Just pipes & Fuel Management

[dave007]

I have seen many threads regarding the need (or lack thereof) for an aftermark fuel processor (power commander, FI2000R or my personal favorite, the Dobeck Performance TFI) when just installing pipes and not an intake system. Well, I sent an email to Dobeck Performance and received a very informative reply:

"All" bikes that are mass produced are lean for EPA regulations for a good portion of the fuel curve(some more of the fuel curve than others). the upper end of the fuel curve is "never" regulated by the EPA. This means that all manufacturers can keep the upper end richer. By adding a pipe the upper end(top 25% rpm range) will be fine but the lower and mid will be even leaner then EPA standards. We don't say that the bike needs a bunch of fuel but it does need some. Great things happen when you add fuel to an EPA legal fuel curve, better drivability, better throttle response, and a cooler engine. All the areas of concern that you are referring to are tied to the EPA lean fuel curve. The TFI is a great improvement even over stock but noone talks about anything except peak horspower anymore. This is somewhat our fault for the simple fact that we are the guys who created the dynomometer. So all in all the bike needs fuel in the lower and mid areas of the fuel curve. the upper is said to be rich enough to handle a pipe but when you add a high flow air box the upper end also needs help. the air box itself is very restrictive and this is why everyting looks so rich at the upper end. hope this helps out.

This is the best explanation I've received and it makes a lot of sense to me. It also answers some of the questions I've seen posted here about bikes being sluggish at low speeds, pinging or struggling under load in some gears, etc. I'm not saying that adding fuel necessarily cures all of the issues, but I have definitely found that my bike performs differently through the throttle curve, and the explanation above correlates to that observed behavior very well.

I'm going to get the TFI and install it before I install pipes. I'll see if I can make adjustments for my bike that correct the sluggish behavior I see at certain speeds / RPM's.

[ks_greg]

Great feedback / info Dave. Thanks for sharing.

[Buzzman]

Let me know how it goes as I am contemplating these same additions to my 06 Nomad in the near future.

[furious70]

FWIW this has been explained as simply by others in prior threads. This is why you don't see much, if any, peak HP gains from adding a pipe and fueler without the airkit. The stock fuel curve is a bit rich up top, so the pipe can maybe get 1-2hp, maybe a bit more with the fueler. But throttle response down low with a pipe often gets a bit twitchy, and you can certainly have the bike start to 'nose over' from lean surge w/out the fueler.
The fueler really helps the low and mid range, makes the TQ curve taller and broader, but the peak HP usually lands about in the same spot.

[Deeppurple52]

Sluggish at slow speed, pinging, poor throttle response.... Add a fuel processor with just pipes and you will inherit all of these. I am not selling anything but I do know what works and what doesn't. From my experience, your bike will run better without a fuel processor.

[furious70]

The map is key. You don't need much fuel w/out the airkit, but some fuel, esp. in the 2,5,10% columns can really make the throttle response smoother. My Meanie at least was (and still is a little) awfully twitchy with just pipes.

[gdhugh]

My V2K runs MUCH stronger, smoother, and more responsive with pipes and a PCIII. No doubt about it.

[honestlyinsane]

I will testify on my bike I HAD to run a TFI with my bigshots trust me if I could get away with it I would've. I ran the bike 3 weeks before I installed because I got sick of the power loss at low end and it was no longer smooth when loading the engine. I am still amazed that some people say you don't need them even though some have found you do.

[gonzosc1]

Originally Posted by dave007

I'm going to get the TFI and install it before I install pipes. I'll see if I can make adjustments for my bike that correct the sluggish behavior I see at certain speeds / RPM's.

just for your consideration.
I have a 06 1600 classic. Caddmann mod. Cobra speedster longs, and the TFI unit. before anything was added to the bike it ran I guess as good as any stock bike. it had the pinging more then anything when I got on it. first add on was the cobra's. while it sounded better I did lose low end power and of coarse I could still hear the pinging over the pipes believe it or not. about 3-4 weeks after the cobra's I added the Caddmann mod and the TFI. it took about 4-6 weeks of trying to find the best setting. at first I was really adding way to much gas to the whole thing. the pinging stoped but the it was sluggest through the whole low-mid range cuz of the fuel over load.
by the time I got it set to the best I can get it and still have decent mileage, my settings ended up being 2:15,3:00,1:30,9:00, one up mileage around 37-38 in town and about 42-43 on the highway@ 65-70mph.

if you are just adding the TFI only watch the settings. you won't need much. maybe start around what I have or less except for the 3rd pot. try that at "0" or off at first, bump it up if needed.

[RampRat]

I've been planning on getting a Dobeck TFI & asked in there forums about the pot settings for my application and have yet to get a reply.

Why is it they have a forum yet don't monitor the posts or reply to em.

Makes me wonder about their customer service & if it's not just lip service.

[gonzosc1]

Originally Posted by RampRat

I've been planning on getting a Dobeck TFI & asked in there forums about the pot settings for my application and have yet to get a reply.

Why is it they have a forum yet don't monitor the posts or reply to em.

Makes me wonder about their customer service & if it's not just lip service.

yeah you gotta wait forever on those company forums

[dave007]

Originally Posted by gonzosc1

just for your consideration.
I have a 06 1600 classic. Caddmann mod. Cobra speedster longs, and the TFI unit. before anything was added to the bike it ran I guess as good as any stock bike. it had the pinging more then anything when I got on it. first add on was the cobra's. while it sounded better I did lose low end power and of coarse I could still hear the pinging over the pipes believe it or not. about 3-4 weeks after the cobra's I added the Caddmann mod and the TFI. it took about 4-6 weeks of trying to find the best setting. at first I was really adding way to much gas to the whole thing. the pinging stoped but the it was sluggest through the whole low-mid range cuz of the fuel over load.
by the time I got it set to the best I can get it and still have decent mileage, my settings ended up being 2:15,3:00,1:30,9:00, one up mileage around 37-38 in town and about 42-43 on the highway@ 65-70mph.

if you are just adding the TFI only watch the settings. you won't need much. maybe start around what I have or less except for the 3rd pot. try that at "0" or off at first, bump it up if needed.

Thanks, that's great information. I don't suspect I'll need much more fuel... even the Dobeck engineer said it wouldn't need much. I just want to add it and play around with the settings BEFORE introducing another variable (i.e. pipes).

[dave007]

Originally Posted by RampRat

I've been planning on getting a Dobeck TFI & asked in there forums about the pot settings for my application and have yet to get a reply.

Why is it they have a forum yet don't monitor the posts or reply to em.

Makes me wonder about their customer service & if it's not just lip service.

No reason to post to the forum... you can email them directly. Although it took a few days to get a response (which I actually think is very quick all things considered), the response I got was very detailed and very complete - and it makes great sense. I think their customer service is quite good - just don't expect an immediate response. If the actual engineers are responding, you've got to remember these guys have other work to do besides answering email. Give 'em a chance, and I'm sure they'll answer your email questions.

[MeanWon]

I somewhat agree, but have dyno'd my fair share of bikes and find that just adding a pipe does not offer much difference in restriction at the lower rpms of operation and therefore the bikes do not run much leaner than stock. Actually the way bikes and cars engine management programs are programed these days the manufacuture has them as lean as possible at idle and at cruise, (light load, steady throttle) for this is were they have to meet EPA mandates. From what I have personally seen on many dyno runs, mostly care but quite a few bikes, is that the addtion of exhaust does not lean out the motor any more than the stock exhaust systems, if so it was insignificant. And like he said above, at WOT the program is rich enough that when leaned out by the free flowing exhaust it is still operating at a safe A/F ratio.

[honestlyinsane]

Originally Posted by MeanWon

I somewhat agree, but have dyno'd my fair share of bikes and find that just adding a pipe does not offer much difference in restriction at the lower rpms of operation and therefore the bikes do not run much leaner than stock. Actually the way bikes and cars engine management programs are programed these days the manufacuture has them as lean as possible at idle and at cruise, (light load, steady throttle) for this is were they have to meet EPA mandates. From what I have personally seen on many dyno runs, mostly care but quite a few bikes, is that the addtion of exhaust does not lean out the motor any more than the stock exhaust systems, if so it was insignificant. And like he said above, at WOT the program is rich enough that when leaned out by the free flowing exhaust it is still operating at a safe A/F ratio.

Not sure about what pipe you are running but big shots have no restrictions its basically a straight pipe . The stock exhaust runs a cat. converter and a REAL baffle so I am not sure how you can so there isn't much difference in restriction. Furthermore I have seen numerous articles whether it be quads sportbikes or cruiser where just changing the pipes actually lost power or gave virtually no gain without the help of a fuel processor or a change in program to the bikes ECU