Just installed the PowerCore 4 on the Megabomb and raised the needle one notch. Bike power is different than with the stock header and DG-R. First impressions are that power MAY be up across the entire RPM range - but delivery is smoothed out with no "ups" or "downs" in torque delivery during WOT acceleration from 3.5k to rev limiter. This makes it very hard for my seat-o-pants dyno to report results - it power wheelies (still) in first gear and I believe it does so easier than with the stock header and DG-R. That is the main reason why I think it has more power....

That's over $500 in FMF exhaust. The Megabomb and the Powercore 4 mate up perfectly with pipe sizes that are significantly larger (I.D.) than stock. Remember that the Megabomb will not fit any slip-on that is designed to slip right in to the stock header with stock seal in place. So I was in for a penny, in for a pound after buying the Megabomb.

I will try again to get Dyno testing done 8-10 days from now - that is my next window of opportunity - as they are too busy to get me in now...

Any bets on what I'll get outta the FMF ?

 

Is the PowerCore 4 a straight thru design? Their web site doesn't really say other than offering a quiet insert.

Should be interesting!

 

yea PC4 is straight pipe!

 

The bike is quite a bit more quiet with the full FMF system. That DG-R is loud - the way I like it.. Kinda hope the dyno says to keep the stock header and DG-R cause I would miss it.

The FMF system sounds nice - real nice. It's a "mature" performance sound - not the "in your face" boy racer sound of the DG-R.

 

Do you think one system is longer than the other to the muffler outlet? Just curious

Like you said, you're $$ into it now. Might as well take the hp gain with the new set up

 

I don't think the FMF setup is longer - if it is, it ain't much..

 

Very interesting.

I remember reading Bill Blue saying that he found no difference with the megabomb vs stock header. It would be cool if you could also test the FMF pipe with and without the megabomb header, just to see what difference it actually makes.

We need more of these tests. Its the only way we can get real knowledge of what different mods actually do to our bikes.

 

I do know that the PowerCore 4 is slightly shorter then a QuietCore 4.

 

Roll on races against friends with similar or similarly powered bikes who aren't doing mods are also a quick way to check mods


Megabombs might show any gains to be had in the mid range more than at WOT on a dyno. Odd things happen


- I picked up a .25sec by adding a U shaped cross over pipe to a car in back to back tests at the strip years ago. It bolted on to a 3 bolt flange on each side that was T'd into the OE exhaust.

Running with the flanges open didn't show any gain at all with ETs still in the high 12.30s same as with the block off plates connected to the flanges, but the next two runs with the crossover connected were 12.16 and 12.12 on a car with drag radials and a shift lite.

So it's surprising sometimes what works and what doesn't.. So that bomb section may just do something.

 

I've only just now read the entire thread with Bernie's assertion about re-setting the initial advance on the ignition. I figured the ignition issue had been put to rest long ago with RayCour's testing of his CDI unit... Then Ray postulates that his testing could have been less than definitive on his unit... Guess I'll need to get one of his CDI units and Dyno test it one day.. It never ends..lol