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I've _read_ (take that for what its worth!) that 1990 was the pivotal year. Sounds bout right - IMHO it would be when they went to the flat filter as opposed to the big oval one. Sound about right, or am I too tired to be typing
 

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I think Suzukinever did this on our A/O bikes, on the 1100's they never even hooked the fresh air tubes to the airbox! The best way to increase airflow is to loose the Airbox. Someone else may know more about this.
Bones
 

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Well, at least they hooked up one of the two on the 93 1100, the second one, ie on the left went over the head and .....stopped????? Then there is the hole on the left rear of the box.

If nothing else, it does allow air to collect for the carbs at high speed which I _think_ might be a problem for my dual opens, the faster I go...thing is, don't really care, which sure helps, because the box had to go, or project stopped. Can't have stock or a sense of reason getting in the way of a mod!!!
 

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The biggest breathing problem is that the resonance changes with rpm, and these engines have a very wide range. So you need to pick the rpm range where you want the engine to breath best and disregard the rest. Or try to make an average of all the possibilities, which won't maximize any point.

I do a lot of engine testing and we have messed around with the intake runners. The engines I'm tuning are mainly used on generators and run at a set speed. Yet, tuning the intake doesn't really make any more power, but it can help with the transient response time when changing from one rpm to another. This is probably due to the fact that these engines are only turning 1800 rpm, on a gixxer engine at 12,500 rpm it will probably make a difference.

My problem is that I don't have enough schooling to make these calculations
 

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Everyone is so quick to get rid of the airbox, I have a 92 1100 with lots of stuff done to it. I have tried many different combinations with it, the airbox will smooth out the power curve, plus it makes it much quieter. It makes it a bitch to change jetting but with flatslides you don't have to take the carbs off anyway. My bike always ran better with it on. I also know if you take it off a water pumper of any size it will screw everything up. They run like shit without it. On the oil cooled motors i run a k&n and don't use any of the air restrictors they send with it. I also have built some minisprint motors that would run much better after we rigged up some sort of airbox for them.

just my 2 cents though
 

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Hard to know which will and which won't run better with the box... I ran extensive trials both ways on the B12 and always had significantly better success with dual K&N's.

The 1100w, on the other hand, never really ran with any consistency with open filters- and I tried bunches of combination changes, both profound and very very very subtle... when that one goes back together, the airbox will be on it.
 

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I have to agree with Ed (1198). My 93 1100 now runs very smooth from top to bottom with the open dualies (BMC) - BUT, it took a shitload of dynoruns and a guy waaaaaaay better than me at interpreting carb shit to get it that way. The only other diffs that I can think of is that the BMCs I used were substantially larger than the K&Ns I could have put on, plus they are mounted on extended runners to the carb inlet. That plus the (VERY lucky to get) unobtanium WSB Suzuki factory black box for the '90 oiler 750.


PS: FastCat - I'm not a guru, unless 'guru' also means obstinate, opinionated and NOT svelte
. The Jeff paradigms qualify as 'gurus' for the normal meaning


[ 12-12-2002, 09:21 PM: Message edited by: bcjohn ]
 

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Another thing to lok at is where and how you ride. If your rides vary in altitude by more then a couple thousand ft then where you tuned it for and you run open element airfiters you will be running too rich or lean depending which way you go. An airbox helps to keep the density constant to the carbs taking care of this. Tempature also Plays a part in this. I re-jet twice a year once in the late Spring when the temp passes (and Stays) over 70 and then agian in the Fall when it drops back down. I keep the Fall jetting thru the following spring.
Bones
 

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gsxr1198

can you give me a idea of what you've done and what the results were, like power and torque or dragstrip times etc.

i'm curious

my motor has an older gsxr head so its not much different from a bandit
 

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Discussion Starter · #11 ·
Originally posted by Bones_GSXR:
Another thing to lok at is where and how you ride. If your rides vary in altitude by more then a couple thousand ft then where you tuned it for and you run open element airfiters you will be running too rich or lean depending which way you go. An airbox helps to keep the density constant to the carbs taking care of this. Tempature also Plays a part in this. I re-jet twice a year once in the late Spring when the temp passes (and Stays) over 70 and then agian in the Fall when it drops back down. I keep the Fall jetting thru the following spring.
Bones
<font size="2" face="Verdana, Arial">I'm still mullin' it over... on the one hand, I *dread* tryin' to jet the damn carbs with the airbox in place... I have allens in the caps and float-bowls so I don't hafta pull em to tune, but that airbox just eats up so much space and makes everything a bear to reach. ...I *know* that altitude plays hell with jetting... I live no more than 100' above sea-level, but most of my summer riding takes me into the mountains, and my *favorite* set of twisties is a forest-service road that goes nearly to a peak ...but then again, even the fuel-injected, stock-airboxed viffers start to wheeze up there too... and I can *still* do wheelies at the top with the old 36mm carbs and BMC filters... I was hopin' to find out for sure whether or not it was worth the trouble before I spent a buncha hours only to find that it's not...
 

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Bones_GSXR - How does the airbox change the density of the air???
 

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I had my bike dynoed with K&N filter pods and the stock air box and I gained 7bhp with the air box. But then again, I've always heard the the stock 40mm carbs, that come on the European bikes (M-models...like mine) are too big for the engine anyway. It does suck having the air box there.
Hard to get the carbs out, have to remove the battery box to access the filter, and you don't hear the beautiful sound of the needles working their magic.
 
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