Stg2 street cam recommendation

[GARY HARVEY]

Suggestion:

Do some research.

Tim Cole comes with heavy S2 V6 Buick credentials via GM Engineering (Indy Car design).

Gary

 

[Nick Micale]

Why don;t you model your cam specs to something in this build, seems to work well on a v8?
Nelson Racing Engines Small Block Chevy - Hot Rod Magazine


cam & Spring Specs

Comp Cams lobe numbers: 4873S/4873S
Duration at 0.050 tappet lift: 236/236
Lobe lift: 0.377/0.377 inch
Observed lift: 0.600/0.600 with 1.65:1 rockers and 0.022-inch lash
Lobe separation angle: 115 degrees
Valvespring diameter: 1.550 inches
Valvespring installed height: 1.860 inches
Spring pressures: 175 lbs on the seat, 420 lbs open

That is very interesting as my current personal cam, which I have used for a few years [one cam card is dated 2004!], has almost the identical specs as do the springs, and we have done many like it since!

 

[bison]

Why don;t you model your cam specs to something in this build, seems to work well on a v8?
Nelson Racing Engines Small Block Chevy - Hot Rod Magazine


am & Spring Specs

Comp Cams lobe numbers: 4873S/4873S
Duration at 0.050 tappet lift: 236/236
Lobe lift: 0.377/0.377 inch
Observed lift: 0.600/0.600 with 1.65:1 rockers and 0.022-inch lash
Lobe separation angle: 115 degrees
Valvespring diameter: 1.550 inches
Valvespring installed height: 1.860 inches
Spring pressures: 175 lbs on the seat, 420 lbs open

IMO that would be leaving a lot on the table with stage 2 heads. No need to run a single pattern on a stage 2 and considerably more lift could be used without working the valvetrain too hard. I'd be more prone to use a grind like that with production style heads and a little more lift for a serious street strip engine capable of running high to mid 8's

 

[Buickrat]

My car will be a true street car a daily driver to work. I am keeping the cam at zero or nero zero overlap for street abilty. I am a believer in not beating up the valvel train to make power. I am only looking to make 750 - 800 Hp and the cam requirments will be minimal. My stg2 heads only flow 300 cfm @ .600 lift but the low lift numbers, .100-.500, are awesome which I beleive will work great for street application, low to mid range torque and quicker turbo spool. I am purchasing a couple of cams so if my first selection does not pan out I will grind another.

 

[bison]

My car will be a true street car a daily driver to work. I am keeping the cam at zero or nero zero overlap for street abilty. I am a believer in not beating up the valvel train to make power. I am only looking to make 750 - 800 Hp and the cam requirments will be minimal. My stg2 heads only flow 300 cfm @ .600 lift but the low lift numbers, .100-.500, are awesome which I beleive will work great for street application, low to mid range torque and quicker turbo spool. I am purchasing a couple of cams so if my first selection does not pan out I will grind another.

Thats the problem. I agree on not beating up the valvetrain but its hard to have an engine that is really responsive with all the port volume on a stage 2 head.

 

[norbs]

Well Rat, you could go hydraulic roller, it will work, and require no maintenance, if its a daily driver. Whats your take on hyd roller? They dont make offset lifters but it still can work.

 

[Buickrat]

I have considered a hydraulic cam but, the offset lifters dont exist and I will probaly shift the engine above 6500 which becomes an issue with the hydraulic lifters.

 

[Squid4life]

IMO that would be leaving a lot on the table with stage 2 heads. No need to run a single pattern on a stage 2 and considerably more lift could be used without working the valvetrain too hard. I'd be more prone to use a grind like that with production style heads and a little more lift for a serious street strip engine capable of running high to mid 8's

Bison, I have been watching this thread closely because I am in the middle of collecting parts for a 274" Stage 2 with stage heads also. It will see the street most of the time, but considering it will not be a daily, I am not too concerned with "street manners". I have no issue with a higher stall, solid lifters, obscene idle, etc. I am getting down to only needing rods, pistons, and cam now and was curious what the seasoned guys would answer on this thread.

If that cam would be leaving power on the table, what would you suggest for this type of stage 2? I know there are a lot of other variables like converter, turbo, etc, but in a perfect world, with all aspects working together, what do think would be a great cam for this?

Not trying to highjack, but I think the OP and I are pretty similar on setups from the looks of it.

 

[Buickrat]

If I can add to your comments,The combination I am building will produce 750-800 which I know is low for a built stg2 but, i am mainly looking for street ability and reliablity. My plan is to have a car with a smooth idle with quick turbo spool for great 60 fts and enough power to dip the car in the high nines but compete in a 10:00 class.

 

[norbs]

If I can add to your comments,The combination I am building will produce 750-800 which I know is low for a built stg2 but, i am mainly looking for street ability and reliablity. My plan is to have a car with a smooth idle with quick turbo spool for great 60 fts and enough power to dip the car in the high nines but compete in a 10:00 class.

What turbo/converter do you plan to use to achieve this?

 

[Buickrat]

PTE 6765 DBB The recently released, the convertor will be a 3400 non-lock ATI

 

[750H.P.V6]

I'd say that at some point camshaft duration and cylinder head air flow offset each other. If you have a cylinder head that flows poorly you will need a much larger camshaft to get the performance you want conversley if you have a really good cylinder head you can use less camshaft to achieve the same goal. Ultimately you need to look at the target RPM range to figure out approximately how large the camshaft will need to be.

In regard to cams for a street car it is always better to go a little smaller than a little larger or driveability will suffer. I'd say the suggestion of a cam with a duration in the mid 230 degree at .050" on a 115-116 LSA would work great in a street car without giving away too much bottom end and still being able to shift at around 7300 RPM and utilize the airflow potential of the Stage II heads.

If you get to chat with Tim Cole at Comp he's a wealth of information on Stage II stuff and will definately steer you the right direction.

Neal

 

[norbs]

BuickRat can you set me up with a 218 or similar cam?

 

[Buickrat]

Yes let me know what your interested in. I will be racing Saturday so I will not be able to connect via email until Saturday evening. Odd or even fire stg2?

 

[750H.P.V6]

Norb,

You should go bigger than that. Give Tim a call and get his insight. Not only does he work for Comp Cams but he's been playing with Buick V6 engines for the last 3 decades or so. His real world experience is invaluable in selecting the right cam. I sent you a PM with their 800 #.

Neal

 

[norbs]

Norb,

You should go bigger than that. Give Tim a call and get his insight. Not only does he work for Comp Cams but he's been playing with Buick V6 engines for the last 3 decades or so. His real world experience is invaluable in selecting the right cam. I sent you a PM with their 800 #.

Neal

.
Thanks Neal, I will see what Tim , thinks is best for my goals. Tim maybe more accurate than the sim.

 

[qikazel1]

I jus found out the solid lift cam in my 276 stage 2 headed engine has these specs.. 660 lift 248 duration @ 50 and 112 lobe duration

 

[qikazel1]

Any opinions on those specs

 

[750H.P.V6]

It depends on the lobe masters and what your goals are. At first glance it sounds like it's got too much duration at .050" and too much overlap also. Get the lobe #'s off the back of the cam and I'm sure Alan or Bison can tell you everything you want to know.

Neal

 

[turbobitt]

Without exact lobe numbers it's hard to say but it looks to me that there will be to much overlap with the 112 LSA and 246 duration, not saying it won't work but could do better with less.
AG


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