N/A Cams VS TT Cams. Benefits from mixing?

[3000gttom]

I think you need to familiarize yourself more with the meaning "after" and "before" TDC....

just look at the profiles and take your own advice... its not a big deal lol. i mess up reading cam profile all the time

[3000gttom]

you're going in the wrong direction. you want the exhaust hole as small as possible when you have a ton of back pressure from tiny turbo.

do you understand the cam timing information McCoy posted?

i thought it was more about just holding off the spool for a slightly higher rpm because the small turbos heat up fast so efficiency immediately starts dropping off... so spooling a little later can get you better peak numbers... last i checked most people with cam gears are adding overlap

[RealMcCoy]

Fuck.... I may have just had my ass handed to me by a newb....

That would be bad... If I misread those numbers, I did it about five years ago... You know how many posts I'm going to have to go back and correct on four different forums..? Why hasn't anyone else caught that in the last five flippn' years...

I won't have time to actually map it out until I get off work, but it looks like he's right folks... The turbo cams have 4 degrees more duration, and are on the same centerline.

[DK77]

Yep, 50 BBDC is 2 before 48 BBDC, and 17 ATDC is 2 after 15 ATDC, 4 more degrees of duration.

[DrGonzo]

So exhaust side stays open longer with TT cams? Is that what it breaks down too?

[RealMcCoy]

So exhaust side stays open longer with TT cams? Is that what it breaks down too?

To break it down with the correct info: The exhaust on the TT opens 2 degrees earlier, and closes two degrees later, so it is open for a longer period of time, the lobe centers are the same, so there is two degrees more overlap with the TT cams.

[3000gttom]

Fuck.... I may have just had my ass handed to me by a newb....

not really, i actually read them completely backwards at first and though the n/a cam had 4 more than the turbo lol so my mistake was worse,

im just gonna correct my mistakes in this thread so people dont get confused

you dont happen to know if the intake centerline is the same as the exhaust?

[3000gttom]

just looked at the cams and an intake cam will not swap directly with an exhaust