ACE VenTRa

I got to talking about intake air temps with a friend and I realized that there ids a bit of improvement on the table still with the V.

1.) We tend to eliminate the PAIR system on our bikes but, I recently discovered that on CBR's they tend to leave the reed valve in place as designed and connect that to the PCV hose from the valve cover. In doing this they reduce internal pressure and as far as the legend goes, there is a dyno proven difference. I suspect this would also work on the V.

2.) I added a temperature probe to my air filter housing today and went on a long ride to see how much heat would soak in. After a half hour or so in 87 degree weather the intake temps were at about 107 degrees f. Apparently this has obvious effects on air density but it also apparently creates a boundary layer inside the air box and has a detrimental effect on flow.

So, the way I figure it is that we have two sources of heat..the engine itself that radiates heat but also the PCV system pulling hot gas from the valve cover....If you're following along we should modify the PCV system the way the CBR guys do and add a thermal coating to the air box. There are hard numbers out there that I wont go into here but for every 1 degree drop in temp there is a corresponding increase in air density and thus power.

Food for thought

AV


Before I even started the bike

After a half hour or so, engine temp at 190 ish.

Wolverine

Hmm. Interested to see how many horsies you gain on a dyno for all the work done here. If it's enough, I'd consider covering my airbox with something but I suspect very minimal gains. PAIR's blocked off on mine and it's staying that way.

ACE VenTRa

FWIW, the guys on the CBR forum who use the PAIR to vent PCV claim a solid 4hp. Now we all know how claims go but...if you consider that when you connect it in that manner not only is it reducing internal crankcase pressure but it is lowering intake charge temperature and thus increasing the air density charge. It is also, perhaps, providing a cleaner intake charge...possibly. As for the insulation on the airbox I suspect it will simply reduce the intake charge temps by 20 or 30 degrees which would allow for much better around town cruising on hot days. Typically it's the forced induction crowd looking at intake temps but I see no reason why we can't benefit from it as well. Certainly can't hurt.

AV

Wicky

Could try what Guy Martin's team did with a JCB tractor and use ice tanks to cool the air intake

The team also created an innovative charge-air cooling system. It consists of two ice tanks that help reduce intake temperatures by 50-degrees C.

The result is 1,106-horsepower and 1,843 pound-feet of torque.

More power means more heat, however. So to cool the air that makes its way through the large inlet trumpets and turbo, there’s an enormous new charge air cooler and ice box. Yes, an on-board container of ice, with 25kg used per run.

See 0:34

ACE VenTRa

Or....use thermal coatings on the airbox and re route pcv to pair... As tempting as it is to add buckets of ice to the V, it may be unwieldy.

AV

misnblu

I'm a car guy for 40+ years and have built, modded, and restored cars all my life.

On the pcv system has anybody gone to a vent to air setup with the bike?
The pcv is used to draw crankcase emissions and there's a fresh air side that also vent into the crankcase that lets the system breath.
On the last car build and present build I'm doing I let both the pcv and fresh air side vent to air via catch cans. It's worked great in lowering iat's and allowing only clean air into the combustion chamber.

I know on a bike there's little room for a catch can but a vent filter would work or even a tube to allow crankcase emissions to be expelled.

Am I thinking into this too much? 🤔🤷🏼‍♂️
Ive glances at the crankcase system in the bike in the service manual but haven't dug that deep.
Im just wanting to see if any of the long time riders of these 'Hawks have done this and with what results. 👍

ACE VenTRa

Yep, there is another member I spoke to who had excellent results...I'm sure he'll be posting soon. I don't vent to atmosphere because I don't like drips of oil on my bike, no other reason.

AV

Wicky

misnblu

Yes I've seen this picture in another thread I was reading over and this looks good.
Some more detail would be nice or if there is a thread involving the above please link it. 🙏🏽
Thanks.

ACE VenTRa

I considered a canister but did not do it for the reason illustrated in the photo. However, today I walked my talk and re routed the PCV to the PAIR. But first...it's been 1k miles on the new motor so I figured it was time for a valve adjustment and I was right. Only two were in spec and all the other were out by enough to make me cringe. Alas, the VTR had the last laugh,,,after I buttoned it up and started it she clicked and clacked like a tap dancer. Turns out doing shim calc at 530 in the morning is a bad idea, I set mine at .014" on the exhaust side instead of .012". No biggy, I re-adjusted the rear exhaust cam and voila...she is golden. On to the PCV mod...

For those unaware...

This is a dirty reed valve that has been in a bike for 1000 miles.

This is the other side

This is how to route hoses to connect PCV to PAIR.

This is what the reed valve looks like when it's as Honda intended

There are of course much neater ways to make this happen, but this the quick and dirty route to get the PCV out of the airbox and put the PAIR to good use. FWIW, my reed valve was filthy, full of crud and a little bit of condensation. That alone is enough reason for me not to have my reed valve flipped. YMMV...good luck.

AV

ACE VenTRa

A few long rides into this mod and I have nothing but good things to say. I can't put my finger on it exactly but there is a certain something that has changed for the better. Dyno in 2 weeks may tell the tale.

AV

Bald Eagle

Bald Eagle

Hi All who are "venting"....
I had my reed valves blocked off...Because it was done by the previous owner with tape...so I purchased the blank-off plates so it would look good. This was what everyone did on this forum as an improvement.
I do not agree.
I've had excessive crank case pressure, probably due to the purchase of the 11:1 compression ratio JE pistons. This excessive pressure has plagued me, and if you know the details of how the crank is designed, the pistons go up and down at the same time in a staggered formation, which I believe creates a lot of crank case pressure.
I cleaned up and reinstalled the reed valves to the crank case outlets on the cylinder head covers with an excellent result. I'm attaching a photo.
Thanks to Ace for the information!

skokievtr

PAIR = AIR INJECTION TO EXHAUST PORT

to block mine I simply flipped the red stop over so it held the Reed closed with silicone and buttoned it up 90 thousand miles ago or more Positive crankcase ventilation is a whole different animal and they're not related in my opinion more later

Wolverine

I don't ever recall it being for an improvement. It was just to stop popping on decel.
I don't see your photo either. Do you still have it?

Bald Eagle

The Photo was the one previous to the post....I screwed up the original post which should have been with the details you have above.