Turbos and cams

[AB'sLs1]

i am very interested in have a turbo ls1 the thing about it is that i dont know how they act with high lift cams and cams that have a good amount of over lap. ive heard alot of things from people saying that turbos love overlap and other people saying turbos hate overlap. so if anyone has any info on how a turbo and a high performance cam interact it would be much appreciated.

[rbarnes]

Turbos do not like overlap.

Overlap is good for N/A because you can use the vacuum created by
out flowing exhaust to help pull more air in.

But in a turbo set-up the turbo creates a certain amount of
exhaust pressure in the system. At higher boost pressures or with
too small of a turbo, back pressure can get high enough to actually
stop air from coming in. This is called reversion.

Turbo cams can have high lift and duration, but they need a high lobe separation.
LSA of 115-117 not uncommon on tubro cams, where N/A cam might be 110-112.

Stock cams actually usually make nice turbo cams with their high LSA's

[mike13]

Can you get a nice rumble with a turbo type cam?

[AB'sLs1]

Turbos do not like overlap.

Overlap is good for N/A because you can use the vacuum created by
out flowing exhaust to help pull more air in.

But in a turbo set-up the turbo creates a certain amount of
exhaust pressure in the system. At higher boost pressures or with
too small of a turbo, back pressure can get high enough to actually
stop air from coming in. This is called reversion.

Turbo cams can have high lift and duration, but they need a high lobe separation.
LSA of 115-117 not uncommon on tubro cams, where N/A cam might be 110-112.

Stock cams actually usually make nice turbo cams with their high LSA's

thank u that helped alot im trying to plan a nice build and i want to get as much info as i can before hand.

now lets say i wanna run a twin turbo at around 15 psi on a 346 what sort of lobe seperationg would u recommend?

[rbarnes]

Can you get a nice rumble with a turbo type cam?

My custom LSM turbo cam in my TT 351W mustang thumps like a mo-fo
240+ duration with .625 lift, but has like a 115+LSA

thank u that helped alot im trying to plan a nice build and i want to get as much info as i can before hand.

now lets say i wanna run a twin turbo at around 15 psi on a 346 what sort of lobe seperationg would u recommend?

Get a custom cam. I have an LSM cam. Only know Ford cam guys ,,,,, sorry.
Check the site for best custom cam grinders.

Tell the cam guy what you have and what you want ....... and thats what you get, no guessing

[AB'sLs1]

thanks alot everyone any info on how a cam interracts with a turbo is much appreciated. im still learning alot so any info u guys think would be helpful on my quest for amazing power is very helpful. so keep the info and ideas coming

[rbarnes]

If you really want to understand turbo systems get the following book.

Explains everything from engine dynamics to stainless vs mild to how
to read and use compressor maps to pick your turbo correctly.

http://www.amazon.com/Maximum-Boost-...5326590&sr=8-1

[AB'sLs1]

haha shit a book! im not out of high school yet i get books out the wazooo! but this looks like a very valubale peice of info that i really should get my hands on. would u say that for somone who is interested in turbos but little knowledge this is a good buy?

[rbarnes]

haha shit a book! im not out of high school yet i get books out the wazooo! but this looks like a very valubale peice of info that i really should get my hands on. would u say that for somone who is interested in turbos but little knowledge this is a good buy?

Excellent book. Easy to follow along. 8th grade algebra will get you thru the engine
math on calculating airflows for any given engine.

[AB'sLs1]

Excellent book. Easy to follow along. 8th grade algebra will get you thru the engine
math on calculating airflows for any given engine.

alright its sold then haha the math part might get to be a challenge but it sounds like a really good book for me cuz i want to learn as much about motors(in general fbodys only)as i can in every aspect

[TNTramair]

this is a TwinTurbo 402....cant give ya the specs on the cam cause its a prototype but i can tell ya its on a 118lsa.

[AB'sLs1]

wow that sounds amazing! thats the kinda idle i want if not that more aggressive and there r more cams out there that sound like this that r good for turbos? any info on this cam?

[TNTramair]

its a custom Grind cam that HSW did for me..its in the 230's intake and 240's exhaust i beleive, if i remember correctly with no overlap and on a 118lsa.
hearing the car in person it basically sounds like a car with headers and a cat back. there's a very light trace of a cam but it definetly makes the power and im very happy with it. pulls strong to 6500rpms...might go further but i only have about 600miles on the motor and i dont want to break anything just yet.

[AB'sLs1]

what im looking for is something that idles like a normal n/a motors cam would but i dont think im going to find that?

[slims00ls1z28]

Blah so my current MS3 on a 114 LSA (237/242 .605/.610) would be bad for a turbo? Was hoping to salvage some of the parts (and money) from my earlier build.

[rbarnes]

No it will not be a bad cam ......... just may not be the "best" cam

[candlelit]

I always recommend the epp FI cam for a LS1.

it's like a 23x/24x. 115 lsa. lift is pretty close to the .60 mark I think. it's pretty sick

[TNTramair]

Blah so my current MS3 on a 114 LSA (237/242 .605/.610) would be bad for a turbo? Was hoping to salvage some of the parts (and money) from my earlier build.

not an ideal cam for FI. it would work....just about any cam would "technically" work but there are better options suited for FI.

[RedVertTA]

With a turbo, you'll probably want a cam with more on the exhaust side to compensate for the larger amount of air coming in on the intake side.

[crazycat]

What size turbo ? If its a large frame t6 you should be able to cam it like a na car because of the low back pressure.