adamlee05

sorry kris i just wasnt sure what you meant, my post probably wasnt clear enough. you know your stuff so dont worry i wasnt offended

Edward'TLS

OK, Acura uses manifold absolute pressure (MAP) sensor, not MAF sensor. That's the only thing you have got right. Either way, both function the same way. They are both used to detect air flow or air mass going through the intake manifold, although employing different principle of detection mechanism.

http://en.wikipedia.org/wiki/MAP_sensor

The upstream O2 sensor is NOT used to detect how much intake air is coming in, it is solely used to maintain the engine combustion air-to-fuel stoichiometry ratio of 14.7:1 under closed-loop engine operation, by fine tuning the fuel injection pulse width according to how much residual oxygen is left in the exhaust gas. This O2 sensor signal is not used when the engine is cold (coolant temp sensor). When the engine is cold, the PCM will operate the engine in the open-loop mode, at which the engine will run rich in order to warm itself up ASAP. During this time, output emission is very high, and this is why you must only go through emission tests with a fully warmed-up car.

Whereas the downstream O2 sensor is solely used to monitor how well the catalytic converter is operating. This 2nd O2 sensor is there to satisfy the OBD-II requirement which came into law since 1996.

You tell me to stop referring to this "cam lobe profile". But this is what sets apart the non-TypeS cam and the TypeS cam. The valve opening timings and durations are totally different, which means that ignition timings are totally different too in order to reap the most power out of the wilder VTEC valve timing. That's why dyna tuning is necessary.

Let me tell you a little background about myself. One of my previous jobs had been designing engine diagnostic electronics (hand-held and PC-based tools) for diagnosing engine troubles. I had been examining engine operating parameter data files (real time capture of all engine related input sensors and output actuators) for more than 10 years. When I was 23, I had helped and trained many dealerships and local garages to fix all those difficult to troubleshoot vehicles. I made a living working on the engine management and diagnostics.

Now show me what you understand.

RUF87

Okay, slight off subject, but still in the interest of more power - and while we have all this brain trust going on here.

I know several people had their throttle body bored out . . . some have used Kings Motorsports, at a cost of $150. When I had mine done I asked them to explain what all was done. Well I was surprised that people were having just one TB done. Okay, so for TLs there is only one, as I understand it, and the Type-S has 2, well the second is the TCS control body. It made no sense to do only part of the intake system so I had them bore out both. I also bored out the intake neck and rubber TCS mounting. Basically increasing the entire intake system from front to back. A bit more work, but after running around I noticed that the car really came alive. I could barely get the tires to break loose (chirp) when punching it in 1st gear - above 20mph - and now it'll break 'em easily, and even spin them some times, all the time when the temps are below 50 degs.

Anyway, I've not seen much on this, but it sounds like for this mod the ECU may compensate for the increased airflow. I was hoping to dyno it and take it to the track soon, but times have been rough, so it'll be a while for the dyno. Hoping to hit the track in 2 weeks . . if the weather holds out this time.

So if this is the case, why isn't this mod recommended more?

Ruf
02 WDP TLS, Black Interior with Black Grill Inserts
**1/4mile 14.46 @96.07MPH (45-70mph test - 3.5 secs)
(**before headers, Hi-flow CAT, IMMs & Bored & Match Intake System
17x7 Konig Appeals SMF with P225/45ZR-17 Kumho SPT
(used Ziex 512s track only)
CT Icebox, RamAir, Sways & Springs
3nd Gen Innovative Motor Mounts
BBTBs & More, Mugen Cooling Mods & Thermoblok
Ceramic Coated XS Headers & Random-Tech Hiflow CAT
NEO Anti Freeze & NEO 5w-20 oil
Tranny #3 Installed 11.17.2008

Edward'TLS

^^^^^ Yep, that's the purpose of CAI, or high-flow air filters, or/and larger diameter throttle body, or/and RAM-air setup that most people already have. Less restrictive air filters/larger throttle body lets in more air, which will be detected by the MAP sensor inside the intake manifold. The PCM then adjusts the ignition timings and lengthens the fuel injection pulse width in response to this increase in air flow, again using preset values from the pre-programmed timing maps. Thus more air => more fuel & more agressive ignition timing => more power from the engine. Simple. No extra tuning required unless you go to force induction, in which case, you'll need high flow fuel injectors for the extra fuel dumps.

DCap

allow me to interject for a minute......i currently own an 02' TLS and a 92' DB2. last year alone i peeled off no less than 150 dynojet pulls with my Integra (built Ls Vtec) and my tuner is a very close friend. with that being said, adding mods will show gains on most of our cars. but, the sad reality is that most people running modded, untuned TLS' are probably running pretty damn lean (lean afr's= more power for all of the wrong reaons). i highly doubt our ecu's correct afr's well as post obd1 ecu's are designed to run much cleaner than its obd0 & obd1 counterparts. when i state clean, i mean the ecu constantly attempts to correct the timing and fuels maps for stock engine configuration, regarless of mods. next, i must mention that if a car was dynoed in stock configuration on one day, then run on the dyno weeks or months later with new mods, comparing those sheets is an exercise in futility. third many dyno graphs posted on the net vary in readings...sae, std, uncorrected, din, so know 2 sheets can be copared against each other. as for cam mods, the proper heat range plug, cam gear, upgraded valvesprings and retainers must be added to the shortlist of tuning. which makes a cam swap pretty much a huge waste of money and simpy adds stress and reduced longevity to the head, solely.

adamlee05

- MAP and MAF sensors do NOT do the same thing. Nor do they function the same way. MAF sensors can detect on the molecular level the exact amount of air entering the manifold, an O2 sensor is used on those systems only to verify the injectors are giving the correct fuel as set pulse-widths. Yes, an O2 sensor technically does the same thing on a MAP system, but on this system the O2 sensor readings are the ONLY way the ECU can make up for the extra air that is entering the intake system - the "unseen" air not recognized by the less-accurate MAP-based table systems. MAP sensors only determine the amount of air entering the system based on intake air temp (as well as other readings) compared to a pre-set map in the ECU, which is designed around using 100% stock factory air intake systems. Changing the rate at which air is entering the engine, i.e. better flowing CAI system, can NOT be measured by a system using a MAP sensor. Signal voltage from the TP sensor used in conjunction to MAP sensor voltage and IAT sensor readings is going to result in the engine blindly expecting X amount of air to be entering the manifold regardless of if the car is 100% BONE stock or if you have a funnel directly on the throttle body with a wire mesh screen over it. Even though the second induction system is obviously going to result in more air flow into the manifold, the ECU has no way of knowing that and therefore uses pre-mapped values of injector pulse-width to feed the fuel.

"The manifold absolute pressure sensor provides instantaneous manifold pressure information to the engine's electronic control unit (ECU). This is necessary to calculate air density and determine the engine's air mass flow rate, which in turn is used to calculate the appropriate fuel flow."
Great job pointing out EXACTLY what I said in my previous post. Yes they do calculate air density and flow rate into the engine....GIVEN THAT THE INTAKE SYSTEM IS STOCK AND DOES NOT HAVE HIGHER CFM FLOW RATES., which CAI's DO.

MAF sensors can allow the ECU to vary the pulse-width of the injectors to its own tables based on the molecular volume of air entering the system, a MUCH more accurate method to determine air mass and density, not blindly referring to value tables as MAP sensors do.

- Now onto your second point, regarding O2 sensors. Why you provided how open and closed loop operation works is totally beyond me, pointless in regard to what we're discussing since I doubt ANYONE will be running their car in VTEC if and ONLY if the engine hasn't warmed up yet. But alright...

Anyhow...
"The upstream O2 sensor is NOT used to detect how much intake air is coming in, it is solely used to maintain the engine combustion air-to-fuel stoichiometry ratio of 14.7:1 under closed-loop engine operation,".
Who EVER said and O2 sensor is used to detect intake air mass? Nobody. And yes, it is used to maintain the 14.7:1 ratio....and in the case of a system using a MAP sensor, not a MAF, it is the ONLY way the ECU can compensate for the higher quantities of air are entering the system. If the ECU is using the pre-determined value of X amount of air entering the system assuming a stock intake system, yet you have a system that allows more air flow than the engine is expecting, you have a leaner burn. The O2 readings are the only way the ECU is going to compensate for that, by dumping more fuel.

For a demonstration of this, we'll go with a typical 3.5 build in a 3.2TL:
Upon initial startup and breakin of the new 3.5 engine using a 3.2 ECU, the long term fuel trim will be leaner than what the 3.5 demands. The Short term fuel trim can compensate until the LTFT adjusts itself in due time. The reason: The ECU has no way of knowing that due to the larger displacement more air is entering the cylinder. Its reading the same sensor values as it would on a 3.2, but strangely to the ECU its not getting enough fuel. The O2 sensor informs it of this, and the ECU starts adjusting the STFT and eventually things get sorted out. On a MAF sensor-based system you could throw a 6 liter into a 3.2 car and, given the fuel system has the potention to deliver enough fuel, it would recognize the extra air-flow immediately and never run lean until its fuel system gave out.

Finally to your ever-present cam-profile-timing issue:
It is not an issue WHATSOEVER since again the only thing being changed is intake charge into the cylinder. If its burning leaner than it should be at set values, the primary O2 sensors reads that and based on engine load (yes, our "dumb" ECU's have tables for that as well), it can advance its timing and fuel trim.

But sense you were a whatever for however long, you should have already known not to say MAP and MAF sensors are the same or do the same thing, because they don't. Also, you should have figured out which system these cars use before posting the wrong information on a forum dedicated to these cars. And you should read the entire post before replying with something that might suggest somebody implied that O2 sensors are used to read Intake air density, which nobody did.

That's a tiny bit of what I understand, as I'm an ASE/MLR/KW, etc etc certified gasoline and diesel tech.

All I'm saying is please do not spread misinformation on these forums...there's enough of it already as it is. We're all guilty at times and its everyone's responsibility to maintain facts and point out falsities to the otherwise uninformed members of the community. And regardless of what your job was, our ECU's are decently smart in this field...which is one reason things like the VAFC I controllers are useless.

If anyone feel the need to disagree you have the right, but personally I will not say anything in response as we are getting overly technical for the general members of these forums. I may have started that trend in this thread, but I just wanted to correct and inform members of facts. Now however, its getting too deep and doesn't matter. It is great to know though that we have technical-educated members like Edward, fsttyms1, and 01tl4tl - as well as others - lurking around Many forums have no tech-savvy people whatsoever

-Adam

DCap

just trying to be subjective not critical, but larger throttle bodies don't always increase airflow. in most cases, too large a throttle bodies simply decreases intake velocity. cam profile, im plenum size and air intake piping length and diameter all need to be taken into consideration when chosing a throttle body..... especially on a Honda

DCap

adamlee05

DC, where are you from? My best friend is mid-build on a 600WHP 97 DB8 GSR. Genuinely Knowledgeable integra-folk are hard to come by, maybe you might have some tips for him

RUF87

okay, it was way technical, but to be honest, it's that sort of technical insight that helps understand what mods to do, and how far to take them before you reach a point of no return, or in many cases start losing benefits.

I'm just an old V8 Muscle car builder and I used to get on guys for over caming, over carbing, etc. etc. etc. I spent way more time optimizing my set ups to work together and that resulted in a consistently performing engine. It's how back in 1980 I got a V8 to turn 8,000rpm while most everyone else was toping out at 6,700rpm, so keep it up.

Ruf

RUF87

Exactly the point I try to make when I try to explain why I modified the entire intake from airhorn to the intake manifold itself. Another way of putting it that you are limited by the weakest link, or in this case 'bottle neck'. So for example when someone bores out a throttlebody to 4", but the intake tubing is 3.5", there's no or very limited benefit.

I love it when I open up the ramair for the track or to demonstrate how much air is being sucked in . . you can stick your hand in front of the airhorn and feel the air being sucked in. Give it a little gas and it sucks your hand in. And it sounds way cool hearing that hiss and then the deep vacuumn release sound when you turn the engine off.

By the way, at the track guys were always surpised that with just intake mods I was beating guys with intake, headers, pullies, etc. With just the Icebox and ramair component it would run 14.46s. I wish I had the extra $$ to dyno each time, but I'm just an poor old man.

Keep up these helpful post.

Ruf

Edward'TLS

Adamlee05, it's good to know that I'm talking with someone in the same technical field. But ...

Thank you for your lengthy explanation. But, at the end of the day, both MAP and MAF sensor information is used to detect how much intake air is coming into the system and together with other sensor info, the PCM generates ignition timings and injector pulse width according to the pre-programed timing maps.

There is no "unseen" air, and the MAP sensor CAN be used to detect more air-flow/air-volume/air-pressure coming through via for example a CAI. Why not ? Because even when everything is OEM stock, intake air pressure (and therefore air flow) will be different when the car is sitting idle, traveling slow, or traveling fast. The car doesn't care if you have a CAI or high flow filter, all is what the know is how much intake air coming in. It's exactly like when you step on the gas pedal and open the throttle plate opening a little more. So when you are 3/5 throttle, there is so and so air volume coming in. Now you apply 4/5 throttle, the throttle opening becomes bigger and so more air volume is coming in. This will be detected by the MAP sensor and the PCM basically move up the timing curve for more fuel delivery. This is all inside the pre-programmed timing maps. For those unfamiliar, you can graph the timing maps as multi-dimensional curves. All the PCM does is to move along these curves to obtain ignition timings and injector pulse widths info according to the various input sensor readings and processed data.

I admit that I made a mistake in the MAP/MAF naming, but that doesn't mean all my other info is wrong. I had worked on so many different car makers' engine management systems that were easy to mix up, but the concept is the same. Especially with the OBD-II requirement, that all vehicles selling in the US have to adopt, it almost standardizes the emission control systems for all car makers.

The reason is that in cold engine open loop mode, the PCM does not process the O2 sensor readings. Here comes the interesting part. So how does the PCM know how much intake air is coming in ? Answer : the MAP sensor. But without using the O2 sensor readings to fine tune the 14.7:1 A/F mix ratio, output emissions will be enormous. So any vehicle can basically run without O2 sensor(s), but will fail bigtime in regulatory emission tests. In fact, before the OBD-I and OBD-II era's, vehicles didn't have O2 sensor(s) at all and relied solely on MAP/MAF sensors for incoming air calculations.

When the MAP sensor and the O2 sensor readings are graphed real-time next to one other, it's easy to see that the O2 readings are more jagged (lots of ups and downs) compared to the smooth MAP sensor readings. Furthermore, the O2 readings are always jagged even when the throttle is hold steady, i.e., when air flow is constant. However, if you open up the throttle a little, you will immediately see the MAP readings go up in sync. Thus, the MAP readings are used to detect air flow, the O2 readings aren't.

If the O2 readings are to be used to coarse tune the A/F mix ratio, your car will be jerking so bad that you will throw up even before reaching the corner store. The O2 sensor readings are only used to fine tune the 14.7/1 mix ratio to regulate emissions.

adamlee05