flo commander, does it really work?
 

some people claim to have noticed a difference in power, alot of times its a placebo effect i think, were so gung ho that we just bought a new go fast mod or something to clean up the powerband that we want it to be faster no matter what, and even if we lost power we feel a difference in the seat dyno and associate it with a gain. so the flo commander, whats the story on these things? has anyone dynoed with one to see if itll show a smoother cleaner powerband and if itll infact add more fuel into the carbs or is this just a cash grab? ive heard mixed reviews and some of the honda mechanics i talked to said its a waste of cash. ive done some looking around and cant find out exactly how this thing works. is it as simple as venting out some excess air from the carbs to force them to increase fuel pressure? if its something basic it can be made from off the shelf parts this isnt a magical electronic box from the looks of it.

Yes, it most definetly works... But if you think it's a magical gizmo that will give you more horsepower you are sorely mistaken... And that is what I think the mechanics where going for...

The FC cleans up the powerband, it doesn't improve on it or give you a definite gain... You just get the most out of the other parts in there...

Why? In the airbox the factory are trying to optimize airflow, but they have to make some compromises, and as a result you won't always get smooth air to the main jets, certainly not throughout the whole revband...

The FC takes air from a calmer place and gives equal airflow to both carbs throughout the revband... That makes it incredibly easy to sync the carbs, and they stay in better sync all through out the revs... This smoothes out the powerband and will take away a few smaller gaps...

Then the other effect of the FC is that since you have air running through a pipe, and not entering into a pipe-end in the jet you get laminar flow increasing the airvolume available and you can turn the knob to actually run leaner or richer than the main jet...

The result of that is that you can fine tune the jet a bit, say to about half a jet size... Or you can easily find out if you are running the wrong jet size... And the best part is that you can do it without spending money on dyno time... And once you have the jet sizes right you can put the bike on the dyno and fine tune it to perfection with less time and money...

And like it says on FC's own website, you will not find any or much improvement on a perfectly jetted bike... But if you are a tad of, you can find a lot of improvement... And once you have gotten it "perfect" you can easily make small adjustments for changes in temperature/humidity/airpressure and the likes, without tearing the whole airbox apart... Tuning for a different day at the track becomes as easy as finding your favourite screwdriver...

It's a tool for jetting the bike correctly and improving carb sync... It's that easy... And if you get that right, you "gain" in the way that you get the most out of the other parts...

As for what it is... It's a pair of brass adapters and tubes, and an aluminium valve with a central air inlet... That's about it... Nothing too fancy, but there has very obviously been made a lot of calculations and testing in there to get the airflow correct... You need to improve on the airflow capailities of the stock jets... So I kind of doubt that you can just copy it unless you use a CNC mill...

And since the actual price of it is probably less than what a jet kit + dyno run costs I think it's money well spent...

I recently installed a Flo Commander. +1 to what Tweety said. Used according to installation sheet I was able to dial in how lean I was running and make the necessary change in one test cycle, instead of at least two test cycles. It gives you that extra fine carb tuning that you get with the idle drop procedure with out the all the fiddling, since the adjustments can be made in 10 seconds.

Outstanding write-up,Tweety.

Tweety, an excellent write-up and description of what the F/C does.

The only bit I was unsure about was how you're able to find out if you're running the wrong jet size, how exactly are you able to do this using the F/C :confused:

great writeup, very informative. how are you guys fine tuning without a dyno and a wideband? checking the plugs can only tell you so much. its on my xmas list i just wanna make sure im gonna get my moneys worth and it sounds good

Quite easy, if the FC is set at neutral it doesn't affect jetting, just affects the air-flow/turbulence and sync of the carbs... And when fully adjusted to either end it amounts to about one jet size leaner and a bit more than one jet size richer... So if you get a noticable better running bike at either end, you swap a jet size in that direction and re-set the FC and start over...

Well, I installed it, sync'ed carbs and did the idle drop and all that... Kind of square one... Then put a screwdriver under the sadle and go for a ride... Once the bike was warm I turned the knob on the FC either way while listening to the engine...

It really is that simple... You hear the difference... I'll admit it takes some experience with engines, but not much... I'm no genius and certainly not a good engine tuner... I do have unlimited access to a dyno though... So yeah I have done some trial and error...

I did however confirm my findings on the dyno as I got better A/F and a nicer smoother curve with marginaly more HP than after the last attempt on the dyno... All by turning a little knob and listening... And it has affected mileage as well...

If the install is done in conjuntion with a dyno run, you can just as easily do the same tuning on the dyno as I did by ear and ass-dyno... Oh BTW, the reason for doing it off the dyno was to kind of figure out if it did work as it was supposed to... It does...;)

Perfedt. I'm sold man. I'm gonna check ebay for a used unit first and if nothing pops up ill order one up. Wouldn't mind a little edge on my friends. Well more than I have now :)

I understand what you mean now Tweety. Excellent! I appreciate the explanation :D

Not a problem..;)

BTW If you are going for used, make sure they come from a model using Keihin carbs as then the likelyness of getting the correct adapters increases exponentially... Not 100% certain though...

Edit: Or you can probably get the correct adapters from them, just contact them and check...

yeah i checked ebay theres nothing for the vtr, ill just have to buy new in the next little bit.

They`re distributed in Canada by Motovan

perfect thanks man, ill look into them

I guess I will bring it back from the dead with a question. since the FC eliminates teh turbulence and equalizes the pressures then wouldn't it be beneficial to mount the intake of the FC at or just outside the orifice of the airbox? so that it has ambient pressures and not the pulsatile pressure of the air box as the giant slugs take gulps of air?

No, defintely not... since then you will be feeding your jets unfiltered air... Makes for easy clogging... Very bad idea... Plus the FC is already eliminating the pulses by feeding the same pressure to both jets at the same time... Ie the pulses doesn't matter, even if they are there...

nope.. it needs the air pressure in the airbox as that is what the carbs are actually getting. But different parts of the airbox have different pressures, so pulling both carbs from the same location inside the box will help even them out.

Also it allows for minor adjustments to the A/F ratio via the screw.

edit: http://www.flo-commander.com/how_it_works.htm

hmm seems I may be wrong.. they show a CBR900 with the flow commander outside the airbox on their site. I would have thought it wouldn't get the correct actual pressure..

Well... According to their site, you can mount it outside... But then you route a pipe into the box to feed air from inside, the mounting is just because the box is cramped or it affects airflow to mount inside... See the blue pipe on the CBR900 setup...

Or in some cases with podfilters you do mount it "naked" but then you use a filter on it...

very interesting, now I'll check out the DIY post

Installation ?
 

I checked out FC's website but they don't have a link to model specific installation instructions. My ? is does the VTR have the "OEM type restriction" that must be removed & replaced by FC's adapter?

Nope... ;)

Once I had the airbox open and the filter out, the whole installation took me about 5-10 minutes... Drill two holes, one for the bolt holding it, and one to fit the grommet/adjustment screw... Put it in place, stick the adapters on the carbs, cut the hoses and put the bike back together... That's it...

If I can find the manual I'll scan it for you...

Coool, thanks Tweet. A FC along with rewiring my headlight relay system (again but this time with 16 gauge rather than 18 gauge wire, or just buy Eastern Beaver's kit) are on my winter TBC list along with replacing my 20 year old HLM and installing your GPI (all discretionary funds permitting).

Ok as if there aren't enough noob questions rolling around:

Flow commander before velocity stacks? Is one more necessary with the other? Can you do both? The way I understand it, velocity stacks allow for a smoother/ more refined airflow and the flow commander makes the flow consistent and allows you to adjust it...

I have not messed at all with the jets and to be honest have no idea how to tune this part yet. I will learn myself how in the near future and don't need advice on how to do any of this... what I am more curious about if I should purchase any of these as long as I have to tune for different exhaust anyway?

Or just put flow-co/stacks/jets on the to-do list and make sure I can get the bike running in the first place...

They affect completely different parts... The stacks deal with the air in through the carbs (big hole) making it possible to cram more air in there in an orderly fashion...

The FC deals with the air supplied to the jets (very small hole, sitting just outside the big one) feeding both carb jets from the same tube, negating differences... Totaly different and independant...

If you however do the stacks, you need to adjust your jetting... If you don't have access to a dynobench this is easier to do if you have an FC as it makes it possible to "test" which way to go with the jetting to some extent... To say you can adjust your jetting is a bit of an overstatement... You can finetune it to about midway between two jetsizes with great precision, and the extreme ends of adjustment will let you know to swap jets in that direction... But it doesn't replace swapping jets/needles...

The same goes for radically changing the exhaust... You will need to adjust jetting... And here the FC is a great help... (No, a new pair of slip-ons doesn't neccesarily mean you need to re-jet, but it's a good idea...)

But no matter what your choiches... Yeah, I'd start by getting the bike running... Then you add more variables... I have found that it makes finding your own screw-ups much easier if you do it in that order... :rotf:

Ok thanks a bunch (again) Tweety. I'll stick to getting it running first (because I knew it did that, and pretty well, before) and then think about all the other stuff.

I did understand how the FC helps you adjust jetting, not replaces the necessity for it, so I'll keep that in mind for later- and think that answers my question about the order in which I'll be doing things.

I'll have to send you a royalty check or something when I'm all done b/c there is a good chunk of the motorcycle part of my brain loaded with your advice ;)

Great explanation Tweety of the FC and I see you've again used the "laminar airflow" term to assist with a vivid description of what is occurring inside the airbox! :) Good job.