turbo b18c1, valve overlap question

HooliganSKATE

New Member
I was reading the G2IC turbo guide, and read a part that says "due to the VTEC system, cam timing on the B18C raises some issues that need attention. The valve overlap, intake and exhaust valves open at the same time, can lead to exhaust gasses reversion issues. Reversion occurs during valve overlap and exhaust gasses are drawn back into the cylinder. Obviously this is not a good thing when you are forcing an already hot, pressurized intake charge into the cylinder. It can lead to detonation and generally poor performance. Fortunately with the use of adjustable cam gears the overlap can be tuned out. B18C, and all other VTEC motors, will put out more horsepower with less boost than a non-VTEC motor, about 14% on average." with that being said, when I turbo my b18c1, will a tuner be able to tune that out with stock cams, or do I need some adjustable ones? Or, is there any other way that people deal with this problem?

Thanks ahead of time, and sorry if thats a dumb question
 

Kyle

New Member
HooliganSKATE said:
I was reading the G2IC turbo guide, and read a part that says "due to the VTEC system, cam timing on the B18C raises some issues that need attention. The valve overlap, intake and exhaust valves open at the same time, can lead to exhaust gasses reversion issues. Reversion occurs during valve overlap and exhaust gasses are drawn back into the cylinder. Obviously this is not a good thing when you are forcing an already hot, pressurized intake charge into the cylinder. It can lead to detonation and generally poor performance. Fortunately with the use of adjustable cam gears the overlap can be tuned out. B18C, and all other VTEC motors, will put out more horsepower with less boost than a non-VTEC motor, about 14% on average." with that being said, when I turbo my b18c1, will a tuner be able to tune that out with stock cams, or do I need some adjustable ones? Or, is there any other way that people deal with this problem?

Thanks ahead of time, and sorry if thats a dumb question
Click to expand...
What I think you mean is adjustable cam GEARS. And yes you should buy some when you go for a tune. In that article, the OP mentions that stock cams are often just fine for a turbo build.
 

Muckman

Not a M0derator
Reversion is more common with high back pressure / poor flowing exhaust manifold designs. That clip on G2ic is really old school thinking. Most turbo systems today will have more pressure on the intake side than the exhaust. In fact some of the best cams for turbo are mild to nasty NA cams which generally have lots of overlap. You will not need to dial out the overlap but feel free to ask your tuner's advice and observe the results yourself from tuning cam gears on the dyno.
 


You must log in or register to reply here.
Top