Does a slip-on need a tune?

If I put a, lets just say Leo Vince slip-on on my VFR with no other mods, do I need to also get a fuel controller (PC or equal?)
How will the bike run w/o the tune?

I put a Leo full exhaust on the little CBR250 and added a PC(2bros version) to it, made a biiiig difference.

I've been searching other post trying to find an answer, although I'm sure it's out there, I have failed to find a definitive answer.

 

Though I can not say whether or not the PC is required because you are adding a slip-on to the bike, I have noticed a quite a few posts in the past from people who have noticed that the Power Commander can smooth the transition on the VTEC system engagement, improves the throttle response, and clears up a flat spot in the throttle that occurs in the 5000 RPM range.

 

Most aftermarket exhaust manufacturers will tell you that simply adding slip-on pipes doesn't generally require a PC but keep in mind that anytime you alter the exhaust flow and back pressure this can potentially change the air/fuel mixture going through the system which can affect overall performance. To get the best performance out of your new exhaust it is highly recommended that you remap your ECU using a power commander. Not using a PC won't likely damage your bike but you certainly won't be running at full potential and the power delivery won't be as smooth.


Rollin

 

+1 to what rolling said. Many members here gut the exhaust and some just put on the slip on and never used PC and they have no issue. So if you on a budget and run without PC the bike will be fine.

 

I have a staintune slip on and a K&N on my 2000 and it is otherwise 100% bone stock. Bike runs PERFECT with no popping or lean spots. IMO, in all my years of riding, in general, a slip on set does not affect the bike very much tune wise. BUT, that being said, it would probably do better with a PC in general to get rid of the already lean conditions from the factory.

 

So basically just like my little 250, ran fine w/o the pc w/ the exhaust, but ran way batter after the tune. The 250 did have a couple occasions where it suddenly died while riding. According to forums, this was caused by exhaust w/o tune, wasn't a big deal, just an annoyance. Has anyone heard about anything like that on a VFR?

 

The slip on will not (or I say should not) cause the bike to die out.....

Now all this being said, your 6th gen is a different beast than my 5th and from what I can see, they REALLY benefit from a PC in general....so you should consider one.

 

I'm definitely considerig one, but an exhaust and a tune at the same time is a bit over my budget. Think I'll get the exhaust first, save some money, then get the PC, then a fender eliminator and sliders.

 

In my opinion the stock VFR needs a tune so changing the pipe would more than likely also need a tune. Will it run?,,,sure it will. Will it be better than stock? Depends on what you are looking for with the mod. It will sound better, that is for certain.

 

I'm going for sound more than anything, plus the right side pipe is bent in slightly from when i dumped the bike.

 

Well then you have plenty of options to choose from and I think thay all sound pretty darn good. The bike will run as good as it does right now in stock form with a pipe installed and it will only get better with a PC installed and a good tune.

Here's a 2002 I bought in DFW with a Two Brothers system and a PC III installed. It ran well but was still lean on the bottom end till I richened it up.

 

I highly recommend you NOT get a power commander because I'm pretty sure you're not going to get it dyno mapped so it can actually help your engine. I ran a PC for years with all kinds of maps and all it did was gunk up my engine. Just let the O2's and ecm do their job.

 

Perhaps simply running 91 instead of 87 might richin up the fuel for the slip-on or at least run 89. I wonder if running a K+N air filter and a slip is safe?:tinfoil3:

 

Running higher octance in an engine designed for 87 isn't going to do much if nothing at all. This is an EFI system, not carbs where jets most likely have to be changed out when you change anything on an engine.

I tend to run 88-89 in my bike just because I think the 86 here is the bottom of the barrel crap since it's the most used octane. That's just my tin hat theory.

 

I guess your right 89 is best grade-saves a bit a dough too- I sear they put the dumbest people working at Honda-Harley parts department-learned that they are just plain stupid-can't even give me a filter wrench that works and then there mechanic tells me Honda vtec goes out of adj all the time

 

I usually fill it with 93, should I switch to 89?

 

If you wanna save money. It's an 87oct engine.

 

93 Octane fuel is a waste of money unless you are experiencing pre-ignition knocking or your engine is classified as a "high compression" engine and it specifically calls for it which the VFR engine does not. Octane is nothing more than a measure of the fuels resistance to detonation. Higher octane does NOT run better, produce more HP, or run cleaner than regular fuel. In fact 93 Octane is actually designed to detonate less easily under pressure.

The fact of the matter is that you are basically buying the same fuel that is marketed by different companies such as Shell, Chevron, BP, Texaco, etc. and the only difference in what they sell is what additives or "detergents" they add to the fuel to keep fuel system clean. The octane level itself has absolutely nothing to do with this. Save your money and use a premium branded 87 level Octane.

Rollin

 

Good to know

 

Does the engine management unit "compensate" or "adjust" carburation when an aftermarket muffler put on? Sorry I'm not too clear on this. As for octane, here in Quebec & as far as I can tell, Ultramar's 91 octane is the only gasoline without ethanol added so that's why I prefer the higher octane...