Overwhelmed with Exhaust/Tuning decisions...Please Help!

[Guest SBosco]

I made a road trip, from NY to to Ohio and back, last september where I picked up a brand new leftover 2009 VFR800, black, and LOVE IT!!!

I am however a bit disconcerted with how strikingly similar it sounds to a sewing machine and am inclined to do something about it. I'd like to ditch the cats and entire stock exhaust system, in the process gaining a bit more power and losing a few pounds of weight.

There are details I am hung up on and would GREATLY appreciate everyone's help with.

From what I've read, the Motad headers seem to be the way to go in terms of quality. I really like the FMF carbon exhaust. Details beyond that I am shakey on...

Best way to handle ditching the cats?

I have read about several ways of handling catless VFRs...installing O2 sensors back into catless header, O2 eliminators, Power Commander (III, III EX, V) w/or w/o AutoTune [(1) sensor vs (2) sensors], and simple 320-ohm resistors in place of cats.

Headers?

Do the Motad headers come with O2 sensor fittings?

Will I lose the center stand with Motad headers?

Tuning?

I have heard about custom tuned fuel maps for various combinations of modifications.

What is the functional difference between PCIII and PCV?

Does the PC AutoTune make enough of a difference to justify the expense?

Will I have a problem passing inspection without catalytic converters, like in a car?

Additional Modification Questions:

What are the most promising airbox/filter modification results?

Thank you very much in advance for all of your input, as I assure you it is very well appreciated.

I hope to be installing and photographing soon!

[Guest]

Should I interpret the total lack of response as my failure of locating this post in the appropriate section?

...should I repost under "Modification Questions?"

[RED RUNNER]

Don't overdo it. If you want your bike to sound like a 60's muscle car, just install some staintunes. They have removable baffles. With or without the baffles the bike will sound terrific. You may also want to install a power commander and an O2 eliminator.

[craigandi]

I felt the same way, so I picked up a spare set of stock pipes and gutted them. Bike sounds great. Looks stock.

[dgordon]

+1 to the recommendation on Staintunes. Love them. I would definitely get the PCV over the III. Much smaller and works the same with much more expansion capabilities. The PC in either guise totally eliminates any vtec transition issue. So smooth. The PC and Staintunes (Or Leo Vince if you're inclined) work really well. Truth be told, the Leo's don't sound as good, but they are cheaper.

[Guest]

Hi SBosco,

When I first got my Viffer, I must say I was a bit disappointed... I guess I was expecting too much of its V4 engine. With Blackbird being my previous bike I also lacked the torque/power. But what annoyed me most was that V4 was jerky on low revs which was not helpful while commuting in dense traffic. Nowhere near smoothnes of my previous in-line fours! On top of that bike sounded like CB500 on low revs and like a kitchen blender when revved. I still dont like the drop of power V4 gives you over 9-10k rpm, but that's just the V engine I guess. Most issues I had, I eliminated with mods.

Here is what I have done to mine:

0. I got the bike already with snorkel out and flapper and PAIR mods done. I undone flapper, as I believe it has been put there for a good reason. Left the snorkel out and left PAIR valve disconnected.

1. I lowered the bike as I am rather "vertically challenged" person. I have done it by changing rear dogbone link with one from VF1000 and dropping yokes on front suspension legs. This gave me a drop of around 3-4cms. Still looking for a shorter side stand and have to be careful when parking my bike on steep surfaces. With the mass-centre lowered, bike (even more) easily falls into the corners. I love it, but you have to get used to that.

2. I grabbed 2-nd hand pair of LeoVince's slip ons from eBay. I ride them without buffles, but will have to put them in for an annual MOT inspection. I love the ducati-like sound they give while dropping on revs. Sensibly quiet below 4k but they really roar when you unwind over. I did not have not have a chance to hear staintunes so cannot tell.

3. As an engine mod, I first put o2 sensors eliminators (without PC). I have done is just to see the effect and this seemed to have elimnated jerk-iness on lov revs, resulting in much smooter ride! If you dont want to go for Power Commander, just disconnect lambda sensors and put 320-330ohm resistors in the plugs and tape them. I guess this prevents ECU from fiddling with the air-fuel mixtures on low revs to lower emmisions. BEST mod of all, IMO!

4. Power commander + K&N filter - good choice. I have not dynoed mine yet, just used one of the maps from VFRD from bikes with similar mods to mine. I have a feeling that bike is a bit rich, though... At first I had PC-3 fitted and after a year I changed it to PC-V (for better expandability and different mapping for particular gears). I am going to use boost sensor input that it gives soon. This gives you even smoother ride and better torque/power through all range of revs. VTEC kick is much less noticable.

5. Replaced original CAT-ed downpipes with ones comeing from early VFR800's (98-00, as 01+ had CAT box). I had to play with the lenght of rear cyllinders link pipes to adjust as downpipes appeared to go too low. but this was probably because I got links and downpipes separately. Again, I loaded the map from VFRD, apropriate for my mods. This gives really good mid-range boost and very angry roar on higher revs. Worth going for. Downside - I had to get rid of a centre stand as when folded, it was banging into the exhaust... There are aftermarket exhaust makers (motad, viper) which can weld you the support element for the centre stand. Or you can ask your local garage and do a bit of a DIY there. I could not be bothered :) I never dynoed mine, but I read that Viffers with following mods done can get up to 105 BHP on the wheel. With V4 torque, it is enough for me for now. My bike lifts the wheel when I unwind the throttle with an 80kgs+ adult pillion sitting behind me (to balance mass towards the back). Keep in mid that VFR800A6 (A stands for ABS) is a heavy and rather long-chasis tourer, not a BMX-like CBR,

Next to do:

RAM-AIR induction to boost the air intake a bit and hopefully eliminate bit of the ugly 10k drop in power... I will not complain if I get some extra mid-range boost on the way :)

I have heard of compressor kits avialable for VFR800VTECs which could give you up to 180BHP on the wheel, but that is a bit over the top for me :) That would make Viffer a real draggster! But I want to keep my bike in quick-commuter-tourer class :)

Hope that helps!

PM me if you have questions.

M.

[Dutchy]

If you want V4 sound just gut the pipes or get an aftermaket one.....

http://s113.photobuc...nt=HPIM2493.mp4

[zRoYz]

Best end cans are really what you like as they all have a nice note & make the same power give or take 1 odd hp, if you fit stainless steel you get a better echo more like a V8 sound, carbon you get a more refined sound which is deeper. I personally don't like the new link pipe design staintunes & would say you will lose 1 odd hp over the old design, I would look for end cans that have a nice free flowing link pipe system. On that note I had Laser extreme end cans first & now have LEO EVO & the Lasers made 2 hp more which is strange but I put it down to the Laser link pipe uses two pipes so less restrictive.

Best way to handle ditching the cats?

There are really only 2 options here, cut open the standard headers at the lower collector & remove CAT material & then re weld access hatch you cut back onto collector (any good exhaust place can do this if you can't but you will need to remove headers to do so). Or fit Motad headers which are the only headers worth fitting.

Headers?

Do the Motad headers come with O2 sensor fittings? yes they do but it is recommended you plug the holes & simply fit 02 eliminators even if you don't fit a power commander.

Will I lose the center stand with Motad headers? no they are designed to retain the center stand.

Tuning?

I have heard about custom tuned fuel maps for various combinations of modifications. When installing a power commander it is best to try different free maps to see what you like try to choose closest config you have, there is nothing better than a dyno map but your best to have done when you have finished mods, so only do once you have completely finished the exhaust upgrades you intend to do. Not changing air filter from standard to aftermarket really has zero difference in performance so you can dyno with standard filter even if your changing later don't bother with K&N fit BMC or Pipercross.

What is the functional difference between PCIII and PCV? The main difference is the PCV will let you fit autotune & map selection switch (will allow 2 loaded maps) the cost is about same for both so fit the PCV. Note any pc fitted needs 02 eliminators or resistor mod or you will have a FI warning light on the VFR.

Does the PC AutoTune make enough of a difference to justify the expense? My opinion is there a waste of money if you have access to a dyno tuner which you only need to do once, power commander designed it mainly for people without access to dyno. The problem with autotune is it makes changes on the way your riding at the time so not optimal total operation of engine like a dyno tune. The good thing is it only makes changes when you accept the tables it suggests. I have my bike dyno tuned friend has autotune & we loaded my map his bike runs the best it has even after many autotune updates, he is now having his own dyno done & removing autotune.

Will I have a problem passing inspection without catalytic converters, like in a car? It is very hard for the authorities to pick up you have no CAT it is best if questioned to play ignorant & say you bought the bike like that if found out. If your worried it is best to keep the standard headers intact if you need to change back due to needing inspection.

Additional Modification Questions:

What are the most promising airbox/filter modification results? None leave it alone it is designed to work with a certian pressure, the only mod is disable the flapper & pair valve system but both of these have really zero effect on performance. Again the standard air filter is that good you can lose performance fitting a K&N reason other filters recommended above but they will work no better than the standard.

[Guest]

Thanks everybody for all the great advice!!!

R600TOY, I can relate to several of your experiences...my first bike was a 2004 Triumph Daytona 600.

...so I can relate to the difference between an inline-4 and the V-4 (with V-tec) in terms of smoothness and linearity of power delivery. I also notice the difference between weight and geometry of the VFR versus a typical sport bike. I prefer the VFR geometry, as it is more stable (not as nervous) and comfortable than typical sport/race bikes.

zRoYz, that's an interesting analysis comparing exhaust can material and sound output. I will have to spend some time listening to clips of the various VFR exhaust systems. I must admit I love the look of the VFR FMF pipes and am pretty confident I can invert their mounting so the exhaust remains undertail and avoids fitment problems with side-mount hard luggage...I uncovered the discussion here: http://vfrworld.com/...nally-here.html

Looks like I will contact Motad and inquire about adding the center-stand support on their headers. I have a MIG welder and can stick, MIG, and TIG weld. However, if the center stand support is a simple addition for the manufacturer to make I would rather it be done by them.

It also looks like I will go the route of PCV. What is the consensus towards running without cats and/or O2 sensors? How well do the downloadable maps work?...will I get popping/backfiring/etc. without feedback from the O2 sensors? If so, it sounds like the AutoTune may be a worthwhile investment?

What has two thumbs and appreciates all the help/advice?...this newbie.

Edit: I didn't read the full zRoYz post before replying. Now I feel like an idiot because some questions were already answered!