Turbo guys- Your cams overlap?
09-27-2005, 08:35 AM
#1
TECH Fanatic
Thread Starter
iTrader: (1)
Join Date: Jul 2004
Location: Palm Harbor, FL
Posts: 1,453
Likes: 0
Received 0 Likes
on
0 Posts
Turbo guys- Your cams overlap? overlap:
((((intake dur. + exhaust dur.)/4)-lsa)*2)
how many +/- degrees of overlap are you running? I know alot of people have differing opinions on how much overlap is ideal for a turbo setup, but 'm just looking to get a general consensus. I basically know what sized cam I want to get, i'm just not sure hoe much LSA I want, or how much overlap.
It seems that every shop has a very different view on what sort of cam works best for a turbo, but I just want a general idea of whats working.
((((intake dur. + exhaust dur.)/4)-lsa)*2)
how many +/- degrees of overlap are you running? I know alot of people have differing opinions on how much overlap is ideal for a turbo setup, but 'm just looking to get a general consensus. I basically know what sized cam I want to get, i'm just not sure hoe much LSA I want, or how much overlap.
It seems that every shop has a very different view on what sort of cam works best for a turbo, but I just want a general idea of whats working.
09-27-2005, 11:47 AM
#3
Teching In
Join Date: May 2002
Location: Norfolk, VA
Posts: 10
Likes: 0
Received 0 Likes
on
0 Posts
TTT
VERY interested in this! It seems that 114LSA is the norm, I am in the market for a new cam not and being reccomended possibly a 110 LSA. Any thoughs? The logic I am told is to lower EGTs. Thoughts?
VERY interested in this! It seems that 114LSA is the norm, I am in the market for a new cam not and being reccomended possibly a 110 LSA. Any thoughs? The logic I am told is to lower EGTs. Thoughts?
09-27-2005, 11:52 AM
#4
TECH Fanatic
Thread Starter
iTrader: (1)
Join Date: Jul 2004
Location: Palm Harbor, FL
Posts: 1,453
Likes: 0
Received 0 Likes
on
0 Posts
Higher EGTs = faster exhaust gas velocity, correct? therefore faster spooling? Then again in a restrictive exhaust setup perhaps that is needed?
I would imagine that a large amount of negative overlap would give the combustion chamber time to cool, but i really dont know. I know for a turbo setup, large amounts of positive overlap is not ideal because of blowby. The question is, what do you gain from 0* overlap to say -20* overlap?
edit: perhaps the negative overlap helps prevent exhaust gas from backflowing into the cylinder if there is excess exhaust backpressure?
I would imagine that a large amount of negative overlap would give the combustion chamber time to cool, but i really dont know. I know for a turbo setup, large amounts of positive overlap is not ideal because of blowby. The question is, what do you gain from 0* overlap to say -20* overlap?
edit: perhaps the negative overlap helps prevent exhaust gas from backflowing into the cylinder if there is excess exhaust backpressure?
Last edited by LSONE; 09-27-2005 at 11:58 AM.
