I feel like I have a few curiosity novice mechanical questions to bring up and I figured this was the place.

First off, I've noticed a drop in total miles I get out of my tank. I've got an '04 LX w/ an AEM CAI and bypass valve. I usually average 312 miles to the point where my idiot light (gas emergency light or w/e) goes on and I'll fill up roughly 12.5 gallons (which I find weird because the tank is rated at 17.1 gallons). Recently, I noticed I would get to the point where my light would turn on at only 270 miles. I thought, hey it's only one tank, then I drove to Gainesville and back (probably 225 mile drive) and got 300 miles on that tank going at speed of avg 80 mph? This has been going on for awhile, but I have noticed recently that it is going back up slowly. Which could mean that the computer is resetting itself for the different air that is being taken into the engine?
BTW, I had the intake installed by a honda tech at the dealership so there shouldn't be anything wrong with it.

Second, in a recent post about getting the dual exhaust installed, I was told that a "myth" was heard that if you put dual on a weak engine like mine, it will lose torque. I talked to a few other tuner friends and they thought this absurd?

Third, would it be right to sell any of my stock intake parts back to the dealership to use as replacement parts? Would that be right?

Fourth, and I apologize for the lengthy post, but I needed to get these questions off my chest. What advice do any of you fellow "tuners" have on upgrading my car (the mods are listed in my sig). I was looking to go into the performance side of things and maybe get the rear bumper custom cut to wrap around my new exhaust because it looks slightly goofy at the moment.

Thanks in advance for any help

 

1st answer: CAI wont make you lose gas milage, it should be backwards it should even add a few miles or so (i think) lol

2nd answer: again it is a myth, it will just let gasses flow more freely so i dont think it will make u lose TQ so scratch that idea.

3rd answer: if i was you i would just keep it for security purposes (example: you take your car to get it serviced and they might void your warrentee due to Aftermarket parts) so i would just keep it just incase something happens its always nice to have a backup intake unless you sell it back and they deduct a payment on your car which i doubt

4th answer: check out the picture thread at the very top, and also check the "1/4 times....." people have posted their setups

i always say, a stock clean look is the way to go. and dont get nothing thats fiberglass like bumper lol wow its a pain in the ***!

 

more air into engine = more fuel = lower milage.

 

Ive looked at both the picture thread and 1/4 times threads.

I've noticed that a lot of people replaced their spark plugs and ignition wires? good idea to follow through with? Expensive? What to get?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by msedacca &raquo;</TD></TR><TR><TD CLASS="quote">Ive looked at both the picture thread and 1/4 times threads.

I've noticed that a lot of people replaced their spark plugs and ignition wires? good idea to follow through with? Expensive? What to get?</TD></TR></TABLE>

If your arent fully built you'll barely gain anything from upgraded wires and plugs. Just stick to simple OEM parts.

Loss of mpg could from your happy feet now. I know it happened to me cuz the intake just sounds so COOL!

 

did you reset the ECU after the intake was put on? If not, do this and the computer will reset itself based on the new air/fuel settings.

 

Yep, like legend put it. People always think that they are saving gas by letting the engine "breathe" easier. But really, they accelerate faster and take it up to higher rpms to hear that CAI suck up the air, putting a smile on their face, but you lower your mpg by doing so. If you drive normally, you should see improvements in your gas mileage.

 

Also, as for the dual exhaust. Many people say that you lose torque due to loss of back pressure. Well, apparently thats bs:

http://www.team-integra.net

You want zero backpressure not some backpressure as you may sometimes hear from a salesman or an oldtimer domestic V8 hot rodder.

there is this incorrect belief that having a little backpressure prevents the fresh air/fuel from shooting into the header at cam overlap (when both the opening intake valve & the closing exhaust valve are simultaneously, partially open). The backpressure supposedly "pushed" the fresh air/fuel back into the combustion chamber rather than having it go into the header. This shooting of fresh air/fuel from the intake manifold and intake port into the header cannot happen at cam overlap, since the pressure inside the header is already much higher than on the intake side , even when there is zero backpressure.

In reality, having more backpressure reduces the difference between the higher pressure in the head's exhaust port and lower pressure in the header and cat. You need this difference in pressure going from the head to the exhaust system or "pressure gradient" to keep the exhaust flow speed or energy at a high level. Having some backpressure during cam overlap and the exhaust stroke means that the exhaust gas must now push against something and therefore, this backwards force slows exhaust gas down.


This need for backpressure no longer exists when you have a properly tuned (timed) engine and a good stepped header. In fact, increased backpressure may lead to backwards flow or "reversion", where the exhaust gas travels backwards into the combustion chamber and dilutes the fresh intake charge at cam overlap. At the very least, it slows exhaust flow velocity or energy and prevents the creation of a vacuum for scavenging.

So please ignore the obsolete "you should have at least some backpressure" sales pitch. It's all about the creating high exhaust flow velocity/speed or energy leaving the exhaust port, in order for the header-cat-exhaust SYSTEM to do it's job properly (i.e. remove all the burnt exhaust gases and help pull in fresh intake charge by scavenging at cam overlap) and make power for you.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by YeuEmMaiMai &raquo;</TD></TR><TR><TD CLASS="quote">more air into engine = more fuel = lower milage.

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God damnit For sale: Aem C A I w/ bypass valve 20cents shipped! lol j/k gas to expensive for that shyt!!! what if i put a sock on my intake will that slow the air flow lol

 

you said that on the trip you had better gas mileage at an avg of 80mph..still makes sense. because it was probably mostly highway, and not alot of stop and go.

city miles burn gas alot faster than highway miles. i wouldnt think that your CAI would drop your gas mileage enough to make you want to sell it because of gas prices.

and i dont think it should drop your miles to the tank from 312 to 270. thats got to be your foot a little harder on the gas pedal.

 

I agree what was said earlier, could be your more aggressive driving due to the cool sound you like to hear.

 

i don't want to sell it, i was just curious because it was a noticeable drop.

You're probably right, I could have gotten a heavy foot to hear the VROOM coming out of a stoplight, but that won't be so much of a problem with the new exhaust because I hear it whenever I touch the gas.

As far as the loss of gas mileage. When I did the trip last time to Gainesville (I've done it a few times) I would get somewhere in the range of 375-400 miles for that tank. I'll do what zumiez007 said and reset my ECU for the new air/fuel mix. Is there a post that someone could point me towards where it has been done before?
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Legendaryyaj &raquo;</TD></TR><TR><TD CLASS="quote">

If your arent fully built you'll barely gain anything from upgraded wires and plugs. Just stick to simple OEM parts.

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Can you please explain what OEM parts I should look into?

Thanks again for all the help and informative responses


Modified by msedacca at 2:16 PM 1/18/2006

 

when i had my civic, installing my intake took me from 400 a tank to 450 a tank

im installing my intake on my accord when it stops raining, i hope to get close to the same results

 

its simple: you are being heavier on the throttle with the CAI.

w/ CAI your milege will increase if you drive the EXACT same way as you did before it was installed. by slightly increasing airflow, you are making the engine more effecient. however if you are heavy on the throttle, the extra air will then force the ECU to send more fuel, thusly milege will go down, as this extra gas used trumps the motor's more effecient running

 

Miles since last fill up divided by gallons for current fill up = MUCH more accurate measure of fuel mileage than when the light comes on etc.

 

Just to comment on the loss of torque myth with dual exhaust on 4cyl engines. He may not have been wholly wrong. I've noticed (granted I've only had the exhaust for 3 days so its just a noticing) that in first gear there is a loss of torque from what it used to be. There isn't that same "push" as there has been with the FWD. But that's just when I'm not making a full acceleration, only when it hits about 3k rpm's. When I go full out in 1st, theres the same feeling, yet stronger. Odd.

 

Just buy regular Honda wires and plugs. Dont buy like $200 Nology wires or anything like that. Its just a waste of money if you are stock or doing basics.

Oh and another thing. Keep all your stock parts you take off. It'll be much easier when you try to sell your car. I dont know why people like to sell off their stock parts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by msedacca &raquo;</TD></TR><TR><TD CLASS="quote">
As far as the loss of gas mileage. When I did the trip last time to Gainesville (I've done it a few times) I would get somewhere in the range of 375-400 miles for that tank. I'll do what zumiez007 said and reset my ECU for the new air/fuel mix. Is there a post that someone could point me towards where it has been done before?
</TD></TR></TABLE>

you also have to remember that your car gets way better gas mileage on the highway since there is less stop and go, and usually your car kicks into overdrive gear and keeps the rpm's low.

 

weird question, i was reading in the "basic guide to accords" sticky thread that if you put your silencers in your mufflers that it will negate the performance that you get from the catback? is this true? because if it is, i just wasted a bunch of money because my exhaust w/o silencers shakes my car and would easily get me a ticket.