JTso

iTrader: (2)

It depends on the temp the IAT sensor detected. The ECU is programmed to advance timing and add fuel when IAT sensor detects cold temp. On the other hand, the ECU retards timing and reduces fuel when the IAT is hot.

kaikai114

so advancing timing and adding fuel will have more significant effects than SRI instant scoop of air?

vidgamer

.....
If all else were equal, I would guess that peak HP wins, but hey, what do I know?




We do have pretty much the same point, but I'd go a bit further and say that there's no point in making mods that increase low-end, as you can always downshift and have more power on tap. If you just always have the need for speed, then drive all the time in a lower gear. When you get tired of that and want to go back to saving money on gas or are bogged down in slow traffic or whatever, keep the revs low.

Only when you are taking it to the rev limit and still need more power do you need to do something. I guess my point is, unless you're flat out drag racing, I'm not sure how you come to the point of deciding whether you need more power.

Now if you just like the thrill of going fast, I guess that's good enough of a reason for me.

And as for the TSX not having enough torque, what RPM range are we talking about?

peter_bigblock

I did exactly that, slotted the fog light cover and positioned the SRI filter directly over that hole left in the fender/engine bay. Quite honestly, the filter is about 1 foot from where it would be as a CAI -- I wonder how much lower the IAT would be. If I were to rent a generic OBD2 scan tool from the local auto-parts place, is that enough to pull up IAT or do I need a more specialized OBD2 tool/software? Do you just leave the tool plugged into the OBD2 port while driving?

JTso

iTrader: (2)

A generic scan tool should pull the IAT data, and you just drive/dyno with it plugged in.

Newplay1

how does the filter sit? just chillin in the mid-air?

peter_bigblock

On an SRI (diy or not) it sits in the engine bay in mid-air (supported by the intake pipe and whatever brackets that has bolted to the engine bay). The CAI filter is sitting just in front of the driver's wheel well, behind the bumper, also supported by the intake pipe.

peter_bigblock

To make my DIY CAI, I'll likely use 3.5" od 6061-T6 pipe and either a 90-deg elbow (more like the K&N) or two 45-deg elbows (more like the Injen). Anyone have an opinion of which would be better? I'm leaning towards the two 45-deg since it's a more gradual turn than one 90-deg.

I notice, too, that both Injen and K&N use smaller-diam tubing (3.0" and 2.75" resp, I think). I'll be using 3.5" that necks down to whatever the diameter is of the stock throttle body -- I'm guessing 2.75" -- via the stock intake pipe.

I'll post pics, etc. when I finally figure out what I'm going to do. If nothing else, it's interesting. Sort of.

feuss2

iTrader: (1)

I've seen resistor kits on ebay with 20HP claims to accomplish this but that is NOT what I am suggesting!

If I were to make a board that would say subtract 10 or 15 degrees off the the perceived air intake temperature, would that be a good performance mod? The ones on ebay work by putting in a fixed resistor and making your car think its always freezing out. On a 95 degree days that difference is probably enough to result in some detonation. However, tricking it into thinking its on 80 or 85 out and getting that little extra fuel and advance probably wouldnt be the worst thing...

JTso

iTrader: (2)

Yeah... the ebay IAT mod is junk and the constant low temp signal to the ECU is flaw. Jackson Racing has done something similar to provide additional fuel by using a vacuum/pressure switch mounted to the intake manifold. Once the switch senses 1 psi of pressure, it triggers a relay which routes the "added resistor value" to the IAT circuit. You probably can get an adjustable vacuum switch to customize the activation point of the low temp value (probably at 0 vacuum during WOT) and not sending a constant low temp signal all the time. Another option is to tap into the MAP sensor and monitor the actual load, then modify the IAT signal accordingly with a custom built circuit.

This is the fun part about modificatoins. It's not always about how much money you can save. Sometimes it's about how much you can improve over an existing design or available solution. Have fun and keep on modding!

feuss2

iTrader: (1)

Do you have any references on the MAP sensor and how it works? Or for the air intake temp sensor?

I've read somewhere that the air intake temp sensor just a "thermistor" and is wired as a leg on a voltage divider with +5V across it. The supposely the ECU has a table that relates voltage to temperature.

I can't seem to find that reference, or know where you could get such wiring data but you seem to be really up on this stuff.

Any help you be appreciated. And you're right, its not always about saving money. I think the coolest thing you can do is get results from DIY mods. Anyone can buy bolt-ons and install them.

JTso

iTrader: (2)

I think the service manual might have the reference tables and signal data points for the IAT and MAP sensors. I can look in up when I get home.

peter_bigblock

I agree 100%, it's not the money for me, it's the sense that I figured out my own solution or, sometimes, a better solution than the aftermarket bolt-ons. Plus I've learned a lot. to Feuss2 for prompting this process!

I have Hondata -- any reason why I'd want to fool the computer into riching-up the mixture at all at any given air temp? Wouldn't that already be optimized by Hondata, if not originally by Acura?

JTso

iTrader: (2)

When you start changing air/fuel ratio and such, you are getting into the "tuning" aspect of modification. Which means you need to know where to change, by how much and why. That means equipments to monitor changes such a wideband O2 setup, dyno, and ways to make the change - Programmable ECU or some forms of piggyback devices (aftermarket or DIY).

peter_bigblock

Thanks, JTso. Here are some photos of my completed diy CAI. I took my TSX out for a few "test" runs on the freeway and around town. It pulls hard and sounds great, a little quieter and deeper than the SRI setup. Once I got back, I let the car idle a little before shutting it off, opened the hood, and felt the aluminum pipe going into the stock intake pipe -- it was ice cold (outside temp 34F)! With the SRI (I had done the same "test" before) it would have been very warm. Excellent!

Two 45-deg elbows and two 3.5" o.d. aluminum pipes:


A little further back:


K&N filter (3.5" i.d. opening):

kaikai114

very nice

are you planning to dyno your car?

Chris_F

wow nice work! not as pretty as the injen cai but i'm sure it'd get the job done just as well.

peter_bigblock

Yes, I'm planning on taking it over to the dyno after Thanksgiving some time. It's not as pretty as the Injen or K&N, but when I put a little tire dressing on the rubber it looks very "factory". And it works like a champ. I need to figure out a better brace, though.

jlukja

Nice work McGyver....er.. Peter.

JTso

iTrader: (2)

The TSX manual doesn't have the reference tables. I did find tables in my Civic manual so you can use them as reference to get an idea on how they work.

IAT



MAP

feuss2

iTrader: (1)

AAAAAAAAAAAH!!!!!!! A non-linear device!!!!!!!!! Surely the ECU has tables to handle that, and its not just at simple as adding in a resistor in series if you want to evenly subtract off a set number of degrees across the range!

I'm ready for the challenge!!!!

Thank you very much for that info! The actual data points and the pin output of those devices are so far, extremely hard to come by. I also wanted to track down male and female mating connectors for those sensors so i could do this mod without cutting any wires...

Anyone got a resource for that kind of stuff???

peter_bigblock

Thanks, jlukja. Man, these guys are REALLY into diy modification. I'm very much in the dark when it comes to modifying the electrical sensor systems. I'm limited to bolting together various pipes, ducts, and sleeves from the hardware store!

I will say that the SRI is quite a bit louder than the CAI. The tone of the CAI is much deeper than the SRI -- neither is nearly as obtrusively loud as most posts on AZ lead me to believe. You need to be WOT and above 5k for it to get loud. Under any other circumstances it sounds stock or maybe like an Icebox.

jlukja

Just curious, how's the throttle response with your setup? The reason I really like the Icebox is the significant improvement in the throttle response which I attribute to the larger airbox (more already filtered air available to the throttle body at the instant of throttle change).

peter_bigblock

My seat-of-the-pants is that throttle response is excellent with the CAI and SRI at speed, when the air temp difference probably isn't as great. From a stop, the CAI is better -- noticeably better than stock or my diy Icebox (albeit with the stock filter box cover). Mid- and upper-range power is strong with the CAI, you can feel it pull harder and harder as you go above 4k to redline. Combined with the reflash and DC Headers, the CAI and SRI both work well. I'm anxious to do dyno runs with both CAI and SRI (with the hood down and a cooling fan in front of the car). It'll be a pain in the ass to swap from CAI to SRI but I can't resist the comparison and (I'm assuming) the attendant "take one for the team" points.

The surprising thing to me was how much I like the sound. I didn't want to be driving around with my wife with this ricer sound all the time. She never noticed until I said, "Listen to this" and floored it. Then she asked me if I was going to mount a huge wing on the trunk. I told her I was leaving that to jlukja!

jlukja

I was going to, but then I saw this pic of joerockt's TSX and I just couldn't do that to my baby.














j/k sorry joe.

JTso

iTrader: (2)

Here is the diagram that has the MAP and IAT wiring connections.

dom

Thats not Joe's its eviljon's TSX.

jlukja

Really? I thought I'd have a little fun at joerockt's expense and googled "TSX wing" and posted the pic of the biggest wing I could find. I guess it belongs to another member. Who knew?

dom

Ya eviljohn is from Lets just say he's taken some slack for that wing.

feuss2

iTrader: (1)

Another awesome contribution to the cause!

I have a basic circuit constructed that will do two things:

1) Make the MAP sensor output a little more aggresive (rise 10% quicker)

and

2) Add a proportional series resistor! Since radio shack sells thermistors, a few of them in parallel )that are physically located in a place to sense ambient temperature accurately) wired in series with the sensor on the car will get that temperature scaled output needed.

I'm searching (very un-successfully at the moment) get a set of mating connectors for both sensors to that I can insert my electronics in between without cutting into any of the stock wires. Any help with this would be much appreciated.

I'm envisioning a more finished product with some DIP switches to tune the temperature offset and MAP progression to the other mods you have. Ramping up the MAP sensor will cause a little more fuel to be dumped and the AIT sensor mod will trigger a slight timing advance.

The car is tuned for 91 octane, but the only thing I've ever had an option to buy is 87, 89, 93, or 94. So I always buy 93, and I'd like to get whatever extra power I can squeeze out of it!

vidgamer

Feuss2, about this circuit....

My first thought was, if it is a simple matter of more gas, the ECU will simply figure out that it's running rich and re-tune itself. But, as you mentioned, somewhere I read that if it's colder outside, it'll use a more aggressive timing. Hmm, now it gets interesting. I don't want it to run rich, but I'll take a timing advance if it comes for free (or close to it). :-)

I've also seen things sold online that supposedly do this -- are they just resistors? Do they not work? (If they did, why isn't everyone doing it? :-) )

About 93 octane, it gets pretty hot here, so would that counteract the octane level a bit? I mean, your point about 93 is that the car is tuned for 91, but at what ambient temperature is it tuned at 91? 70 degrees? I need something that'll work at 95 degrees!



As for the home-brew intake, I'd try it to, if I thought that I could do it without looking really low budget. Peter's looks pretty clean....

JTso

iTrader: (2)

The ECU does maintain a certain a/f ratio base on what the O2 sensor reads during normal condition. However, it also depends on the throttle position and/or MAP sensor load condition, the ECU exits out of closed-loop mode and doesn't maintain the 14.7:1 ratio during WOT. This means another circuit to think about... I want my programmable ECU now.

feuss2

iTrader: (1)

There is a pretty widespread scam on ebay and other places suggesting you replace the air intake temp sensor with a fixed resistor. This is not [and I repeat from a previous posting in this thread] what I am trying to do.

Most people selling these "dyno-proven mod chips" just bought resistors from radio shack and sold them for a profit on ebay. I actually asked a seller what value the resistor was, and what temperature it was simulating. The answer I got back was something like "The stripes are..." So he picked up an 6.8k resistor that according to the chart that JTso posted... is making the ECU think its about 20 degrees F out, regardless of the outside temp. If you read a little more on this topic, you'll find some really pissed off people that not only paid $8-25 for a .05 resistor, but also have everything from check engine lights to detonation damage as a result of doing this mod...

My suggestion is to make the MAP curve a little more aggressive, and when it senses load (goes over 1.75 or 2.0V) to click over a relay that puts a few thermistors wired in parallel in series with the stock sensor. This way the thermistors would vary in proportion to outside air temp and can be used to subtract off a REASONABLE amount of perceived temp (I am suggesting 10-15 degrees here, NOT 70!!!!) and do it only when the engine is under load.

This obviously cant be done with a fixed resistor, because adding 1k of resistance at different temperatures has a much different effect!

This way, you accelorate a little faster, but dont leave the engine dumping fuel with the timing advanced while you're just cruising down the highway! In fact, when the MAP sensor goes back below 1.75-2.0V you could even make the ECU things its 10-15 degrees WARMER out with some additional modifications to the circuit. It would retard the timing and lean out the mixture a little bit. It would make a little less power under that running condition, but it would save some gas!

vasu

any updates on this? peter_bigblock, did you ever get the dynos done?

feuss2

iTrader: (1)

Why is everyone so concerned with getting a DYNO???

You're talking about such an insignificant difference in power from one version of the air intake mod to the next. In fact, the weight of installing something like a CAI vs a SRS will more than negate the .3HP average HP difference throughout the rev range by increasing the car's inertia. Do you realize you could put 1000lbs of brick in the back of your car and call that a mod? A dyno will tell you that it didnt affect the horsepower, which is a true statement. Then go for a drive.... Do you care more about that number, or what the car feels and sounds like when you drive?

jlukja

^^ because its the only way to quantify any gains without introducing a lot of variables.

Benz_05_TSX

iTrader: (1)

Damn, i can't believe I missed this post! Awesome read!

Now I finally can justify myself buying a SRI instead of a CAI. Since, everyone says a CAI is preferred on a TSX, but I don't even rev my car at all. I just want more low end torque.

feuss2

iTrader: (1)

People presume CAI is better in general because it has a greater impact on the PEAK HP reading on a dyno. This completely ignores what it takes away from the low and mid-range torque. For people driving on the street, especially with long-stroke motors like the TSX, you just want to cut the air intake resistance as much as possible. That will make the biggest noticeable difference!

JTso

iTrader: (2)

What are you talking about? Large tube CAI and SRI lose low end torque. Also, have you ever noticed why certain intake manifolds design have two stage runners? The longer runners are used during low rpm for low end torque, and the shorter runners open up during higher rpm for higher end power.

feuss2

iTrader: (1)

Are you confused by my entire post or do you have a specific question?

Benz_05_TSX was talking about SRS vs CAI in a TSX. I responded to him, staying on the topic. We are not talking about stock vs any kind of air intake in a 500rpm segment of the rev range. I don't see why your very general comments regarding intake manifold designs are relevant to the topic at all.

I never said or implied that I think installing a SRS will produce a gain at every rpm. All modifications are just a choice between a different set of compromises. I do beleive that if you are modifying an engine with a lower than average bore to stroke ratio that you ought to be installing a SRS. Several aftermarket manufacturers have studied this and published their findings.

If you want to cite the design of commercially available products, that visit http://www.aempower.com There, you will notice that they have not even bothered to manufacture and attempt to sell an cold air intake for the TSX. That is for a reason.

It looks like you are arguing with a different point than was made, and your presentation is rather unfocused and confusing.