Short Stacks in airbox

O

OB_cbxchris

Registered
I`ve put the short stacks in the airbox...on #2 and #3. Anyone tried this yet? Yosh says a good improvement 2-3 HP...what do you think?
 
i'm sure by now you've ripped down
on that baby.

tell us cbx, what did you feel?

ps...you know we need all the help
we can get, since the "big bad"
green monsters are upon us!!!!!!

kinda scary...huh?

i'm nervous...does anyone have a xanax?
 
YEAH,I TRIED IT BUT I DID NOT LIKE THE TORQUE CURVE.MIDRANGE FELL PRETTY BAD I GUESS THE LEAN MIXTURE FROM THE SHORTER STACKS AND NOT ABLE TO DIAL THOSE TWO IN INDIVIDUAL.THERE WAS A HP INCREASE UP TOP BUT I'LL KEEP MY MIDRANGE
 
Rubber velocity stacks that are mounted on the airbox side of the throttle bodies. The 1 and 4 cylinders have differant lenghts than 2 and 3. Yoshimura posted a claim about useing all the same length parts for a hp gain.
 
Busa did you have a PC2 to tune with or possibly the yosh box? Did you also have the rest of the airbox mod...flapper removal,etc.
 
yes,airbox mod and yosh box.i just recieve pc11 but you still can't tune each cylinder individually.not to my knowledge.
 
I changed the two center stacks to the same shorter sized outer stacks, haven't dynoed but it doesn't feel any stronger.

[This message has been edited by badbus (edited 21 October 1999).]
 
busa: if what you are saying is that changing the two middle ones lean it out?
thats possible. but now the thing to do is richen it up. then see what the dyno says.

we all need to follow this one tip! when your on the dyno and your adjusting your box to find the highest hp reading, and after you astablish that, we(my setup, your setup) then need to richen it up enough to take in account for the ramair! i'm only saying this because some guy's don't understand how much more fuel the busa needs when the airbox is jamming air down the head.
 
i just wanta know if any of thought about riching it up for the ram air?

and if anyone has been serious about the fuel settings with a ram air fan turned on while they were on the dyno?

kinda pointless, dialing the bike for max hp if your not going to take the ram air in to consideration.

the ecm can't do what it needs to if theres not a base line setting. and things change with each little mod you do.

so the big question for me to know is, has anyone pumped air into the airbox while adjusting the power commander?
 
Bob any thoughts on useing an O2 sensor to validate settings?

I have a stainless steel threaded O2 adapter you are welcome to if you like.
 
Yes, I have using the Superflow 250-dual fan model.
The reason the two stacks are shorter than the other two is to reduce the effect of each cylinder's 325cc intake gulps from the intake path of the cylinder next to it.
Suzuki took all riding conditions into account for sure, not just top rpm power for drag racing.
I have not experimented with the stacks on the dyno, though. Only fuel addition from 6500 rpm up. With the air box mod/filter the BUSA likes more fuel up top. This will not show up unless air is on to the nose.
I have not gone back to the strip since i did this work though.
I have posted this before--10 hp more with the air on and more fuel (between 2%-5% more depending on speed and throttle position)
It starts to show at 5500 rpm and becomes significant at 7000 rpm up.
The bike has a IAP sensor thats supposed to make up for the airbox pressure increase. But, apparently it does not add enough after the airbox/filter mod.
It means about 2 hp more when the additional fuel was added. This shows up at a peak at 10,243 rpm. Some day when Big Dog provides a jpeg section i will forward the comparative dynocharts showing the difference. I have e-mailed a few this already.
Bob
 
Bob, do you still have your PAIR lines connected? If so take off the large line on the right rear of the airbox and plug it. This will fix your backfire problem.
 
I already have this in my collector. Its the only way you can connect to the O2 sensor on the dyno.
All cars nowadays with fuel injection have this already, and I gotta believe it will show up on Bikes someday.
The O2 sensor measures the how much oxygen is in your exhaust. Too much oxygen indicates a lean condition, too little--rich.
Its a very good way to tune, but not cheap due to time required.(Did it with air on the nose)
I only targeted areas that felt weak when riding and wide open throttle througout the range only. Then we tuned those target points on a load step Dyno.
You will need to get on a load step dyno and check at every 500 rpm and every throttle position to do the whole map. $100/hour for me. This is what DynoJet did.
The map was pretty close in most areas. My plugs are tan and do not have a backfire problem.
Bob
 
I'm working on a pair of short pipes with pre-heated O2 sensors that slide on behind the cans. It will look strange but might provide the tools to tune for ramair. The idea is to slip these pipes on, hook up a Fluke scopemeter to the output. A second lead will go to a spark plug to provide a pulse to count RPM's. Bungee the meter to the rear seat and go for a ride winding through the gears. Hopefully the result will be a graph of fuel mixture vs RPM. That might be a way to solve the ramair/airbox-change tuning question.

It would also be a way to find out if stack changes help.

A lot of guys on this forum seem to add pipes/cans, clean up the airbox, put a Yosh or PC2 on and richen it buy guesstimating and then do a dyno to see if there's a gain. No allowance for ramair, or better flow. This is way too imprecise for me, hence the O2 sensor R&D.

[This message has been edited by Lyle (edited 10 November 1999).]
 
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