Where do you stop?
 

What is the best side for an air box then? Obviously, as big as possible. So then, sacrifice the passenger side front seat and put the air box there.
Stupid, isn't it? Obviously the airbox is built to a size and cost as well.
Naturally when a car is designed for the mass market there are cost, longevity and reliablility factors involved also.

I was with regards to dirt bikes actually referring to four strokes as that is where my experience lies. The reason that all the pros run aftermarket pipes is? - Sponsorship dollars. If you run them on dynos, there is not a lot that can be improved by simply bolting on a slip on exhaust can. It is, as I said before, only part of a bigger picture.

I don't think Bubba would be last on a stock race bike!!

The bigger the size the bigger the cost, not only for the box, but for everything around it. Generally they make it just big enough to get by. They don't need to be pass seat sized either, just made by K&N. ;)
Racers have a rule of thumb for air filter size: "The biggest you can get in there"

Oic, dirt bikes and peaky power curves I was sure we wer talkin 2-stroke. They're not very popular where I live, I've only had one, a Yamaha 500. I put a pipe and Supertrapp on it soon after I bought it. It certainly made a bigger difference in power than any ex mod on any other 4-stroke motor I've played with. I too bet the gain was mostly in the muffler.
I put in a K&N as well but didn't feel anything.

John,

A big bore Busa with NO2 ? A 180 rwhp velvet hammer? Your a wild man!
A friend had a CBX with pipes back in the day. Beautiful music! I had a ported H2 and could keep up but it wasn't a pleasant sound to say the least. I sold my last street bike, a box stock GSXR1100 when my son was born 11 years ago. I ran open class MX bikes recreationaly for another 6 years after that but it got too hard on the joints.

I've been thinking about gettng back into it again and the need for two up travel has me looking at cruisers, but like you say, pretty weak. Do you think a Busa could work for two up riding with gear?

Jorg

Chevota, my engine is full boogie, 320 RWHP, 12.9 @111 @3550#. I run a stock 84 Mustang dual snorkel air cleaner for the dual cold air inlets and that with a stock paper element has made more power than the K&N with a open element or in the 84 air cleaner. The only way to tell what you get is to do it on a dyno as I have. We have tried some other cheap tricks also like carb spacers and venturies for the carb without any gains. Make sure you use the wide band O2 sensor when on a dyno to verify the mixture is correct.

Dan

I'm not sure how big the filter is on one of those. I would imagine most stock paper elements of decent size could support that. The one my 3.2 V6 is the same as my V8. The V6 is getting enough air for sure, the 340hp V8 I don't know about, but don't really care since it's an SUV.
No need for a dyno to feel the power loss in my chevota, it's obvious. The filter area is 150sq", the next size up filter and the hood won't close. :( So who knows, maybe there's even more power to be had?

So your car reads the O2 sensor at full throttle, or the dyno does?? I tried a Holley projection 4di about 5 years ago and I hated it! Open loop only at full throttle and very slow responding, it was joke actually. I'd buy one if it worked, but efi is still nothing more than a smog device imo. So tell me about that O2 sensor, if nothing else I might like to get one for my Autometer A/F gauge.

I don't have my own wide band, the dyno has one and they weld a bung in your exhaust for it. Some one just came out with a good A/F gauge for street use but it is expensive, I think $395.

Dan

These days, nearly all manufacturers do a fairly good job of designing intakes. Yes, there is usually less pressure drop across a K&N or other oiled cloth type filter at idle, but often the "design" of the piping causes flow disruptions at high rpm due to the fact that the "design" normally consists of aluminum ducting with elbows in it, no laminar flow possible. Believe it or not, but an improperly designed pipe will have terrible flow resistance.

Ditto for not having a filter housing at all -- another member posted dyno curves from his 280 SEL 4.5, and it generated MORE hp and torque with the filter housing on that with it off -- all has to do with getting air to move properly.

If you oil a K&N lightly enough to prevent damage to the air flow sensor, it will pass huge amounts of fine dirt and you will grind the engine up, and if you oil it well enough to catch the fine grit was well as paper, it will toast the MAF sensor. The good platinum MAFs usually last forever if they are kept clean.

It's easy to mistake noise for more hp, by the way......

Peter

Peter
 

YAY! Someone who understands how many factors go into tuning an engine.

With the exhaust thing, many people don't understand that a properly designed exhaust will not only have good flow, but in fact develop suction due to air inertia. This, coupled with a carefully designed camshaft/s profile means that it is possible to "overfill" the cylinder with air/fuel resulting in increased performance.

By "overfill" I mean that say the maximum amount of air/fuel that can be sucked into the chamber by a down-moving piston is 100%. Now, say that as the exhaust exits the chamber through a properly designed exhaust pipe and cam, the inertia of the exhaust gasses causes a sucking effect resulting in there being vacuum in the bore after the valves have closed. Say this vacuum is 10% of the cylinder capacity.
Then, as the air/fuel is drawn in through an impeccably designed intake system, the same happens but in reverse. The 10% vacuum fills. Then the normal fill takes place (100%). So far we have 110% of the standard fill. Then the inertia of the fuel/air causes yet another 10% to be drawn into the cylinder before the valves close (you can see how important the valve durations are here!).

Now we have a maximum cylinder fill of 120% where before it was only 100%. It is in fact possible to get up to 125% filling depending on bore dimensions.

It's almost as good as forced induction. It's very important to have everything right. The most free flowing intake (i.e biggest airbox) and exhaust are not perhaps the best.

Ok. Now which average workshop has the tools and resources required to measure all of these factors and then design an induction and exhaust system to suit? Indy teams and Formula One teams do. The big motorcycle and car manufactures do! Look at their budgets!!
When you buy a K&N filter or an aftermarket exhaust for your motorcycle, what are the chances that it has been subject to this sort of testing on your type make and model of vehicle?
Answer? NO CHANCE.

Wonder if anyone agrees?

Is this thread still a K&N thread? Just for the record, I over oil all my K&N filters, but the MAF and intake tube are dry as a bone.

I understand very well how an engine works, from before air enters ‘till I leaves, but making the correct intake and ex for our cars would not look much like the oem setup, and would be very difficult and/or expensive. Oh, and not that it matters much to me, but the real fixes are not be legal either.
A K&N is an easy and legal bolt-on that’s reusable and won’t clog up like paper. If there was a better intake tube design, or mod for this one, I’d be interested to hear about it.
I would love to have an efi that worked right, or a nice carb, intake, cam, headers etc. But in real life my choices are limited on a 3.2 Benz to bs like a filter and muffler. I could buy a blower, but I just can’t see spending that kind of $$ for what I’d get.
If I really wanted to make everything right, the easiest and cheapest would be to pull the motor and put in and old chevy v8 with all the goodies that do flow right. Which btw is exactly what I’d do if this benz motor ever took a dump.

Not worth the risk
 

What is the power gain from adding a K&N filter to you M112? 1% ? 2% ?
Is it worth the risk for an extra 2-4 horsepower?
Also, I do not attribute all MAF failures on engines with K&N filters fitted to the filter as cause. We all know how reliable the MAF's are.
Having said that though, just because the tube after the filter is dry, it is impossible to know for sure, without measuring, if any oil is sucked into the motor and over the MAF.
Who knows how much oil it takes to screw a MAF?

Power gain may be 0%, but like I said, it will never cost me power and it will last for life.
If there is no oil in the intake tube, then there's none on the sensor, pretty simple. Not that I believe oil will hurt it anyway.
Yes, it's worth the "risk" imo. I've done far worse to engines iso power. :rolleyes:

I'm starting to get the impression you don't approve of K&N filters. ;)

It's not that I don't approve of K&N filters alone. I just bundle them into a same category as all that other useless crap that people bolt to their cars with absolutely no proof that they result in power gains and then they swear black and blue that the car goes better.
Don't get me wrong, I've fallen into the same trap. I put a yamaha motorcross exhaust on my yamaha trailbike and am swear it goes better. But it's probably just the horny noise it makes now that lets me think that :D

I know what you mean, it's like fishing lures. there are two types; the kind that catch fish, and the kind that catch fishermen.
I also see lots of people bolt on genuine hi-po parts and endup dissapointed. A K&N or a big carb, etc doesn't help much when everything else is stock.
A K&N on my stock 3.2L car = nuthin, my free flowing 6.6L chevota = power!
The muffler on my 3.2 car works ok I guess, but if I put it on my chevota it would screw everything up.

I almost forgot; If you want a real power gain you need a fuel line magnet and a Qt of Slick 50. They're guaranteed! Itz gotta b reel f itz gotta gayronteee! :rolleyes:

Lol
 

Hey, they say that stuff works man!!