How pair system works precisely ?
08-05-2005, 04:53 AM
#1
Senior Member
Back Marker
Thread Starter
Join Date: Jun 2005
Location: Paris
Posts: 126
How pair system works precisely ?
Looking at the service manual, I was surprised !
I was thinking pair system works when deccelerating and that's why we here exhaust popping at deceleration...
But "the pair control valve cuts off supply of fresh air during engine deceleration, thereby preventing afterburn in the exhaust system" as the service manual says.
looking one time more at the service manual, the pair system is flowing fresh air almost all the time, it cuts only at deceleration (high intake vacuum) to eliminate afterburns.
Then, here are some questions :
- Why is there a popping effect at deceleration with pair system enable ? Maybe, the hoses connected to headers have enough fresh air to deliver during a little time and cause afterburns ? or pair valve is not very quick ?
Or it is because of downshifting that leaves the engine to take revs ?
- What are the effects on a dyno gaz analysis with a pair system enabled ? The carburation may always seems to be "lean", isn't it ?
Anyway, I think I will disable this pair system this week end !
and redo a carbs sync by the way
I was thinking pair system works when deccelerating and that's why we here exhaust popping at deceleration...
But "the pair control valve cuts off supply of fresh air during engine deceleration, thereby preventing afterburn in the exhaust system" as the service manual says.
looking one time more at the service manual, the pair system is flowing fresh air almost all the time, it cuts only at deceleration (high intake vacuum) to eliminate afterburns.
Then, here are some questions :
- Why is there a popping effect at deceleration with pair system enable ? Maybe, the hoses connected to headers have enough fresh air to deliver during a little time and cause afterburns ? or pair valve is not very quick ?
Or it is because of downshifting that leaves the engine to take revs ?
- What are the effects on a dyno gaz analysis with a pair system enabled ? The carburation may always seems to be "lean", isn't it ?
Anyway, I think I will disable this pair system this week end !
and redo a carbs sync by the way
08-05-2005, 08:36 AM
#2
Guest
Posts: n/a
Re: How pair system works precisely ?
Bear in mind that this is a system born of the need to reduce emissions, not increase performance. I removed mine... also re-routed my crankcase breathers to external filters instead of to the airbox. May not make more HP
, but it seems to make more sense.
08-05-2005, 01:12 PM
#3
Moderator
MotoGP
Join Date: May 2005
Posts: 2,708
also be aware that honda techs did tune this bike to run WITH the pair system. it does greatly reduce emissions, i can tell you that for sure. the only way i can see it robbing power is if you have a claifornia model....
08-05-2005, 04:17 PM
#4
Guest
Posts: n/a
By injecting air in to the exhaust stream, it probably does have some small detrimental effect on scavenging of the cylinders which helps draw in a fresh intake charge. So would have some effect on power, especially at the top end. Probably very small. My heads have aluminum plugs bonded in and ground flush with the ports, never to be imPAIRed again!
I have left the crankcase breathers routed to the airbox to clear the blowby gases from the crankcase and keep them from coating everything with black goop.
I have left the crankcase breathers routed to the airbox to clear the blowby gases from the crankcase and keep them from coating everything with black goop.
Thread
Thread Starter
Forum
Replies
Last Post
EngineNoO9
General Discussion
8
09-11-2006 07:23 PM
EngineNoO9
Technical Discussion
9
12-22-2005 01:06 PM
