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Discussion Starter · #1 ·
Ram air and air box mods / pressurization look like a relatively easy way to find power - this is not new technology. If the ECU and sensors can handle the difference between inlet air flow / air box pressure when the bike is stationary or on a dyno Vs the boosted inlet effects of ram air at varying road speed, then redirecting cool air ducts into a sealed air box may show benefits particularly if the ram air inlet dimensions are large enough.

Could a 0.010" - 0.015" reduction in head gasket thickness (raise comp ratio a touch), cam chain adjustment, air filter and exhaust flow upgrade plus appropriately sized ram air set up shift the FJR power to weight ratio to that of a more responsive mount - particularly when 2 up or loaded to tour solo with luggage.

The Hayabusas apparently show even further performance with a little rise in compression on top of an air filter and exhaust upgrade. A very smooth result has been recently posted by Human - Cans PCIII K&N Filter in the farkle forum with a little more detail given there. Any thoughts or experience on the subject ?
 

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At 1300cc and 145 horses at the crank, this mill could easily produce another 20 or 30 horses and still be very streetable. Tire wear would be more of a problem than it already is. Remember kids, this isn't a pure sport bike. If you put true sport bike hp in this heavy, comfy beast, you may have a mis-match with the chassis.
 

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lenz said:
Any thoughts or experience on the subject ?
I'll only say this much...

Changing the oil on a bike gives it an extra 20 HP, but...

anytime a gain in horsepower is claimed, I rarely see the details of the two dyno runs. Why, because who wants to camp out at the dyno shop, and undo all of your mods for a baseline, and then replace all of your mods for a second run... and back-to-back runs are the only way to get a reasonably reliable number. Remember, two different, new rear tires gave the 2005 CBR1000RR different dyno readings to the tune of 18 HP!!

The FJR will only yield pocket-change more power with any of the mods listed, short of revised cams, reworked valves, head work and major computer work. Even so, there would be SIGNIFICANT trade-offs, like an irregular torque curve, popping and sputtering at certain revs, excessive engine heat (not only to the rider, but to the engine - probably need a larger radiator)

The performance level of the FJR is respectible enough, that in order to get much more, you'd have to make serious compromises. (I was hoping Yamaha was working on it, while they were petering around with electric shifting)

A Hyabusa is a completely different animal.

:)
 

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Discussion Starter · #4 ·
[quote="Liquidsilver
anytime a gain in horsepower is claimed, I rarely see the details of the two dyno runs. Why, because who wants to camp out at the dyno shop, and undo all of your mods for a baseline, and then replace all of your mods for a second run... and back-to-back runs are the only way to get a reasonably reliable number.
[/quote]

I found this site that can be used for correction of dyno results with changes in important variables subject to change from day to day.

http://www.csgnetwork.com/relhumhpcalc.html

Many of the observations that I took as a surveyor were regularly subjected to all sorts of corrections to bring the raw data to standard. While it is undoubtedly preferable to have dyno runs carried out under unvaried conditions its entirely possible that carefully recording local ambient conditions that the bike is operating under should yield standardized results for useful comparisions. A small shift in relative humidity, inlet air temp etc etc and the resultant air density can make significant differences in results over a couple of hours. Adding a little science into a testing program should allow useful time between dyno runs and mod stages.

Retro fitting output related parts is always gonna have a ripple effect on the remaining systems - you make a good point 20valves but how much more is too much for this "platform". The most bang for your buck is most definitely had without opening the engine so bolt on mods make sense to me. Positive ram air pressure in a dimensionally unchanged but sealed airbox works for other engines and bikes. It seems the real art is to find the right inlet and ducting sizing to provide useful gains in the slower mid range without exceeding the ECU's adjustment range at higher speeds and higher air box pressures. Maybe a simple pressure relief valve in the air box would be useful.

I liked David1300's April Fools joke with the upgraded engine specs etc but I also thought his improved specs were areas that had been previously discussed to some degree and generally accepted as positive. IMHO the 06 FJR1300A is a very, very attractive package but an added 10 - 15% increase in power and torque would still be a workable bonus if any gains can be found relatively simply ie without "open heart surgery".
 

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Discussion Starter · #6 ·
gr8eyes said:
About 2 years ago our very own JOOS tried modifying the air box to boost the hp and torque figures. He spent several months on it but in the end decided their was no appreciable gain to be made from it.

Glenn
Airbox harmonics are an arcane art that I have heard referred to in the dark mutterings of others as "best attempted with a spirit rattle in one hand and a chicken bone secreted in one's beard...."

I've had a scratch around through the old site and can't find much in the way of specific info on previous work in this area.

How about leaving the dimensions of the original air box unchanged to preserve its unique, magical properties but using a well sized air pickup and ducting directly into the air box or into a surrounding pressurised structure feeding the airbox. I haven't looked at induction design on other bikes with proven ram air systems but I've got very positive results using this approach on a fat, underpowered four wheel drive / SUV that has gone from 325km to 370km on the same amount of fuel. Its making more power but the striking difference is the improved engine response from around 90k/h - 130k/h. The bloody thing is still accellerating at 150k/h - not as hard but still pulling - time to shut down - not safe. A reasonable result from a very poor aero aspect, vehicle over 2000kg and a 3.5lt V6 engine. The only mods on the 4WD are the ram air, oiled foam UNI air filter and bigger exhaust.

I would be interested to hear what has been attempted on airbox mods so far. It would surprise me if there wasn't 10% - 15% power and torque gains hiding that could be found with exhaust and filter / induction changes plus PCIII and custom map. Dale Walker's new 4 - 2 headers plus cans definitely look the goods for the exhaust changes. Staintune cans with the Holeshot headers are also interesting.
 

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Lenz,
IIRC Jooses airbox mods went under the working title of "Project X" :lol: so if you search the archives for that it might throw up some more detail.

Having heard of his extensive engineering contacts I suspect that they were done in conjunction with those familiar with the black arts (Renegade exhausts possibly?) and with some dyno time thrown in (IIRC he posted some curves showing the effect of the mods), but nothing has been heard about it for a year or so.
 

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marshman said:
Lenz,
IIRC Jooses airbox mods went under the working title of "Project X" :lol: so if you search the archives for that it might throw up some more detail.

Having heard of his extensive engineering contacts I suspect that they were done in conjunction with those familiar with the black arts (Renegade exhausts possibly?) and with some dyno time thrown in (IIRC he posted some curves showing the effect of the mods), but nothing has been heard about it for a year or so.
Marshman,
I thought Joos had dropped it as not cost effective & not easy to obtain the extra BHP.

The air box on the Fjr is very small and is the main cause of poor/slow air flow, if the box can be made larger the motor would breath far easier.
 

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Discussion Starter · #10 ·
Woody wrote:
"I thought Joos had dropped it as not cost effective & not easy to obtain the extra BHP. The air box on the Fjr is very small and is the main cause of poor/slow air flow, if the box can be made larger the motor would breath far easier."


I went back to the old site and found the last entry by Sir JOOS regarding the air box project "Don't take a Dremel to your air box" - Dec 04. It doesn't appear that there has been much in the way of specific detail publicly disclosed on the development work carried out. Perhaps there was an issue with IP and potential future value of a successful worthwhile design amendment. The project direction @ Dec 04 was apparently not worth the trouble due to minimal gains.

At the risk of re opening old wounds and debates as to the sense of expensive, unneccessary, minimal return mods these are the alternatives that come to mind:

(1) Get rid of the air box and fit the biggest air filter possible into the cleared space. This tactic works for dirt bikes and methanol burning speedway bikes. If there was an advantage to having an air box on a speedway racing bike they would already be there but realistically these engines don't live in low rev zones.

(2) Retain the air box in its approx form and cut & shut on an inspired basis with plenty of spares - apparently not an enjoyable experience according to Sir JOOS.

(3) Go for the doctor with a pressure managed air box via ram air. This would preserve any design induction harmonics.
.......(a) A larger surrounding structure could be used to receive the ram air duct/s with the air box drilled to allow inlet flow but largely maintaining the box walls for the orig harmonics.
.......(b) Drill the orig air box end walls or replace them by a drilled plate that functioned as a "harmonic bulkhead" and take the full cross section of the air box from the end walls into a 90deg connection with ram air ducts.
.......(c) Provide a pressure relief valve somewhere in the structure so when the best compromise of "boost" is determined, that pressure can be maintained to some degree.

The question must be asked would you rather just accept the bike in its very capable standard form and just ride the damn thing or would you rather skin your hands on sharp fittings and bruise your bank a/c in pursuit of better design. .........I hate poor design work and still can't help myself when I see it. ( You'd think I'd know better by now, as if I haven't got enough to do......)
 

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Discussion Starter · #12 ·
I figured I had to get that burst of "inspiration" out before it was swamped by the "Have To's" of family life. There is a strong probability these suggestions will remain in my "To Do" file. Please feel free to build on them or tear these suggestions to shreds - as I have mentioned in earlier posts, I've got a fairly thick hide. There are a lot of people out there smarter than I am........

Roughly paraphrasing Douglas Adams:

" true age is relative to the degree of pain experienced when confronted with a new concept "
 

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Air box mods

Well I wont claim to know a graet deal about all the dynamics that are involved with mods like this but I will just tell you guys what I have done.

First. I left the inside cap off of the airbox. The one that uses 3 Phillips scews to hold in place.
Second. the plastic tubular shaped piece that inserts one third into the air filter itself. I have cut a U-shape out of the surface that faces the front of the bike. This In my opinion lets air reach the inlet ports easier.
Third (this is the bold one).. The surface that the air filter nets up against when you push it on. I carefully laid out the centre of this and using a 1 3/8 hole saw drilled thru. On the other side I simply glued an 1 1/2 ABS 22 degree elbow pointing down and a little towards the rear of the bike. RAM air, but not really at the same time.

I also installed a new Throttle Position Sensor and the same time. (mine was acting up at low RPMs.

Now for the results.

More deep sound when under full power (love that)
Seems to Rev up quicker.
I am spinning the rear more for sure
The front end creeps up with quick Second Gear changes (never has before with 30000 KM on the clock)

I think that the mod was a complete success. I think that the bike runs better than it has ever run before to. (bold statement I know)

As far as any damaging effects, I know of none.

I suppose pics will be requested at some time..but I think you can follow the idea easily.

If there I one regret it is doing all these at one time. Now it is hard to really say that any one thing has made the most improvment. Thats the risk in modifying too much at one time..
:|
 

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Re: Air box mods

aavmannn said:
Well I wont claim to know a graet deal about all the dynamics that are involved with mods like this but I will just tell you guys what I have done.
:|
I thought of doing something like you have just done, but I assumed the extra air pressure would go strait out the otherside! and didnt bother in the end!
So your end result is worth it then!
I'll have to give it a rethink now.

Is there any chance you could block it off for a while and see if the TPS maybe someway helping?
 

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BugR said:
afterburn said:
One could use something like this: http://www.electricsupercharger.com/eram2.php

Electric supercharger, 1psi pressure, claims to add 15hp for for mere $300. Or take the 1.7psi two stage electric blower and gain a claimed 27hp.
Where are you going to get the 833 Watts required to drive this?
Chris
From the battery. :) It only operates on full-throttle, so the battery should be able to take it (starting takes more juice) unless you run full-throttle all the time. :mrgreen:

Personally, I think the FJR has plenty. It just delivers it in a somewhat boring way.
 

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Better look at the example install pics. That thing isn't small.
 

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woody... sure can..it would be as easy as capping the elbow with one of the fitted caps.
weather in Toronto is a littel cool this week so wait a bit and stay tuned for the update.
I would however start with the cutting of the tube that enters the airfilter first. seems the air has to travel to far and kind od misses the intake of the first cylinder.
 
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