David: Thanks for delivering the goods. I'm wondering about the difference on a stock car and as soon as someone can show it, I'll be placing my order. I'd settle for half of what you saw with header and exhaust.

I think it is now safe to say that BS has walked.

Deadpedal: (or should I say Lord OverEngineer) Your plan sounds cool

 

Jim,
I am sure that those that bought already will be posting some results, too. I would expect gains fairly close, but maybe not as good, as the addition of a higher flow header and exhaust necessitates more intake of air. All three work together nicely.

 

O.k. folks, here is the deal:

1. The Honda ECU does learn. There are two parameters of particular interest to us. Short term fuel trim and long term fuel trim (look in your FSM if you want verification). Both allow variations of up to +/-20% on the injector pulsewidth from the original map. That's correct, the ECU has the ability to lean or richen the mixture up to 40% from the standard map. The ECU looks at O2 sensor readings in closed loop operation to create the trim numbers. Short term is altered very rapidly (don't know the exact frequency of update). If there is a decided trend in the short term trim, the long term trim begins to change. That is, if the car is consistently requiring a 5% richening of the mixture, the long term trim will gradually trend to +5% which allows the short term to return to near zero.

When the car goes to WOT, the ECU no longer pays attention to short term trim (because it isn't looking at the O2 sensor anymore). However, it does still apply the long term trim numbers to the WOT map. That's why, Jim, the car continues to run rich. It's set up that way to begin with at WOT and high rpm. Add a change which adds more airflow and the ECU will add additional fuel to compensate. If you would like more info, I suggest contacting the fellows at Hondata or Zdyne. These folks have completely dissassembled the ECU coding and behavior and can tell you how just about anything works.

2. The ECU _shouldn't_ be dialing out power from an intake upgrade. The job of the ECU is to ensure proper mixture (as defined by the Honda engineers). If an intake provides more airflow, then you'll need more fuel to maintain the same mixture and this should provide more power. There is a possibility that if something makes the car run too lean it will go into a limp-home rich mode (as we saw on Prolene's car when he lowered the fuel pressure too much). On something like a VAFC, you'll have to make sure that the VAFC doesn't make any changes unless the car is running at WOT. That's the only place it won't alter trim numbers. If you try and make part throttle corrections (or full time corrections like the old SFC-VTEC from Fields) then the ECU will try to eliminate them. You can make more power by leaning out the mixture up top, but the ECU doesn't like that, so you have to be tricky. An intake is different. It leans not by reducing fuel, but by adding air. More air+more fuel = more power. Is more power possible with a lean mixture and the intake? Probably, but that's a tuning deal.

3. Based upon R&D's response, I have to say that these two intakes are pretty much identical. The first run you do after any down time on a dyno needs to be a throw away. Operating temps are uncertain as is engine behavior. If you'll note that both intakes performed almost identically on their 2nd runs.

AEM from 3.5k MAX HP 210.4 TQ 140.1
INJEN from 3.5k MAX HP 210.2 TQ 139.5

I'll bet the graphs are similar too. This is the only safe way to compare since engine conditions are likely to be more similar on the 2nd run. The fact that there was such a variance between runs 1 and 2 for each intake tells me that conditions were not stable on the first run.

UL

 

Hey, I made a thread for the air duct controller:
https://www.s2ki.com/forums/showthread.php?...&threadid=32214

 

UL is dead right about the dyno variation. My knowledge about the inner workings of the ECU is very fragmented, but what UL is saying jives with everything I've ever heard.

Now, the big question, UL, you gunna make it out to our mountain drive on 11/3???

 

For anyone with concerns about water injestion, wouldn't a $50 AEM Air Bypass Valve be the answer? http://www.aempower.com/new_products_f.htm

 

Dave - I just came across your post in Group Buys and see you don't recommend the use of the AEM Air Bypass Valve. It sounds like it's an opinion, which is not based on substantiated evidence. Perhaps, during your testing, you can include one dyno run with this valve installed, to show figures which would prove the loss of top-end performance when using one. Thanks.

 

AEM doesn't even recommend using it unless you think you're REALLY just not going to be able to resist driving through that two foot deep flooded road.

 

As for the water issue, I can assure you that you will not have a problem as long as you don't go through a puddle thatt is going to entirely submerge the air filter. I have had the holes cut out right in front of the AEM on both of my other cars (del sol and crx) and have never had a problem and have driven them in crazy rain storms. Ever heard of water injection on a supercharged car, a little water isn't going to hurt anything. BTW, the holes I cut out have nothing in front of them, so I think that the coastal covers are alot safer than what I had. I am awaiting th arrival of both. Brian

 

All,

Installed the AEM last night. I was impressed with the quality and fitment.

For people who want to cut open the fake air duct or already have it cut, I have a solution for keeping the air filter dry. The air filer sits to the right of the fake air duct and in my opinion has a good chance of getting wet while driving through the rain. My solution has to do with extending the right portion of the duct to channel air flow and water away from the air filter.

1. Go to Home Depot and buy a $3.00 black rectangular/oval shaped plastic trash can. Also, buy some epoxy...the kind that you have to mix together and sets in 5 minutes.

2. Cut a rectangular piece out of the trash can that is taller than the air duct and about 5 inches wide. You want to cut a peice that will look like a wide sled. The whole idea of using the trash can is to get a peice that will curve the air flow from hitting the air filter directly.

3. Epoxy the sled looking peice on the inside of the bumper with the curve pointing away from the air filter...and you are done!

I have plenty of pics that I will post on Monday!