Axiom Home Page Forums General Discussion The Water Cooler CatBrat

The mechanic and salesman are correct.

Did a quick search to try I couldn't see if it is a "positive displacement" supercharger or other. I "think" (and JakeWash can certainly correct me as I am going from memory and limited knowledge) but I think the answer to that could effect the answer of mileage.

In short, "positive displacement" types are 'always on' so to speak and are less efficient in the long term as they steal a good bit of the eventual crank shaft power but provide a better airflow ratio across all RPMs.

The best way I've heard it described is that "Basically, other types give you a satisfying boost when you ask for it but with a PD supercharger, it always feels like you have a bigger motor than you do."

The other types (is "dynamic" the word I am looking for) only engage when you nail it. There are several types of these as well, in how they work. Generally, there is a bit of a lag as they spin up but then you feel it. They are the norm for after market units as they are smaller and require a lot less rejigging to install if no system was there before.

I believe a lot of factory systems are of the positive displacement type so that's why I mention it. Someone can correct me but I think the 'PD' systems effect your mileage greater in the long run as they are always engaged. Perhaps modern engines and more complex chips make it more negligible though.

I only recall some of this from listening in to several arguments in my old Jeep Club where one type was pitted over the other because rock crawling is a different thing altogether. You definitely need lots of power but you also often need it at very low RPMs. Gearing is often extremely low and much of the technique is about slow & controlled vs hitting the gas, not that hitting the gas never happens either.

Jason?
Let me know if I'm wrong. I don't want to give him a wrong idea.

I'll probably be skipping that option now anyway, since I see the price for it is around $4,000. I thought it was much less. It's what's called a root type, whatever that means.

All of the vehicles I've been looking at get around 17-18 MPG. The only other negative that I've been able to muster up seems to be the windshield and blind spots.

The windshield is almost at a 90 degree angle which is both a bug collector and breaks and chips easily when it gets hit by small pebbles. The earlier models seem to have this problem more than the newer ones did. Maybe an improvement in the glass. Would probably pay to get insurance with zero deductible. Definitely want the bug deflector installed.

The blind spots can be helped with conical mirror attachments to the existing mirrors. This would be one vehicle that would benefit from blind spot warning detectors. I don't understand why they don't come with one as an option.

To help in gas mileage, I won't order one with the top railings. I don't see myself using them anyway. Also, lighter aluminum wheels, and bigger wheels to eliminate as much rubber as possible to lessen weight would also help with gas mileage. (Pimp my FJ, have to get something that still looks decent). Will be used 100% of the time on highways anyway. But at the same time, don't want to lose it's ability to get around in snow covered roads. Would rather error on tires that are bigger.

ARRGGHHH! Another exceptionally capable off-road vehicle that will be pimped out for city bling.

Sorry, pet peeve of mine.

Seriously though.... Winter tires generally are not made in low profile formats because they require softer rubber compounds and generally flex a bit more to allow more rubber contact to the road surface. If winter is a concern, I would recommend finding out what winter tire sizes are available in a chosen brand and not going with a larger wheel than that. That way you can maintain as much light/bling as you can but still be able to fit a decent snow tire.

It looks like 18 is the largest. The wheels that come with the FJ Cruiser are 16 or 17.

What I had originally said, is that when using M22's and a sub, there was a hole in the upper bass region. And after I installed a VP160, I could now hear this upper bass region. The primary source material used for this determination was the Police concert on blu-ray called Certifiable.



Actually, all I have to do, is listen and measure with, and without, the VP160 being plugged into the mix. There is still an M80 plugged into the center channel. The front wall consists of 3 M22's over the TV as (Left Main) (Center) (Right Main). It also consists of 2 M22's under the TV as (Left Main) (Right Main), and a VP160 under the TV as (Center).

Moving this discussion over to the Water Cooler, CatBrat thread.

If possible, I'll try and get other's opion also, so it's not just my ears. But I do have to tell them what it is they are listening for. If I'm wrong, I'll readily admit it.

Brian, the M22 has been designed with an enclosure tuned to about 59Hz(shown by the low point in the bass impedance valley)and the Axiom spec shows good response down to at least 60Hz. My personal use over about 25,000 hours has always confirmed this and the Audyssey measurements for calibration resulted in a 60Hz setting(which I raised to 80Hz to give the EP500 more work), indicating a measured -3dB point somewhere below 60hz.

I just now repeated a test I did long ago with my Stryke test tone disc. It includes a 1Hz to 100Hz continuous sweep band which takes 5 minutes to complete. Setting my M22s to full band and no sub, the sweep began to be audible a bit under 40Hz, and the 60Hz-100Hz frequencies were continuously strong and certainly had no "hole". Whatever you're experiencing isn't typical to say the least. Both the measured and audible results confirm the competence of the Axiom design and the accuracy of their specs.

Getting into superchargers etc. is a specialty all their own. I work with a guy that runs a couple cars with blowers as a hobby on the drag strips around here. From what I rememeber Murph has it pretty well but the FJ's charger is too small to really mess much with the fuel economy except when your foot is into it.

I basically see the fj's supercharger as a waste of money. Would perhaps consider it if it somehow increased mileage, but that's apparently not the case.

I haven't run my frequency tests yet. Will do that in the next few days when I have the time to devote to it. I just remember what differences I heard and my past comments on it. I'd be more than happy to say that I don't hear those differences now. I don't have any reason to be anti-axiom. I'm just reporting what it is I've experienced. Whether good, or bad. It sounded good with the hole I noticed, but sounds much better without it. That's my memory on the subject. If by adding the Vp160 cured that problem, then the problem would logically be the M22's.

Another anomaly I've experienced is what I believe to be comb filtering. I don't know what to attribute this to. It's only noticeable when I'm listening to the cd that produces the tones for frequency measurement. When a tone is playing and I slowly walk across the room, the volume of the tone will waver up and down. The meter proves this out also. Anytime I become stationary the wavering stops. Back when I had both on wall and bookshelf speakers both playing, I disconnected the bookshelf ones so that only the on wall were playing and I'd get the comb filtering. When I reversed the procedure and played only the bookshelf ones, the comb filtering stopped. Today, before adding the QS8's, with only the bookshelf speakers playing, I got the comb filtering. Seems odd that nobody else has reported this. It could affect how the sound is picked up at the mic, especially with Audyssey when using multiple mic positions, if in one spot the volume is higher than other spots, due to a null created by comb filtering. I'm not saying it's a fault with the speaker. It's probably some strange interaction with my room.

If you're going to get that Toyota and you're concerned about the snowability(new word?)of the tires, note that the original equipment Bridgestone D684 IIs don't look very impressive in the Tire Rack reviews here , especially in winter weather.