PUT UP OR SHUT UP!THE FACTS OF THE AIRBOX MOD

[Guest]

We've been discussing box mods for ages now. There is no dispute that the mod shows more power on a static air dyno. The questions have been concerning the function of the stock flapper valve at speed with ram air and it's usability for street riders, the loss of the valve and it's effect on streetability, and ram air power for both setups at higher speeds. We have also been hoping to see side by side dyno graphs of stock versus modded box Busas WITH simulated ram air so that we might compare the differences and see if low end torque is sacraficed by ditching the stock flapper valve even though higher peak hp is/may be seen at higher rpm range. Considering the design and function of the stock flapper valve there is every reason to believe that the advantage to having it is completely lost with its removal. A full time 1/4 mile racer may not need or care about the loss of higher vilocity intake airflow/higher torque at low rpm but those of us who spend more time on the street may appreciate it. It appears we really don't know much more than we did last summer/fall except that Mhead's hp increase claims sound more reasonable than the +10 that was published in the article about Lee.


[This message has been edited by Todd (edited 10 May 2000).]

 

[DaveO]

Motor,

Those #'s would discount the statement that your box takes longer to pressurize. Like you said "it's simple physics". If you increase the intake CFM limitation, then the box will pressurize FASTER. IF you increased the box's VOLUME, then it might take a higher speed for same "boost".

Finally got the Haltech, when I have time(LOL) I'll weld the sensor in and let you know. I will start with stock pipe/map to characterize it.

When I get a spare box I'll send it your way.


Dave

 

[Frank Adams]

If you have made all these runs at the strip, then post your time slips on Photo Point so we can view the differences in the two airbox's.

Make the date is visible so we'll know it was done on the same DAY.(that makes a difference)

What "setting changes" did you do to your pw2 at the dragstrip, when you did the airbox swapping?

 

[OB_Tangram]

This one is going to run and run. Me, I'm a novice at this stuff and know little about air-box pressure and all that stuff. My tuppance worth however....

If the flapper is designed to improve low-speed engine power and torque characteristics then so be it. I've managed to make said low speed engine responses smooth and silky through the use of a PCII and a little time and effort. So to come to the point, if the flapper opens up once the engine starts making any sort of serious progress, then surely it is no longer effectively in use. Therefore, at any sort of revs above 'toddling' it's [The Flapper] being there is only going to achieve two things at this point.... 1) It's another obstacle in the way of the airflow through the system, so it's going to slow things up. 2) The flow itself (now slower!) is also going to be as turbulent as all hell! Now I'm no rocket scientist, but I do know that air/fuel mix in 'clean' air will burn better then the same mix in 'dirty' air. You don't get any variations in the air pressure across the volume of the mix once in the piston so the burn is more efficient. From other posts, I think we do have some jet-engine specialists on site, I'm sure they can confirm that.

My conclusion then is that by removing the flapper, you MAY be degrading low-speed rideability. I'm sure that most people will not just do the air-box however, but will be doing a series of mod's including re-mapping which will solve this problem anyway, so it's hardly an issue.

The second conclusion is that by removing said obstacle, how can the airflow NOT be improved, and if the airflow is improved then you stick a little more fuel in as well and you get more bang for your buck!

This argument has definitely brought out the worst in everybody and I for one can't wait to see the point where the raw science starts getting quoted. Me, I'm into computers and love all that technical stuff. Bring on the math!

 

[OB_THE MOTORHEAD]

FRANK I HVE RUNS ON FILM TOO.WHY NOT ASK PEOPLE WHO HAVE A BOX FROM ME?WHO ARE YOU TO THROW AROUND NEGATIVE STATEMENTS?WHAT EVIDENCE TO THE CONTRARY?IT THE LAWS OF PHYSICS THAT PROVE MY MOD PERIOD.WHEN I FEEL LIKE POSTING MY SLIPS I WIL.TILL THEN DEAL WITH IT.BY ARGUEING A PROVEN PHYSICS LAW WITHOUT SOME TYPE OF FOUNDATION.AND FOR US TO ALTER THE LAWS OF PHYSICS TO YOUR THEORIES IS TOO FUNNY .IT IS BECOMING A JOKE.A MOUTH AHEAD OF THE CONTROLLLER.MY CUSTOMERS MAKE MORE POWER WITH THE MOD. STATIC SHOWS THEY WILL MAKE MORE AT HIGHER SPEEDS SINCE IT IS STILL RAM AIR.TELL ME FRANK WHAT STUDIES YOU HAVE DONE ON DIFFUSERS AIRFLOW ETC.?NOT ONE THATS HOW MANY.OTHERWISE YOU WOULD NOT MAKE STATEMENTS THAT CONTRADICT THE LAWS OF PHYSICS.PS.SUPPLY ME WITH A SENSATIVE PRESSURE GUAGE THAT READS IN MILLIBAR AND 2 CITRIFIGAL SUPERCHARGERS AND 2 AIR SPEED METERS AND I'LL TELL YOU WHAT THE HP IN ITS TRUE FORM IS AT TOP SPEED.I'LL SETTLE FOR THE GUAGE AND SENSOR TO READ MILLIBAR AND A DATA RECORDER.,I'LL SUPPLY THE ROAD!OR I'LL CONTINUE TO PROVE IT ON THE DYNO AND ON PAPER.

 

[OB_Jamie]

Motorhead,

I don't want to start a piss contest like on the other thread but I had a question.

I realize the bike makes more power with the modification. The drag times and the dyno charts agree that is does.

My question is how does it affect the low RPM cruising of the bike? The valve was added for a reason. Do we agree on that? Airbox valves and cambers are put there to quiet the engine noise and/or enhance low rpm power. If you removed the valve something was affected or the designers wouldn't have gone to the extra expence to put the valve in there in the first place. Does it run as well at low (1500-2500) rpm? The busa has big ports and big valves and 46mm throttles. The designers probably put the flapper in there to help bring the veleocity of the intake back up.

BTW, don't flame me over this post.
Thanks,
Jamie

These questions are for anyone not just MH. If you have a moded box tell me how it runs thanks.

 

[OB_THE MOTORHEAD]

TAKE THE STOCK HOLE -S- AND ITS AREA ,AND A GUTTED FLOOR BOX AREA-M-NOWSUBTRACT S FROM M TO GET YOUR INCREASE IN AREA OVER STOCK.NOW YOU CAN PROVE WHICH IS GOING TO CREATE LESS RESISTANCE TO SAID GIVEN AIR FLOW-A-.NOW WHICH ONE WILL FLOW MORE WITH THE SAME GIVEN FORCE-F-OR AT THE SAME GIVEN VACUUM APPLIED-V-.WAY TOO SIMPLE HUH?

 

[DaveO]

Motor,


Get out on the road and datalog the IAP sensor!!!! Then duplicate it on the 200. Do you have windows on it. I don't like the way you have to create the split screen. I guess I'm too used to the old software.

Dave

 

[OB_THE MOTORHEAD]

WHY A FLAPPER ON 1300 CC BIKE ?KAWS DON'T HAVE IT.I INSTALL THE BOX ON EVERY BUSA I TOUCH.I WILL NOT USE THE STOCK BOX EVER.MAYBE THE INCREASE IN INTAKE NOISE WOULD NOT HAVE PASSED THE E P A .I LIKE THE GUTTED MOD EVERYWHERE IN THE RPMS PERIOD.IF YOU WANTBREAL TORQUE USE LONG STACKS AND THE MODDED BOX.WITH THIS COMBO AND STOCK PIPES YOU'LL GET 96-99#AT ONLY 6200 RPMS

 

[OB_THE MOTORHEAD]

REALY I COULD USE A FLUKE METER ON THE MAP SENSOR AND COMPARE ITS READINGS VS THE STOCK BOX MAP READINGS.DESCIPHER THE VOLTAGE READINGS INTO PRESSURE VALUES TO GET SOME CONCLUSIVE READINGS .

 

[OB_ZXALAN]

Hey Motorhead, did you see my post" Hey Motorhead, quote me" Is this something you can do?

 

[OB_GSXRTURBO1]

Good thinking. How often will the Fluke meter sample and how much pressure does it take for the MAP to change voltage?

 

[OB_THE MOTORHEAD]

GOTYA COVERED YOU'LL HAVE TO WAIT THOUGH

 

[OB_greg0420]

motorhead,

show my dyno ,before and after airbox mod low end went way up

 

[OB_THE MOTORHEAD]

I KNOW YOU KNOW BUT I POSTED RESULTS BEFORE WITH PICS OF PRINTOUTS.HOW SHE RUNNIN NOW?

 

[DaveO]

Motor,

Your Fluke will work. A peak detector would be best to measure max pressure. If you have a 70 series meter they sample a little slow. I think the 80 series has min/max function, the 87 is 250us peak hold.

Dave

 

[OB_Bob]

I'm getting tired of reading the same old crap on both sites.
Tell you what MotorH--I'll send you one of my boxes so that you can perform a 15 minute cut-up. AND I will send you your $75 bucks.

I will go to the dyno using ram air (superflow w/ twin fans) and to Joliet (Rte 66) drag strip for the comparo.
If it does not out perform the stock box you SEND ME BACK MY MONEY. IF IT DOES I"LL SEND YOU $25 more. I will take photos of both the dyno session and the drag strip (scan the the times). And also have another ORG member with me.
AS CERTAIN AS YOU ARE, THIS IS A NO BRAINER RIGHT?
E-mail me at ramair1@flash.net and I will get it going.
Bob
I have a PC2 and the YOSH box so I can remap exactly as you like, if needed.

[This message has been edited by Bob (edited 10 May 2000).]

 

[Frank Adams]

Wow!....thats about a 2hr 20min drive for Me Bob.
Maybe I'll have bring up My digital camcorder for that one?

I can also bring up a stock motor Busa with the full airbox Mod & TI FORCE pipe for an comparison?

 

[OB_VegasDude]

hey bob, if it works i'll buy one right then................................ok motorhead.........?

 

[OB_godzuki 31]

Looks like im going to Joliet!!!