posts
Waste of money is one's opinion...and I'm glad you at least have one (or several as I've read lol).

I installed the Volant 2 weeks ago - LOVE IT on my C. Does it give me 10hp? Not sure, don't care. Do I need a dyno sheet to prove it works? Nope. Again, for 10hp, I don't care. Does the computer recognize it and adjust - nope..does it matter?

What I do know is this:
Increased throttle response (per my SOTP meter or my butt dyno), better mileage (when I can keep my foot out of it), and it now sounds AWESOME (I also have the Borla exhaust).

The SRT8 airbox claims a 8hp gain over a stock C airbox? (at least that's what someone already posted)...http://www.300cforums.com/forums/showthread.php?t=5388

Waste of money is subjective - my personal opinion?

Worth every penny.
 

·
BLOODY ADMENSTRUATOR
Joined
·
7,554 Posts
The argument over mass air sensing and speed density sensing is only of interest to those doing major air input changes.

Minor improvements, such as better breathing filters such as K&N, or CAI systems, such as Volant or Airaid, definitely improve performance and fuel economy. The parameters that adjust timing and mixture will take advantage of denser air volume, paticularily over 2500 rpm in the case of the 5.7 litre Hemi.

The stock filter and the stock intake with its massive silencers is inherently restrictive. DCX wanted the car to be as quiet as possible.
 

·
Premium Member
Joined
·
4,071 Posts
5point7 said:
Waste of money is one's opinion...and I'm glad you at least have one (or several as I've read lol).

I installed the Volant 2 weeks ago - LOVE IT on my C. Does it give me 10hp? Not sure, don't care. Do I need a dyno sheet to prove it works? Nope. Again, for 10hp, I don't care. Does the computer recognize it and adjust - nope..does it matter?

What I do know is this:
Increased throttle response (per my SOTP meter or my butt dyno), better mileage (when I can keep my foot out of it), and it now sounds AWESOME (I also have the Borla exhaust).

The SRT8 airbox claims a 8hp gain over a stock C airbox? (at least that's what someone already posted)...http://www.300cforums.com/forums/showthread.php?t=5388

Waste of money is subjective - my personal opinion?

Worth every penny.
I'm not saying don't buy it. It looks cool and all. It won't hurt.

FWIW, I just saw a dyno of an SRT-8 and he said he's running very rich stock. If the 5.7's run rich like this at WOT it might actually make a difference now that I think about it.

:)
 

·
BLOODY ADMENSTRUATOR
Joined
·
7,554 Posts
vvv90 said:
I'm not saying don't buy it. It looks cool and all. It won't hurt.

FWIW, I just saw a dyno of an SRT-8 and he said he's running very rich stock. If the 5.7's run rich like this at WOT it might actually make a difference now that I think about it.

:)
Yeah, we found the 5.7 Hemi C ran rich as well. Pretty standard for manufacturers to program a rich setting these days. By improving cold air flow, performance increases.
 

·
Premium Member
Joined
·
4,071 Posts
Northern Rider said:
Yeah, we found the 5.7 Hemi C ran rich as well. Pretty standard for manufacturers to program a rich setting these days. By improving cold air flow, performance increases.
If that is the case I bet there WILL be gains....Maybe not enough for the SOTP meter but some.

I'd like to see a before and after dyno. (Not one put out by the manufacturer either) That should put the issue rest.
 

·
Premium Member
Joined
·
1,151 Posts
vvv90 said:
If that is the case I bet there WILL be gains....Maybe not enough for the SOTP meter but some.

I'd like to see a before and after dyno. (Not one put out by the manufacturer either) That should put the issue rest.
Ironically enough, we agree on this...as I tried to point out in the EBAY thread...
 

·
Premium Member
Joined
·
4,071 Posts
jjs said:
Ironically enough, we agree on this...as I tried to point out in the EBAY thread...
Does it make you feel ignored that I don't read all your posts?

I'm sorry, I'll try to pay you more attention. :D
 

·
Premium Member
Joined
·
1,151 Posts
vvv90 said:
Does it make you feel ignored that I don't read all your posts?

I'm sorry, I'll try to pay you more attention. :D
Hey, butt head!! ;)

No, I just find it interesting we CAN agree on some things.

:D

OH, BTW, thanks for the nomination for moderator!! :D
 

·
Registered
Joined
·
714 Posts
5point7 said:
Waste of money is one's opinion...and I'm glad you at least have one (or several as I've read lol).

I installed the Volant 2 weeks ago - LOVE IT on my C. Does it give me 10hp? Not sure, don't care. Do I need a dyno sheet to prove it works? Nope. Again, for 10hp, I don't care. Does the computer recognize it and adjust - nope..does it matter?

What I do know is this:
Increased throttle response (per my SOTP meter or my butt dyno), better mileage (when I can keep my foot out of it), and it now sounds AWESOME (I also have the Borla exhaust).

The SRT8 airbox claims a 8hp gain over a stock C airbox? (at least that's what someone already posted)...http://www.300cforums.com/forums/showthread.php?t=5388

Waste of money is subjective - my personal opinion?

Worth every penny.


right now im looking at buying the volant intake and the borla exhaust.... how loud is the borla... when cruising? pedal to the metal? also does the exhaust get louder with the intake.... im prolly gonna have them both put on at the same time... im jus wondering how it all sounds and performs... together, thinkin about ordering this week.... hope this will make up for the acceleration loss from the 22s
 

·
Registered
Joined
·
14 Posts
5point7 said:
Waste of money is one's opinion...and I'm glad you at least have one (or several as I've read lol).

I installed the Volant 2 weeks ago - LOVE IT on my C. Does it give me 10hp? Not sure, don't care. Do I need a dyno sheet to prove it works? Nope. Again, for 10hp, I don't care. Does the computer recognize it and adjust - nope..does it matter?

What I do know is this:
Increased throttle response (per my SOTP meter or my butt dyno), better mileage (when I can keep my foot out of it), and it now sounds AWESOME (I also have the Borla exhaust).

The SRT8 airbox claims a 8hp gain over a stock C airbox? (at least that's what someone already posted)...http://www.300cforums.com/forums/showthread.php?t=5388

Waste of money is subjective - my personal opinion?

Worth every penny.
Um yeah, just wanted to reiterate that point. Worth every penny for sure. GRRRR...

 

·
Registered
Joined
·
750 Posts
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.

PRO:
• 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)

NEUTRAL/UNSURE

• 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

FUNNY
• Everybody send me a check for $350 and I'll send you a tape of me making vroom vroom noises.

MY OPINION
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

Zilla

* 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 :D
 

·
Administrator
Joined
·
3,667 Posts
Zilla, Thank you for that very well-thought-out explanation. As usual, you have done an extremely effective job of putting mechanics into layman's terms, while both drawing in even a novice, yet not insulting the experienced.

That having been said, my Volant CAI should ship any day now and will await it's eventual pairing with a Corsa (ever???) or Borla exhaust.... Baa-aaa-aaah! :p
 

·
BLOODY ADMENSTRUATOR
Joined
·
7,554 Posts
Zilla, that was quite a mouthful.

I have a fair amount of modding experience. When I say manufacturers set on the rich side, that is my experience. It is a hedge from permitting the engine to operate in the leaner ranges, possibly causing overheating, knock and higher octane requirements. As to emission requirements, the catalytic converters are just big waste gas burners (of a sort) - cheaters to give the required readings at the tail pipe.

The CAI systems like Volant seem to render up 5% on their own and more when coupled with free flow exhaust systems.

Most of my recent work has been on small displacement rally engines. The 5.7 Hemi C as DCX present it to us is detuned to render fuel mileage. I feel this engine responds well to little tweaks. The first rule of performance is air in and air out.

Hey, if a CAI gives a small boost, especially mid range and gives that throaty V8 sound - it's probably worth the price of admission.

Oh yeah, and the Volant looks neat!:D
 

·
Registered
Joined
·
666 Posts
Zilla,
I agree with most of the things you have said, and it is lots of good info. Thanks. I love all this great discussion. I feel that DCX has left the wide open throttle (WOT) mixture a little on the rich side (11-12:1) to preclude any potential engine damage. Almost everyone on the "other" forums that has dyno'ed their LX Hemi's has come up with a rich reading at WOT. When at WOT the fuel management system is in the "open loop" mode and the oxygen sensors are not monitoring the mixture. DCX probably gets away with this because it is at WOT and not at cruise, when fuel management is in "closed loop" mode and mixture is maintained at 14.7:1 by the PCM with input from the oxygen sensors. I don't know of any state that does emission testing at WOT. I think most test under idle and cruise conditions, and would not catch this. I have built a WOT mixture control rheostat that theoretically will richen the mixture, hopefully to 12.8-13.5:1 which is where maximum performance is achieved. I based my assumptions on the shop manual's vague statements that the mixture is always programmed for 14.7:1 under all conditions. After seeing others' dyno results I may have to modify this setup to lean the mixture out to get the desired results, if this is true. I am thinking of buying an onboard exhaust gas analyzer to verify this before messing with it anymore. As far as the CAI goes, I am sure there is some improvement with most descent ones. I personally built my own. It is a double wall, double insulated intake that maintains the stock filter to plenum length and utilizes the stock air box, K and N drop-in filter and one additional 3 inch cold air duct into the airbox from just behind the grill. My intake air at cruise on the highway runs at ambient, and in town, 0-8 degrees above ambient. The reason I maintained stock filter to plenum length is because of an article in Poplular Hot Rodding Magazine. I will quote the part that sold me: "The system has a tuned length from the filter to the plenum and from here each port runner to valve is a tuned length. Computer modeling and dyno testing has allowed the ports, plenum and filter-to-plenum runner length and diameter/volume to be sized near optimally for a wide power band consistent with street performance needs." I've also enclosed a thread from "maneval69" off another forum that shows the HP/Torque difference between stock and with NO filter, which demonstrates there is room for improvement (almost 20 HP) and the rich condition I was talking about at WOT. Maneval69 writes, "Here are the dyno results for my stock RT. 2500 miles on the car.
I did 4 pulls all with the #17 fuse pulled and the car in 3rd gear.
The first 2 where as I pulled it in the shop with all stock equipment in place.
the best of the first 2
SAE Max Power 278.1 @ 5100
SAE Max torque 318.2 @between 4000 and 4400(it's not marked on my sheet)

For runs 3&4 I unhooked the intake from the air box and left the hose unfiltered.
ready for this!
SAE Max Power 296.5 @ 5200
SAE Max torque 327.9 @between 4000 and 4400(it's not marked on my sheet)

It would appear that a free flowing intake is well worth it.
My brother dynoed his ls1 right after I got through. He gained only 5 horsepower by opening his air box to eliminate the filter. His does have the ram-air box though.

Air- fuel ratio
Mine read 11.7 to 12 from 4100 through 5200 rpm on all runs. That means there is power to be made by leaning the mixture (programmer)


One more thing -This motor sounded awesome with the intake elbow unhooked from the airbox!"
 

·
Registered
Joined
·
349 Posts
My butt dyno said damn this thing works
 
1 - 20 of 50 Posts
Top