BHP Increase with Aftermarket Exhaust

I've finally received and installed the o2 eliminators to go with my PC3 yesterday.  The Power Commander is mapped for a stock exhaust with eliminators.  I took it for a spin at a friends place and it feels ssooo much smother than previously.  Then I opened it up on one long straight and the speedo read 149 full throttle.  Given the speedo overreads by approx 8% I figured my bike hasn't quite got the top end that it should have.  I've put this down to the standard airfilter and stock exhaust, plus the cat is still in the headers.

For anyone in the know could I ask if an airfilter, aftermarket exhaust and PC3 re-map would produce many more BHP?  It's not that I particulaly want to go at warp factor three but I also don't want to have less power than the bike should run.

Thanks in advance for any repsonses.

I wouldn't expect much with a high flow air filter and after market exhaust.  Maybe an increase of 5 bhp on the high side?  And that's if you take it to a shop and have it dyno tuned.  Good oil and chain maintenance schedules are going to have your highest immediate impact.

The biggest benefit I see most after market exhausts adding is in their weight savings.  These are not light bikes after all and the more weight you (and your VFR) lose the faster it will go.

You can also change up your sprockets for better acceleration and some claim you can even getter a better top end speed if you get the front/rear ratio correct.  Or you can save up and invest in the Torocharger and embarrass super sports with your sport touring bike all day long.

For your indicated WOT speed though I don't think you are out of the norm.

Thats really good to know Vanion2, thank you for the quick response.  I did read in another thread on here that they claimed to get a 15hp increase with Motad headers and an aftermarket exhaust.  Given my previous experience with mods I'd never heard of such a large percentage increase in power with just these changes.  I didn't think it would be correct so thought I'd throw it out there for comment.

Thanks again.

It will be a cold day in hell if that brings 15 horses....

This is from another thread on this forum:-

My 04 that has a dyno read out on this site somewhere made from memory 115hp with Motad headers & Laser slipons so that is a good 15hp increase from stock, my CBR1000RR with full race Akra system only gained 12hp so the Motads do a good job. The hp increase is a bonus the effect not having a cat makes is the motor will spin up faster with no hesitation, that is why I fitted them (cutting out cat standard headers would feel the same in that respect).

Apologies to the OP fo not checking first before quoting!!

I have an '03 with Motad headers, Laser slip ons, K&N filter, PCV with O2 eliminators that dyno-ed at 105 HP during the PCV set-up.

That's interesting as that would still be about an eight hp gain over stock :)

Cold weather would help, Dutchy. :)

Mine has motad headers and LV pipes with PC3 and dynoed at +8 hp ...

You can't trust most dyno's, unless you do Before & After dyno runs on the same dyno in the same conditions, numbers will be all over the place.

Full catless headers, filter, after market cans with PC will avg 3-5 hp gain. Anything over that is usual, lucky or overly optimistic. Best I've ever heard was +10, but doubt the validity of those numbers.
PS stock HP is suppose to be 100hp, but most never see that.

BR

i made 90hp on my dinosaur of a VFR... i'd hope something 21 years newer could make over 100hp lol.  anyway, don't expect top end from a bike... gearing limits top speed very much so.  If you can get to 100 fast, you're golden :P