Hello i was wondering
A guy told me iff you put another exhaust cam on the intake side you get more power out of it
because the exhaust cam are 244 degrees and the intake one 233 or something like that
what is true about this and what kind of power figures can be made?
Greetings
It does work, and you can gain a little more power, but personally I don't think it's worthwhile.
if you increase the valve overlap to a certain extent, you can gain more performance. TO A POINT.
It looks like(based on my training) an overlap in the ballpark of 10* is most beneficial. This is because as the exhaust valve is closing, the intake is opening. As such, the escaping exhaust gasses create a high velocity, and Pull in more fresh air/fuel which in turn causes a better fill of the cylinder. more air/fuel, equals more power. worth it? depends ALOT on the design of cams, intake, exhaust...but i'd say between 10-20 hp isnt far fetched. especially if you get into turbo/super charging.
However, if the overlap is too big, it will kill performance. The velocity out of the valve isnt as great, and the exhaust valve can actually remain open as the piston is going down. that will pull in exhaust gasses, which cant burn, just take space. however, this will cool down cylinder temps a bit, allowing you to pass emissions, if your failing because of NOx. yeah.
if you have a DOHC motor, just get adjustable cam gears, can produce almost the same thing, but with more control!
i was runnin two exhaust cams on my old CA. you just got to move the cam timing one tooth on the intake side. pretty good power gain for 20 bucks from the junkyard.
i think iggy is running two exhaust cams too, hes makin pretty good power out of it as well.
there is A LOT more info on this elsewhere. google is ur friend but heres the magic copy&paste that nobody can ever seem to find.
JPN spec CA18DET S13...
In lift - 7.8mm
Ex lift - 8.5mm
In duration - 240
Ex duration - 248
In opens - 0 BTDC
In closes - 60 ABDC
In center lobe angle - 120deg
Ex opens - 64 BBDC
Ex closes - 4 ATDC
Ex center lobe angle - 120deg
TADA!
All differeces in performance from the exhaust cam swap are... small. Its a good mod if the extra exhaust cam is cheap. If u find a Pulsar NX SE in a junkyard u can use the exhaust cam out of it. Same lift and duration but the lobe timing is different.
IggyEGuanathere is A LOT more info on this elsewhere. google is ur friend but heres the magic copy&paste that nobody can ever seem to find.
JPN spec CA18DET S13...
In lift - 7.8mm
Ex lift - 8.5mm
In duration - 240
Ex duration - 248
In opens - 0 BTDC
In closes - 60 ABDC
In center lobe angle - 120deg
Ex opens - 64 BBDC
Ex closes - 4 ATDC
Ex center lobe angle - 120deg
TADA!
All differeces in performance from the exhaust cam swap are... small. Its a good mod if the extra exhaust cam is cheap. If u find a Pulsar NX SE in a junkyard u can use the exhaust cam out of it. Same lift and duration but the lobe timing is different.
heres the rest of the fleet. idk how the USDM FWD CA16DE & CA18DE cams compare to any of these.
EURO spec CA16DE....
In lift - 8.5mm
Ex lift - 8.5mm
In duration - 248
Ex duration - 248
In opens - 15 BTDC
In closes - 53 ABDC
In center lobe angle - 109deg
Ex opens - 59 BBDC
Ex closes - 9 ATDC
Ex center lobe angle - 115deg
EURO spec CA18DE...
In lift - 8.5mm
Ex lift - 8.5mm
In duration - 248
Ex duration - 248
In opens - 16 BTDC
In closes - 52 ABDC
In center lobe angle - 108deg
Ex opens - 50 BBDC
Ex closes - 18 ATDC
Ex center lobe angle - 104deg
EURO spec CA18DET...
In lift - 7.8mm
Ex lift - 8.5mm
In duration - 240
Ex duration - 248
In opens - 0 BTDC
In closes - 60 ABDC
In center lobe angle - 120deg
Ex opens - 59 BBDC
Ex closes - 9 ATDC
Ex center lobe angle - 115deg
JPN spec CA18DE S13...
In lift - 7.8mm
Ex lift - 8.5mm
In duration - 240
Ex duration - 248
In opens - 0 BTDC
In closes - 60 ABDC
In center lobe angle - 120deg
Ex opens - 59 BBDC
Ex closes - 9 ATDC
Ex center lobe angle - 115deg
JPN spec CA18DET S13...
In lift - 7.8mm
Ex lift - 8.5mm
In duration - 240
Ex duration - 248
In opens - 0 BTDC
In closes - 60 ABDC
In center lobe angle - 120deg
Ex opens - 64 BBDC
Ex closes - 4 ATDC
Ex center lobe angle - 120deg
look on sxoc.com for further info and spares