Wow, take a red hot poker and stick it in your valve.

Really, has there ever been a dyno test that would show the difference in power that would be created from this mod? My guess is that it would be so low that it wouldn't turn up or wouldn't be repeatable.

There is the risk of substantial damage to the engine for what would be a very low and unsubstantiated return.

 

? not if you're making the tiny opening larger at the AIRBOX. Its just awkward to get too. The video incorrectly shows MrDuhfactor drilling the crank itself. In the comments of his own video he admits its an error, even BillBlue has commented on that video, saying do not drill the crankcase but the airbox...

He even told me that on the phone.

 

You could go a bit nuts, run the breather line clear up around the head set where it won't get caked. Maybe behind the radiator or something.

 

I ran my breather line up into the airbox (lid off). Then to the side of the airbox (lid on). Used a little filter on the end, I think it was a K&N. It was a pain so I put it back to stock, then I drilled out the airbox hole and tried again. I couldn't notice from the butt dyno any difference. I doubt a full 1/2 inch is needed in the airbox. If the small stock hole causes restriction, going just a little larger will make a large difference in flow capacity. You know, the whole pie are squared thing.

 

IDRIDR, you think your DynoButt is sensitive enough to detect 1/2-1 mo HP in the upper mid to top end on your 351 ? If so, then "no change" is good enough for me - as much as I like the idea of sticking something with a red hot poker..

 

Of course not. That's the point. Also, I spend little time taking the 351 beyond 7,500 rpm, probably less than 1% of run time.

Next time you're at the dyno, make a run, then pull the breather hose off the airbox and take another run. Let's see what it looks like.

 

Hey, I was being serious about your Dyno Butt.. Mine detected such small increases.. I'm "done" with the dyno testing for the forseeable future as he doesn't want to, and will not, spin it up to 10k - so I can't get an accurate picture of the entire powerband.. Especially the huge top end power a full exhaust system can produce (with the proper mods.)..

(But my charts do go up to around 9k and that is good enough for testing AFR's on CV setups..)

 

9K is a pinch over where the peak power was for stock and for Marcelino's work, so that makes sense. I think it would take a change of cams to actually push it up over 10,000 for real. Everything over peak is just over rev if needed when riding hard. Normal stuff for off roaders when they just need to rev a bit more to avoid a shift coming up on a corner or a serious hill.

 

Yeah, you see I can't show proof of power levels over 9K - All I can say is that I understand "over rev" to be a top end slackening off of thrust/power as the engine continues to rev, and I'm getting continuous thrust until the rev limiter puts and end to the fun..

I can't get Marcellino's charts to come up..

 

His bike actually peaked a few hundred rpm below stock, but with more HP at its peak.