Possible Ram Air idea for baja sport

[ebbie97]

I'm confused here. So Kev are you saying that a CAI is not going to give you anything except more engine grumble? Is it than even worth putting in? I know very little about this, but you all seem to make reasonable arguments. Please enlighten me.
-EB

[Kev M]

I'm confused here. So Kev are you saying that a CAI is not going to give you anything except more engine grumble? Is it than even worth putting in? I know very little about this, but you all seem to make reasonable arguments. Please enlighten me.
-EB

I personally don't think a CAI is going to give you much in the way of additional power over the stock set up.

HOWEVER, IF IT DOES, I am saying that it would then give you more hp, but less fuel mileage.

Still, I think you'd be measuring in RCHs.

The only way to know for sure would be back-to-back 4-wheel dyno runs,

OR at the very least, capturing data with a scan tool, looking at differences in intake air fuel temp and MAF signal (these are mass air flow sensor motors right, otherwise you'd be looking at MAP and throttle position).

But mostly I think a CAI is going to lighten your wallet a little.

[diderich]

intakes are a huge argument with motorcycles, where turbos are rare. It might be worth checking out data from there.

There are two things that factory designers are trying to do when they design an air box. One, they are trying to make it as quiet as possible, and two, they are trying to even out the torque curve a little bit. Any changes you make are going to affect these two things.

For example, most people are pretty aware of how exhaust pressure waves affect torque. Without going into it too much, you get torque bumps, both high and low depending on the phase of the pressure wave and the rpm. Well, the same thing happens in the intake. Intake volume and geometry affects where those bumps occur. Ideally you want a low bump in the intake cancelled by a high bump in the exhaust and vice versa so you get a nice flat torque curve. Or at least you want to avoid holes in the torque..especially in the 3500-4500 rpm range.

So a cold air intake, if well designed, can eliminate the compromises that designers had to make in the quest for quiet intakes. It can also rearange the torque curve to give you a little extra high RPM boost, at the expense of low end torque.

A POORLY designed intake..could gut the power in the middle of the power band and add it back at 8000 rpm, well beyond where you can use it.

Only the dyno knows for sure....

Also, I don't know if anyone has noticed, but the intake on my car at least is right in the grill...I doubt if it gets any more "cold air" than that...yeah, there is that other part of the intake that is in the engine bay...so maybe there is a gain there...i don't know...

[Kev M]

intakes are a huge argument with motorcycles, where turbos are rare. It might be worth checking out data from there.

There are two things that factory designers are trying to do when they design an air box. One, they are trying to make it as quiet as possible, and two, they are trying to even out the torque curve a little bit. Any changes you make are going to affect these two things.

For example, most people are pretty aware of how exhaust pressure waves affect torque. Without going into it too much, you get torque bumps, both high and low depending on the phase of the pressure wave and the rpm. Well, the same thing happens in the intake. Intake volume and geometry affects where those bumps occur. Ideally you want a low bump in the intake cancelled by a high bump in the exhaust and vice versa so you get a nice flat torque curve. Or at least you want to avoid holes in the torque..especially in the 3500-4500 rpm range.

So a cold air intake, if well designed, can eliminate the compromises that designers had to make in the quest for quiet intakes. It can also rearange the torque curve to give you a little extra high RPM boost, at the expense of low end torque.

A POORLY designed intake..could gut the power in the middle of the power band and add it back at 8000 rpm, well beyond where you can use it.

Only the dyno knows for sure....

Also, I don't know if anyone has noticed, but the intake on my car at least is right in the grill...I doubt if it gets any more "cold air" than that...yeah, there is that other part of the intake that is in the engine bay...so maybe there is a gain there...i don't know...

You make some GREAT points.

But be careful with the motorcycle analogies.

First off until the past 5 years or so most bikes were carbureted still.

And the EPA hand't changed emissions regulations on them for like 20 years.

Though noise emissions had increased, which IS what led to some restrictive intakes, especially on air cooled motors.

And even today, VERY few are running cat-cons, even when they have closed-loop EFI.

So today, changing an air intake on say a Harley will (along with appropriate jetting or reflash) and a well-tuned exhaust will net you 10-20% additional HP, but that is there on purpose (to get around the EPA noise standards while lining the corporate pockets with additional parts and labor). Such dramatic gains are not the norm. And heck, I've seen dozens (if not hundreds) of Harley owners screw that up over the years going with bad designs, or fully-open exhausts that totally kill midrange power. Overjetting is one of the most common mistakes of a Harley owner.

Anyway, you're right only the dyno knows for sure.

But good observation on the location of the air intake at the end of the snorkle on our NA Bajas, I was well aware of that, and it was part of my position on this from the start.

[nacho]

I know that these manufacturers state that you can gain 10-15 HP and gain some fuel economy with certain upgrades. I don't believe the manufacturers on their stated gains. I just try some parts out and see what they do. Adding an intake and an exhaust has helped me out in the previous 3 vehicles I had with the MPG. I do not have a dyno and can't check actual HP. All I have to go by is MPG. My previous vehicles all had intakes and exhaust systems but I had them installed after two years of ownership. The baja was the first time I installed an intake at such an early time(less than a year). I check the MPG everytime I fill up and have been doing this since my first car. This means that I fill up everytime. I think that if you are having engine problems, your fuel economy will be the first to suffer. This is completely my opinon and have no way of justifying this theory. Still the intake and exhaust have given me some increased MPG results. Not drastic results but I average about 2-3 MPG in the city and 1-2 on the highway. I would think that there is also some increase of HP but to say I got 10-20 HP would be crazy. I think real world power would be around 5-8 HP with an exhaust and intake. This also has no justification because like I stated. I have no dyno to check this out. I did ask auto mechanic instructors at the local college about intakes and exhaust systems. I was told that the computer will always try to make adjustments due to enhancements to the intake and exhaust. Also was told that if you do upgrades to the engine, the less bends on the exhaust and intake will help get the air moving in and out better which means that the engine will produce more power to the wheels than use up the power produced to force the air in and out of the engine. I think that manufacturers always try to build cars that have a balance of cost vs. performance. If performance suffers to keep cost down, a company will do it to make money. This is why the after market has lots of parts available. Just remember that they also are out there to make money too.