hey guys i am thinking about getting a cam to go into my engine that will soon be turbocharged. i am looking to do the cam just to have a little more power until the turbo goes on, have a little fun with the install, and better learn to tune with EFILive.

i have read all kinds of things about turbo cams and what they should have/be. what works well, what doesnt, etc.

I have a pretty decent amount of what i want it to be but before i decide on what exactly i want, i was wondering if anyone could answer a couple things for me.

First, i know that a higher LSA is desired. but i am not exactly sure why. i know that we dont want overlap cause that will bleed boost...but is having 0* of overlap just as good as having 5*, or 10*? in other words is more overlap better? or is it all pretty uch the same.

Second, i read on smokinhawk's turbo FAQ on another forum that the higher LSA helps with the spool of the turbo, but is that actually directly related to the LSA or does it go back to the Overlap?

Now that that is out of the way i am going to assume that the duration and lift will be something to determing based on my desired rpm band that i am shooting for. and i am shooting to have a high reving engine...maybe shift at like 6900even. i dont know if this is something that is ok on a turbo engine, but that would be the goal.

Now i have more questions, but they heavily rely on the answers to the first two questions so if anyone knows the answers to those...that's be great.

Thanks
Louie

 

Don't take this the wrong way but you're not getting answers because you have a lot more reading to do before you even ask the 'right questions.'

For example:

Not even close, it's to prevent exhaust gas from rushing into the intake as the intake valve opens.

No idea what that faq says but I doubt that there is much correlation, more of one with tuning and the overall combination'¦

 

i rarely take anything the wrong way...i am here to learn.

ok that is fair...i completely understand what you are saying, from what i hear the exhaust side on a turbo kit may have up to, and even more than, double the pressure of the intake...is this correct? that would make the chance of exhaust gas rushing into the intake a possibility...
but i do assure you that i have read...and i have read a lot more since posting this thread, bleeding boost is definately something that i have read before...apparently i took it the wrong way, or read it wrong.

in the end, i appreciate the input.

Thanks
Louie

 

yep, that’s the issue… the only real way to avoid it is to either keep overlap to a minimum and/or open the intake valve late, as in after the piston starts moving down in the bore lowering residual pressure. The higher the intended rpm and the better the exhaust side/larger the exhaust turbine the less important this is.

Yea, I went looking for it during a free moment at work today. No, you didn’t misread it, I guess there are crack heads everywhere.

That’s more of an idea that applies to supercharged setups at low rpm’s and their reasons for bigger then normal LSA’s, but at the same time they usually also run big exhaust durations

 

WOW what in the hell did i type here...lol should have prrof read.


Refering to the article, smokinhawk actually seems extremely knowledgeable and i am pretty sure built a couple of near 1000rwhp turbo LS1s...

but i am not here to start a war...

after a little decision and looking into my options, what others are running i may buy a custom ground cam, but first i am going to wait and try to find a used cam that fits my specs for a better deal.

I am thinking for my setup right now i will want something like:

227/224 114LSA. depending on the valve events of this cam it seems like it may fit my goals fairly well...of course i will always consider bigger or smaller or changes altogether. if i go custom...i will go bigger most likely.

Thanks for the input and feel free to include more

Louie

 

War, what war? I'm willing to listen to what people have to say but when it's foolish something to that effect will probably come out of my mouth.

I'm not sure having built a couple of engines that made decent hp makes or breaks the argument, it just sorta is. There's plenty of people that have spent the duckets on parts, slapped them together and have successfully made some power without really knowing the finer points of how or why. More likely in this case it's just a mistake or an attempt to over simplify it so most people reading it would understand that went too far. It doesn't really matter.

Barring more input on the combination, that's probably a reasonable choice, something that will rev to the mid 6K range, probably make peak power at 5800-6000rpm'¦

 

Well just an FYI...shifting mid to upper 6k range is great for me.

I am going to go with a LS1 truck manifold setup. with a Gt42t76 turbo. 2.5 inch up piping, T4 flange. most likely 3 or 3.5 inch downpipe.
6.0l heads
plenty of fuel and i already have a SD tune that only needs to be modified when the turbo is finally in. front mount air-air intercooler.

If you have any input that would be awesome.

Thanks
Louie

 

that's the exact cam (.569"/.563") i am running on my otherwise stock Ls1...should work well for you.